| 50 record(s) printed from Clarivate Web of Science |
| Record 1 of 50 |
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| Author(s): Nutt, JG (Nutt, John G.); Bloem, BR (Bloem, Bastiaan R.); Giladi, N (Giladi, Nir); Hallett, M (Hallett, Mark); Horak, FB (Horak, Fay B.); Nieuwboer, A (Nieuwboer, Alice) |
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| Abstract: Freezing of gait (FoG) is a unique and disabling clinical phenomenon characterised by brief episodes of inability to step or by extremely short steps that typically occur on initiating gait or on turning while walking. Patients with FoG, which is a feature of parldnsonian syndromes, show variability in gait metrics between FoG episodes and a substantial reduction in step length with frequent trembling of the legs during FoG episodes. Physiological, functional imaging, and clinical pathological studies point to disturbances in frontal cortical regions, the basal ganglia, and the midbrain locomotor region as the probable origins of FoG. Medications, deep brain stimulation, and rehabilitation techniques can alleviate symptoms of FoG in some patients, but these treatments lack efficacy in patients with advanced FoG. A better understanding of the phenomenon is needed to aid the development of effective therapeutic strategies. |
| Record 2 of 50 |
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| Author(s): Bloem, BR (Bloem, BR); Hausdorff, JA (Hausdorff, JA); Visser, JE (Visser, JE); Giladi, N (Giladi, N) |
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| Abstract: Falls and freezing of gait are two “episodic” phenomena that are common in Parkinson’s disease. Both symptoms are often incapacitating for affected patients, as the associated physical and psychosocial consequences have a great impact on the patients’ quality of life, and survival is diminished. Furthermore, the resultant loss of independence and the treatment costs of injuries add substantially to the health care expenditures associated with Parkinson’s disease. In this clinically oriented review, we summarise recent insights into falls and freezing of gait and highlight their similarities, differences, and links. Topics covered include the clinical presentation, recent ideas about the underlying pathophysiology, and the possibilities for treatment. A review of the literature and the current state-of-the-art suggests that clinicians should not feel deterred by the complex nature of falls and freezing of gait; a careful clinical approach may lead to an individually tailored treatment, which can offer at least partial relief for many affected patients. (C) 2004 Movement Disorder Society. |
| Record 3 of 50 |
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| Author(s): Giladi, N (Giladi, N); Shabtai, H (Shabtai, H); Simon, ES (Simon, ES); Biran, S (Biran, S); Tal, J (Tal, J); Korczyn, AD (Korczyn, AD) |
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Abstract:
Background: Freezing of gait (FOG) is a common, poorly understood, parkinsonian symptom interfering with daily functioning and quality of life. Assessment of FOG is complex because of the episodic nature of this symptom, and the influence of mental and environmental factors on it.
Objective: To design a self-reportable reliable questionnaire for FOG. Method: A questionnaire consisting of 16 items regarding gait and falls was administered together with the Unified Parkinson’s Disease Rating Scale (UPDRS) to 40 Parkinson’s disease (PD) patients (26 males) with a mean age of 72.3 +/- 9.3 years and mean Hoehn and Yahr (H&Y) stage at “Off” of 2.85 +/- 0.84. A principal component analysis with Varimax rotation was conducted on the results. Item analyses were performed and reliability computed for an abbreviated FOG questionnaire. Results: Based on these analyses, a short (six item) FOG questionnaire was constructed, which was found to be highly reliable (Cronbach alpha = 0.94) for assessment of FOG and with moderate correlation with the activity of daily living (ADL) and motor parts of the UPDRS (0.43 and 0.40, respectively). Moderate correlation was also found with the FOG item at the ADL part of the UPDRS (alpha = 0.66 for the “Off” and 0.77 for the “On” state). Conclusion: The FOG questionnaire that was constructed is highly reliable in assessing freezing of gait, unrelated to falls, in patients with PD. (C) 2000 Elsevier Science Ltd. All rights reserved. |
| Record 4 of 50 |
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| Author(s): Schaafsma, JD (Schaafsma, JD); Balash, Y (Balash, Y); Gurevich, T (Gurevich, T); Bartels, AL (Bartels, AL); Hausdorff, JM (Hausdorff, JM); Giladi, N (Giladi, N) |
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| Abstract: To assess the effect of levodopa on distinct freezing of gait (FOG) subtypes in patients with ‘off’ FOG. Nineteen patients (12 men, mean age 62.0 +/- 8.4 years) with Parkinson’s disease and clinically significant FOG during ‘off’ states were videotaped whilst walking 130 m during ‘off’ and ‘on’ states. Three independent observers characterized the type, duration, and clinical manifestations and quantified FOG by analyzing the videotapes. Their combined mean scores were used for statistical analysis. The intra-class correlation coefficient assessed inter-observer reliability. Wilcoxon and Friedman tests evaluated differences in mean frequencies of FOG characteristics. During ‘off’ states, FOG was elicited by turns (63%), starts (23%), walking through narrow spaces (12%) and reaching destinations (9%). These respective values were only 14, 4, 2 and 1% during ‘on’ states (P < 0.011). Moving forward with very small steps and leg trembling in place were the most common manifestations of FOG; total akinesia was rare. Most FOG episodes took < 10 s and tended to be shorter during ‘on’ states. Levodopa significantly decreased FOG frequency (P < 0.0001) and the number of episodes with akinesia (P < 0.001). Distinction amongst FOG subtypes enables evaluation of distinctive therapeutic response. Levodopa helps in reducing the frequency and duration of ‘off’-related FOG. |
| Record 5 of 50 |
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| Author(s): Nieuwboer, A (Nieuwboer, Alice); Rochester, L (Rochester, Lynn); Herman, T (Herman, Talia); Vandenberghe, W (Vandenberghe, Wim); Emil, GE (Emil, George Ehab); Thomaes, T (Thomaes, Tom); Giladi, N (Giladi, Nir) |
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| Abstract: Freezing of gait (FOG) is difficult to measure due to its unpredictable occurrence. This study investigated: (1) whether the new freezing of gait questionnaire (NFOG-Q) is a reliable measure of freezing by comparing patients’ ratings with those of carers’ and (2) whether adding a video improved its reliability. Non-demented people with Parkinson’s disease (PD) (N = 102) and their carers of similar age and cognitive status were recruited from movement disorders clinics in three countries. The NFOG-Q was administered to carers and patients independently before and after watching a video showing several examples of FOG. Patients had very high agreement between their pre- and post-video detection of FOG (Kappa = 0.91). However, this was less than in carers (Kappa = 0.79). The video had a significant influence (p = 0.01) on the rating of FOG severity (duration) but not on the estimation of its functional impact. Post-video freezing severity scores in the 69 freezers showed high agreement with carers’ scores (ICC = 0.78 [0.65;0.87]). We conclude that the NFOG-Q is a reliable tool to detect and evaluate the impact and severity of FOG. Adding a video does not add to the sensitivity and specificity of FOG detection but influences the estimation of FOG severity. (C) 2009 Elsevier B.V. All rights reserved. |
| Record 6 of 50 |
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| Author(s): Bächlin, M (Baechlin, Marc); Plotnik, M (Plotnik, Meir); Roggen, D (Roggen, Daniel); Maidan, I (Maidan, Inbal); Hausdorff, JM (Hausdorff, Jeffrey M.); Giladi, N (Giladi, Nir); Tröster, G (Troester, Gerhard) |
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| Abstract: In this paper, we present a wearable assistant for Parkinson’s disease (PD) patients with the freezing of gait ( FOG) symptom. This wearable system uses on-body acceleration sensors to measure the patients’ movements. It automatically detects FOG by analyzing frequency components inherent in these movements. When FOG is detected, the assistant provides a rhythmic auditory signal that stimulates the patient to resume walking. Ten PD patients tested the system while performing several walking tasks in the laboratory. More than 8 h of data were recorded. Eight patients experienced FOG during the study, and 237 FOG events were identified by professional physiotherapists in a post hoc video analysis. Our wearable assistant was able to provide online assistive feedback for PD patients when they experienced FOG. The system detected FOG events online with a sensitivity of 73.1% and a specificity of 81.6%. The majority of patients indicated that the context-aware automatic cueing was beneficial to them. Finally, we characterize the system performance with respect to the walking style, the sensor placement, and the dominant algorithm parameters. |
| Record 7 of 50 |
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| Author(s): Giladi, N (Giladi, N); McDermott, MP (McDermott, MP); Fahn, S (Fahn, S); Przedborski, S (Przedborski, S); Jankovic, J (Jankovic, J); Stern, M (Stern, M); Tanner, C (Tanner, C) |
| Group Author(s): Parkinson Study Grp |
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| Abstract: Objective: To study the development of freezing of gait in PD. Background: Freezing of gait is a common, disabling, and poorly understood symptom in PD. Methods: The authors analyzed data from 800 patients with early PD from the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) clinical trial who were assigned either placebo, deprenyl, tocopherol, or the combination of deprenyl and tocopherol. The primary outcome measure was the time from randomization until the freezing of gait score on the Unified Parkinson’s Disease Rating Scale (UPDRS) became positive. Results: Fifty-seven patients (7.1%) had freezing of gait at study entry and 193 (26%) of the remaining patients experienced the symptom by the end of the follow-up period. Those with freezing of gait at baseline had significantly more advanced disease than those without the symptom, as measured by total UPDRS and Hoehn and Yahr stage. High baseline risk factors for developing freezing of gait during the follow-up period were the onset of PD with a gait disorder; higher scores of rigidity, postural instability, bradykinesia and speech; and longer disease duration. In contrast, tremor was strongly associated with a decreased risk for freezing of gait. At the end of follow-up, the signs most strongly associated with the freezing phenomenon were gait, balance, and speech disorders, not rigidity or bradykinesia. Deprenyl treatment was strongly associated with a decreased risk for developing freezing of gait; tocopherol had no effect. Conclusions: Freezing of gait is directly related to duration of PD. Risk factors at onset of disease are the absence of tremor and PD beginning as a gait disorder. The development of freezing of gait in the course of the illness is strongly associated with the development of balance and speech problems, less so with the worsening of bradykinesia, and is not associated with the progression of rigidity. These results support the concept that the freezing phenomenon is distinct from bradykinesia. Deprenyl, in the absence of L-dopa, was found to be an effective prophylactic treatment and should be considered for patients with PD who have an onset of gait difficulty. |
| Record 8 of 50 |
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| Author(s): Moore, ST (Moore, Steven T.); MacDougall, HG (MacDougall, Hamish G.); Ondo, WG (Ondo, William G.) |
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| Abstract: Freezing of gait (FOG) is common in advanced Parkinson’s disease (PD), is resistant to treatment and negatively impacts quality of life. In this study an ambulatory FOG monitor was validated in 11 PD patients. The vertical linear acceleration of the left shank was acquired using an ankle-mounted sensor array that transmitted data wirelessly to a pocket PC at a rate of 100 Hz. Power analysis showed high-frequency components of leg movement during FOG in the 3-8 Hz band that were not apparent during volitional standing, and power in this ‘freeze’ band was higher (p = 0.00003) during FOG preceded by walking (turning or obstacles) than FOG preceded by rest (gait initiation). A freeze index (FI) was defined as the power in the ‘freeze’ band divided by the power in the ‘locomotor’ band (0.5-3 Hz) and a threshold chosen such that FI values above this limit were designated as FOG. A global threshold detected 78% of FOG events and 20% of stand events were incorrectly labeled as FOG. Individual calibration of the freeze threshold improved accuracy and sensitivity of the device to 89% for detection of FOG with 10% false positives. Ambulatory monitoring may significantly improve clinical management of FOG. (c) 2007 Elsevier B.V. All rights reserved. |
| Record 9 of 50 |
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| Author(s): Giladi, N (Giladi, Nir); Tal, J (Tal, Joseph); Azulay, T (Azulay, Tali); Rascol, O (Rascol, Oliver); Brooks, DJ (Brooks, David J.); Melamed, E (Melamed, Eldad); Oertel, W (Oertel, Wolfgang); Poewe, WH (Poewe, Werner H.); Stocchi, F (Stocchi, Fabrizio); Tolosa, E (Tolosa, Eduardo) |
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| Abstract: To revalidate the Freezing of Gait Questionnaire (FOG-Q), patients with Parkinson’s disease (PD) were randomly assigned to receive rasagiline (1 mg/day) (n = 150), entacapone (200 mg with each dose of levodopa) (n = 150), or placebo (n = 154). Patients were assessed at baseline and after 10 weeks using the FOG-Q. Unified Parkinson’s Disease Rating Scale (UPDRS), Beck Depression Inventory (BDI), and Parkinson’s Disease Questionnaire (PDQ-39). FOG-Q dimensionality test-retest reliability, and internal reliability were examined. Convergent mid divergent validities were assessed by correlating FOG-Q with UPDRS, BDI, and PDQ-39. Comparisons between FOG-Q item 3 and UPDRS item 14 were also made. Principal component analysis indicated that FOG-Q measures a single dimension. Test-retest reliability and internal reliability of FOG-Q score was high. FOG-Q was best correlated to items of the UPDRS relating to walking, general motor issues, and mobility. Conclusions between baseline and end-point suggested that FOG-Q item 3 is at least as reliable as UPDRS item 14. At baseline, 85.9% of patients were identified as “Freezers” using FOG-Q item 3 (>= 1) and 44.1%, using UPDRS item 14 (>= 1) (P < 0.001). FOG-Q was a reliable tool the assessment of treatment intervention. FOG-Q item 3 was effective as, a screening question for the presence of FOG. (C) 2009 Movement Disorder Society |
| Record 10 of 50 |
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| Author(s): Hausdorff, JM (Hausdorff, JM); Schaafsma, JD (Schaafsma, JD); Balash, Y (Balash, Y); Bartels, AL (Bartels, AL); Gurevich, T (Gurevich, T); Giladi, N (Giladi, N) |
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| Abstract: Patients with Parkinson’s disease (PD) often experience freezing of gait, a debilitating phenomenon during which the subject suddenly becomes unable to start walking or to continue to move forward. Little is known about the gait of those subjects with PD who experience freezing of gait or the pathophysiology of freezing. One possibility is that freezing of gait is a truly paroxysmal phenomenon and that the usual walking pattern of subjects who experience freezing of gait is not different than that of other patients with PD who do not experience these transient episodes of freezing of gait. On the other hand, a recent study noted gait changes just prior to freezing and concluded that dyscontrol of the cadence of walking contributes to freezing. To address this question, we compared the gait of PD subjects with freezing of gait to PD subjects without freezing of gait. Given the potential importance of the dyscontrol of the cadence of walking in freezing, we focused on two aspects of gait dynamics: the average stride time (the inverse of cadence, a measure of the walking pace or rate) and the variability of the stride time (a measure of “dyscontrol,” arrhythmicity and unsteadiness). We found that although the average stride time was similar in subjects with and without freezing, stride-to-stride variability was markedly increased among PD subjects with freezing of gait compared to those without freezing of gait, both while “on” (P<0.020) and “off” (P<0.002) anti-parkinsonian medications. Further, we found that increased gait variability was not related to other measures of motor control (while off medications) and levodopa apparently reduced gait variability, both in subjects with and without freezing. These results suggest that a paradigm shift should take place in our view of freezing of gait. PD subjects with freezing of gait have a continuous gait disturbance: the ability to regulate the stride-to-stride variations in gait timing and maintain a stable walking rhythm is markedly impaired in subjects with freezing of gait. In addition, these findings suggest that the inability to control cadence might play an important role in this debilitating phenomenon and highlight the key role of dopamine-mediated pathways in the stride-to-stride regulation of walking. |
| Record 11 of 50 |
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| Author(s): Giladi, N (Giladi, N); Treves, TA (Treves, TA); Simon, ES (Simon, ES); Shabtai, H (Shabtai, H); Orlov, Y (Orlov, Y); Kandinov, B (Kandinov, B); Paleacu, D (Paleacu, D); Korczyn, AD (Korczyn, AD) |
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Abstract:
Background. Freezing of Gait (FOG) is one of the most disturbing and least understood symptom in advanced stage of Parkinson’s disease (PD). The contribution of the underlying pathological process and the antiparkinsonian treatment to the development of FOG are controversial.
Objective. To study the relationships between clinical features of PD and therapeutic modalities in patients with advanced PD and FOG. Methods. Consecutive patients with 5 years or more of PD symptoms (n = 172) (99 men) with mean age at symptoms onset of 58.3 +/- 13.2 years and mean symptoms duration of 11.8 +/- 5.6 years were studied. Clinical data were collected during the last office visit through physical examination, detailed history, review of patients’ charts, and other documents. A patient was considered as “freezer” if he/she reported recent experience that the legs got stuck to the ground while trying to walk. The presence df dyskinesia, early morning dystonia or significant postural reflex abnormalities were assessed through history and neurological examination. Duration of treatment with antiparkinsonian drugs was calculated from history charts. Chi square and t test were used to compare the patients with and without FOG. Logistic regression was used for the comparison of association between the presence of FOG (dependent variable) disease duration and disease stage (explanatory variables) and duration of treatment with anti-parkinsonian drugs. Results. The study population consisted of 45 patients at Hoehn and Yahr (H&Y) stage 2.5 (26%), 104 patients at stage 3 (60.5%), and 23 patients at H&Y stages 4-5 (13.5%). Ninety one patients (53%) reported FOG at the time of the study. Severity of the disease expressed by H&Y stage at “off” was a significant contributing factor for FOG with a significant trend (z = 4.38, p < 0.0001), as was longer duration of levodopa treatment, and confirmed by FOG using the multivariate logistic regression (p = 0.01 and p = 0.004, respectively). Using a univariate model, longer duration of treatment with dopamine agonists contribute to the appearance of FOG (p = 0.07) while longer duration of amantadine treatment decreased the appearance of FOG (p = 0.09). There was a significant association between FOG and the presence of dyskinesia (p < 0.002), early morning foot dystonia (p < 0.003) and significant postural instability (p < 0.0005). Conclusion. FOG is a common symptom in advanced PD. It is mainly related to disease progression and levodopa treatment. |
| Record 12 of 50 |
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| Author(s): Giladi, N (Giladi, Nir); Nieuwboer, A (Nieuwboer, Alice) |
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| Record 13 of 50 |
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| Author(s): Snijders, AH (Snijders, Anke H.); Leunissen, I (Leunissen, Inge); Bakker, M (Bakker, Maaike); Overeem, S (Overeem, Sebastiaan); Helmich, RC (Helmich, Rick C.); Bloem, BR (Bloem, Bastiaan R.); Toni, I (Toni, Ivan) |
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| Abstract: Freezing of gait is a common, debilitating feature of Parkinson’s disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between planning and imagining a movement. In addition, it avoids confounds introduced by brain responses to altered motor performance and somatosensory feedback during actual freezing episodes. We included 24 patients with Parkinson’s disease: 12 patients with freezing of gait, 12 matched patients without freezing of gait and 21 matched healthy controls. Subjects performed two previously validated tasks-motor imagery of gait and a visual imagery control task. During functional magnetic resonance imaging scanning, we quantified imagery performance by measuring the time required to imagine walking on paths of different widths and lengths. In addition, we used voxel-based morphometry to test whether between-group differences in imagery-related activity were related to structural differences. Imagery times indicated that patients with freezing of gait, patients without freezing of gait and controls engaged in motor imagery of gait, with matched task performance. During motor imagery of gait, patients with freezing of gait showed more activity than patients without freezing of gait in the mesencephalic locomotor region. Patients with freezing of gait also tended to have decreased responses in mesial frontal and posterior parietal regions. Furthermore, patients with freezing of gait had grey matter atrophy in a small portion of the mesencephalic locomotor region. The gait-related hyperactivity of the mesencephalic locomotor region correlated with clinical parameters (freezing of gait severity and disease duration), but not with the degree of atrophy. These results indicate that patients with Parkinson’s disease with freezing of gait have structural and functional alterations in the mesencephalic locomotor region. We suggest that freezing of gait might emerge when altered cortical control of gait is combined with a limited ability of the mesencephalic locomotor region to react to that alteration. These limitations might become particularly evident during challenging events that require precise regulation of step length and gait timing, such as turning or initiating walking, which are known triggers for freezing of gait. |
| Record 14 of 50 |
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| Author(s): Moreau, C (Moreau, C.); Defebvre, L (Defebvre, L.); Destee, A (Destee, A.); Bleuse, S (Bleuse, S.); Clement, F (Clement, F.); Blatt, JL (Blatt, J. L.); Krystkowiak, P (Krystkowiak, P.); Devos, D (Devos, D.) |
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Abstract:
Background: Severe gait disturbances and freezing episodes (frequently resistant to optimal dopaminergic treatment) often appear in advanced Parkinson disease (PD). Even several years after initiation, high-frequency subthalamic nucleus deep brain stimulation (STN-DBS) is still very effective for controlling segmental symptoms. However, there are no long-term data on the management of gait disorders and freezing in STN-DBS.
Objectives: To compare the effects of various STN-DBS parameters on freezing of gait and to determine whether such effects are more related to stimulation energy (usual voltages vs high voltages at 130 Hz) or frequency (130 Hz vs approximately half this frequency: 60 Hz). Methods: We blindly assessed STN- DBS parameters in 13 PD patients reporting severe gait disorders. We compared the effects on gait of two different voltages (the patient’s usual voltage [median 3 volts] and a high voltage [median 3.7 volts]) and two different frequencies ( 60 and 130 Hz, while maintaining the same total energy delivered) vs “off-stimulation” conditions. Results: The number of freezing episodes was significantly lower at the 60-Hz “high voltage/ equivalent energy” and higher at the 130-Hz/high voltage than for “off stimulation.” The slight improvement in the Unified Parkinson’s Disease Rating Scale motor score observed (at 130 Hz) did not achieve statistical significance. Conclusions: Our results prompt consideration of a new strategy for two-stage subthalamic nucleus deep brain stimulation (STN- DBS) frequency optimization, with stimulation at 130 Hz and the usual voltage during the initial years of STN- DBS and then at 60 Hz at a high voltage in Parkinson disease patients who develop severe gait disorders. |
| Record 15 of 50 |
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| Author(s): Plotnik, M (Plotnik, M); Giladi, N (Giladi, N); Balash, Y (Balash, Y); Peretz, C (Peretz, C); Hausdorff, JM (Hausdorff, JM) |
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| Abstract: Freezing of gait (FOG) is a disabling phenomenon common in patients with advanced Parkinson’s disease (PD). The cause of FOG is unclear. The objective of this study was to explore a novel hypothesis stating that FOG is related to asymmetric motor performance. We compared PD patients that experience FOG episodes (PD+FOG) with PD patients that do not (PD-FOG) and studied the relationship of FOG to asymmetry in gait and in rhythmic hand movement performance to determine whether potential FOG-related gait asymmetry is unique to walking or whether it is systemic. Subjects were tested in an “off” (unmedicated) and again in an “on” (medicated) state. Gait was more asymmetric in PD+FOG than in PD-FOG during “off” state (p = 0.005) and during “on” (p = 0.016). Rhythmicity of foot swing in one leg was correlated with the other leg in PD-FOG but not in PD+FOG. There was no difference in asymmetry in performance of rhythmic hand movements between the two groups. No correlation was found between asymmetry of clinical symptoms and gait asymmetry. Taken together, the results of this study suggest that bilateral uncoordinated gait and marked gait asymmetry, but not asymmetry in motor performance in general, are associated with FOG. |
| Record 16 of 50 |
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| Author(s): Nonnekes, J (Nonnekes, Jorik); Snijders, AH (Snijders, Anke H.); Nutt, JG (Nutt, John G.); Deuschl, G (Deuschl, Guenter); Giladi, N (Giladi, Nir); Bloem, BR (Bloem, Bastiaan R.) |
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| Abstract: Freezing of gait is a common and disabling symptom in patients with parkinsonism, characterised by sudden and brief episodes of inability to produce effective forward stepping. These episodes typically occur during gait initiation or turning. Treatment is important because freezing of gait is a major risk factor for falls in parkinsonism, and a source of disability to patients. Various treatment approaches exist, including pharmacological and surgical options, as well as physiotherapy and occupational therapy, but evidence is inconclusive for many approaches, and dear treatment protocols are not available. To address this gap, we review medical and non-medical treatment strategies for freezing of gait and present a practical algorithm for the management of this disorder, based on a combination of evidence, when available, and clinical experience of the authors. Further research is needed to formally establish the merits of our proposed treatment protocol. |
| Record 17 of 50 |
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| Author(s): Lewis, SJG (Lewis, Simon J. G.); Barker, RA (Barker, Roger A.) |
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| Abstract: Freezing of gait (FOG) is a common phenomenon in Parkinson’s disease (PD) affecting over half of those in the advanced stages of the disease and often does not respond to standard drug therapies. This article proposes a possible mechanism by which this disorder of movement comes about. Co-ordinated neural activities are dependent on a series of parallel neuronal networks passing through the basal ganglia connecting and integrating functions. In healthy subjects, these competing, yet complementary, networks permit tight regulation in the broad domains of motor, cognitive, and limbic functions. In patients with PD, the loss of striatal dopamine coupled with the limited repertoire of the output nuclei within these pathways allows for an element of ‘cross-talk’ between competing inputs, which in turn could lead to a paroxysmal excessive inhibition of the thalamus and pedunculopontine nucleus triggering freezing of gait. It is further postulated that this phenomenon may be acting via a transient period of increased synchronization within the basal ganglia oscillations. (C) 2008 Elsevier Ltd. All rights reserved. |
| Record 18 of 50 |
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| Author(s): Spildooren, J (Spildooren, Joke); Vercruysse, S (Vercruysse, Sarah); Desloovere, K (Desloovere, Kaat); Vandenberghe, W (Vandenberghe, Wim); Kerckhofs, E (Kerckhofs, Eric); Nieuwboer, A (Nieuwboer, Alice) |
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| Abstract: Background: Turning is the most important trigger for freezing of gait (FOG) in Parkinson’s disease (PD), and dual-tasking has been suggested to influence FOG as well. Objective: To understand the effects of dual tasking and turning on FOG. Methods: 14 Freezers and 14 non-freezers matched for disease severity and 14 age-matched controls were asked to turn 1808 and 3608 with and without a cognitive dual-task during the off-period of the medication cycle. Total number of steps, duration, cadence, freezing-frequency, and secondary-task performance were measured. Results: Seven freezers froze during the protocol. Freezing occurred in 37.5% of trials during 1808 turning compared to 0% during straight-line walking (X-2 = 10.44, p < 0.01). The occurrence of FOG increased during 3608 when also a dual-task was added (X-2 = 4.23, p = 0.04). Freezers took significantly more steps and were slower than controls in all conditions. The presence of a dual-task increased these differences. Cadence increased significantly for freezers during 3608 and 1808 compared to straight-line walking. In contrast, cadence was decreased during turning in controls and non-freezers. During straight-line walking, only freezers made errors in the secondary task. Controls increased their error-rate during 1808 turning, whereas freezers deteriorated their secondary task performance during 360 degrees. Conclusions: 3608 turning in combination with a dual-task is the most important trigger for freezing. During turning, non-freezers and controls decreased their cadence whereas freezers increased it, which may be related to FOG. Freezers adopted a posture second strategy in contrast to non-freezers when confronted with a dual task. (C) 2010 Movement Disorder Society |
| Record 19 of 50 |
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| Author(s): Perez-Lloret, S (Perez-Lloret, Santiago); Negre-Pages, L (Negre-Pages, Laurence); Damier, P (Damier, Philippe); Deivai, A (Deivai, Arnaud); Derkinderen, P (Derkinderen, Pascal); Destée, A (Destee, Alain); Meissner, WG (Meissner, Wassilios G.); Schlosky, L (Schlosky, Ludwig); Tison, F (Tison, Francois); Rascol, O (Rascol, Olivier) |
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Abstract:
IMPORTANCE Freezing of gait (FOG) is a common axial symptom of Parkinson disease (PD).
OBJECTIVE To determine the prevalence of FOG in a large group of PD patients, assess its relationship with quality of life and clinical and pharmacological factors, and explore its changes from the off to on conditions in patients with motor fluctuations. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional survey of 683 patients with idiopathic PD. Scores for FOG were missing in 11 patients who were not included in the analysis. Patients were recruited from referral centers and general neurology clinics in public or private institutions in France. EXPOSURE Patients with FOG were identified as those with a score of 1 or greater on item 14 of the Unified Parkinson’s Disease Rating Scale (UPDRS) in the on condition. Item 14 scores for FOG in the off condition were also collected in patients with fluctuating motor symptoms. MAIN OUTCOMES AND MEASURES Quality of life (measured by the 39-item Parkinson’s Disease Questionnaire and 36-Item Short Form Health Survey), anxiety and depression (Hospital Anxiety and Depression Scale), clinical features (UPDRS), and drug consumption. RESULTS Of 672 PD patients, 257 reported FOG during the on state (38.2%), which was significantly related to lower quality of life scores (P < .01). Freezing of gait was also correlated with longer PD duration (odds ratio, 1.92 [95% CI, 1.28-2.86]), higher UPDRS parts II and III scores (4.67 [3.21-6.78]), the presence of apathy (UPDRS item 4) (1.94 [1.33-2.82]), a higher levodopa equivalent daily dose (1.63 [1.09-2.43]), and more frequent exposure to antimuscarinics (3.07 [1.35-6.97]) (logistic regression). The FOG score improved from the off to on states in 148 of 174 patients with motor fluctuations (85.1%) and showed no change in 13.8%. The FOG score improved by more than 50% in 43.7% of patients. Greater improvement in the on state was observed in younger patients (r = -0.25; P < .01) with lower UPDRS II and Ill scores (r = -0.50; P < .01) and no antimuscarinic use (r = -0.21; P < .01). CONCLUSIONS AND RELEVANCE Freezing of gait in PD patients correlates with poor quality of life, disease severity, apathy, and exposure to antimuscarinics. Dopaminergic therapy improved FOG in most patients with motor fluctuations, especially younger ones with less severe disease and no antimuscarinic use. This finding suggests that quality of life is impaired in PD patients with FOG and that optimizing dopaminergic therapy and avoiding antimuscarinics should be considered. |
| Record 20 of 50 |
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| Author(s): Amboni, M (Amboni, Marianna); Cozzolino, A (Cozzolino, Autilia); Longo, K (Longo, Katia); Picillo, M (Picillo, Marina); Barone, P (Barone, Paolo) |
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| Abstract: Freezing of gait (FOG) is a frequent, disabling symptom of Parkinson’s disease (PD). FOG usually lasts a few seconds. It refers to brief paroxysmal events during which a subject is unable to start or continue locomotion. Despite its frequency, FOG pathophysiology is unclear. Because a frontal lobe dysfunction or a disconnection between the frontal lobe and basal ganglia has been implicated in FOG, we explored frontal functions in PD patients using neuropsychological tests. Thirteen early-stage PD patients [Hoehn & Yahr score (H&Y) <= 2.5] with freezing during “on” state (FOG+), and 15 age-, H&Y score-, and disease-duration-matched PD patients without freezing (FOG-) were investigated. No patient was demented or depressed. Assessment included the Unified Parkinson’s Disease Rating Scale (UPDRS), FOG questionnaire, Mini Mental State Examination (MMSE), frontal assessment battery (FAB), phonemic verbal fluency, Stroop test (parts 11 and 111), and ten-point clock test (TPCT). UPDRS and MMSE scores did Dot differ between the two groups. FAB, verbal fluency, and TPCT scores were significantly lower in FOG+ patients than in FOG- patients (FAB: P = 0.008; phonemic verbal fluency: P = 0.011; TPCT: P = 0.024). FOG correlated with lower scores at frontal tests in patients with early-stage PD. (c) 2007 Movement Disorder Society. |
| Record 21 of 50 |
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| Author(s): Moore, O (Moore, Orna); Peretz, C (Peretz, Chava); Giladi, N (Giladi, Nir) |
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| Abstract: The aim of this study was to examine the association between freezing of gait (FOG) and quality of life (QoL) in patients with Parkinson’s disease (PD). PD patients (n = 118) completed the PDQ-39 (QoL) and FOG-Q questionnaires. Disease severity was assessed by the Hoehn and Yahr (H&Y) staging and the Unified Parkinson’s Disease Rating Scale (UPDRS). The relations between those parameters were assessed using regression models. 66 men and 52 women (mean age 65.8 +/- 10.2 years, UPDRS total score 48.4 +/- 17.1, disease duration 8.5 +/- 5.8 years, H&Y stage 2.7 +/- 0.8) participated. FOG severity had a significant effect on QoL (P < 0.0015), accounting for disease severity assessed by UPDRS. Specifically, FOG severity was correlated with all the dimensions of the PDQ-39 except for stigma and social support, as follows: with mobility, bodily discomfort, activity of daily living (ADL) (P < 0.005 in all), with emotional, communication, and coa,nition (P < 0.05 in all). FOG severity (FOG-Q) was also found to affect a modified PDQ total score, without the mobility aspect (P = 0.0081). FOG should be viewed as a highly important symptom with regard to QoL of PD patients beyond its effect on gait and mobility. On the basis of the present results, special attention should be given to FOG in the treatment of patients with PD. (c) 2007 Movement Disorder Society. |
| Record 22 of 50 |
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| Author(s): Tessitore, A (Tessitore, Alessandro); Amboni, M (Amboni, Marianna); Esposito, F (Esposito, Fabrizio); Russo, A (Russo, Antonio); Picillo, M (Picillo, Marina); Marcuccio, L (Marcuccio, Laura); Pellecchia, MT (Pellecchia, Maria Teresa); Vitale, C (Vitale, Carmine); Cirillo, M (Cirillo, Mario); Tedeschi, G (Tedeschi, Gioacchino); Barone, P (Barone, Paolo) |
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Abstract:
Background: Freezing of gait is a common cause of disability and falls in patients with Parkinson’s disease. We studied brain functional connectivity, by means of resting-state functional magnetic resonance imaging, in patients with Parkinson’s disease and freezing of gait.
Methods: Resting-state functional magnetic resonance imaging at 3 T was collected in 29 patients with Parkinson’s disease, of whom 16 presented with freezing of gait as determined by a validated freezing of gait questionnaire, and 15 matched healthy controls. Single-subject and group-level independent component analysis was used to identify the main resting-state networks differing between Parkinson’s disease patients with and without freezing of gait. Statistical analysis was performed using BrainVoyager QX. Results: Between-group differences in resting-state networks revealed that patients with freezing of gait exhibit significantly reduced functional connectivity within both “executive-attention” (in the right middle frontal gyrus and in the angular gyrus) and visual networks (in the right occipito-temporal gyrus) [p < 0.05 corrected for multiple comparisons]. Freezing of gait clinical severity was significantly correlated with decreased connectivity within the two networks. Consistent with their “executive-attention” network impairment, patients with freezing of gait scored lower on tests of frontal lobe functions (phonemic verbal fluency: p = 0.005; frontal assessment battery: p < 0.001; ten point clock test: p = 0.04). Conclusions: Our findings suggest that a resting-state functional connectivity disruption of “executive-attention” and visual neural networks may be associated with the development of freezing of gait in Patients with Parkinson’s disease. (c) 2012 Elsevier Ltd. All rights reserved. |
| Record 23 of 50 |
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| Author(s): Shine, JM (Shine, James M.); Matar, E (Matar, Elie); Ward, PB (Ward, Philip B.); Frank, MJ (Frank, Michael J.); Moustafa, AA (Moustafa, Ahmed A.); Pearson, M (Pearson, Mark); Naismith, SL (Naismith, Sharon L.); Lewis, SJG (Lewis, Simon J. G.) |
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| Abstract: Recent neuroimaging evidence has led to the proposal that freezing of gait in Parkinson’s disease is due to dysfunctional interactions between frontoparietal cortical regions and subcortical structures, such as the striatum. However, to date, no study has employed task-based functional connectivity analyses to explore this hypothesis. In this study, we used a data-driven multivariate approach to explore the impaired communication between distributed neuronal networks in 10 patients with Parkinson’s disease and freezing of gait, and 10 matched patients with no clinical history of freezing behaviour. Patients performed a virtual reality gait task on two separate occasions (once ON and once OFF their regular dopaminergic medication) while functional magnetic resonance imaging data were collected. Group-level independent component analysis was used to extract the subject-specific time courses associated with five well-known neuronal networks: the motor network, the right- and left cognitive control networks, the ventral attention network and the basal ganglia network. We subsequently analysed both the activation and connectivity of these neuronal networks between the two groups with respect to dopaminergic state and cognitive load while performing the virtual reality gait task. During task performance, all patients used the left cognitive control network and the ventral attention network and in addition, showed increased connectivity between the bilateral cognitive control networks. However, patients with freezing demonstrated functional decoupling between the basal ganglia network and the cognitive control network in each hemisphere. This decoupling was also associated with paroxysmal motor arrests. These results support the hypothesis that freezing behaviour in Parkinson’s disease is because of impaired communication between complimentary yet competing neural networks. |
| Record 24 of 50 |
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| Author(s): Jacobs, JV (Jacobs, Jesse V.); Nutt, JG (Nutt, John G.); Carlson-Kuhta, P (Carlson-Kuhta, Patricia); Stephens, M (Stephens, Marilee); Horak, FB (Horak, Fay B.) |
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| Abstract: Freezing of gait (FoG) is an episodic, brief inability to step that delays gait initiation or interrupts ongoing gait. FoG is often associated with an alternating shaking of the knees, clinically referred to as knee trembling or trembling in place. The pathophysiology of FoG and of the concomitant trembling knees is unknown; impaired postural adjustment in preparation for stepping is one hypothesis. We examined anticipatory postural adjustments (APAs) prior to protective steps induced by a forward loss of balance in 10 Parkinson’s disease (PD) subjects with marked FoG and in 10 control subjects. The amplitude and timing of the APAs were determined from changes in the vertical ground-reaction forces recorded by a force plate under each foot and were confirmed by electromyographic recordings of bilateral medial gastrocnemius, tibialis anterior and tensor fascia latae muscles. Protective steps were accomplished with a single APA followed by a step for control subjects, whereas PD subjects frequently exhibited multiple, alternating APAs coexistent with the knee trembling commonly observed during FoG as well as delayed, inadequate or no stepping. These Multiple APAs were not delayed in onset and were of similar or larger amplitude than the single APAs exhibited by the control subjects. These observations suggest that multiple APAs produce the knee trembling commonly associated with FoG and that FoG associated with a forward loss of balance is caused by an inability to couple a normal APA to the stepping motor pattern. Published by Elsevier Inc. |
| Record 25 of 50 |
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| Author(s): Chee, R (Chee, Rachel); Murphy, A (Murphy, Anna); Danoudis, M (Danoudis, Mary); Georgiou-Karistianis, N (Georgiou-Karistianis, Nellie); Iansek, R (Iansek, Robert) |
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| Abstract: Freezing of gait (FOG) has been identified as one of the main contributors to gait disturbances in Parkinsons disease. While the pathophysiology remains enigmatic, several factors such as step length and the sequence effect (step to step reduction in amplitude) may lead to the occurrence of FOG. It was hypothesized that by reducing step length, FOG episodes would present more frequently if a significant sequence effect (measured as a regression slope) was co-existent in the subject. Twenty-six participants with Parkinsons disease were separated clinically into a freezing (PD FOG, n 16) and non-freezing (PD FOG, n 10) group, with 10 age-matched control participants. Testing involved walking trials where preferred step length was set at 100, 75, 50 and 25 of normalized step length. The number of FOG episodes increased in the 50 condition and further increased in the 25 condition compared to other conditions. The participants with FOG also demonstrated a larger average regression slope, with significant differences in the 75, 50 and 25 conditions when compared to the PD FOG and control groups. There were no significant differences when comparing the slope of the PD FOG and control group, indicating the reduced step length and the sequence effect may have led to the occurrence of FOG. These findings support the possible dual requirement of a reduced step length and a successive step to step amplitude reduction to lead to FOG. |
| Record 26 of 50 |
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| Author(s): Fling, BW (Fling, Brett W.); Cohen, RG (Cohen, Rajal G.); Mancini, M (Mancini, Martina); Nutt, JG (Nutt, John G.); Fair, DA (Fair, Damian A.); Horak, FB (Horak, Fay B.) |
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| Abstract: Freezing of gait is one of the most debilitating symptoms in Parkinson’s disease as it causes falls and reduces mobility and quality of life. The pedunculopontine nucleus is one of the major nuclei of the mesencephalic locomotor region and has neurons related to anticipatory postural adjustments preceding step initiation as well as to the step itself, thus it may be critical for coupling posture and gait to avoid freezing. Because freezing of gait and postural impairments have been related to frontal lesions and frontal dysfunction such as executive function, we hypothesized that freezing is associated with disrupted connectivity between midbrain locomotor regions and medial frontal cortex. We used diffusion tensor imaging to quantify structural connectivity of the pedunculopontine nucleus in patients with Parkinson’s disease with freezing of gait, without freezing, and healthy age-matched controls. We also included behavioural tasks to gauge severity of freezing of gait, quantify gait metrics, and assess executive cognitive functions to determine whether between-group differences in executive dysfunction were related to pedunculopontine nucleus structural network connectivity. Using seed regions from the pedunculopontine nucleus, we were able to delineate white matter connections between the spinal cord, cerebellum, pedunculopontine nucleus, subcortical and frontal/prefrontal cortical regions. The current study is the first to demonstrate differences in structural connectivity of the identified locomotor pathway in patients with freezing of gait. We report reduced connectivity of the pedunculopontine nucleus with the cerebellum, thalamus and multiple regions of the frontal cortex. Moreover, these structural differences were observed solely in the right hemisphere of patients with freezing of gait. Finally, we show that the more left hemisphere-lateralized the pedunculopontine nucleus tract volume, the poorer the performance on cognitive tasks requiring the initiation of appropriate actions and/or the inhibition of inappropriate actions, specifically within patients with freezing. These results support the notion that freezing of gait is strongly related to structural deficits in the right hemisphere’s locomotor network involving prefrontal cortical areas involved in executive inhibition function. |
| Record 27 of 50 |
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| Author(s): Giladi, N (Giladi, Nir); Hausdorff, JM (Hausdorff, Jeffey M.) |
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| Abstract: Freezing of gait (FOG) is a disabling episodic gait disturbance that is common among patients with Parkinsonism. FOG typically lasts a few seconds and is associated with a unique sensation: the patient feels that his feet are glued to the ground, causing him to remain in place despite making a concerted effort to overcome the motor block and move forward. Traditionally, FOG has been viewed as a motor symptom of advanced Parkinson’s disease. Here we describe evidence which demonstrates that mental conditions also likely play an important role in the pathogenesis of FOG. Stress, anxiety, depression and cognitively challenging situations are associated with FOG, and may set the stage for and increase the likelihood that FOG occurs. A conceptual model that explains how mental conditions may modulate FOG is developed. (C) 2006 Elsevier B.V. All rights reserved. |
| Record 28 of 50 |
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| Author(s): Nieuwboer, A (Nieuwboer, Alice); Giladi, N (Giladi, Nir) |
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| Abstract: Freezing of gait (FOG) is a very disabling and common gait disorder in Parkinson’s disease (PD). The first aim of this article was to provide a methodological and critical review of the most common research approach to understand FOG, ie, comparing the behavior of freezers with that of non-freezers. The review demonstrates that studies often fall short in clearly defining the freezer\non-freezer groups and in controlling for disease severity and other confounders. These problems complicate data interpretation on FOG. The second aim of this article was to summarize the literature on the potential mechanisms behind the episodic nature of FOG in the following four models: (1) The threshold model assumes that FOG occurs when the accumulation of various motor deficits reinforce each other to a point of motor breakdown; (2) the interference model proposes that FOG represents an inability to deal with concurrent cognitive, limbic, and motor input, causing an interruption of locomotion; (3) the cognitive model views FOG as induced by a failure to process response conflict, leading to behavioral indecision; and (4) the decoupling model sees FOG as a disconnection between preparatory programming and the intended motor response as a result of which automatic movement generation gets stuck. These four theoretical premises are still incomplete and do not fully explain FOG. The depletion of motor and cognitive reserves and an increasingly complex response to levodopa with disease progression will also have an impact on the emergence of FOG episodes. (c) 2013 International Parkinson and Movement Disorder Society |
| Record 29 of 50 |
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| Author(s): Ginis, P (Ginis, Pieter); Nackaerts, E (Nackaerts, Evelien); Nieuwboer, A (Nieuwboer, Alice); Heremans, E (Heremans, Elke) |
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| Abstract: Freezing, which manifests during gait and other movements, is an incapacitating motor symptom experienced by many patients with Parkinson’s disease (PD). In rehabilitation, auditory and visual cueing methods are commonly applied to evoke a more goal-directed type of motor control and, as such, reduce freezing severity in patients with PD. In this narrative review, we summarize the current evidence regarding the effects of external cueing in patients with PD with freezing of gait (FOG) and provide suggestions on how to further improve cueing effectiveness with emerging technological developments. For this paper, we reviewed 24 articles describing the assessment of the effects of cues in patients with FOG (n = 354). Because these studies mostly involved quasi-experimental designs, no methodological analysis was undertaken. In general, the evidence suggests that cue-augmented training can reduce FOG severity, improve gait parameters and improve upper-limb movements immediately after training. However, findings were not univocal, and long-term consolidation and transfer of the effects appear to be hampered specifically in this subgroup. With the increasing use of wearable technology, new possibilities are allowing for adapting the cue type, cue content and dose of cues to the needs of individual patients, which may boost the clinical use and efficiency of cued training in PD patients with FOG. (C) 2017 Elsevier Masson SAS. All rights reserved. |
| Record 30 of 50 |
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| Author(s): Almeida, QJ (Almeida, Q. J.); Lebold, CA (Lebold, C. A.) |
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| Abstract: While freezing of gait (FOG) is typically considered a motor impairment, the fact that it occurs more frequently in confined spaces suggests that perception of space might contribute to FOG. The present study evaluated how doorway size influenced characteristics of gait that might be indicative of freezing. Changes in spatiotemporal aspects of gait were evaluated while walking through three different-sized doorways (narrow (0.675 m wide x 2.1 m high), normal (0.9 m wide x 2.1 m high) and wide (1.8 m wide x 2.1 m high)) in three separate groups: 15 individuals with Parkinson’s disease confirmed to be experiencing FOG at the time of test; 16 non-FOG individuals with Parkinson’s disease and 16 healthy age-matched control participants. Results for step length indicated that the FOG group was most affected by the narrow doorway and was the only group whose step length was dependent on upcoming doorway size as indicated by a significant interaction of group by condition (F(4,88)=2.73, p<0.034). Importantly, the FOG group also displayed increased within-trial variability of step length and step time, which was exaggerated as doorway size decreased (F(4,88) 2.99, p<0.023). A significant interaction between group and condition for base of support measures indicated that the non-FOG participants were also affected by doorway size (similar to Parkinson’s disease FOG) but only in the narrow doorway condition. These results support the notion that some occurrences of freezing may be the result of an underlying perceptual mechanism that interferes with online movement planning. |
| Record 31 of 50 |
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| Author(s): Williams, DR (Williams, David R.); Holton, JL (Holton, Janice L.); Strand, K (Strand, Kate); Revesz, T (Revesz, Tamas); Lees, AJ (Lees, Andrew J.) |
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| Abstract: The clinical syndrome of pure akinesia has most often been associated with progressive supranuclear palsy (PSP) and is characterized by difficulty initiating gait and “freezing” during walking, writing and speaking. Similar syndromes have been described under the rubrics of primary progressive freezing gait and primary gait ignition failure. We investigated the specificity of the clinical syndrome of pure akinesia with gait freezing (PAGF) for PSP-tau pathology. Among 749 patients archived at the QSBB, only 7 fulfilled proposed diagnostic criteria of: gradual onset of freezing of gait or speech; absent limb rigidity and tremor; no sustained response to levodopa; and no dementia or ophthalmoplegia in the first 5 years of disease. In these cases detailed pathological examination was performed. PSP was the pathological diagnosis in six patients, and Parkinson’s disease (PD) in the seventh. As defined, this syndrome had a positive predictive value of 86% for PSP-tau pathology. In the cases with PSP there were no additional features of coexistent vascular or PD and the median PSP-tau score was 3, reflecting relative mild tau load. The clinical syndrome of PAGF appears to have a high specificity for PSP-tau pathology. This relatively uncommon presentation of PSP-tau pathology has less severe tau accumulation than in the more common, “classic” PSP clinical phenotype: Richardson’s disease. (c) 2007 Movement Disorder Society. |
| Record 32 of 50 |
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| Author(s): Snijders, AH (Snijders, Anke H.); Haaxma, CA (Haaxma, Charlotte A.); Hagen, YJ (Hagen, Yolien J.); Munneke, M (Munneke, Marten); Bloem, BR (Bloem, Bastiaan R.) |
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Abstract:
Introduction: Freezing of gait (FOG) is both common and debilitating in patients with Parkinson’s disease (PD). Future pathophysiology studies will depend critically upon adequate classification of patients as being either ‘freezers’ or ‘non-freezers’. This classification should be based ideally upon objective confirmation by an experienced observer during clinical assessment. Given the known difficulties to elicit FOG when examining patients, we aimed to investigate which simple clinical test would be the most sensitive to provoke FOG objectively.
Methods: We examined 50 patients with PD, including 32 off-state freezers (defined as experiencing subjective ‘gluing of the feet to the floor’). Assessment including a FOG trajectory (three trials: normal speed, fast speed, and with dual tasking) and several turning variants (180 degrees vs. 360 degrees turns: leftward vs. rightward turns; wide vs. narrow turning; and slow vs. fast turns). Results: Sensitivity of the entire assessment to provoke FOG in subjective freezers was 0.74, specificity was 0.94. The most effective test to provoke FOG was rapid 360 degrees turns in both directions and, if negative, combined with a gait trajectory with dual tasking. Repeated testing improved the diagnostic yield. The least informative tests included wide turns, 180 degrees turns or normal speed full turns. Sensitivity to provoke objective FOG in subjective freezers was 0.65 for the rapid full turns in both directions and 0.63 for the FOG trajectory. Discussion: The most efficient way to objectively ascertain FOG is asking patients to repeatedly make rapid 360 degrees narrow turns from standstill, on the spot and in both directions. (C) 2011 Elsevier Ltd. All rights reserved. |
| Record 33 of 50 |
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| Author(s): Fling, BW (Fling, Brett W.); Cohen, RG (Cohen, Rajal G.); Mancini, M (Mancini, Martina); Carpenter, SD (Carpenter, Samuel D.); Fair, DA (Fair, Damien A.); Nutt, JG (Nutt, John G.); Horak, FB (Horak, Fay B.) |
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| Abstract: Freezing of gait (FoG) is a transient inability to initiate or maintain stepping that often accompanies advanced Parkinson’s disease (PD) and significantly impairs mobility. The current study uses a multimodal neuroimaging approach to assess differences in the functional and structural locomotor neural network in PD patients with and without FoG and relates these findings to measures of FoG severity. Twenty-six PD patients and fifteen age-matched controls underwent resting-state functional magnetic resonance imaging and diffusion tensor imaging along with self-reported and clinical assessments of FoG. After stringent movement correction, fifteen PD patients and fourteen control participants were available for analysis. We assessed functional connectivity strength between the supplementary motor area (SMA) and the following locomotor hubs: 1) subthalamic nucleus (STN), 2) mesencephalic and 3) cerebellar locomotor region (MLR and CLR, respectively) within each hemisphere. Additionally, we quantified structural connectivity strength between locomotor hubs and assessed relationships with metrics of FoG. FoG+ patients showed greater functional connectivity between the SMA and bilateral MLR and between the SMA and left CLR compared to both FoG- and controls. Importantly, greater functional connectivity between the SMA and MLR was positively correlated with i) clinical, ii) self-reported and iii) objective ratings of freezing severity in FoG+, potentially reflecting a maladaptive neural compensation. The current findings demonstrate a reorganization of functional communication within the locomotor network in FoG+ patients whereby the higher-order motor cortex (SMA) responsible for gait initiation communicates with the MLR and CLR to a greater extent than in FoG- patients and controls. The observed pattern of altered connectivity in FoG+ may indicate a failed attempt by the CNS to compensate for the loss of connectivity between the STN and SMA and may reflect a loss of lower-order, automatic control of gait by the basal ganglia. |
| Record 34 of 50 |
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| Author(s): Iansek, R (Iansek, Robert); Huxham, F (Huxham, Frances); McGinley, J (McGinley, Jennifer) |
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| Abstract: Festination and freezing of gait (FOG) are poorly understood gait disorders that cause disability and falls in people with Parkinson disease (PD). In PD, basal ganglia malfunction leads to motor set deficits (hypokinesia), while altered motor cue production leads to a sequence effect, whereby movements becomes progressively smaller as in festination. We suggest both factors may contribute to FOG. Disturbance of set maintenance by the basal ganglia in PD has previously been examined in gait, but limited systematic evaluation of the sequence effect exists. In this study, we investigated the step-to-step amplitude relationship in 10 PD subjects with clinical evidence of festination and FOG. Four conditions were examined: off levodopa, off with attentional strategies, off with visual cues, and on levodopa. Participants demonstrated a sequence effect (F = 6.24; P = 0.001), which was reversed only by use of visual cues. In contrast, medication, attentional strategies, and visual cues all improved hypokinesia. Variability was marked both within and between participants in all conditions. The variability of FOG is suggested to relate to a combination of factors, including the sequence effect and its variability, as well as the severity of hypokinesia and its response to medications. (c) 2006 Movement Disorder Society. |
| Record 35 of 50 |
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| Author(s): Naismith, SL (Naismith, Sharon L.); Shine, JM (Shine, James M.); Lewis, SJG (Lewis, Simon J. G.) |
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| Abstract: Freezing of gait (FOG) in Parkinson’s disease (PD) is common and the pathophysiology of FOG is poorly understood. It has been hypothesized to reflect complementary yet competing frontostriatal pathways that reduce the ability to keep different tasks (motor or cognitive) on-line. This inability to “set-shift” has been proposed to trigger a freezing episode. If correct, this hypothesis would predict a differential pattern of executive dysfunction with FOG being most specifically related to attentional set-shifting. In this study, 31 patients with a range of self-reported FOG symptom severities were administered tests of executive functioning. The results demonstrate that FOG symptoms were selectively correlated with poorer performance on tasks of set-shifting, but not with a range of other executive tasks. This was apparent even after controlling for slowed processing speed, disease stage and depressive symptoms. The results support the recently proposed hypothesis for the pathophysiology underlying FOG in PD. (C) 2010 Movement Disorder Society |
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| Author(s): Espay, AJ (Espay, A. J.); Fasano, A (Fasano, A.); van Nuenen, BFL (van Nuenen, B. F. L.); Payne, MM (Payne, M. M.); Snijders, AH (Snijders, A. H.); Bloem, BR (Bloem, B. R.) |
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Abstract:
Objective: To describe the phenotype of levodopa-induced “on” freezing of gait (FOG) in Parkinson disease (PD).
Methods: We present a diagnostic approach to separate “on” FOG (deterioration during the “on state”) from other FOG forms. Four patients with PD with suspected “on” FOG were examined in the “off state” (>12 hours after last medication intake), “on state” (peak effect of usual medication), and “supra-on” state (after intake of at least twice the usual dose). Results: Patients showed clear “on” FOG, which worsened in a dose-dependent fashion from the “on” to the “supra-on” state. Two patients also demonstrated FOG during the “off state,” of lesser magnitude than during “on.” In addition, levodopa produced motor blocks in hand and feet movements, while other parkinsonian features improved. None of the patients had cognitive impairment or a predating “off ” FOG. Conclusions: True “on” FOG exists as a rare phenotype in PD, unassociated with cognitive impairment or a predating “off “FOG. Distinguishing the different FOG subtypes requires a comprehensive motor assessment in at least 3 medication states. Neurology (R) 2012;78:454-457 |
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| Author(s): Moore, ST (Moore, Steven T.); Yungher, DA (Yungher, Don A.); Morris, TR (Morris, Tiffany R.); Dilda, V (Dilda, Valentina); MacDougall, HG (MacDougall, Hamish G.); Shine, JM (Shine, James M.); Naismith, SL (Naismith, Sharon L.); Lewis, SJG (Lewis, Simon J. G.) |
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Abstract:
Background: We have previously published a technique for objective assessment of freezing of gait (FOG) in Parkinson’s disease (PD) from a single shank-mounted accelerometer. Here we extend this approach to evaluate the optimal configuration of sensor placement and signal processing parameters using seven sensors attached to the lumbar back, thighs, shanks and feet.
Methods: Multi-segmental acceleration data was obtained from 25 PD patients performing 134 timed up and go tasks, and clinical assessment of FOG was performed by two experienced raters from video. Four metrics were used to compare objective and clinical measures; the intraclass correlation coefficient (ICC) for number of FOG episodes and the percent time frozen per trial; and the sensitivity and specificity of FOG detection. Results: The seven-sensor configuration was the most robust, scoring highly on all measures of performance (ICC number of FOG 0.75; ICC percent time frozen 0.80; sensitivity 84.3%; specificity 78.4%). A simpler single-shank sensor approach provided similar ICC values and exhibited a high sensitivity to FOG events, but specificity was lower at 66.7%. Recordings from the lumbar sensor offered only moderate agreement with the clinical raters in terms of absolute number and duration of FOG events (likely due to musculoskeletal attenuation of lower-limb ‘trembling’ during FOG), but demonstrated a high sensitivity (86.2%) and specificity (82.4%) when considered as a binary test for the presence/absence of FOG within a single trial. Conclusions: The seven-sensor approach was the most accurate method for quantifying FOG, and is best suited to demanding research applications. A single shank sensor provided measures comparable to the seven-sensor approach but is relatively straightforward in execution, facilitating clinical use. A single lumbar sensor may provide a simple means of objective FOG detection given the ubiquitous nature of accelerometers in mobile telephones and other belt-worn devices. |
| Record 38 of 50 |
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Title:
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| Author(s): Tripoliti, EE (Tripoliti, Evanthia E.); Tzallas, AT (Tzallas, Alexanclros T.); Tsipouras, MG (Tsipouras, Markos G.); Rigas, G (Rigas, George); Bougia, P (Bougia, Panagiota); Leontiou, M (Leontiou, Michael); Konitsiotis, S (Konitsiotis, Spiros); Chondrogiorgi, M (Chondrogiorgi, Maria); Tsouli, S (Tsouli, Sofia); Fotiadis, DI (Fotiadis, Dimitrios I.) |
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| Abstract: The aim of this study is to detect freezing of gait (FoG) events in patients suffering from Parkinson’s disease (PD) using signals received from wearable sensors (six accelerometers and two gyroscopes) placed on the patients’ body. For this purpose, an automated methodology has been developed which consists of four stages. In the first stage, missing values due to signal loss or degradation are replaced and then (second stage) low frequency components of the raw signal are removed. In the third stage, the entropy of the raw signal is calculated. Finally (fourth stage), four classification algorithms have been tested (Naive Bayes, Random Forests, Decision Trees and Random Tree) in order to detect the FoG events. The methodology has been evaluated using several different configurations of sensors in order to conclude to the set of sensors which can produce optimal FoG episode detection. Signals recorded from five healthy subjects, five patients with PD who presented the symptom of FoG and six patients who suffered from PD but they do not present FoG events. The signals included 93 FoG events with 405.6 s total duration. The results indicate that the proposed methodology is able to detect FoG events with 81.94% sensitivity, 98.74% specificity, 96.11% accuracy and 98.6% area under curve (AUC) using the signals from all sensors and the Random Forests classification algorithm. (C) 2012 Elsevier Ireland Ltd. All rights reserved. |
| Record 39 of 50 |
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| Author(s): Plotnik, M (Plotnik, Meir); Giladi, N (Giladi, Nir); Hausdorff, JM (Hausdorff, Jeffrey M.) |
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| Abstract: Freezing of gait (FOG) in Parkinson’s disease (PD) occurs most frequently during turns or step initiation, two tasks that likely demand a high degree of bilateral coordination between the legs. Our objective was to test the hypothesis that impairments in bilateral coordination of stepping are associated with FOG in PD. We compared locomotion features while walking on level ground between patients with PD that experience FOG (PD + FOG; n = 21) and patients with PD that do not (PD – FOG; n = 13). To study bilateral stepping coordination, we defined the stride duration of one foot as a gait cycle or 360 degrees, determined the relative timing of contralateral heel-strikes and defined this as the phase, phi (ideally, phi = 180 degrees). The sum of the coefficient of variation of phi and the mean absolute difference between phi and 180 degrees was defined as the phase coordination index (PCI), representing variability and inaccuracy, respectively, in phase generation. During the ‘Off’ state (= 12 h off anti-parkinsonian medication), PCI values were higher (poorer coordination) in PD + FOG compared with PD – FOG (P < 0.024). Stride-to-stride phase adjustments, Delta phi, were also studied. Both groups scaled their ‘converging’ adjustments (towards 180 degrees) to the same extent, but when generating diverging Delta phi (away from 180 degrees), PD + FOG patients exhibited larger errors compared with PD – FOG patients (P < 0.006). This study demonstrates that patients with PD who experience FOG have distinctive impairments in the bilateral coordination of locomotion. Poor bilateral coordination of walking may predispose to FOG, especially during challenging tasks that demand a high degree of left-right coordination. |
| Record 40 of 50 |
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| Author(s): Camps, J (Camps, Julia); Samà, A (Sama, Albert); Martín, M (Martin, Mario); Rodríguez-Martín, D (Rodriguez-Martin, Daniel); Pérez-López, C (Perez-Lopez, Carlos); Arostegui, JMM (Moreno Arostegui, Joan M.); Cabestany, J (Cabestany, Joan); Català, A (Catala, Andreu); Alcaine, S (Alcaine, Sheila); Mestre, B (Mestre, Berta); Prats, A (Prats, Anna); Crespo-Maraver, MC (Crespo-Maraver, Maria C.); Counihan, TJ (Counihan, Timothy J.); Browne, P (Browne, Patrick); Quinlan, LR (Quinlan, Leo R.); Laighin, GO (Laighin, Gearoid O.); Sweeney, D (Sweeney, Dean); Lewy, H (Lewy, Hadas); Vainstein, G (Vainstein, Gabriel); Costa, A (Costa, Alberto); Annicchiarico, R (Annicchiarico, Roberta); Bayés, A (Bayes, Angels); Rodríguez-Molinero, A (Rodriguez-Molinero, Alejandro) |
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Abstract:
Among Parkinson’s disease (PD) motor symptoms, freezing of gait (FOG) may be the most incapacitating. FOG episodes may result in falls and reduce patients’ quality of life. Accurate assessment of FOG would provide objective information to neurologists about the patient’s condition and the symptom’s characteristics, while it could enable non-pharmacologic support based on rhythmic cues.
This paper is, to the best of our knowledge, the first study to propose a deep learning method for detecting FOG episodes in PD patients. This model is trained using a novel spectral data representation strategy which considers information from both the previous and current signal windows. Our approach was evaluated using data collected by a waist-placed inertial measurement unit from 21 PD patients who manifested FOG episodes. These data were also employed to reproduce the state-of-the-art methodologies, which served to perform a comparative study to our FOG monitoring system. The results of this study demonstrate that our approach successfully outperforms the state-of-the-art methods for automatic FOG detection. Precisely, the deep learning model achieved 90% for the geometric mean between sensitivity and specificity, whereas the state-of-the-art methods were unable to surpass the 83% for the same metric. (C) 2017 Elsevier B.V. All rights reserved. |
| Record 41 of 50 |
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| Author(s): Snijders, AH (Snijders, Anke H.); Takakusaki, K (Takakusaki, Kaoru); Debu, B (Debu, Bettina); Lozano, AM (Lozano, Andres M.); Krishna, V (Krishna, Vibhor); Fasano, A (Fasano, Alfonso); Aziz, TZ (Aziz, Tipu Z.); Papa, SM (Papa, Stella M.); Factor, SA (Factor, Stewart A.); Hallett, M (Hallett, Mark) |
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| Abstract: Freezing of gait (FOG) is a common and debilitating, but largely mysterious, symptom of Parkinson disease. In this review, we will discuss the cerebral substrate of FOG focusing on brain physiology and animal models. Walking is a combination of automatic movement processes, afferent information processing, and intentional adjustments. Thus, normal gait requires a delicate balance between various interacting neuronal systems. To further understand gait control and specifically FOG, we will discuss the basic physiology of gait, animal models of gait disturbance including FOG, alternative etiologies of FOG, and functional magnetic resonance studies investigating FOG. The outcomes of these studies point to a dynamic network of cortical areas such as the supplementary motor area, as well as subcortical areas such as the striatum and the mesencephalic locomotor region including the pedunculopontine nucleus (PPN). Additionally, we will review PPN (area) stimulation as a possible treatment for FOG, and ponder whether PPN stimulation truly is the right step forward. Ann Neurol 2016;80:644-659 |
| Record 42 of 50 |
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| Author(s): Vandenbossche, J (Vandenbossche, Jochen); Deroost, N (Deroost, N.); Soetens, E (Soetens, E.); Coomans, D (Coomans, D.); Spildooren, J (Spildooren, J.); Vercruysse, S (Vercruysse, S.); Nieuwboer, A (Nieuwboer, A.); Kerckhofs, E (Kerckhofs, E.) |
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| Abstract: Recent studies emphasize a key role of controlled operations, such as set-shifting and inhibition, in the occurrence of freezing of gait (FOG) in Parkinson’s disease (PD). However, FOG can also be characterized as a de-automatization disorder, showing impairments in both the execution and acquisition of automaticity. The observed deficits in automaticity and executive functioning indicate that both processes are malfunctioning in freezers. Therefore, to explain FOG from a cognitive-based perspective, we present a model describing the pathways involved in automatic and controlled processes prior to a FOG episode. Crucially, we focus on disturbances in automaticity and control, regulated by the frontostriatal circuitry. In complex situations, non-freezing PD patients may compensate for deficits in automaticity by switching to increased cognitive control. However, as both automatic and controlled processes are more severely impaired in freezers, this hampers cognitive compensation in FOG, resulting in a potential breakdown. Future directions for cognitive rehabilitation are proposed, based on the cognitive model we put forward. |
| Record 43 of 50 |
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| Author(s): Nieuwboer, A (Nieuwboer, Alice) |
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| Abstract: Freezing of gait (FOG) has been known to respond favorably to sensory tricks and cues. However, FOG is a complex phenomenon with various motor control deficits at play. In this review, we examined and summarized the currently available evidence for the effectiveness of cueing for FOG to determine its value as a clinical method. The results showed that the immediate effects of cues have no consistent impact but longer periods of cued training may be beneficial. The review also showed (1) the limited statistical power and methodological weakness of the studies involved; (2) measurement difficulties of FOG, and (3) the need to better understand its underlying causal factors. Overall, the findings suggest a smaller capacity for compensation in patients suffering from FOG. Especially when attention is overloaded, the therapeutic window and the practical applicability of cueing seem more limited. These aspects need to be incorporated in the development of future cueing programs designed to alleviate FOG. (C) 2008 Movement Disorder Society. |
| Record 44 of 50 |
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| Author(s): Canu, E (Canu, Elisa); Agosta, F (Agosta, Federica); Sarasso, E (Sarasso, Elisabetta); Volontè, MA (Volonte, Maria Antonietta); Basaia, S (Basaia, Silvia); Stojkovic, T (Stojkovic, Tanja); Stefanova, E (Stefanova, Elka); Comi, G (Comi, Giancarlo); Falini, A (Falini, Andrea); Kostic, VS (Kostic, Vladimir S.); Gatti, R (Gatti, Roberto); Filippi, M (Filippi, Massimo) |
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| Abstract: Objective: To use a multimodal approach to assess brain structural pathways and resting state (RS) functional connectivity abnormalities in patients with Parkinson’s disease and freezing of gait (PD-FoG). Methods: T1-weighted, diffusion tensor (DT) MRI and RS functional MRI (fMRI) were obtained from 22 PD-FoG patients and 35 controls on a 3.0 T MR scanner. Patients underwent clinical, motor, and neuropsychological evaluations. Gray matter (GM) volumes and white matter (WM) damage were assessed using voxel based morphometry and tract-based spatial statistics, respectively. The pedunculopontine tract (PPT) was studied using tractography. RS fMRI data were analyzed using a model free approach investigating the main sensorimotor and cognitive brain networks. Multiple regression models were performed to assess the relationships between structural, functional, and clinical/cognitive variables. Analysis of GM and WM structural abnormalities was replicated in an independent sample including 28 PD-FoG patients, 25 PD patients without FoG, and 30 healthy controls who performed MRI scans on a 1.5 T scanner. Results: Compared with controls, no GM atrophy was found in PD-FoG cases. PD-FoG patients showed WM damage of the PPT, corpus callosum, corticospinal tract, cingulum, superior longitudinal fasciculus, and WM underneath the primary motor, premotor, prefrontal, orbitofrontal, and inferior parietal cortices, bilaterally. In PD-FoG, right PTT damage was associated with a greater disease severity. Analysis on the independent PD sample showed similar findings in PD-FoG patients relative to controls as well as WM damage of the genu and body of the corpus callosum and right parietal WM in PD-FoG relative to PD no-FoG patients. RS fMRI analysis showed that PD-FoG is associated with a decreased functional connectivity of the primary motor cortex and supplementary motor area bilaterally in the sensorimotor network, frontoparietal regions in the default mode network, and occipital cortex in the visual associative network. Conclusions: This study suggests that FoG in PD can be the result of a poor structural and functional integration between motor and extramotor (cognitive) neural systems. (C) 2015 Wiley Periodicals, Inc. |
| Record 45 of 50 |
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| Author(s): Moreau, C (Moreau, Caroline); Delval, A (Delval, Arnaud); Defebvre, L (Defebvre, Luc); Dujardin, K (Dujardin, Kathy); Duhamel, A (Duhamel, Alain); Petyt, G (Petyt, Gregory); Vuillaume, I (Vuillaume, Isabelle); Corvol, JC (Corvol, Jean-Christophe); Brefel-Courbon, C (Brefel-Courbon, Christine); Ory-Magne, F (Ory-Magne, Fabienne); Guehl, D (Guehl, Dominique); Eusebio, A (Eusebio, Alexandre); Fraix, V (Fraix, Valerie); Saulnier, PJ (Saulnier, Pierre-Jean); Lagha-Boukbiza, O (Lagha-Boukbiza, Ouhaid); Durif, F (Durif, Frank); Faighel, M (Faighel, Mirela); Giordana, C (Giordana, Caroline); Drapier, S (Drapier, Sophie); Maltête, D (Maltete, David); Tranchant, C (Tranchant, Christine); Houeto, JL (Houeto, Jean-Luc); Debû, B (Debu, Bettina); Sablonniere, B (Sablonniere, Bernard); Azulay, JP (Azulay, Jean-Philippe); Tison, F (Tison, Francois); Rascol, O (Rascol, Olivier); Vidailhet, M (Vidailhet, Marie); Destée, A (Destee, Alain); Bloem, BR (Bloem, Bastiaan R.); Bordet, R (Bordet, Regis); Devos, D (Devos, David) |
| Group Author(s): Parkgait-II Study Grp |
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Abstract:
Background Despite optimum medical management, many patients with Parkinson’s disease are incapacitated by gait disorders including freezing of gait. We aimed to assess whether methylphenidate through its combined action on dopamine and noradrenaline reuptake-would improve gait disorders and freezing of gate in patients with advanced Parkinson’s disease without dementia who also received subthalamic nucleus stimulation.
Methods This multicentre, parallel, double-blind, placebo-controlled, randomised trial was done in 13 movement disorders departments in France between October, 2009, and December, 2011. Eligible patients were younger than 80 years and had Parkinson’s disease, severe gait disorders, and freezing of gate despite optimised treatment of motor fluctuations with dopaminergic drugs and subthalamic stimulation. We randomly assigned patients (1:1 with a computer random-number generator in blocks of four) to receive methylphenidate (1 mg/kg per day) or placebo capsules for 90 days. Patients, their carers, study staff, investigators, and data analysts were masked to treatment allocation. To control for confounding effects of levodopa we assessed patients under standardised conditions with an acute levodopa challenge. Our primary outcome was a change in the number of steps during the stand-walk-sit (SWS) test without levodopa. We compared the respective mean numbers of steps at day 90 in the methylphenidate and placebo groups in a covariance analysis and adjusted for baseline differences. This trial is registered with ClinicalTrials.gov, number NCT00914095. Findings We screened 81 patients and randomly assigned 35 to receive methylphenidate and 34 to receive placebo. 33 patients in the methylphenidate group and 32 patients in the placebo group completed the study. Efficacy outcomes were assessed in the patients who completed the study. Compared with patients in the placebo group (median 33 steps [IQR 26-45]), the patients in the methylphenidate group made fewer steps at 90 days (31 [26-42], F-(1.62) =6.1, p=0.017, adjusted size effect 0.61). Adverse events were analysed in all randomly assigned patients. There were significantly more adverse events in the methylphenidate group compared with placebo. Patients on methylphenidate had a significant increase in heart rate (mean 3.6 [SD 7.2] beats per min) and decrease in weight (mean 2.2 [SD 1.8] kg) compared with the placebo group. Interpretation Methylphenidate improved gait hypokinesia and freezing in patients with advanced Parkinson’s disease receiving subthalamic nucleus stimulation. Methylphenidate represents a therapeutic option in the treatment of gait disorders at the advanced stage of Parkinson’s disease. The long term risk-benefit balance should be further studied. Funding French Ministry of Health and Novartis Pharma. |
| Record 46 of 50 |
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| Author(s): Thevathasan, W (Thevathasan, Wesley); Coyne, TJ (Coyne, Terry J.); Hyam, JA (Hyam, Jonathan A.); Kerr, G (Kerr, Graham); Jenkinson, N (Jenkinson, Ned); Aziz, TZ (Aziz, Tipu Z.); Silburn, PA (Silburn, Peter A.) |
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Abstract:
BACKGROUND: Pedunculopontine nucleus (PPN) stimulation is a novel therapy for Parkinson disease. However, controversies remain regarding the clinical application of this new therapy, including patient selection, electrode positioning, and how best to assess outcomes.
OBJECTIVE: To clarify the clinical application of PPN stimulation in Parkinson disease. METHODS: Five consecutive patients with Parkinson disease complicated by severe gait freezing, postural instability, and frequent falls (all persisting even while the patient was on medication) received bilateral stimulation of the mid-lower PPN without costimulation of other brain targets. Outcomes were assessed prospectively over 2 years with gait-specific questionnaires and the Unified Parkinson Disease Rating Scale (part III). RESULTS: The primary outcome, the Gait and Falls Questionnaire score, improved significantly with stimulation. Benefits were maintained over 2 years. Unified Parkinson Disease Rating Scale (part III) items assessing gait and posture were relatively insensitive to these treatment effects. Beneficial effects often appeared to outlast stimulation for hours or longer. Thus, single-session on-vs off-stimulation assessments may be susceptible to “delayed washout effects.” Stimulation of the PPN did not change akinesia scores or dopaminergic medication requirements. CONCLUSION: Bilateral stimulation of the mid-lower PPN (more caudal than previous reports) without costimulation of other brain targets may be beneficial for the subgroup of patients with Parkinson disease who experience severe gait freezing and postural instability with frequent falls, which persist even while on medication. Choosing appropriate outcome measures and accounting for the possibility of prolonged stimulation washout effects appear to be important for detecting the clinical benefits. |
| Record 47 of 50 |
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| Author(s): Snijders, AH (Snijders, Anke H.); Nijkrake, MJ (Nijkrake, Maarten J.); Bakker, M (Bakker, Maaike); Munneke, M (Munneke, Marten); Wind, C (Wind, Carina); Bloem, BR (Bloem, Bastiaan R.) |
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| Abstract: The clinical assessment of freezing of gait (FOG) provides great challenges. Patients often do not realize what FOG really is. Assessing FOG is further complicated by the episodic, unpredictable, and variable presentation, its well as the complex relationship with medication. Here, we provide some practical recommendations for a standardized clinical approach. During history taking, presence of FOG is best ascertained by asking about the characteristic feeling of “being glued to the floor.” Detection of FOG is greatly facilitated by demonstrating what FOG actually looks like, not only to the patient but also to the spouse or other carer. History taking further focuses on the specific circumstances that provoke FOG and on its severity, preferably using standardized questionnaires. Physical examination should be done both during the ON and OFF state, to judge the influence of treatment. Evaluation includes a dedicated “gait trajectory” that features specific triggers to elicit FOG (gait initiation; a narrow passage; dual tasking; and rapid 360 degrees axial turns in both directions). Evaluating the response to external cues has diagnostic importance, and helps to determine possible therapeutic interventions. Because of the tight interplay between FOG and mental functions, the evaluation must include cognitive testing (mainly frontal executive functions) and judgment of mood. Neuroimaging is required for most patients in order to detect underlying pathology, in particular lesions of the frontal lobe or their connections to the basal ganglia. Various quantitative gait assessments have been proposed, but these methods have not proven value for clinical practice. (c) 2008 Movement Disorder Society. |
| Record 48 of 50 |
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| Author(s): Plotnik, M (Plotnik, Meir); Hausdorff, JM (Hausdorff, Jeffrey M.) |
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| Abstract: Freezing of gait (FOG) is a disabling episodic gait disturbance that is common among patients with Parkinson’s disease (PD). In this review, we describe a new approach for understanding the mechanisms underlying this puzzling phenomenon. We propose that impairments in the ongoing regulation of gait, even during periods in which freezing is not present, set the stage for the occurrence of a FOG episode. More specifically, three “interictal” walking attributes are associated with FOG: gait rhythmicity, gait asymmetry, and bilateral dyscoordination of left-right stepping. Gait is less rhythmic, more asymmetric, and less coordinated among PD patients with FOG, when compared with PD patients without FOG. We describe the relationship between these changes and other features of patients with FOG and discuss whether these gait changes may predispose to FOG or if they also cause FOG, perhaps, when they are altered beyond a certain threshold or exacerbated by another trigger. (c) 2008 Movement Disorder Society. |
| Record 49 of 50 |
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| Author(s): Bohnen, NI (Bohnen, Nicolaas, I); Kanel, P (Kanel, Prabesh); Zhou, Z (Zhou, Zhi); Koeppe, RA (Koeppe, Robert A.); Frey, KA (Frey, Kirk A.); Dauer, WT (Dauer, William T.); Albin, RL (Albin, Roger L.); Müller, MLTM (Mueller, Martijn L. T. M.) |
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| Abstract: Objective Postural instability and gait difficulties (PIGDs) represent debilitating disturbances in Parkinson’s disease (PD). Past acetylcholinesterase positron emission tomography (PET) imaging studies implicate cholinergic changes as significant contributors to PIGD features. These studies were limited in quantification of striatal cholinergic synapse integrity. Vesicular acetylcholine transporter (VAChT) PET ligands are better suited for evaluation of high binding areas. We examined associations between regional VAChT expression and freezing of gait (FoG) and falls. Methods Ninety-four PD subjects underwent clinical assessment and VAChT ([F-18]FEOBV) PET. Results Thirty-five subjects (37.2%) reported a history of falls, and 15 (16%) had observed FoG. Univariate volume-of-interest analyses demonstrated significantly reduced thalamic (p = 0.0016) VAChT expression in fallers compared to nonfallers. VAChT expression was significantly reduced in the striatum (p = 0.0012) and limbic archicortex (p = 0.004) in freezers compared to nonfreezers. Whole-brain voxel-based analyses of FEOBV PET complemented these findings and showed more granular changes associated with falling history, including the right visual thalamus (especially the right lateral geniculate nucleus [LGN]), right caudate nucleus, and bilateral prefrontal regions. Freezers had prominent VAChT expression reductions in the bilateral striatum, temporal, and mesiofrontal limbic regions. Interpretation Our findings confirm and extend on previous PET findings of thalamic cholinergic deficits associated with falling history and now emphasize right visual thalamus complex changes, including the right LGN. FoG status is associated with reduced VAChT expression in striatal cholinergic interneurons and the limbic archicortex. These observations suggest different cholinergic systems changes underlying falls and FoG in PD. Ann Neurol 2019;85:538-549 |
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| Author(s): Rodríguez-Martín, D (Rodriguez-Martin, Daniel); Samá, A (Sama, Albert); Pérez-López, C (Perez-Lopez, Carlos); Catalá, A (Catala, Andreu); Arostegui, JMM (Moreno Arostegui, Joan M.); Cabestany, J (Cabestany, Joan); Bayés, A (Bayes, Angels); Alcaine, S (Alcaine, Sheila); Mestre, B (Mestre, Berta); Prats, A (Prats, Anna); Crespo, MC (Cruz Crespo, M.); Counihan, TJ (Counihan, Timothy J.); Browne, P (Browne, Patrick); Quinlan, LR (Quinlan, Leo R.); OLaighin, G (OLaighin, Gearoido); Sweeney, D (Sweeney, Dean); Lewy, H (Lewy, Hadas); Azuri, J (Azuri, Joseph); Vainstein, G (Vainstein, Gabriel); Annicchiarico, R (Annicchiarico, Roberta); Costa, A (Costa, Alberto); Rodríguez-Molinero, A (Rodriguez-Molinero, Alejandro) |
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| Abstract: Among Parkinson’s disease (PD) symptoms, freezing of gait (FoG) is one of the most debilitating. To assess FoG, current clinical practice mostly employs repeated evaluations over weeks and months based on questionnaires, which may not accurately map the severity of this symptom. The use of a non-invasive system to monitor the activities of daily living (ADL) and the PD symptoms experienced by patients throughout the day could provide a more accurate and objective evaluation of FoG in order to better understand the evolution of the disease and allow for a more informed decision-making process in making adjustments to the patient’s treatment plan. This paper presents a new algorithm to detect FoG with a machine learning approach based on Support Vector Machines (SVM) and a single tri-axial accelerometer worn at the waist. The method is evaluated through the acceleration signals in an outpatient setting gathered from 21 PD patients at their home and evaluated under two different conditions: first, a generic model is tested by using a leave-one-out approach and, second, a personalised model that also uses part of the dataset from each patient. Results show a significant improvement in the accuracy of the personalised model compared to the generic model, showing enhancement in the specificity and sensitivity geometric mean (GM) of 7.2%. Furthermore, the SVM approach adopted has been compared to the most comprehensive FoG detection method currently in use (referred to as MBFA in this paper). Results of our novel generic method provide an enhancement of 11.2% in the GM compared to the MBFA generic model and, in the case of the personalised model, a 10% of improvement with respect to the MBFA personalised model. Thus, our results show that a machine learning approach can be used to monitor FoG during the daily life of PD patients and, furthermore, personalised models for FoG detection can be used to improve monitoring accuracy. |
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