Role of hypokinesia and bradykinesia in gait disturbances in Huntington's disease

Glucocorticoid receptor antagonist CORT113176 attenuates motor and neuropathological symptoms of Huntington's disease in R6/2 mice

Huntington's Disease (HD) is a progressive neurodegenerative disease caused by a mutation in the huntingtin gene. The mutation leads to a toxic gain of function of the mutant huntingtin (mHtt) protein resulting in cellular malfunction, aberrant huntingtin aggregation and eventually neuronal cell death. Patients with HD show impaired motor functions and cognitive decline. Elevated levels of glucocorticoids have been found in HD patients and in HD mouse models, and there is a positive correlation between increased glucocorticoid levels and the progression of HD. Therefore, antagonism of the glucocorticoid receptor (GR) may be an interesting strategy for the treatment of HD. In this study, we evaluated the efficacy of the selective GR antagonist CORT113176 in the commonly used R6/2 mouse model. In male mice, CORT113176 treatment significantly delayed the loss of grip strength, the development of hindlimb clasping, gait abnormalities, and the occurrence of epileptic seizures. CORT113176 treatment delayed loss of DARPP-32 immunoreactivity in the dorsolateral striatum. It also restored HD-related parameters including astrocyte markers in both the dorsolateral striatum and the hippocampus, and microglia markers in the hippocampus. This suggests that CORT113176 has both cell-type and brain region-specific effects. CORT113176 delayed the formation of mHtt aggregates in the striatum and the hippocampus. In female mice, we did not observe major effects of CORT113176 treatment on HD-related symptoms, with the exception of the anti-epileptic effects. We conclude that CORT113176 effectively delays several key symptoms related to the HD phenotype in male R6/2 mice and believe that GR antagonism may be a possible treatment option.

Gene-dosage- and sex-dependent differences in the prodromal-Like phase of the F344tgHD rat model for Huntington disease

In Huntington disease (HD) the prodromal phase has been increasingly investigated and is currently in focus for early interventional treatments. Also, the influence of sex on disease progression and severity in patients is under discussion, as a sex-specific impact has been reported in transgenic rodent models for HD. To this end, we have been studying these aspects in Sprague Dawley rats transgenic for HD. Here, we took up on the congenic F344tgHD rat model, expressing a fragmented Htt construct with 51 CAG repeats on an inbred F344 rat background and characterized potential sexual dimorphism and gene-dosage effects in rats during the pre-symptomatic phase (1-8 months of age). Our study comprises a longitudinal phenotyping of motor function, emotion and sensorimotor gating, as well as screening of metabolic parameters with classical and automated assays in combination with investigation of molecular HD hallmarks (striatal cell number and volume estimation, appearance of HTT aggregates). Differences between sexes became apparent during middle age, particularly in the motor and sensorimotor domains. Female individuals were generally more active, demonstrated different gait characteristics than males and less anxiolytic-like behavior. Alterations in both the time course and affected behavioral domains varied between male and female F344tgHD rats. First subtle behavioral anomalies were detected in transgenic F344tgHD rats prior to striatal MSN cell loss, revealing a prodromal-like phase in this model. Our findings demonstrate that the congenic F344tgHD rat model shows high face-validity, closely resembling the human disease's temporal progression, while having a relatively low number of CAG repeats, a slowly progressing pathology with a prodromal-like phase and a comparatively subtle phenotype. By differentiating the sexes regarding HD-related changes and characterizing the prodromal-like phase in this model, these findings provide a foundation for future treatment studies.

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.

Therapeutic modulation of JAK-STAT, mTOR, and PPAR-γ signaling in neurological dysfunctions

The cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade is a pleiotropic pathway that involves receptor subunit multimerization. The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine-threonine kinase that perceives and integrates a variety of intracellular and environmental stimuli to regulate essential activities such as cell development and metabolism. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a prototypical metabolic nuclear receptor involved in neural differentiation and axon polarity. The JAK-STAT, mTOR, and PPARγ signaling pathways serve as a highly conserved signaling hub that coordinates neuronal activity and brain development. Additionally, overactivation of JAK/STAT, mTOR, and inhibition of PPARγ signaling have been linked to various neurocomplications, including neuroinflammation, apoptosis, and oxidative stress. Emerging research suggests that even minor disruptions in these cellular and molecular processes can have significant consequences manifested as neurological and neuropsychiatric diseases. Of interest, target modulators have been proven to alleviate neuronal complications associated with acute and chronic neurological deficits. This research-based review explores the therapeutic role of JAK-STAT, mTOR, and PPARγ signaling modulators in preventing neuronal dysfunctions in preclinical and clinical investigations.

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.

Algorithms for Walking Speed Estimation Using a Lower-Back-Worn Inertial Sensor: A Cross-Validation on Speed Ranges

Walking/gait speed is a key measure for daily mobility characterization. To date, various studies have attempted to design algorithms to estimate walking speed using an inertial sensor worn on the lower back, which is considered as a proper location for activity monitoring in daily life. However, these algorithms were rarely compared and validated on the same datasets, including people with different preferred walking speed. This study implemented several original, improved, and new algorithms for estimating cadence, step length and eventually speed. We designed comprehensive cross-validation to compare the algorithms for walking slow, normal, fast, and using walking aids. We used two datasets, including reference data for algorithm validation from an instrumented mat (40 subjects) and shanks-worn inertial sensors (88 subjects), with normal and impaired walking patterns. The results showed up to 50% performance improvements. Training of algorithms on data from people with different preferred speeds led to better performance. For the slow walkers, an average RMSE of 2.5 steps/min, 0.04 m, and 0.10 m/s were respectively achieved for cadence, step length, and speed estimation. For normal walkers, the errors were 3.5 steps/min, 0.08 m, and 0.12 m/s. An average RMSE of 1.3 steps/min, 0.05 m, and 0.10 m/s were also observed on fast walkers. For people using walking aids, the error significantly increased up to an RMSE of 14 steps/min, 0.18 m, and 0.27 m/s. The results demonstrated the robustness of the proposed combined speed estimation approach for different speed ranges. It achieved an RMSE of 0.10, 0.18, 0.15, and 0.32 m/s for slow, normal, fast, and using walking aids, respectively.

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.

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.

Gait variability as digital biomarker of disease severity in Huntington's disease

BACKGROUND

Impaired gait plays an important role for quality of life in patients with Huntington's disease (HD). Measuring objective gait parameters in HD might provide an unbiased assessment of motor deficits in order to determine potential beneficial effects of future treatments.

OBJECTIVE

To objectively identify characteristic features of gait in HD patients using sensor-based gait analysis. Particularly, gait parameters were correlated to the Unified Huntington's Disease Rating Scale, total motor score (TMS), and total functional capacity (TFC).

METHODS

Patients with manifest HD at two German sites (n = 43) were included and clinically assessed during their annual ENROLL-HD visit. In addition, patients with HD and a cohort of age- and gender-matched controls performed a defined gait test (4 × 10 m walk). Gait patterns were recorded by inertial sensors attached to both shoes. Machine learning algorithms were applied to calculate spatio-temporal gait parameters and gait variability expressed as coefficient of variance (CV).

RESULTS

Stride length (- 15%) and gait velocity (- 19%) were reduced, while stride (+ 7%) and stance time (+ 2%) were increased in patients with HD. However, parameters reflecting gait variability were substantially altered in HD patients (+ 17% stride length CV up to + 41% stride time CV with largest effect size) and showed strong correlations to TMS and TFC (0.416 ≤ r_Sp ≤ 0.690). Objective gait variability parameters correlated with disease stage based upon TFC.

CONCLUSIONS

Sensor-based gait variability parameters were identified as clinically most relevant digital biomarker for gait impairment in HD. Altered gait variability represents characteristic irregularity of gait in HD and reflects disease severity.

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.

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.

The influence of motor ability rehabilitation on temporal-spatial parameters of gait in Huntington's disease patients on the basis of a three-dimensional motion analysis system: An experimental trial

OBJECTIVE

There is no existing standard, evidence-based, scientific model for motor ability improvement in Huntington's Disease (HD) patients aimed at maintaining independent gait for as long as possible, or performing activities of daily living, the effectiveness of which would be supported by the results of studies using objective research tools. Under these circumstances, the aim of this study was to analyze the influence of motor ability rehabilitation on the spatial-temporal parameters of gait in HD patients.

DESIGN

It was an experimental trial. The studied group consisted of 30 patients (17 women and 13 men) with HD. In hospital conditions, the patients participated in the 3-week motor ability l rehabilitation programme tailored to individual needs. The study group was tested using the Vicon 250 three-dimensional gait analysis system before and after the physical exercise programme.

RESULTS

Walking speed after therapy increased for the left lower limb from 1.06 (SD 0.24) [m/s] to 1.21 (SD 0.23) [m/s], and for the right lower limb from 1.07 (SD 0.25) [m/s] to 1.20 (SD 0.25) [m/s]. The cycle length increased after the applied therapy for the left lower limb from 1.17 (SD 0.20) [m] to 1.23 (SD 0.19) [m].

CONCLUSION

The three-week motor ability rehabilitation programme positively influences spatial-temporal gait parameters in HD patients.

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.

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.

Quantitative Gait Analysis in Patients with Huntington's Disease

Objective

Gait disturbance is the main factor contributing to a negative impact on quality of life in patients with Huntington’s disease (HD). Understanding gait features in patients with HD is essential for planning a successful gait strategy. The aim of this study was to investigate temporospatial gait parameters in patients with HD compared with healthy controls.

Methods

We investigated 7 patients with HD. Diagnosis was confirmed by genetic analysis, and patients were evaluated with the Unified Huntington’s Disease Rating Scale (UHDRS). Gait features were assessed with a gait analyzer. We compared the results of patients with HD to those of 7 age- and sex-matched normal controls.

Results

Step length and stride length were decreased and base of support was increased in the HD group compared to the control group. In addition, coefficients of variability for step and stride length were increased in the HD group. The HD group showed slower walking velocity, an increased stance/swing phase in the gait cycle and a decreased proportion of single support time compared to the control group. Cadence did not differ significantly between groups. Among the UHDRS subscores, total motor score and total behavior score were positively correlated with step length, and total behavior score was positively correlated with walking velocity in patients with HD.

Conclusion

Increased variability in step and stride length, slower walking velocity, increased stance phase, and decreased swing phase and single support time with preserved cadence suggest that HD gait patterns are slow, ataxic and ineffective. This study suggests that quantitative gait analysis is needed to assess gait problems in HD.

The role of rehabilitation therapy in Huntington disease

The role of rehabilitation interventions is increasingly considered a key component to effective management of people with Huntington disease (HD). Lifestyle factors, such as activity level and exercise, as well as specific motor training may be helpful in managing the functional sequelae of HD and possibly slowing disease progression. In this chapter, we focus on the role of rehabilitation therapy in secondary and tertiary prevention of the potentially devastating consequences of HD. We provide a brief overview of the range of motor and cognitive impairments in HD and their effect on functional abilities. We further discuss emerging evidence in terms of the role of exercise, physical activity, and physical therapies in helping to minimize functional loss and maximize quality of life throughout the disease process. Future directions with respect to intensive and goal-directed exercise, including aerobic and strengthening programs, are also discussed. This is an area of particular importance alongside exploring the potential that motor-training paradigms have in mediating the effects of disease-modifying drugs, cell replacement therapy, or genetic manipulations, when available.

The effects of physiotherapy with PNF concept on gait and balance of patients with Huntington's disease - pilot study

BACKGROUND AND PURPOSE

Huntington's disease (HD) is a neurodegenerative, progressive disorder of the central nervous system which causes significant gait and balance disturbances. This is a pilot study which aims to determine the effects of a physiotherapy programme with use of Proprioceptive Neuromuscular Facilitation (PNF) on gait and balance in HD patients.

MATERIAL AND METHODS

30 HD patients aged 21-60 with genetically confirmed diagnosis participated in the study. Participants followed a 3-week-long PNF-based physiotherapy programme. Gait and balance were evaluated twice in each participant: first at baseline and then after the course of physiotherapy. The following methods were used for gait disturbances: Tinetti Gait Assessment Tool, Up and Go Test, Timed Walking Tests for 10m and 20m (TWT10m, TWT20m). Balance was assessed with use of Berg Balance Scale, Pastor Test and Functional Reach Test.

RESULTS

There was a significant improvement in all measures of balance and gait.

CONCLUSION

PNF-based physiotherapy is effective and safe in HD patients.

Use of a force-sensing automated open field apparatus in a longitudinal study of multiple behavioral deficits in CAG140 Huntington's disease model mice

Behavioral testing of mouse models of Huntington's disease (HD) is a key component of preclinical assessment for potential pharmacological intervention. An open field with a force plate floor was used to quantify numerous spontaneous behaviors in a slowly progressing model of HD. CAG140 (+/+, +/-, -/-) male and female mice were compared in a longitudinal study from 6 to 65 weeks of age. Distance traveled, wall rears, wall rear duration, number of low mobility bouts, in-place movements, number of high velocity runs, and gait parameters (stride rate, stride length, and velocity) were extracted from the ground reaction forces recorded in 20-min actometer sessions. Beginning at 11 weeks, HD mice (both +/- and +/+) were consistently hypoactive throughout testing. Robust hypoactivity at 39 weeks of age was not accompanied by gait disturbances. By 52 and 65 weeks of age the duration of wall rears increased and in-place tremor-like movements emerged at 65 weeks of age in the +/+, but not in the +/- HD mice. Taken together, these results suggest that hypoactivity preceding frank motor dysfunction is a characteristic of CAG140 mice that may correspond to low motivation to move seen clinically in the premanifest/prediagnostic stage in human HD. The results also show that the force plate method provides a means for tracking the progression of behavioral dysfunction in HD mice beyond the stage when locomotion is lost while enabling quantification of tremor-like and similar in-place behaviors without a change in instrumentation. Use of force plate actometry also minimizes testing-induced enrichment effects when batteries of different tests are carried out longitudinally.

Coexistence of Gait Disturbances and Chorea in Experimental Huntington's Disease

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by an expanded CAG repeat. The clinical features are progressive motor dysfunction, cognitive deterioration, and psychiatric disturbances. Unpredictable choreic movements, among the most characteristic hallmarks, may contribute to gait disturbances and loss of balance in HD individuals. In this study, we aimed to investigate and characterize the gait abnormalities and choreic movements in a transgenic rat model of HD (tgHD). TgHD presents typical neuropathological, neurophysiological, and behavioral aspects mimicking some of the key features of human HD and is the only described experimental model for HD that exhibits choreiform movements. We used the Catwalk, with emphasis on static and dynamic gait parameters, to test the hypothesis that at symptomatic age (9 months) the dynamic measures of gait in HD are altered and coexist with choreiform movements. Our results showed that the dynamic parameters seem to be more affected than static parameters at this age in tgHD rats. The number of steps and step cycles and swing speed of the paws were increased in tgHD rat in comparison to wild-type controls. Our study demonstrates that gait abnormalities coexist with chorea rather than being caused by it. These symptoms may originate from distinct networks in the basal ganglia and downstream connections.

Gait in Huntington's disease and the stride length-cadence relationship

Background

The progressive deterioration of gait in Huntington’s disease (HD) leads to functional decline and loss of function. To understand the underlying mechanisms responsible for the gait changes in HD, we examined the automatic control of gait by measuring the relationship between stride length and cadence. The relationship is strongly linked in healthy adults during automatic gait but disrupted in pathological gait disorders, such as Parkinson’s disease (PD).

Methods

The stride length cadence relationship was compared between seventeen participants with HD, twenty with PD and twenty one healthy older adults (HOA). Participants had their gait recorded at self-selected preferred, very slow, slow, fast and very fast speeds. Linear regression analysis was used to determine the slope and intercept of the relationship which were compared between groups. The adjustment of stride length and cadence when changing gait speeds was measured and compared within and between groups.

Results

Linearity was strong in all but two participants with HD and one with PD. Slope did not differ between groups (p > 0.05) but intercept was lower in the HD and PD groups compared to HOA (p < 0.05). Stride length was shorter in the HD and PD groups compared to controls at preferred and most adjusted speed conditions (p < 0.05) but cadence did not differ between groups (p > 0.05) regardless of speed. The HD group adjusted stride length and cadence similar to HOA when changing speed. The range of cadence across speed conditions did not differ between groups.

Conclusion

Scaling of stride length but not the regulation of cadence was found to be disrupted in participants with HD.

Gait disorders

This chapter deals with the neuronal mechanisms underlying impaired gait. The aim is, first, a better understanding of the underlying pathophysiology and, second, the selection of an adequate treatment. One of the first symptoms of a lesion within the central motor system perceived by patients is a movement disorder, which is most characteristic during locomotion, e.g. in patients suffering spasticity after stroke or a spinal cord injury or Parkinson disease. By the recording and analysis of electrophysiological and biomechanical signals during a movement, the significance of impaired reflex behavior or muscle tone and its contribution to the movement disorder can reliably be assessed. Adequate treatment should not be restricted to the correction of an isolated clinical sign but should be based on the mechanisms underlying the movement disorder that impairs the patient. Therapy should be directed toward functional training, which takes advantage of the plasticity of the nervous system. In the future a combination of repair and functional training will further improve the mobility of disabled patients.

Design and testing of statistical methods to classify the severity of steppage gait based on center of pressure data

In this research kinematics parameters derived from ground reaction forces were evaluated to limit differential diagnoses and measure the degree of disabilities during walking among neuropathic subjects. 25 neuropathic subjects affected by drop foot and 20 normal subjects were enrolled in the study. Each subject was tested in average 10±2 times for calculating kinetics parameters derived from ground reaction forces. The results revealed that the center of pressure displacement pattern in sole of foot can be a good index for differential diagnoses and measuring the degree of disabilities. This research can extend the clinical applications of ground reaction force plate and introduce suitable criteria to measure the degree of disability among neuropathic patients.

Are gait initiation parameters early markers of Huntington's disease in pre-manifest mutation carriers?

Huntington's disease (HD) pre-manifest mutation carriers (PMCs) present early-onset gait disturbances. Gait initiation encompasses the preparation and execution of the first step. By using paradigms with and without external cues, a gait initiation analysis can highlight the interaction between motor and cognitive aspects of movement preparation and execution. Hence, gait initiation disorders may constitute particularly interesting early markers of HD. The objective of the present study was to quantify gait initiation in PMCs. In a case-control study, 17 PMCs (median age: 36.5) were compared with a group of 25 healthy controls (HCs, median age: 36) for gait initiation and a group of 57 HCs (median age: 38) for gait. Presymptomatic mutation carriers displayed a shorter first step duration and lower-amplitude postural adjustments. For the first step duration and speed, these impairments were more pronounced under self-triggered (ST) conditions. The PMCs displayed a lower gait speed, cadence and stride length and higher stride-to-stride variability. The latter parameter seemed capable of differentiating between PMCs and HCs with adequate sensitivity (0.81) and specificity (0.87). We confirmed the early-onset impairment of gait in general and first step execution in particular in PMCs (particularly under ST conditions). The temporal parameters of step execution (e.g. duration) and spatial parameters of postural adjustment (e.g. a backward shift in the centre of pressure) may be worth investigating as early markers of HD. However, two such parameters (stride-to-stride variability and first step duration under ST conditions) already appear to be sufficiently reliable diagnostic tools for differentiating between PMCs and HCs.

Normal walking speed: a descriptive meta-analysis

BACKGROUND

Walking speed has implications for community functioning and is predictive of important outcomes. Determining whether an individual's walking speed is limited requires normal values for comparison.

OBJECTIVES

To use meta-analysis to describe normal gait speed for healthy individuals within age and gender strata.

DATA SOURCES

PubMed, the Cumulative Index of Nursing and Allied Health (CINAHL), Scopus, Science Citation Index and articles identified by hand searches.

STUDY SELECTION CRITERIA

Inclusion required that the gait speed of apparently healthy adults was documented as they walked at a normal pace over a course of 3 to 30 m. Summary data were excluded unless obtained from at least 10 participants within a gender and decade stratum.

STUDY APPRAISAL AND SYNTHESIS METHODS

The two authors independently reviewed articles and extracted data. Accuracy was confirmed by the other author. Data were grouped within gender and decade strata. A meta-analysis macro was used to consolidate data by strata and to determine homogeneity.

RESULTS

Forty-one articles contributed data to the analysis. Combined, they provided data from 23111 subjects. The gait speed was homogeneous within strata and ranged from a mean of 143.4 cm/second for men aged 40 to 49 years to a mean of 94.3 cm/second for women aged 80 to 99 years.

LIMITATIONS

The data presented herein may not be useful as a standard of normal if gait is measured over short distances from the command 'go' or if a turn is involved.

CONCLUSIONS AND IMPLICATIONS

The consolidation of data from multiple studies reported in this meta-analysis provides normative data that can serve as a standard against which individuals can be compared. Doing so will aid the interpretation of their performance.

Postural deficits in Huntington's disease when performing motor skills involved in daily living

Previous studies of Huntington's disease (HD) have reported motor control deficits for selected fine and gross motor skills. However, no studies have metrically assessed postural control in this clinical group when performing motor skills involved in daily living. Therefore, the purpose of the present study was to evaluate and compare postural control of individuals with confirmed Huntington's disease and non-gene carriers when completing three functional postural tasks. Eleven individuals with HD (mean age=47.1 years: UHDRS mean=34.5: mean age of HD onset 34.6 years: mean CAG repeat=44.1) and 17 non-gene carriers (NGC) (mean age=39.2 years: UHDRS mean=0.13: mean CAG repeat=20.5) completed three tests on a force plate interfaced with a computer. The tests were a step up and over an obstacle (SUO) test, a sit-to-stand (STS) test, and a step and turn (ST) test. Selected kinematic and kinetic variables were used to quantify postural control. Data were analyzed using MANOVA procedures and discriminant function analysis. HD patients were significantly slower in completing all three tests (HD SUO=2.3 s vs. NGC SUO=1.6 s; HD STS=0.8 s vs. NGC STS=0.5 s; HD ST=1.7 s vs. NGC ST=0.9 s) and developed less rising force during the step up and over test (HD=25.8% body weight vs. NGC=39.4% body weight) but not for the sit-to-stand test. Additionally, sway velocity of the center of gravity (COG) was significantly higher for HD patients when performing the sit-to-stand (HD=4.1°/s vs. NGC=2.9°/s) and step and turn tests (HD=33.7°/s vs. NGC=21.7°/s). HD patients manifest significant postural control deficits when performing motor skills typical of daily living activities.

Early Detection of Huntington Disease

Huntington disease (HD) is a devastating illness, although its autosomal dominant genetic transmission allows a unique opportunity to study apparently healthy individuals before manifest disease. Attempts to study early disease are not unique in neurology (e.g., Mild Cognitive Impairment, Vascular Cognitive Impairment), but studying otherwise-healthy appearing individuals who will go on with nearly 99% certainty to manifest the symptoms of brain disease does provide distinct but valuable information about the true natural history of the disease. The field has witnessed an explosion of research examining possible early indicators of HD during what is now referred to as the "prodrome" of HD. A NIH study in its ninth year (PREDICT-HD) has offered a glimpse into the transition from an apparently healthy state to an obviously diseased state, and can serve as a model for many other genetic diseases, both neurological and non-neurological.

Clinical measurement of mobility and balance impairments in Huntington's disease: validity and responsiveness

BACKGROUND

Mobility and balance in Huntington's disease (HD) are currently assessed in the clinic with three items from the unified Huntington's disease rating scale (UHDRS): walk, tandem and pull tests. These tests may not be optimal because they are scored on an ordinal scale and do not test anticipatory balance. We tested the validity and responsiveness of three clinical tests of mobility and balance.

METHODS

Three clinical tests (FRT, timed up and go (TUG), Berg balance scale (BBS)) were validated with seven quantitative gait measures and two indicators of functional limitation (HD-ADL and total functional capacity) in 30 subjects with HD. These tests were also assessed for responsiveness to disease severity.

RESULTS

FRT and BBS were correlated with five quantitative gait measures, and TUG with eight (all p<0.05). All tests were correlated with indicators of functional limitation (p<0.05) and were responsive to disease severity.

CONCLUSIONS

FRT, TUG and BBS are valid, responsive and easy to administer clinical tests that should be routinely included with the UHDRS in therapeutic trials for subjects with HD.

Spectrum of gait impairments in presymptomatic and symptomatic Huntington's disease

The purpose of this study was to quantify gait impairments in presymptomatic and symptomatic Huntington's disease (HD) subjects, and examine sensitivity of gait measures. Our sample (n = 65) included presymptomatic mutation carriers (PMC) (n = 15), symptomatic HD subjects (SHD) (n = 30) and healthy controls (n = 20). Participants were requested to walk at their preferred speed on a computerized walkway that recorded spatiotemporal variables. We administered the Unified HD Rating Scale (UHDRS) for PMC and SHD. PMC demonstrated decreased gait velocity (P < 0.01), stride length (P < 0.008), and increased time in double support (P < 0.001); and demonstrated higher variability in stride length (P < 0.01) and step time (P < 0.004) compared with controls. These impairments worsened with increasing disease severity for SHD. Gait impairments were correlated with predicted years to onset in PMC (velocity = -0.65; cadence = -0.70, step time = 0.71) and demonstrated high sensitivity and specificity in distinguishing between controls and mutation carriers. In contrast, UHDRS scores did not reveal impairments in gait and balance. Gait bradykinesia and dynamic balance impairments begin in the presymptomatic stage of HD and continue to worsen in the symptomatic stages. Gait measures are sensitive in differentiating between mutation positive and negative individuals even when impairments were not detected by clinical neurological examination. (c) 2008 Movement Disorder Society.

Kinematic angular parameters in PD: reliability of joint angle curves and comparison with healthy subjects

BACKGROUND

Most previous biomechanical studies of Parkinson's disease (PD) have been restricted to the description of spatiotemporal parameters and certain peak values for angular parameters. The reliability of joint angle curves and comparisons with control data are of major interest in PD, since variability in gait cycle timing is a feature of this pathology.

METHODS

We used a video motion analysis system to record kinematic, spatiotemporal and angular parameters in 32 'off-drug' PD patients. The reliability of the patients' lower limb joint angle curves in the sagittal plane were analysed using the intra-class correlation coefficient (ICC), together with fast Fourier transform (FFT) analysis and hierarchical classification for discarding deviant curves. Lastly, we compared average curves (using a mixed model and the bootstrap method) for the less-affected and more-affected sides of PD patients and then compared the patient data with the results from 30 age-matched controls.

RESULTS

The ICC-based procedure was easily applicable. Only 9.4% and 12.5% of the patients' hip and knee curves (respectively) were deemed to be unreliable. However, the PD patients' very high cycle-to-cycle variability in the sagittal plane ankle curves prevented us from applying to this joint. For the knee joint, the curves for the most disabled patients (who walked at below 0.5 m/s) were not reliable. We did not find any differences between the less and more disabled sides. The differences between patient and control curves concerned the double-support time during the stance phase and the time point for maximum knee flexion during the swing phase. Patients and controls differed in terms of the hip extension phase, with lower values in PD.

CONCLUSION

We have developed the use of validated statistic tools for unambiguously comparing PD patients and controls in terms of joint angle curve differences.

Role of attentional resources on gait performance in Huntington's disease

Patients with Huntington's disease (HD) suffer from cognitive deficits with impaired executive functions, including limited attentional resources. We sought to use a dual-task paradigm to evaluate attentional demands and the ability of patients with HD to concentrate on two tasks simultaneously. We analyzed the interference effects of cognitive and motor tasks on walking in HD and the contribution of clinical symptoms to gait disturbances. Patients and controls were asked to perform either a motor task (carrying a tray with four glasses), a cognitive task (counting backwards), or no task at all while walking at their preferred speed. Kinematic spatial parameters, temporal parameters, and angular parameters related to gait were recorded in 15 patients and 15 controls by means of a videomotion analysis system. Gait instability was assessed using the stride-to-stride variability of the various gait parameters. For patients with HD, performing a concurrent cognitive task resulted in a lower gait speed (compared with free walking), with decreased cadence and stride length. However, this effect was not observed in controls. Performing a motor task did not change any kinematic gait parameters in either HD or control subjects. We found correlations between gait speed in the dual cognitive/walking task on one hand and the motor UHDRS score, cognitive status and executive function on the other. Patients with HD had greater difficulty walking while performing a concurrent cognitive task; the drain on attentional resources deteriorated walking performance.

Freezing and hypokinesia of gait induced by stimulation of the subthalamic region

We report a case of a Parkinson's disease patient treated by bilateral deep brain stimulation of the subthalamic nucleus, who developed freezing and hypokinesia of gait induced by stimulation through a left-side misplaced electrode which was more antero-medial than the planned trajectory. Subsequently, correct repositioning of the left electrode afforded complete relief of gait disturbances. Freezing and hypokinesia of gait may be side effects of deep brain stimulation of the subthalamic region due to current spreading antero-medially to the subthalamic nucleus. These side effects are not subject to habituation and restrict any increase in stimulation parameters. We hypothesize that pallidal projections to the pedunculopontine nucleus could be responsible for these gait disturbances in our patient.