Spatiotemporal Gait Parameters in Adults With Premanifest and Manifest Huntington's Disease: A Systematic Review

OBJECTIVE

To systematically review and critically evaluate literature on spatiotemporal gait deviations in individuals with premanifest and manifest Huntington's Disease (HD) in comparison with healthy cohorts.

METHODS

We conducted a systematic review, guided by the Joanna Briggs Institute's Manual for Evidence Synthesis and pre-registered with the International Prospective Register of Systematic Reviews. Eight electronic databases were searched. Studies comparing spatiotemporal footstep parameters in adults with premanifest and manifest HD to healthy controls were screened, included and critically appraised by independent reviewers. Data on spatiotemporal gait changes and variability were extracted and synthesised. Meta-analysis was performed on gait speed, cadence, stride length and stride length variability measures.

RESULTS

We screened 2,721 studies, identified 1,245 studies and included 25 studies (total 1,088 participants). Sample sizes ranged from 14 to 96. Overall, the quality of the studies was assessed as good, but reporting of confounding factors was often unclear. Meta-analysis found spatiotemporal gait deviations in participants with HD compared to healthy controls, commencing in the premanifest stage. Individuals with premanifest HD walk significantly slower (-0.17 m/s; 95% confidence interval [CI] [-0.22, -0.13]), with reduced cadence (-6.63 steps/min; 95% CI [-10.62, -2.65]) and stride length (-0.09 m; 95% CI [-0.13, -0.05]). Stride length variability was also increased in premanifest cohorts by 2.18% (95% CI [0.69, 3.68]), with these changes exacerbated in participants with manifest disease.

CONCLUSION

Findings suggest individuals with premanifest and manifest HD display significant spatiotemporal footstep deviations. Clinicians could monitor individuals in the premanifest stage of disease for gait changes to identify the onset of Huntington's symptoms.

Predicting stroke, neurological and movement disorders using single and dual-task gait in Korean older population

BACKGROUND

Single and motor or cognitive dual-gait analysis is often used in clinical settings to evaluate older adults affected by neurological and movement disorders or with a stroke history. Gait features are frequently investigated using Machine Learning (ML) with significant results that can help clinicians in diagnosis and rehabilitation. The present study aims to classify patients with stroke, neurological and movement disorders using ML to analyze gait characteristics and to understand the importance of the single and dual-task features among Korean older adults.

METHODS

A cohort of 122 non-hospitalized Korean older adult participated in a single and a cognitive dual-task gait performance analysis. The extracted temporal and spatial features, together with clinical data, were used as input for the binary classification using tree-based ML algorithms. A repeated-stratified 10-fold cross-validation was performed to better evaluate multiple classification metrics with a final feature importance analysis.

RESULTS AND SIGNIFICANCE

The best accuracy - maximum >90 % - for gait and neurological disorders classification was obtained with Random Forest. In the stroke classification a 91.7 % of maximum accuracy was reached, with a significant recall of 92 %. The feature importance analysis showed a substantial balance between single and dual-task, while clinical data did not show elevated importance. The current findings indicate that a cognitive dual-task gait performance is highly recommendable together with a single-task in the analysis of older population, particularly for patients with a history of stroke. The results could be useful to medical professionals in treating and diagnosing motor and neurological disorders, and to improve rehabilitation strategies for stroke patients. Furthermore, the results confirm the proficiency of the tree-based ML algorithms in biomedical data analysis. Finally, in the future, this research could be replicated with a non-Asian population dataset to deepen the understanding of gait differences between Asian-Korean population and other ethnicities.

Neurophysiology of cerebellar ataxias and gait disorders

There are numerous forms of cerebellar disorders from sporadic to genetic diseases. The aim of this chapter is to provide an overview of the advances and emerging techniques during these last 2 decades in the neurophysiological tests useful in cerebellar patients for clinical and research purposes. Clinically, patients exhibit various combinations of a vestibulocerebellar syndrome, a cerebellar cognitive affective syndrome and a cerebellar motor syndrome which will be discussed throughout this chapter. Cerebellar patients show abnormal Bereitschaftpotentials (BPs) and mismatch negativity. Cerebellar EEG is now being applied in cerebellar disorders to unravel impaired electrophysiological patterns associated within disorders of the cerebellar cortex. Eyeblink conditioning is significantly impaired in cerebellar disorders: the ability to acquire conditioned eyeblink responses is reduced in hereditary ataxias, in cerebellar stroke and after tumor surgery of the cerebellum. Furthermore, impaired eyeblink conditioning is an early marker of cerebellar degenerative disease. General rules of motor control suggest that optimal strategies are needed to execute voluntary movements in the complex environment of daily life. A high degree of adaptability is required for learning procedures underlying motor control as sensorimotor adaptation is essential to perform accurate goal-directed movements. Cerebellar patients show impairments during online visuomotor adaptation tasks. Cerebellum-motor cortex inhibition (CBI) is a neurophysiological biomarker showing an inverse association between cerebellothalamocortical tract integrity and ataxia severity. Ataxic gait is characterized by increased step width, reduced ankle joint range of motion, increased gait variability, lack of intra-limb inter-joint and inter-segmental coordination, impaired foot ground placement and loss of trunk control. Taken together, these techniques provide a neurophysiological framework for a better appraisal of cerebellar disorders.

Differences in fall-related characteristics across cognitive disorders

Approximately 40-60% of falls in the elderly lead to injuries, resulting in disability and loss of independence. Despite the higher prevalence of falls and morbidity rates in cognitively impaired individuals, most fall risk assessments fail to account for mental status. In addition, successful fall prevention programmes in cognitively normal adults have generally failed in patients with cognitive impairment. Identifying the role of pathological aging on fall characteristics can improve the sensitivity and specificity of fall prevention approaches. This literature review provides a thorough investigation into fall prevalence and fall risk factors, the accuracy of fall risk assessments, and the efficacy of fall prevention strategies in individuals with diverse cognitive profiles. We show that fall-related characteristics differ between cognitive disorders and fall risk assessment tools as well as fall prevention strategies should critically consider each patient's cognitive status to facilitate the identification of fallers at an earlier stage and support clinical decision-making.

Comorbidities and clinical outcomes in adult- and juvenile-onset Huntington's disease: a study of linked Swedish National Registries (2002-2019)

BACKGROUND

Huntington's disease (HD) is a rare, neurodegenerative disease and its complex motor, cognitive and psychiatric symptoms exert a lifelong clinical burden on both patients and their families.

OBJECTIVE

To describe the clinical burden and natural history of HD.

METHODS

This longitudinal cohort study used data from the linked Swedish national registries to describe the occurrence of comorbidities (acute and chronic), symptomatic treatments and mortality in an incident cohort of individuals who either received the first diagnosis of HD above (adult onset HD; AoHD) or below (juvenile-onset HD; JoHD) 20 years of age, compared with a matched cohort without HD from the general population. Disease burden of all individuals alive in Sweden was described during a single calendar year (2018), including the occurrence of key symptoms, treatments and hospitalizations.

RESULTS

The prevalence of HD in 2018 was approximately 10.2 per 100,000. Of 1492 individuals with a diagnosis of HD during 2002 and 2018, 1447 had AoHD and 45 had JoHD. Individuals with AoHD suffered a higher incidence of obsessive-compulsive disorder, acute psychotic episodes, pneumonia, constipation and fractures compared with matched controls. Individuals with JoHD had higher incidence rates of epilepsy, constipation and acute respiratory symptoms. Median time to all-cause mortality in AoHD was 12.1 years from diagnosis. Patients alive with HD in Sweden in 2018 displayed a pattern of increased clinical burden for a number of years since diagnosis.

CONCLUSIONS

This study demonstrates the significant and progressive clinical burden in individuals with HD and presents novel insights into the natural history of JoHD.

Accidental Falls in Patients with Hyperkinetic Movement Disorders: A Systematic Review

Background:

The significance of falls and their repercussions in Parkinson’s disease has been extensively researched. However, despite potentially serious effects on health and quality of life and negative impact on the healthcare system, there is not a sufficient understanding of the role of falls in hyperkinetic movement disorders (HKMDs). This review aims to provide an overview of the prevalence of falls, injuries, and preventive measures in the most common HKMDs.

Methods:

Studies up to May 1, 2022 were searched in PubMed using Medical Subjects Headings of relatively prevalent HKMDs associated with the terms “accidental falls”, “injuries”, “fractures”, and “accident prevention”.

Results:

In our review of 37 studies out of 155, we found evidence that for several HKMDs, such as spinocerebellar ataxia, essential tremor, Huntington’s disease, and dystonia, fall risk is increased. Falls were reported in up to 84% of spinocerebellar ataxia patients, 59% of essential tremor patients, and 79% of Huntington’s patients, with 65% of the latter falling frequently. Injuries occurred in up to 73% in Huntington and 74% in ataxia patients. Most of the common diseases characterized by HKMDs were investigated for both fall causes and consequences, but prevention studies were limited to spinocerebellar ataxia and Huntington’s disease.

Discussion:

The limited available data suggest that patients with several HKMDs can be considered to be at increased risk of falling and that the consequences can be serious. As a result, physicians should be advised to include fall exploration in their routine workup and provide advice for safer mobility. In general, more research into fall-related concerns in HKMDs is necessary.

Highlights:

In contrast to Parkinson’s disease, the prevalence of accidental falls, their repercussions, and preventive strategies are under-investigated in hyperkinetic movement disorders (HKMDs). Several HKMDs such as essential tremor, ataxia, and Huntington’s disease have reported fall rates of up to 84% and fall-related injury rates of up to 74%. Therefore, routine examinations of HKMD patients should include a fall exploration and provide advice on safe mobility.

Increased temporal stride variability contributes to impaired gait coordination after stroke

Heightened motor variability is a prominent impairment after stroke. During walking, stroke survivors show increased spatial and temporal variability; however, the functional implications of increased gait variability are not well understood. Here, we determine the effect of gait variability on the coordination between lower limbs during overground walking in stroke survivors. Ambulatory stroke survivors and controls walked at a preferred pace. We measured stride length and stride time variability, and accuracy and consistency of anti-phase gait coordination with phase coordination index (PCI). Stroke survivors showed increased stride length variability, stride time variability, and PCI compared with controls. Stride time variability but not stride length variability predicted 43% of the variance in PCI in the stroke group. Stride time variability emerged as a significant predictor of error and consistency of phase. Despite impaired spatial and temporal gait variability following stroke, increased temporal variability contributes to disrupted accuracy and consistency of gait coordination. We provide novel evidence that decline in gait coordination after stroke is associated with exacerbated stride time variability, but not stride length variability. Temporal gait variability may be a robust indicator of the decline in locomotor function and an ideal target for motor interventions that promote stable walking after stroke.

Postural control and gait measures derived from wearable inertial measurement unit devices in Huntington's disease: Recommendations for clinical outcomes

BACKGROUND

Postural control impairments begin early in Huntington's disease yet measures most sensitive to progression have not been identified. The aims of this study were to: 1) evaluate postural control and gait in people with and without Huntington's disease using wearable sensors; and 2) identify measures related to diagnosis and clinical severity.

METHODS

43 individuals with Huntington's disease and 15 age-matched peers performed standing with feet together and feet apart, sitting, and walking with wearable inertial sensors. One-way analysis of variance determined differences in measures of postural control and gait between early and mid-disease stage, and non-Huntington's disease peers. A random forest analysis identified feature importance for Huntington's disease diagnosis. Stepwise and ordinal regressions were used to determine predictors of clinical chorea and tandem walking scores respectively.

FINDINGS

There was a significant main effect for all postural control and gait measures comparing early stage, mid stage and non-Huntington's disease peers, except for gait cycle duration and step duration. Total sway, root mean square and mean velocity during sitting, as well as gait speed had the greatest importance in classifying disease status. Stepwise regression showed that root mean square during standing with feet apart significantly predicted clinical measure of chorea, and ordinal regression model showed that root mean square and total sway standing feet together significantly predicted clinical measure of tandem walking.

INTERPRETATIONS

Root mean square measures obtained in sitting and standing using wearable sensors have the potential to serve as biomarkers of postural control impairments in Huntington's disease.

Use of Objective Outcomes Measures to Verify the Effects of ICF-Based Gait Treatment in Huntington's Disease Patient on Globus Pallidus Deep Brain Stimulation: A Case Report

In advanced stages of in Huntington's disease (HD) gait impairments and severe chorea are usually medication-refractory. The long-term effects on gait in HD of physiotherapy ICF-based management post- globus pallidus deep brain stimulation (GPi DBS) are not well-established. Physiotherapy has been recognized as an essential element in HD treatment. Here, we present a case report of a 56-year-old woman with HD on the advanced stage and severe chorea medication-refractory after GPi-DBS. We performed multidisciplinary motor assessments ICF-based to identify the disability at clinical and home-setting, including environmental and personal factors before and after GPi-DBS surgery and at 11-time points follow-up. The surgery was very successful and directly post GPi-DBS, there were a significant improvement in chorea and a substantial decrease in medication dose. A framework ICF- based physiotherapy protocol with external cues was developed to improve gait was delivered post-surgery and was continued three times/week during 18-months. Physiotherapy sessions consisted of a personalized protocol of exercises with functional movements, balance, and gait training with external cues. Improvements in gait were observed in 3-months post-intervention and were more expressive in 6-months follow-up. Our patient improved substantially HD motor symptoms and her quality of life after GPi-DBS intervention and a physiotherapy program ICF-based. The objective outcomes measures used to assess gait have served as endpoints to assessing the patient's motor profile during the pre-operative period. Assessments were helpful to verify the efficacy of the multidisciplinary intervention in long-term.

Conclusion

Periodically assessing function and disability using outcome improvements may support clinicians' decisions about DBS, medication adjustments and guide physiotherapists to personalize the ICF-based intervention.

Neurodegenerative diseases categorization by applying the automatic model selection and hyperparameter optimization method

Neurodegenerative diseases affect a large part of the population in the world and also in Mexico, deteriorating gradually the quality of patients’ life. Therefore, it is important to diagnose them with a high degree of reliability. In order to solve it, various computational methods have been applied in the analysis of biomarkers of human gait. In this study, we propose employing the automatic model selection and hyperparameter optimization method that has not been addressed before for this problem. Our results showed highly competitive percentages of correctly classified instances when discriminating binary and multiclass sets of neurodegenerative diseases: Parkinson’s disease, Huntington’s disease, and Spinocerebellar ataxias.

Measuring Movement in Health and Disease

Evaluating and quantifying the many aspects of movement -- from open-field locomotion and stepping patterns in rodent models to stride trajectory and postural sway in human patients -- are key to understanding brain function. Various experimental approaches have been used in applying these lines of research to investigate the brain mechanisms underlying neurodegenerative disease. Although valuable, data on movement are often limited by the shortcomings inherent in the data collection process itself. Steve Fowler and his research group have been instrumental in pioneering a technology that both minimizes these pitfalls in studies of rodent behavior and has applications to research on human patients. At the center of this technology is the force-plate actometer, developed by the Fowler group to assess multiple aspects of movement in rodent models. Our review highlights how use of the actometer and related behavioral measurements provides valuable insight into Huntington's disease (HD), an autosomal dominant condition of progressively deteriorating behavioral control. HD typically emerges in mid-life and has been replicated in multiple genetically engineered mouse models. The actometer also can be a valuable addition to cutting-edge neuronal and synaptic technologies that are now increasingly applied to studies of behaving animals. In short, the impact of the Fowler contribution to the neuroscience of movement is both meaningful and ongoing.

Dysphagia, Fear of Choking and Preventive Measures in Patients with Huntington's Disease: The Perspectives of Patients and Caregivers in Long-Term Care

OBJECTIVES

To explore the prevalence of dysphagia and fear of choking in patients with Huntington's disease (HD) as well as preventive measures, both those applied and those not included in managing dysphagia. Also, to investigate related problems encountered by their formal and informal caregivers.

DESIGN

A multi-center observational cross-sectional study.

SETTING AND PARTICIPANTS

158 HD patients, recruited from six Dutch nursing homes specialized in HD, and their formal and informal caregivers.

MEASUREMENTS

Patients were assessed by means of questionnaires enquiring about dysphagia, fear of choking and measures to manage dysphagia. Also, questionnaires were administered about awareness of dysphagia symptoms, cognition and anxiety. Because we expected individuals with greater care dependency to have a higher severity of dysphagia, we distinguished between a care-independent and a care-dependent group of HD patients.

RESULTS

In the total group, 90.5% of HD patients had one or more dysphagia symptoms. The prevalence of FoC in HD patients and the formal and informal caregivers' fears about choking in HD patients was 45.7%, 19.0% and 59.5%, respectively, for care-independent patients and 58.7%, 50.1% and 77.5% for care-dependent patients. The score on the Huntington's Disease Dysphagia Scale was a predictor for fear of FoC in care-independent patients. Speech-language therapy, supervision during eating and drinking and adaptation of food and drink consistency were the most frequently applied measures to manage dysphagia, a combination was used in most HD patients.

CONCLUSIONS

In HD patients, the prevalence of dysphagia is high and fear of choking is common among both patients and caregivers. A more severe degree of dysphagia is a predictor of FoC in care-independent HD patients. A combination of measures was used to manage dysphagia in most HD patients.

Falls, Fear of Falling, and Preventive Measures in Huntington's Disease: The Perspectives of Individuals with Huntington's Disease and Caregivers in Long-Term Care

BACKGROUND

Falls are common in Huntington's disease (HD), which can have serious consequences and may therefore lead to fear of falling (FoF). There is little knowledge about falls or FoF in individuals with HD or about formal and informal caregivers' fear about falls in individuals with HD.

OBJECTIVE

To explore prevalence of falls, FoF and fall preventive measures both those applied and those not included in managing falls in individuals with HD and their formal and informal caregivers, and to identify the relationship between FoF and, anxiety, awareness and cognitive functioning respectively.

METHODS

In a multi-center observational cross-sectional study, care-independent and -dependent individuals with HD and their formal and informal caregivers were recruited from six Dutch nursing homes specialized in HD. The participants were assessed by means of questionnaires enquiring about falls, FoF, awareness of fall risk, cognition, anxiety and fall preventive measures.

RESULTS

For all included 158 individuals with HD, the fall prevalence over the last 30 days was 28.8%. The prevalence of FoF in individuals with HD, formal caregivers and informal caregivers was 47.6%, 25.6%, and 63.5%, respectively, for care-independent individuals with HD and 46.9%, 26.3%, and 62.0%, respectively, for care-dependent individuals with HD. Anticipatory awareness of fall risks and gender are predictors of FoF in care-independent individuals with HD, though not in the care-dependent group. A combination of fall preventive measures is used in most individuals with HD.

CONCLUSION

Fall prevalence is high and FoF is common in individuals with HD and their caregivers. Gender and anticipatory awareness are risk factors for FoF. In addition to the use of individual multifactorial fall prevention strategies, it is important to support both formal and informal caregivers in coping with falls.

Huntington's Disease in Israel: A Population-Based Study Using 20 Years of Routinely-Collected Healthcare Data

BACKGROUND

Huntington's disease (HD) is a rare, genetic, neurodegenerative disease. Obtaining population-level data on epidemiology and disease management is challenging.

OBJECTIVE

To investigate the epidemiology, clinical manifestations, treatment, and healthcare utilization of patients with HD in Israel.

METHODS

Retrospective population-based cohort study, including 20 years of routinely collected data from Maccabi Healthcare Services, an insurer and healthcare provider for one-quarter of the Israeli population.

RESULTS

The study cohort included 109 adult patients (aged ≥18 years) diagnosed with HD, with mean age of 49.9 years and 56%females. The most common HD-related conditions were anxiety (40%), behavioral problems (34%), sleep disorders (21%), and falls (13%). Annual incidence rates for HD ranged from 0.17 to 1.34 per 100,000 from 2000 to 2018; the 2018 crude prevalence in adults was 4.36 per 100,000. Median survival from diagnosis was approximately 12 years (95%CI: 10.4-15.3). The most frequent symptomatic treatments were antidepressants (69%), antipsychotics (63%), and tetrabenazine (63%), the only drug approved for the treatment of HD chorea in Israel during the examined period. Patterns of healthcare utilization changed as disease duration increased, reflected by increased frequency of emergency department visits and home visits.

CONCLUSION

This retrospective population-based study provides insights into the prevalence, incidence, clinical profile, survival, and resource utilization of patients with HD in ethnically diverse Israel. The findings in this study are generally consistent with the international literature and demonstrate the value of routinely collected healthcare data as a complementary resource in HD research.

Approach to Posture and Gait in Huntington's Disease

Disturbances of gait occur in all stages of Huntington’s disease (HD) including the premanifest and prodromal stages. Individuals with HD demonstrate the slower speed of gait, shorter stride length, and increased variability of gait parameters as compared to controls; cognitive disturbances in HD often compound these differences. Abnormalities of gait and recurrent falls lead to decreased quality of life for individuals with HD throughout the disease. This scoping review aims to outline the cross-disciplinary approach to gait evaluation in HD and will highlight the utility of objective measures in defining gait abnormalities in this patient population.

Force-Control vs. Strength Training: The Effect on Gait Variability in Stroke Survivors

Purpose: Increased gait variability in stroke survivors indicates poor dynamic balance and poses a heightened risk of falling. Two primary motor impairments linked with impaired gait are declines in movement precision and strength. The purpose of the study is to determine whether force-control training or strength training is more effective in reducing gait variability in chronic stroke survivors.

Methods: Twenty-two chronic stroke survivors were randomized to force-control training or strength training. Participants completed four training sessions over 2 weeks with increasing intensity. The force-control group practiced increasing and decreasing ankle forces while tracking a sinusoid. The strength group practiced fast ankle motor contractions at a percentage of their maximal force. Both forms of training involved unilateral, isometric contraction of the paretic, and non-paretic ankles in plantarflexion and dorsiflexion. Before and after the training, we assessed gait variability as stride length and stride time variability, and gait speed. To determine the task-specific effects of training, we measured strength, accuracy, and steadiness of ankle movements.

Results: Stride length variability and stride time variability reduced significantly after force-control training, but not after strength training. Both groups showed modest improvements in gait speed. We found task-specific effects with strength training improving plantarflexion and dorsiflexion strength and force control training improving motor accuracy and steadiness.

Conclusion: Force-control training is superior to strength training in reducing gait variability in chronic stroke survivors. Improving ankle force control may be a promising approach to rehabilitate gait variability and improve safe mobility post-stroke.

Impact of Chorea on Self-care Activity, Employment, and Health-care Resource Use in Patients with Huntington's Disease

Background: Chorea is recognized as a prototypic motor feature of Huntington's disease (HD), but its effect on health-related quality of life (HRQoL) has not been fully explored. This study describes the impact of chorea on HRQoL in patients with HD. Objective: To determine the impact of HD-related chorea on employment, self-care activities, activities of daily living, and health-care resource utilization (HCRU). Methods: Data were drawn from the Adelphi HD Disease Specific Programme, a real-world point-in-time survey of 144 neurologists and 427 patients in the United States between July and October 2017. HD patients with and without chorea were identified and examined for differences in employment status, reasons for employment changes, self-care activities, and modifications to cope with involuntary movements. Bivariate tests and inverse probability weighted regression adjustment methods were used to determine differences in outcomes between patients with and without chorea. Results: HD patients with (n=287) and without (n=140) chorea were identified. Patients with chorea were less likely to be employed full-time (16.7% vs 25.7%; P<0.04) and more likely to be on long-term sick leave (17.4% vs 5.0%; P<0.01). The onset of motor symptoms in HD-related chorea patients coincided with a change in employment status (42.7% vs 20.8%; P<0.01). Among those still working (n=145), more than two-fifths of patients with chorea required changes to their workplace and required these changes more frequently (45% vs 17%; P<0.001). HD patients with chorea required aid to help them get around significantly more frequently than those without chorea (55% vs 34%; P<0.001). Discussion: These results demonstrate that HD patients with chorea experienced greater negative impact to employment, self-care activities, and HCRU than patients without chorea experienced. These patients were more likely to stop working due to motor, cognitive, and behavioral symptoms; require modifications in the home and workplace; and need more assistance from caregivers than patients without chorea. Conclusions: Patients with HD-related chorea have greater detriments to emotional, interpersonal, and professional functioning that could be improved by reducing chorea.

Integrated analysis on transcriptome and behaviors defines HTT repeat-dependent network modules in Huntington's disease

Huntington's disease (HD) is caused by a CAG repeat expansion in the huntingtin (HTT) gene. Knock-in mice carrying a CAG repeat-expanded Htt will develop HD phenotypes. Previous studies suggested dysregulated molecular networks in a CAG length genotype- and the age-dependent manner in brain tissues from knock-in mice carrying expanded Htt CAG repeats. Furthermore, a large-scale phenome analysis defined a behavioral signature for HD genotype in knock-in mice carrying expanded Htt CAG repeats. However, an integrated analysis correlating phenotype features with genotypes (CAG repeat expansions) was not conducted previously. In this study, we revealed the landscape of the behavioral features and gene expression correlations based on 445 mRNA samples and 445 microRNA samples, together with behavioral features (396 PhenoCube behaviors and 111 NeuroCube behaviors) in Htt CAG-knock-in mice. We identified 37 behavioral features that were significantly associated with CAG repeat length including the number of steps and hind limb stand duration. The behavioral features were associated with several gene coexpression groups involved in neuronal dysfunctions, which were also supported by the single-cell RNA sequencing data in the striatum and the spatial gene expression in the brain. We also identified 15 chemicals with significant responses for genes with enriched behavioral features, most of them are agonist or antagonist for dopamine receptors and serotonin receptors used for neurology/psychiatry. Our study provides further evidence that abnormal neuronal signal transduction in the striatum plays an important role in causing HD-related phenotypic behaviors and provided rich information for the further pharmacotherapeutic intervention possibility for HD.

Imaging and Clinical Data on Swallowing Function of Individuals with Huntington's Disease and Dysphagia

BACKGROUND

Dysphagia is common in Huntington's disease (HD) affecting all phases of swallowing. Correlations exist between non-instrumental measures of dysphagia and clinical features of HD, including age, disease duration and degree of motor impairment. Lack of instrumental data limits our ability to wholly characterize HD-related dysphagia and prognosticate swallowing changes over time.

OBJECTIVE

To retrospectively describe a relatively large database of videofluoroscopic studies (VFSSs) and determine the relationships between dysphagia and HD clinical parameters, including disease duration and burden of pathology score.

METHODS

Medical and swallowing data of 49 individuals with HD and dysphagia were examined. VFSS data were interpreted using the Bethlehem Assessment Scale and Penetration-Aspiration Scale. Data from clinical bedside examination and social information were collated to describe the impact of dysphagia in HD. Repeated VFSS data were available for seven individuals.

RESULTS

Swallowing was characterized by lingual dysfunction, reduced soft palate elevation, delayed pharyngeal swallow initiation, and inability to clear matter from the pharynx. Two-thirds of cases presented with compromised airway protection with both liquid and solid consistencies. Tachyphagia and difficulty self-feeding were common. Dysphagia correlated with disease severity and duration. Longitudinal analysis revealed a mixed pattern of progression with some individuals presenting with worsening dysphagia whilst others appeared to remain stable or improved in function.

CONCLUSIONS

Dysphagia in HD is exacerbated by difficulties with self-feeding and monitoring feeding rate. Burden of pathology relates to pharyngeal swallow initiation and penetration and aspiration of fluid. Dysphagia did not appear to worsen in a systematic way in a subset of participants.

The use of wearable/portable digital sensors in Huntington's disease: A systematic review

In chronic neurological conditions, wearable/portable devices have potential as innovative tools to detect subtle early disease manifestations and disease fluctuations for the purpose of clinical diagnosis, care and therapeutic development. Huntington's disease (HD) has a unique combination of motor and non-motor features which, combined with recent and anticipated therapeutic progress, gives great potential for such devices to prove useful. The present work aims to provide a comprehensive account of the use of wearable/portable devices in HD and of what they have contributed so far. We conducted a systematic review searching MEDLINE, Embase, and IEEE Xplore. Thirty references were identified. Our results revealed large variability in the types of sensors used, study design, and the measured outcomes. Digital technologies show considerable promise for therapeutic research and clinical management of HD. However, more studies with standardized devices and harmonized protocols are needed to optimize the potential applicability of wearable/portable devices in HD.

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Wearable/portable sensors have been proposed to detect and quantify manifestations of many neurodegenerative diseases.

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No systematic review so far has examined their use in Huntington's disease (HD).

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This work draws a broad picture of the digital wearable-based landscape in HD.

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The utility of wearables in clinical practice and therapeutic research still needs to be proved.

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Collaborative efforts are needed to further investigate their clinical use in HD.

Neural modeling of antisaccade performance of healthy controls and early Huntington's disease patients

Huntington's disease (HD), a genetically determined neurodegenerative disease, is positively correlated with eye movement abnormalities in decision making. The antisaccade conflict paradigm has been widely used to study response inhibition in eye movements, and reliable performance deficits in HD subjects have been observed, including a greater number and timing of direction errors. We recorded the error rates and response latencies of early HD patients and healthy age-matched controls performing the mirror antisaccade task. HD participants displayed slower and more variable antisaccade latencies and increased error rates relative to healthy controls. A competitive accumulator-to-threshold neural model was then employed to quantitatively simulate the controls' and patients' reaction latencies and error rates and uncover the mechanisms giving rise to the observed HD antisaccade deficits. Our simulations showed that (1) a more gradual and noisy rate of accumulation of evidence by HD patients is responsible for the observed prolonged and more variable antisaccade latencies in early HD; (2) the confidence level of early HD patients making a decision is unaffected by the disease; and (3) the antisaccade performance of healthy controls and early HD patients is the end product of a neural lateral competition (inhibition) between a correct and an erroneous decision process, and not the end product of a third top-down stop signal suppressing the erroneous decision process as many have speculated.

Rapid and robust patterns of spontaneous locomotor deficits in mouse models of Huntington's disease

Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by severe disruption of cognitive and motor functions, including changes in posture and gait. A number of HD mouse models have been engineered that display behavioral and neuropathological features of the disease, but gait alterations in these models are poorly characterized. Sensitive high-throughput tests of fine motor function and gait in mice might be informative in evaluating disease-modifying interventions. Here, we describe a hypothesis-free workflow that determines progressively changing locomotor patterns across 79 parameters in the R6/2 and Q175 mouse models of HD. R6/2 mice (120 CAG repeats) showed motor disturbances as early as at 4 weeks of age. Similar disturbances were observed in homozygous and heterozygous Q175 KI mice at 3 and 6 months of age, respectively. Interestingly, only the R6/2 mice developed forelimb ataxia. The principal components of the behavioral phenotypes produced two phenotypic scores of progressive postural instability based on kinematic parameters and trajectory waveform data, which were shared by both HD models. This approach adds to the available HD mouse model research toolbox and has a potential to facilitate the development of therapeutics for HD and other debilitating movement disorders with high unmet medical need.

Vitamin D and Hyperkinetic Movement Disorders: A Systematic Review

Background

The importance of vitamin D deficiency in Parkinson's disease, its negative influence on bone health, and even disease pathogenesis has been studied intensively. However, despite its possible severe impact on health and quality of life, there is not a sufficient understanding of its role in other movement disorders. This systematic review aims at providing an overview of the prevalence of vitamin D deficiency, bone metabolism alterations, and fractures in each of the most common hyperkinetic movement disorders (HKMDs).

Methods

The study search was conducted through PubMed with keywords or Medical Related Subjects (MeSH) of common HKMDs linked with the terms of vitamin D, osteoporosis, injuries, and fractures.

Results

Out of 1585 studies screened 40 were included in our review. They show that there is evidence that several HKMDs, including Huntington disease, Restless Legs Syndrome, and tremor, are associated with low vitamin D serum levels in up to 83% and 89% of patients. Reduced bone mineral density associated with vitamin D insufficiency was described in Huntington disease.

Discussion

Our survey suggests that vitamin D deficiency, bone structure changes, and fractures are important but yet under-investigated issues in HKMDs. HKMDs-patients, particularly with a history of previous falls, should have their vitamin D-levels tested and supplemented where appropriate.

Highlights

Contrary to Parkinson's disease, vitamin D deficiency, and bone abnormalities are under-investigated in hyperkinetic movement disorders (HKMDs). Several HKMDs, including essential tremor, RLS, and Huntington disease, are associated with vitamin D deficiency in up to 89%, the latter also with reduced bone mineral density. Testing and where appropriate supplementation is recommended.

Impaired Isometric Force Matching in Upper and Lower Limbs Revealed by Quantitative Motor Assessments in Huntington's Disease

BACKGROUND

Assessment of motor symptoms in Huntington's disease (HD) is based on the Unified-HD-Rating-Scale-Total-Motor-Score (UHDRS-TMS). Its categorical and rater-dependent nature reduces the ability to detect subtle changes and often placebo effects have been observed in trials. We have previously shown that impairments in isometric force matching can be detected by quantitative motor (Q-Motor) assessments of tongue protrusion forces (glossomotography) in HD.

OBJECTIVE

We aimed to investigate whether similar impairments in isometric force matching can be detected in tasks assessing hand and foot force coordination and whether correlations with clinical measures and the disease burden score can be found.

METHODS

Using a pre-calibrated force transducer, the ability of subjects to generate and maintain isometric forces at different target levels displayed on a monitor was assessed. Target forces applied in the hand were 1.5 and 5 Newton [N] and in feet 1, 5, and 10 N. Subjects with HD (n = 31) and age-matched controls (n = 22) were recruited from the HD out-patient clinic.

RESULTS

All paradigms distinguished controls from HD. The static coefficient of variability (%) was the most robust measure across all matching tasks. Correlations with clinical measures, such as the UHDRS-TMS, TFC, and the DBS were found.

CONCLUSIONS

Assessment of hand and foot force matching tasks was feasible and provided quantitative objective measures for severity of motor phenotype in HD. Since both upper and lower extremity motor function are relevant for everyday activities, these measures should be further assessed as candidates for developing functionally meaningful quantitative motor tasks.

Quantifying Postural Control in Premanifest and Manifest Huntington Disease Using Wearable Sensors

Background. Impairments in postural control in Huntington disease (HD) have important consequences for daily functioning. This observational study systematically examined baseline postural control and the effect of sensory attenuation and sensory enhancement on postural control across the spectrum of HD. Methods. Participants (n = 39) included healthy controls and individuals in premanifest (pHD) and manifest stages (mHD) of HD. Using wearable sensors, postural control was assessed according to (1) postural set (sit vs stand), (2) sensory attenuation using clinical test of sensory integration, and (3) sensory enhancement with gaze fixation. Outcomes included sway smoothness, amplitude, and frequency. Results. Based on postural set, pHD reduced postural sway in sitting relative to standing, whereas mHD had pronounced sway in standing and sitting, highlighting a baseline postural deficit. During sensory attenuation, postural control in pHD deteriorated relative to controls when proprioceptive demands were high (eyes closed on foam), whereas mHD had significant deterioration of postural control when proprioception was attenuated (eyes open and closed on foam). Finally, gaze fixation improved sway smoothness, amplitude, and frequency in pHD; however, no benefit was observed in mHD. Conclusions. Systematic examination of postural control revealed a fundamental postural deficit in mHD, which further deteriorates when proprioception is challenged. Meanwhile, postural deficits in pHD are detectable when proprioceptive challenge is high. Sensory enhancing strategies using gaze fixation to benefit posture may be useful when introduced well before motor diagnosis. These findings encourage further examination of wearable sensors as part of routine clinical assessments in HD.

The effects of multidisciplinary rehabilitation on neuroimaging, biological, cognitive and motor outcomes in individuals with premanifest Huntington's disease

BACKGROUND

Huntington's disease (HD) is a chronic, progressive neurodegenerative condition for which there are currently no proven disease-modifying therapies. Lifestyle factors have been shown to impact on the age of disease onset and progression of disease features. We therefore investigated the effects of a nine-month multidisciplinary rehabilitation intervention on neuroimaging, biological and clinical disease outcomes in individuals with premanifest HD.

METHODS

31 individuals with premanifest HD participated in the study. Eighteen participants underwent a nine-month multidisciplinary rehabilitation intervention comprising aerobic and resistance exercise, computerised cognitive training, dual-task training and sleep hygiene and nutritional guidance. The remaining 13 participants were allocated to a standard care control group. Neuroimaging, biological, cognitive, motor and cardiorespiratory fitness data was collected.

RESULTS

Participants displayed good adherence (87%) and compliance (85%) to the intervention. Maintenance of the shape of the right putamen was observed in the intervention group when compared to the control group. The intervention group displayed significant improvements in verbal learning and memory, attention, cognitive flexibility and processing speed following the intervention when compared to the control group. Performance on the mini-social cognition and emotional assessment (mini-SEA) was maintained in the intervention group, but decreased in the control group. No changes were observed in serum neurofilament light protein levels, postural stability outcomes or cardiorespiratory fitness.

CONCLUSION

This study adds to the accumulating body of literature to suggest that multidisciplinary rehabilitation is of clinical benefit for individuals with HD. Large randomised controlled trials are necessary to determine the extent to which benefits occur across the spectrum of the disease.

Biological Motion Perception in Huntington's Disease

BACKGROUND

The ability of healthy individuals to detect biological motion by using a small number of moving points is well established in animals and humans. Perception of human movements may depend on internal models that drive self-generated movements and influence motion discrimination (Reed CL et al. 1995 and 2007). As a person's motor repertoire deteriorates, the accuracy of these models may also decrease.

OBJECTIVE

Determine if people with symptomatic Huntington's disease (HD) have difficulty perceiving movements.

METHODS

In this study point-light displays were created with a Vicon Motion Capture System by recording one individual with (impaired) and one individual without (healthy) Parkinson's disease using a 13 joint marker set. Participants were asked to distinguish between three movements and determine if the movement was impaired or healthy. The ability of participants with and without HD to distinguish movement patterns and the time to perception were recorded.

RESULTS

Analyses found participants with HD had a decreased ability to correctly detect movements and point-light image type. The stair climbing motion showed the largest effect as participants with HD had more difficulty correctly identifying both the movement and whether it was impaired or healthy. In addition, the participants without HD showed an improvement as trials progressed which could not be observed in the HD cohort.

CONCLUSIONS

As people with symptomatic HD have difficulty perceiving movements further investigations using point-light displays should be done to determine if these impairments might serve as an easily administered, non-invasive marker of disease state.

Heart rate variability and falls in Huntington's disease

PURPOSE

Persons with Huntington's disease (HD) have a high incidence of falls. Autonomic nervous system dysfunction has been reported even in early stages of this disease. To date, there has been no analysis of the relationship between heart rate variability (HRV) and falls in this patient population. The aim of the study reported here was to evaluate the relationship between HRV and falls in persons with HD.

METHODS

Huntington's disease patients enrolled in a prospective study on fear of falling and falls were assessed using short-term HRV analyses and blood pressure measures in both the resting and standing states. Time-frequency domains and nonlinear parameters were calculated. Data on falls, the risk of falling (RoF) and disease-specific scales were collected at baseline and at the end of the 6-month follow-up.

RESULTS

Of the 24 HD patients who were invited to participate in the study, 20 completed the baseline analysis and 18 completed the 6-month follow-up. At baseline, seven (35%) HD patients reported at least one fall (single fallers) and 13 (65%) reported ≥ 2 falls (recurrent fallers) in the previous 12 months. At baseline, recurrent fallers had lower RMSSD (root mean square of successive RR interval differences) in the resting state (RMSSD-resting), higher LF/HF (low/high frequency) ratio in both states and higher DFA-α1 parameter (detrended fluctuation analyses over the short term) in both states. This association was similar at the 6-month follow-up for recurrent fallers, who showed lower RMSSD-resting and higher LF/HF ratio in the standing state (LF/HF-standing) than single fallers. Significant correlations were found between the number of falls, RMSSD-resting and LF/HF-standing. No differences were found between recurrent and single fallers for any blood pressure measures.

CONCLUSIONS

The observed HRV pattern is consistent with a higher sympathetic prevalence associated with a higher RoF. Reduced parasympathetic HRV values in this patient population predict being a recurrent faller at 6 months of follow-up, independently of orthostatic phenomena.

The effects of dual-task cognitive interference on gait and turning in Huntington's disease

Huntington’s disease (HD) is characterized by motor, cognitive, and psychiatric dysfunction. HD progression causes loss of automaticity, such that previously automatic tasks require greater attentional resources. Dual-task (DT) paradigms and fast-paced gait may stress the locomotor system, revealing deficits not seen under single-task (ST). However, the impact of gait “stress tests” on HD individuals needs further investigation. Therefore, the aims of this study were to investigate whether: 1) fast-paced and dual-task walking uncover deficits in gait and turning not seen under single-task, 2) cognitive and gait outcomes relate to fall incidence, and 3) gait deficits measured with wearable inertial sensors correlate with motor symptom severity in HD as measured by the Unified Huntington’s disease Rating Scale-total motor score (UHDRS-TMS). Seventeen HD (55 ± 9.7 years) and 17 age-matched controls (56.5 ± 9.3 years) underwent quantitative gait testing via a 25m, two-minute walk test with APDM^TM inertial sensors. Gait was assessed under a 1) ST, self-selected pace, 2) fast-as-possible (FAP) pace, and 3) verbal fluency DT. The UHDRS-TMS and a cognitive test battery were administered, and a retrospective fall history was obtained. During ST, DT, and FAP conditions, HD participants demonstrated slower gait, shorter stride length, and greater lateral step and stride length variability compared to controls (p<0.00001 to 0.034). Significant dual-task costs (DTC) were observed for turns; HD participants took more time (p = 0.013) and steps (p = 0.028) to complete a turn under DT compared to controls. Higher UHDRS-TMS correlated with greater stride length variability, less double-support, and more swing-phase time under all conditions. Decreased processing speed was associated with increased gait variability under ST and FAP conditions. Unexpectedly, participant’s self-reported falls did not correlate with any gait or turn parameters. HD participants demonstrated significantly greater DTC for turning, which is less automatic than straight walking, requiring coordination of body segments, anticipatory control, and cortical regulation. Turn complexity likely makes it more susceptible to cognitive interference in HD.

Autoregressive modeling to assess stride time pattern stability in individuals with Huntington's disease

Background

Huntington’s disease (HD) is a progressive, neurological disorder that results in both cognitive and physical impairments. These impairments affect an individual’s gait and, as the disease progresses, it significantly alters one’s stability. Previous research found that changes in stride time patterns can help delineate between healthy and pathological gait. Autoregressive (AR) modeling is a statistical technique that models the underlying temporal patterns in data. Here the AR models assessed differences in gait stride time pattern stability between the controls and individuals with HD. Differences in stride time pattern stability were determined based on the AR model coefficients and their placement on a stationarity triangle that provides a visual representation of how the patterns mean, variance and autocorrelation change with time. Thus, individuals who exhibit similar stride time pattern stability will reside in the same region of the stationarity triangle. It was hypothesized that individuals with HD would exhibit a more altered stride time pattern stability than the controls based on the AR model coefficients and their location in the stationarity triangle.

Methods

Sixteen control and twenty individuals with HD performed a five-minute walking protocol. Time series’ were constructed from consecutive stride times extracted during the protocol and a second order AR model was fit to the stride time series data. A two-sample t-test was performed on the stride time pattern data to identify differences between the control and HD groups.

Results

The individuals with HD exhibited significantly altered stride time pattern stability than the controls based on their AR model coefficients (AR1 p < 0.001; AR2 p < 0.001).

Conclusions

The AR coefficients successfully delineated between the controls and individuals with HD. Individuals with HD resided closer to and within the oscillatory region of the stationarity triangle, which could be reflective of the oscillatory neuronal activity commonly observed in this population. The ability to quantitatively and visually detect differences in stride time behavior highlights the potential of this approach for identifying gait impairment in individuals with HD.

Parkinsonism in Huntington's disease

Huntington's disease (HD) is usually characterized by involuntary hyperkinetic movements, called chorea. The intensity of chorea exhibits a peak in middle stages of HD and then decreases as HD progresses. In contrast, Pakinsonian signs of HD are often less appreciated. They typically progress in a fairly linear pattern over time. In fact, bradykinesia is detectable early on in premanifest gene carriers up to two decades prior to the clinical manifestation of HD symptoms using quantitative motor (Q-Motor) assessments such as finger tapping (digitomotography). Other Parkinsonian symptoms besides bradykinesia are rigidity and postural instability. They typically results in falls and injuries in advanced stages of HD. A primarily Parkinsonian motor phenotype, often seen with little to no chorea, is characteristically observed in older, late manifesting patients and in pediatric HD subjects. Establishing a diagnosis of HD is difficult in these groups and patients are often misdiagnosed in early stages.

An exploration of physical activity experiences throughout the Huntington's disease journey: supporting development of theoretically underpinned complex interventions

PURPOSE

Huntington's disease is an autosomal dominant neurodegenerative disease. Progressive physical, behavioural and cognitive impairments cause loss of independent function. Physical activity interventions are important components of comprehensive intervention strategies and may help alter the functional decline trajectory. Qualitative research has an important role to play in developing theoretically sound, well-defined physical activity interventions in Huntington's disease.

MATERIALS AND METHODS

Eight focus groups were conducted with people with prodromal to late stage Huntington's disease, caregivers (family members/formal), and healthcare professionals. An analytical coding framework was developed from the data and Levanthal's self-regulation model to assist analysis.

RESULTS AND CONCLUSIONS

Key themes were identified: evolving representations of Huntington's disease and physical activity; varying social environment of the person with Huntington's disease and the impact on physical activity; achieving physical activity participation while coping with the nuances of Huntington's disease. Levanthal's model facilitated understanding of physical activity experiences, however with progression, self-regulation of activities needs to become more collaborative with caregivers. A modified self-regulation model specific to physical activity in Huntington's disease is presented. Using a novel approach to generate new understanding of physical activity across the Huntington's disease lifespan facilitated development of an original and significant theoretical foundation to underpin development of a range of much needed physical activity and exercise interventions in Huntington's disease.Implications for rehabilitationSocial and familial context of individuals with HD is a key consideration for health care professionals supporting physical activity participation.Strategies such as using physical activity as a way of achieving control and adjusting expectations can help people with HD to continue to be active.People with HD adapt physical activity from high level to more functional activities with symptom progression.

Therapeutic Use of Music, Dance, and Rhythmic Auditory Cueing for Patients with Huntington's Disease: A Systematic Review

Background:

Studies have assessed the therapeutic effect of music, dance, and rhythmic auditory cueing for patients with Huntington’s disease (HD). However, the synthesis of evidence in support of their positive impact on symptoms is lacking.

Objective:

We conducted a systematic literature review to evaluate the potential benefits of music, dance, and rhythm on the cognitive, psychiatric and motor function in patients with HD.

Methods:

Two- and three-keyword searches and a manual search identified medical literature published from 1999 through 2019. We considered literature that assessed outcomes of art-based rehabilitation programs or individual modalities for persons with early, middle, or advanced HD. Structured analysis was conducted using data entry tables with categories for patient health status, art methods, and outcomes.

Results:

Seven articles and six abstracts met eligibility criteria, of which nine evaluated art-based rehabilitation programs. Studies mainly assessed cognitive, psychiatric, and motor functions through music, dance, or rhythm modalities. Although results were conflicting, in summary improvements to motor function were dependent on disease severity and more responsive to art therapy programs than rhythm-motor synchronization. Benefits to global cognition that resulted from rhythmic training correlated with microstructural changes. Qualitative data verified a positive impact on language production, chorea, behavior, and quality of life.

Conclusions:

Our review has shown a potential benefit of music, dance, and rhythm for patients with HD, which is particularly important for a disease that has no cure. Art forms seemed to affect cognitive, psychiatric, motor, psychosocial, and neuroanatomical domains. However, evidence is preliminary, warranting further investigation to establish the foundation for this field.

The Step Test Evaluation of Performance on Stairs (STEPS): Validation and reliability in a neurological disorder

Background

Individuals with neurological disorders often have difficulty negotiating stairs that can lead to injurious falls. Clinicians lack a clinical tool to identify impairments in stair negotiation and to assist their decision making regarding treatment plans to improve stair performance and safety. We developed a new tool called the Step Test Evaluation of Performance on Stairs (STEPS) that is designed to assess stair performance and safety in neurological populations.

Objectives

This study aimed to determine interrater and intrarater reliability of STEPS and its concurrent content validity to various clinical balance and mobility measures using individuals with Huntington’s disease (HD) as the first test population.

Methods

Forty individuals with HD (mean age 50.35) participated. Three observers rated live performances of the STEPS (interrater reliability) and seven observers rated videotaped performances twice (intrarater reliability). STEPS scores correlated with clinical mobility and balance test scores.

Results

Excellent inter- and intrarater reliability (ICCs = 0.91 and 0.89 respectively) and good internal consistency (α = 0.83) were found. Better STEPS performance correlated with better performance on co-administered motor and mobility measures and Stair Self-Efficacy scores. Per multivariable regression analysis, the Unified Huntington’s Disease Rating Scale modified motor score and descent time were significant predictors of STEPS performance.

Conclusions

The STEPS tool is easy to administer, requires no special devices and can be completed in less than five minutes. In the HD test population, it shows high reliability and validity making it a potentially useful tool for assessing maneuverability and safety on stairs in HD. The results suggest that the STEPS tool warrants further study to determine STEPS cut-off values for fall prediction in HD and may prove useful as an assessment tool for other neurological disorders.

Perceptions of the impact of chorea on health-related quality of life in Huntington disease (HD): A qualitative analysis of individuals across the HD spectrum, family members, and clinicians

Chorea, a hallmark symptom of Huntington's disease (HD), is characterized by jerky involuntary movements affecting the whole body that can interfere with daily functioning and impact health-related quality of life (HRQOL). To characterize chorea's impact on everyday functioning and HRQOL and identify patterns of perception and experiences of chorea among patients, caregivers, and providers. Data from focus groups of individuals with manifest HD (n = 8 early-stage HD; n = 16 late-stage HD), individuals at-risk or prodromal HD (n = 16), family HD caregivers (n = 17), and HD clinicians (n = 25). Focus group recordings were transcribed verbatim and analysed via constant comparison to identify meaningful and salient themes of living with chorea. Global themes of chorea's impact identified included: watching for chorea, experiences of stigma, and constraints on independence and relationships. Themes distinct to specific respondent groups included: Vigilance (at risk, prodromal); adaptation to chorea (early-stage); loss of autonomy and social life (late-stage); monitoring engagement (family caregivers) and safety (clinical providers). Living with chorea significantly constrains daily functioning, interactions, and HRQOL across the HD disease spectrum. Addressing these impacts via appropriate management of chorea can potentially enhance functioning, HRQOL, and overall satisfaction for persons with HD and their families.

Non-motor symptoms in Huntington's disease: a comparative study with Parkinson's disease

BACKGROUND/AIMS

The presence of non-motor symptoms in Huntington's disease (HD) has not been systematically assessed so far. Our objective was to know their prevalence and to compare it with a cohort of patients with Parkinson's disease (PD).

MATERIALS AND METHODS

Participants were consecutively recruited from our outpatient clinic. They were assessed through the motor part of the Unified Huntington's Disease Rating Scale, the motor part of the Unified Parkinson's Disease Rating Scale, the total functional capacity scale and the PD non-motor symptoms questionnaire.

RESULTS

We enrolled 123 participants: 53 HD, 45 PD and 25 healthy controls (HC). Non-motor symptoms were significantly more prevalent in HD patients than in HC. The most frequent non-motor symptoms in HD, involving more than 50% of patients, were attentional deficits, apathy, dysphagia, memory complaints, depression falls, insomnia and urinary urgency. The total score of non-motor symptoms correlated with disease duration, total functional capacity and disease stage. HD scored significantly higher than PD in 11 items (dysphagia, constipation, bowel incontinence, faecal tenesmus, weight loss, memory, apathy, attention, falls, nightmares, delusions) and in four domains (cognitive, hallucinations and delusions, digestive and cardiovascular). PD did not score significantly higher than HD in any domain.

CONCLUSIONS

HD patients have a high prevalence of non-motor symptoms, which is even higher than in PD, and correlates with disease progression.

The Relationship between Saccades and Locomotion

Human locomotion involves a complex interplay among multiple brain regions and depends on constant feedback from the visual system. We summarize here the current understanding of the relationship among fixations, saccades, and gait as observed in studies sampling eye movements during locomotion, through a review of the literature and a synthesis of the relevant knowledge on the topic. A significant overlap in locomotor and saccadic neural circuitry exists that may support this relationship. Several animal studies have identified potential integration nodes between these overlapping circuitries. Behavioral studies that explored the relationship of saccadic and gait-related impairments in normal conditions and in various disease states are also discussed. Eye movements and locomotion share many underlying neural circuits, and further studies can leverage this interplay for diagnostic and therapeutic purposes.

String Grammar Unsupervised Possibilistic Fuzzy C-Medians for Gait Pattern Classification in Patients with Neurodegenerative Diseases

Neurodegenerative diseases that affect serious gait abnormalities include Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington disease (HD). These diseases lead to gait rhythm distortion that can be determined by stride time interval of footfall contact times. In this paper, we present a new method for gait classification of neurodegenerative diseases. In particular, we utilize a symbolic aggregate approximation algorithm to convert left-foot stride-stride interval into a sequence of symbols using a symbolic aggregate approximation. We then find string prototypes of each class using the newly proposed string grammar unsupervised possibilistic fuzzy C-medians. Then in the testing process the fuzzy k-nearest neighbor is used. We implement the system on three 2-class problems, i.e., the classification of ALS against healthy patients, that of HD against healthy patients , and that of PD against healthy patients. The system is also implemented on one 4-class problem (the classification of ALS, HD, PD, and healthy patients altogether) called NDDs versus healthy. We found that our system yields a very good detection result. The average correct classification for ALS versus healthy is 96.88%, and that for HD versus healthy is 97.22%, whereas that for PD versus healthy is 96.43%. When the system is implemented on 4-class problem, the average accuracy is approximately 98.44%. It can provide prototypes of gait signals that are more understandable to human.

Objective assessment of gait and posture in premanifest and manifest Huntington disease - A multi-center study

BACKGROUND

Deficits in posture and gait are known to contribute to the complex motor phenotype of Huntington disease (HD). Objective and quantitative measures of posture and gait provided by posturography and GAITRite^® assessments may supplement categorical rating scales such as the UHDRS-TMS and increase power and sensitivity of clinical trials.

OBJECTIVES

To investigate whether posturography and GAITRite^® measures reveal (1) changes in manifest or premanifest HD mutation-carriers, (2) a correlation to the UHDRS-TMS and functional measures in manifest HD, and (3) a correlation to the disease-burden-score (based on CAG-repeat-length and age).

METHODS

Posturography and GAITRite^® were applied in premanifest (n = 26) and manifest HD gene-mutation-carriers (n = 40) in different paradigms compared to age-matched controls (n = 30) in a cross-sectional multi-site study conducted in three centers. Subjects were assessed clinically with the UHDRS Total-Motor-Score, Total-Functional-Capacity and Functional-Assessment-Scale.

RESULTS

Several posturography measures were able to discriminate between controls, premanifest, and manifest mutation-carriers in both conditions assessed. Only one GAITRite^® measure separated controls and premanifest participants, while discrimination between controls and manifest same as between premanifest and manifest participants was possible in several measures. Correlation with all clinical measures was seen in only one measure per device while correlations to the disease-burden-score seen in posturography only.

CONCLUSION

Overall the results suggests that posturography detects alterations in premanifest and manifest mutation-carriers more reliably than GAITRite^® measures. Correlations with clinical assessment scores are limited; correlation with disease-burden-score is seen in posturography only. Data acquisition and analysis was easier with posturography than GAITRite^® assessments in out-patient settings.

Minipigs as a Large-Brained Animal Model for Huntington's Disease: From Behavior and Imaging to Gene Therapy

Large animal models offer novel opportunities in exploring safety, biology, and efficacy of novel therapeutic approaches for Huntington's disease (HD). Challenges in the development of, for example, gene therapy, such as delivery, distribution, and persistence of virus vectors or oligo sense nucleotides, can be explored in large brains and organisms approaching human size. We here introduce the transgenic Libechov minipig as a large animal model of HD. Methods developed to assess motor, cognitive, and behavioral features expected to manifest in an HD model are described. We also outline established protocols for magnetic resonance imaging (MRI) including magnetic resonance spectroscopy (MRS) for minipigs. The successful conduct of long-term follow-up studies over several years with repeated behavioral testing and imaging is reported. We discuss the advantages and limitations of using this model with regard to translational reliability, homology to humans and with respect to feasibility, breeding, housing, handling, and finally ethical considerations. It is concluded that minipigs can fulfill an important role in preclinical development to bridge the gap between rodents and nonhuman primate research in the translation to humans.

Time-Restricted Feeding Improves Circadian Dysfunction as well as Motor Symptoms in the Q175 Mouse Model of Huntington's Disease

Huntington's disease (HD) patients suffer from a progressive neurodegeneration that results in cognitive, psychiatric, cardiovascular, and motor dysfunction. Disturbances in sleep/wake cycles are common among HD patients with reports of delayed sleep onset, frequent bedtime awakenings, and fatigue during the day. The heterozygous Q175 mouse model of HD has been shown to phenocopy many HD core symptoms including circadian dysfunctions. Because circadian dysfunction manifests early in the disease in both patients and mouse models, we sought to determine if early intervention that improve circadian rhythmicity can benefit HD and delay disease progression. We determined the effects of time-restricted feeding (TRF) on the Q175 mouse model. At six months of age, the animals were divided into two groups: ad libitum (ad lib) and TRF. The TRF-treated Q175 mice were exposed to a 6-h feeding/18-h fasting regimen that was designed to be aligned with the middle of the time when mice are normally active. After three months of treatment (when mice reached the early disease stage), the TRF-treated Q175 mice showed improvements in their locomotor activity rhythm and sleep awakening time. Furthermore, we found improved heart rate variability (HRV), suggesting that their autonomic nervous system dysfunction was improved. Importantly, treated Q175 mice exhibited improved motor performance compared to untreated Q175 controls, and the motor improvements were correlated with improved circadian output. Finally, we found that the expression of several HD-relevant markers was restored to WT levels in the striatum of the treated mice using NanoString gene expression assays.

Gait, balance, and falls in Huntington disease

Huntington disease (HD) is an autosomal-dominant, progressive, neurodegenerative disorder, characterized by involuntary movements and other motor impairments, cognitive/behavioral symptoms, and psychiatric disorders. Gait and balance impairments and falls greatly impact on the quality of life among people with HD, and being fall-prone is one of the strongest predictors of nursing-home placement. Gait impairment in HD is characterized by bradykinesia, reduced velocity, and increased variability in spatiotemporal features. Detrimental changes in symmetry, step length, stride time, balance measures, gait adaptability (external cues, dual tasking), and hypo/hyperkinesia have also been observed. Balance impairment is characterized by impairments of anticipatory balance without a change in base of support, anticipatory balance with a change in base of support, and reactive balance. In addition to gait and balance impairment, people with HD have a range of intrinsic and extrinsic factors that increase fall risk, including reduced cognitive reserve for dual tasking. Currently there is some evidence to suggest exercise interventions can address some HD-specific gait and balance deficits. However, no intervention studies to date have specifically targeted falls. Large, well-designed, randomized controlled trials are needed to guide future fall prevention interventions in people with HD.

Of rodents and men: understanding the emergence of motor and cognitive symptoms in Huntington disease

Arguably, one of the most important milestones in Huntington disease research since the discovery of the gene responsible has been the generation of different genetic animal models. Although clinical reports have shown evidence of progressive cognitive impairments in gene carriers before motor symptoms are diagnosed, such symptoms have been much less obvious in animal models. In this review, we summarize the three main classes of animal models for Huntington disease and describe some relevant translational assays for behavioural deficits evaluation. Finally, we argue that a good knowledge of the emergence of motor and cognitive symptoms in mice and rat models is indispensable for the selection of endpoint measures in early preclinical drug screening studies.

Impairments in Spatiotemporal Gait Adaptation During Obstacle Navigation in Huntington's Disease

BACKGROUND

Navigating obstacles whilst walking might be associated with poorer balance and a higher risk of falling in individuals with symptomatic Huntington's disease (symp-HD). However, this issue has not been investigated within the literature.

OBJECTIVE

A unique obstacle navigation experiment was designed to examine adaptive gait patterns in order to identify spatiotemporal gait characteristics that might be associated with poorer balance and a higher risk of falling in symp-HD.

METHOD

Sixteen diagnosed symp-HD participants and 16 age- and sex-matched healthy controls were included. Gait was examined in 3 experimental conditions: baseline walking, walking while navigating around 1 obstacle, and walking while navigating around 2 obstacles. Navigation around obstacle walks was divided into three step phases (approach, navigation, recovery). Group differences in gait variables were analyzed at baseline and during walking for each obstacle condition respectively. Gait variables were also correlated with the Berg Balance Scale (BBS) and Timed Up and Go (TUG) test.

RESULTS

Symp-HD participants, compared with controls, performed significantly poorer on most gait variables during baseline walking. Symp-HD participants significantly decreased their step-length while navigating around 1 obstacle, and increased their step-time while navigating around 1 and 2 obstacles. There were no significant group differences in step-width. Variables associated with navigating around obstacles correlated significantly with BBS and TUG clinical tools, which have been associated in the literature with an increased risk of falling in symp-HD.

CONCLUSION

These findings could aid clinicians in better managing risk of falls in people with Huntington's disease through targeted and effective strategies.

A Longitudinal Motor Characterisation of the HdhQ111 Mouse Model of Huntington's Disease

Background: Huntington’s disease (HD) is a rare, incurable neurodegenerative disorder caused by a CAG trinucleotide expansion with the first exon of the huntingtin gene. Numerous knock-in mouse models are currently available for modelling HD. However, before their use in scientific research, these models must be characterised to determine their face and predictive validity as models of the disease and their reliability in recapitulating HD symptoms.

Objective: Manifest HD is currently diagnosed upon the onset of motor symptoms, thus we sought to longitudinally characterise the progression and severity of motor signs in the Hdh^Q111 knock-in mouse model of HD, in heterozygous mice.

Methods: An extensive battery of motor tests including: rotarod, inverted lid test, balance beam, spontaneous locomotor activity and gait analysis were applied longitudinally to a cohort of Hdh^Q111 heterozygous mice in order to progressively assess motor function.

Results: A progressive failure to gain body weight was demonstrated from 11 months of age and motor problems in all measures of balance beam performance were shown in Hdh^Q111 heterozygous animals in comparison to wild type control animals from 9 months of age. A decreased latency to fall from the rotarod was demonstrated in Hdh^Q111 heterozygous animals in comparison to wild type animals, although this was not progressive with time. No genotype specific differences were demonstrated in any of the other motor tests included in the test battery.

Conclusions: The Hdh^Q111 heterozygous mouse demonstrates a subtle and progressive motor phenotype that begins at 9 months of age. This mouse model represents an early disease stage and would be ideal for testing therapeutic strategies that require elongated lead-in times, such as viral gene therapies or striatal transplantation.

Three-Dimensional Trunk and Lower Limbs Characteristics during Gait in Patients with Huntington's Disease

Objective: A number of studies on gait disturbances have been conducted, however, no clear pattern of gait disorders was described. The aim of the study was to characterize the gait pattern in HD patients by conducting analysis of mean angular movement changes the lower limb joints and trunk (kinematics parameters). Methods: The study group consisted of 30 patients with HD (17 women and 13 men). The reference data include the results of 30 healthy subjects (17 women and 13 men). Registration of gait with the Vicon 250 system was performed using passive markers attached to specific anthropometric points directly on the skin, based on the Golem biomechanical model (Oxford Metrics Ltd.). The research group and the control group were tested once. Results: Statistically significant (p < 0.05) angular changes in gait cycle for HD patients were observed in: insufficient plantar flexion during Loading Response and Pre-swing phases; insufficient flexion of the knee joint during Initial Swing and Mid Swing phases; excessive flexion of the hip in Terminal Stance and Pre-swing phases and over-normative forward inclination of the trunk in all gait phases. It should be noted that the group of patients with HD obtained, for all the mean angular movement changes higher standard deviation. Conclusion: A characteristic gait disorder common to all patients with HD occurring throughout the whole duration of the gait cycle is a pathological anterior tilt of the trunk. The results will significantly contribute to programming physiotherapy for people with HD, aimed at stabilizing the trunk in a position of extension during gait.

Medical management of motor manifestations of Huntington disease

The motor and movement disorders of Huntington disease (HD) are managed in the context of the other disease features. Chorea and dystonia are the most common HD-associated movement disorders, and they can be assessed on research rating scales. However other motor manifestations have a significant impact. In particular, dysphagia influences choice and tolerance of treatment for the movement disorder, as will comorbidities, patient awareness, and distress related to the motor feature or movement. Treatment for other disease features may aggravate the motor disorder, e.g., increased swallowing difficulty associated with antipsychotic agents. Basic principles in deciding to institute a treatment are outlined as well as treatment of specific motor manifestations and movements. There is a paucity of evidence to support the treatments available for the motor disorder, with only one agent with class 1 evidence, tetrabenazine, for chorea. There are, however, treatments informed by expert opinion which reflect the management of a wider HD phenotype than that represented in clinical trials. Some treatments are based on evidence from use in other conditions. Medical management is usually undertaken later in the disease with concurrent nonmedical interventions after multidisciplinary assessments. Medication review with HD progression is essential.