Investigating gait-responsive somatosensory cueing from a wearable device to improve walking in Parkinson's disease.

Freezing-of-gait (FOG) and impaired walking are common features of Parkinson's disease (PD). Provision of external stimuli (cueing) can improve gait, however, many cueing methods are simplistic, increase task loading or have limited utility in a real-world setting. Closed-loop (automated) somatosensory cueing systems have the potential to deliver personalised, discrete cues at the appropriate time, without requiring user input. Further development of cue delivery methods and FOG-detection are required to achieve this. In this feasibility study, we aimed to test if FOG-initiated vibration cues applied to the lower-leg via wearable devices can improve gait in PD, and to develop real-time FOG-detection algorithms. 17 participants with Parkinson's disease and daily FOG were recruited. During 1 h study sessions, participants undertook 4 complex walking circuits, each with a different intervention: continuous rhythmic vibration cueing (CC), responsive cueing (RC; cues initiated by the research team in response to FOG), device worn with no cueing (NC), or no device (ND). Study sessions were grouped into 3 stages/blocks (A-C), separated by a gap of several weeks, enabling improvements to circuit design and the cueing device to be implemented. Video and onboard inertial measurement unit (IMU) data were analyzed for FOG events and gait metrics. RC significantly improved circuit completion times demonstrating improved overall performance across a range of walking activities. Step frequency was significantly enhanced by RC during stages B and C. During stage C, > 10 FOG events were recorded in 45% of participants without cueing (NC), which was significantly reduced by RC. A machine learning framework achieved 83% sensitivity and 80% specificity for FOG detection using IMU data. Together, these data support the feasibility of closed-loop cueing approaches coupling real-time FOG detection with responsive somatosensory lower-leg cueing to improve gait in PD.

'Recoupling' the attentional and motor control of preparatory postural adjustments to overcome freezing of gait in Parkinson's.

OBJECTIVES: This study examined if people with Parkinson's and freezing of gait pathology (FoG) could be trained to increase preparatory weight-shift amplitude, and facilitate step initiation during FoG. METHODS: Thirty-five people with Parkinson's and FoG attempted to initiate forward walking from a stationary position caused by a freeze (n = 17, FoG-F) or voluntarily stop (n = 18, FoG-NF) in a Baseline condition and two conditions where an increased weight-shift amplitude was trained via: (i) explicit verbal instruction, and (ii) implicit movement analogies. RESULTS: At Baseline, weight-shift amplitudes were smaller during: (i) unsuccessful, compared to successful step initiations (FoG-F group), and (ii) successful step initiations in the FoG-F group compared to FoG-NF. Both Verbal and Analogy training resulted in significant increases in weight-shift amplitude in both groups, and a corresponding pronounced reduction in unsuccessful attempts to initiate stepping (FoG-F group). CONCLUSIONS: Hypometric preparatory weight-shifting is associated with failure to initiate forward stepping in people with Parkinson's and FoG. However, impaired weight-shift characteristics are modifiable through conscious strategies. This current study provides a novel and critical evaluation of preparatory weight-shift amplitudes during FoG events. The intervention described represents an attractive 'rescue' strategy and should be further scrutinised regarding limitations posed by physical and cognitive deficits.

Freezing/festination during motor tasks in early-stage Parkinson's disease: A prospective study.

BACKGROUND: Parkinsonian patients have a tendency to speed up during repetitive motor tasks (festination) and to experience sudden motor blocks (freezing). In this article, we prospectively studied the appearance and progression of these phenomena in 30 early-stage PD patients. METHODS: A total of 30 controls and early-stage PD patients were assessed in the "off-drug" condition at baseline and 2 years later. Freezing of gait was evaluated using a standardized gait trajectory with the usual triggers. Patients also performed diadochokinetic tasks with 3 different effectors (repetitive, antiphase movements for the hands and feet, and repetitive syllable production for the orofacial effector) at frequencies ranging from 1 to 7 Hz (in random order). The primary endpoint was the occurrence of freezing and festination. RESULTS: At baseline, freezing was observed in 6.5% of the trials in PD patients (43% of the patients) and 2.3% of the trials in controls, and festination was observed in 5.7% of the trials in patients (53% of the patients) and 0.8% of the trials in controls. These proportions were slightly higher in patients 2 years later. None of the patients presented freezing of gait at baseline, but 2 displayed this condition 2 years later. These phenomena occurred more frequently for the limb effectors than for the orofacial effector. Freezing and festination were associated with the akinetic-rigid subtype, although tremor-dominant patients displayed greater rhythm variability outside episodes. CONCLUSION: Freezing and festination of the upper and lower limbs are observed soon after the diagnosis of PD and may be early biomarkers for disease progression. © 2016 International Parkinson and Movement Disorder Society.

Dopa-responsive Rest Tremor Preceding Tachyphemia in Progressive Supranuclear Palsy: A Case Report.

Progressive supranuclear palsy (PSP) is characterized by progressive postural instability, falls, and supranuclear vertical gaze abnormalities. In this report, we present the case of a 71-year-old woman with dopa-responsive rest tremor followed by tachyphemia and postural instability. She initially presented with dopa-responsive slowness and tremor in the right hand. Two years later, she developed speech difficulties (tachyphemia) and a propensity for falls. Based on the diagnostic criteria for PSP, the patient was diagnosed with probable PSP-RS. The clinical manifestations observed in our patient are unique and are considered important for illustrating a broad spectrum of PSP syndrome.

Weighting for the Beat: Using a Dance Cue to Facilitate Turning in People with Parkinson's Disease and Freezing of Gait.

Freezing of gait (FOG) can severely compromise daily functioning in people with Parkinson's disease. Inability to initiate a step from FOG is likely underpinned, at least in part, by a deficient preparatory weight-shift. Conscious attempts to weight-shift in preparation to step can improve success of initiating forward steps following FOG. However, FOG often occurs during turning, where weight-shifting is more complex and risk of falling is higher. We explored the effectiveness of a dance-based ('cha-cha') weight-shifting strategy to re-initiate stepping following FOG during turning. Results suggest that this simple movement strategy can enhance turning steps following FOG, without compromising safety.

TAILORED USE OF COMPENSATION STRATEGIES TO ENABLE EXERCISE DESPITE FESTINATION IN PARKINSON'S DISEASE.

Despite increasing evidence for, and heightened awareness of, the importance of exercise in Parkinson's disease, many patients remain sedentary. This tendency to lead an inactive lifestyle has various underlying reasons, including the presence of gait and balance impairments that complicate the patients' ability to perform sports activities. This case report illustrates that a personally tailored approach may be required in these patients, supported, if needed, by the use of compensation strategies or novel technological advances.

The Minimal Clinically Relevant Change of the FOG Score.

BACKGROUND: Freezing of gait is a highly disabling symptom in persons with Parkinson's disease (PwP). Despite its episodic character, freezing can be reliably evaluated using the FOG score. The description of the minimal clinically relevant change is a requirement for a meaningful interpretation of its results. OBJECTIVE: To determine the minimal clinically relevant change of the FOG score. METHODS: We evaluated video recordings of a standardized freezing-evoking gait parkour, i.e., the FOG score just before and 30 minutes after the intake of a regular levodopa dose in a randomized blinded fashion. The minimal clinically relevant response was considered a value of one or more on a 7-step Likert-type response scale [-3; +3] that served as the anchor. The minimal clinically relevant change was determined by ROC analysis. RESULTS: 37 PwP (Hoehn & Yahr stages 2.5-4, 27 male, 10 female) were aged 68.2 years on average (range 45-80). Mean disease duration was 12.9 years (2-29 years). Minimum FOG score was 0 and Maximum FOG score was 29. Mean FOG scores before medication were 10.6, and 11.1 after medication intake, with changes ranging from -14.7 to +16.7. The minimal clinically relevant change (MCRC) for improvement based on expert clinician rating was three scale points with a sensitivity of 0.67 and a specificity of 0.96. CONCLUSIONS: The FOG score is recognized as a useful clinical instrument for the evaluation of freezing in the clinical setting. Knowledge of the MCRC should help to define responses to interventions that are discernible and meaningful to the expert physician and to the patient.

Gait festination in parkinsonism: introduction of two phenotypes.

Gait festination is one of the most characteristic gait disturbances in patients with Parkinson's disease or atypical parkinsonism. Although festination is common and disabling, it has received little attention in the literature, and different definitions exist. Here, we argue that there are actually two phenotypes of festination. The first phenotype entails a primary locomotion disturbance, due to the so-called sequence effect: a progressive shortening of step length, accompanied by a compensatory increase in cadence. This phenotype strongly relates to freezing of gait with alternating trembling of the leg. The second phenotype results from a postural control problem (forward leaning of the trunk) combined with a balance control deficit (inappropriately small balance-correcting steps). In this viewpoint, we elaborate on the possible pathophysiological substrate of these two phenotypes of festination and discuss their management in daily clinical practice.

Predictors of freezing of gait in Chinese patients with Parkinson's disease.

Objective: To explore the clinical predictors of freezing of gait (FOG) in Chinese patients with Parkinson's disease (PD). Methods: This study included 225 patients with PD who completed a three-year follow-up visit. The end-point was the presence of FOG (freezers), which was assessed during the follow-up visit. Group comparisons were conducted, followed by a further forward binary logistic regression analysis. Results: Eighty-five patients with PD (38%) had developed FOG at the end of study. At baseline, freezers exhibited higher age, longer disease duration, higher scores in Unified PD Rating Scale (UPDRS) III and Hamilton Depression/Anxiety Rating Scale, lower Frontal Assessment Battery (FAB) score, higher subscores (e.g., "urgency") and frequencies (e.g., "hallucinations") in Non-Motor Symptoms Scale, higher annual changes in MoCA, UPDRS III and FAB scores, and higher incidences of festination and falls than nonfreezers (p < .05). The forward binary logistic regression model indicated that a longer disease duration, a higher UPDRS III score, higher annual changes in UPDRS III score and "visuospatial/executive abilities" subscore, onset in lower limbs, and the presence of festination, falls, and hallucinations were associated with the development of FOG. Conclusions: Patients with onset in the lower limbs and the presence of festination, falls, and hallucinations may be prone to develop FOG episodes. FOG also likely occurs with the deterioration of PD severity and visuospatial function.

Spatial constraints evoke increased number of steps during turning in Parkinson's disease.

OBJECTIVE: Turning and limitations to step length were shown to trigger progressive shortening of steps, which can lead to freezing of gait. By reducing the base area in which the turn had to take place, we aimed to evaluate the contribution of spatial constraints on 360° axial turns in people with Parkinson's disease with and without freezing. METHODS: We evaluated 40 patients with and without freezing and 16 age-matched healthy subjects. We assessed clinical data, and used body-worn inertial sensors to describe stepping and turn duration of 360° in quadratic squares of different sizes marked on the floor. RESULTS: We found that, when subjects had to perform turns in smaller as compared to larger squares, this spatial constraint strongly affected the turning behavior, i.e. increased the number of steps, and the duration of turns. However, turning was significantly more impaired in patients as compared to controls, and patients with freezing were significantly worse as patients without freezing. CONCLUSION: Our data show that spatial constraint during axial turning has the potential to deteriorate stepping performance, especially in patients reporting freezing of gait. SIGNIFICANCE: The size of the base area needs to be defined in any item or scale that makes diagnostic use of turning.

Festination in Chinese patients with Parkinson's disease.

OBJECTIVE: To investigate the occurrence and clinical associations of festination in Chinese patients with Parkinson's disease (PD). METHODS: A total of 480 PD patients were recruited in this cross-sectional study. Assessments scales included the Unified PD Rating Scale (UPDRS) part III, PD Questionnaire-39 (PDQ-39), Non-Motor Symptoms Scale (NMSS), Mini-Mental State Examination (MMSE), frontal assessment battery (FAB), Montreal Cognitive Assessment (MoCA), Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA). RESULTS: One hundred and forty PD patients (29.2%) reported festination. Festination occurred more frequently in patients with lower limbs as the site of onset and patients with longer disease duration or higher Hoehn and Yahr (H&Y) stage (P<0.05). The mean age, levodopa and entacapone use, incidences of motor complications, falls and freezing of gait, and the scores for the UPDRS part III, NMSS, HAMD and HAMA were higher in patients with festination than those without festination (P<0.05). There were no differences in the scores for the PDQ-39, MMSE, FAB and MoCA between the patients with and without festination. The binary logistic regression model indicated that UPDRS part III, lower limbs as the site of onset, freezing of gait and falls were associated with festination. CONCLUSIONS: Festination is a relatively common disabling symptom in Chinese PD patients. Patients with lower limbs as the site of onset and more severe disability were more likely to experience festination. Festination in PD is not related to non-motor symptoms and cognitive dysfunction.

Automatic Evaluation of Speech Rhythm Instability and Acceleration in Dysarthrias Associated with Basal Ganglia Dysfunction.

Speech rhythm abnormalities are commonly present in patients with different neurodegenerative disorders. These alterations are hypothesized to be a consequence of disruption to the basal ganglia circuitry involving dysfunction of motor planning, programing, and execution, which can be detected by a syllable repetition paradigm. Therefore, the aim of the present study was to design a robust signal processing technique that allows the automatic detection of spectrally distinctive nuclei of syllable vocalizations and to determine speech features that represent rhythm instability (RI) and rhythm acceleration (RA). A further aim was to elucidate specific patterns of dysrhythmia across various neurodegenerative disorders that share disruption of basal ganglia function. Speech samples based on repetition of the syllable /pa/ at a self-determined steady pace were acquired from 109 subjects, including 22 with Parkinson's disease (PD), 11 progressive supranuclear palsy (PSP), 9 multiple system atrophy (MSA), 24 ephedrone-induced parkinsonism (EP), 20 Huntington's disease (HD), and 23 healthy controls. Subsequently, an algorithm for the automatic detection of syllables as well as features representing RI and RA were designed. The proposed detection algorithm was able to correctly identify syllables and remove erroneous detections due to excessive inspiration and non-speech sounds with a very high accuracy of 99.6%. Instability of vocal pace performance was observed in PSP, MSA, EP, and HD groups. Significantly increased pace acceleration was observed only in the PD group. Although not significant, a tendency for pace acceleration was observed also in the PSP and MSA groups. Our findings underline the crucial role of the basal ganglia in the execution and maintenance of automatic speech motor sequences. We envisage the current approach to become the first step toward the development of acoustic technologies allowing automated assessment of rhythm in dysarthrias.

Freezing of gait in Chinese patients with Parkinson disease.

A total of 474 Chinese Parkinson disease (PD) patients were evaluated to explore the prevalence and clinical correlates of freezing of gait (FOG) in this cross-sectional study. Two hundred and twenty-one PD patients (46.62%) reported FOG (freezers). FOG occurred more frequently in older patients and patients with low limbs as the site of onset, longer disease duration and higher Hoehn and Yahr (H&Y) stage (P<0.05). After adjusting for confounding factors, the freezers had higher scores for the Unified PD Rating Scale (UPDRS) part III, Non-Motor Symptoms Scale (NMSS), PD Questionnaire 39 (PDQ-39), Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA), and lower scores for the Mini-Mental status examination (MMSE), frontal assessment battery (FAB) and Montreal Cognitive Assessment (MoCA) compared with the non-freezers (P<0.05). The binary logistic regression analysis indicated that festination, falls, a high daily dose of levodopa, the use of a dopamine receptor agonist, a high H&Y stage, the severity of urinary symptoms and a high HAMD score were associated with FOG. FOG is a relatively common disabling symptom in Chinese PD patients. Patients that were older, or reported a longer disease duration, low limbs as the site of onset and a more severe disability were more likely to experience FOG. Non-motor symptoms, especially urinary symptoms and depression, may also be related to FOG.

Freezing beyond gait in Parkinson's disease: a review of current neurobehavioral evidence.

Besides the continuous motor impairments that characterize Parkinson's disease (PD), patients are frequently troubled by sudden paroxysmal arrests or brief episodes of movement breakdown, referred to as 'freezing'. Freezing of gait (FOG) is common in advanced PD and typically occurs in walking conditions that challenge dynamic motor-cognitive control. Mounting evidence suggests that episodic motor phenomena during repetitive upper limb (e.g. writing), lower limb (e.g. foot tapping) and speech sequences resemble FOG and may share some underlying neural mechanisms. However, the precise association between gait and non-gait freezing phenomena remains controversial. This review aimed to clarify this association based on literature on non-gait freezing published between 2000 and 2013. We focused on clinical and epidemiological features of the episodes and their relevance to current influential models of FOG, including recent neuroimaging studies that used a non-gait freezing paradigm as a proxy for FOG. Although not capturing the full complexity of FOG, the neurobehavioral insights obtained with non-gait freezing paradigms will contribute to an increased understanding of disturbed brain-behavior output in PD.