Effects of Non-Invasive Brain Stimulation for Degenerative Cerebellar Ataxia: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to assess the effectiveness of non-invasive brain stimulation (NIBS), including repetitive transcranial magnetic stimulation (rTMS) and transcranial electrical stimulation (tES), as a neurological intervention for degenerative cerebellar ataxia (DCA) based on preregistration (PROSPERO: CRD42023379192).

OBJECTIVE

We aimed to explore clinical outcomes and examine the parameters associated with NIBS efficacy in DCA patients.

METHODS

The PubMed, Cochrane Library, CHINAL, and PEDro databases were searched for relevant randomized controlled trials (RCTs). Data extraction, quality assessment, and heterogeneity analyses were conducted; the Grading, Recommendations, Assessment, Development, and Evaluation was used to assess the quality of evidence and a meta-analysis was performed.

RESULTS

Seventeen RCTs that included 661 patients on the scale for assessment and rating of ataxia (SARA) and 606 patients on the International Cooperative Ataxia Rating Scale (ICARS) were included. These RCTs showed a serious risk of bias (RoB) and low certainty of evidence for both outcomes. NIBS significantly reduced SARA (MD = -2.49, [95% confidence interval: -3.34, -1.64]) and ICARS (-5.27 [-7.06, -3.47]); the subgroup analysis showed significant effects: rTMS and tES reduced both outcomes. However, there were no significant differences in the effects of rTMS and tES. Additional subgroup analysis indicated the impact of rTMS frequency and the total number of tES sessions on ataxia.

CONCLUSION

Non-invasive brain stimulation may reduce ataxia in DCA patients, but the estimated effect size may change in future studies because the RoB was serious and the certainty of evidence was low, and the heterogeneity was high. To establish evidence for selecting NIBS methods and parameters, continued high-quality RCTs are required.

Local Dynamic Stability of Trunk During Gait is Responsive to Rehabilitation in Subjects with Primary Degenerative Cerebellar Ataxia

This study aimed to assess the responsiveness to the rehabilitation of three trunk acceleration-derived gait indexes, namely the harmonic ratio (HR), the short-term longest Lyapunov's exponent (sLLE), and the step-to-step coefficient of variation (CV), in a sample of subjects with primary degenerative cerebellar ataxia (swCA), and investigate the correlations between their improvements (∆), clinical characteristics, and spatio-temporal and kinematic gait features. The trunk acceleration patterns in the antero-posterior (AP), medio-lateral (ML), and vertical (V) directions during gait of 21 swCA were recorded using a magneto-inertial measurement unit placed at the lower back before (T0) and after (T1) a period of inpatient rehabilitation. For comparison, a sample of 21 age- and gait speed-matched healthy subjects (HSmatched) was also included. At T1, sLLE in the AP (sLLEAP) and ML (sLLEML) directions significantly improved with moderate to large effect sizes, as well as SARA scores, stride length, and pelvic rotation. sLLEML and pelvic rotation also approached the HSmatched values at T1, suggesting a normalization of the parameter. HRs and CV did not significantly modify after rehabilitation. ∆sLLEML correlated with ∆ of the gait subscore of the SARA scale (SARAGAIT) and ∆stride length and ∆sLLEAP correlated with ∆pelvic rotation and ∆SARAGAIT. The minimal clinically important differences for sLLEML and sLLEAP were ≥ 36.16% and ≥ 28.19%, respectively, as the minimal score reflects a clinical improvement in SARA scores. When using inertial measurement units, sLLEAP and sLLEML can be considered responsive outcome measures for assessing the effectiveness of rehabilitation on trunk stability during walking in swCA.

Effects of Anodal tDCS Applied Over the Cerebellum Combined with Physical Therapy on Center of Gravity Sway in a Patient with Cerebellar Ataxia: A Single-Case Study

Damage to the cerebellum results in dysfunctional standing postural control. Patients with cerebellar ataxia have a larger sway in the center of gravity (COG) while standing. Transcranial direct current stimulation (tDCS) has been applied in the rehabilitation of patients with central nervous system disorders; however, its effect on COG sway in patients with cerebellar ataxia remains unknown. We aimed to confirm the effects of anodal cerebellar tDCS (ctDCS) combined with physical therapy on COG sway in a patient with cerebellar ataxia using a retrospective ABA single-case study design. This study involved a patient with left cerebellar hemorrhage. Walking and postural balance rehabilitation were conducted in phase A. Anodal ctDCS was combined with the walking and postural balance rehabilitation in phase B. We measured COG sway in the open- and closed-eyes standing conditions daily throughout all the phases. In the open-eyes standing condition, there was no significant change in COG sway in phase B. Conversely, in the closed-eyes standing condition, the circumferential area, total sway path length, and anteroposterior sway path length decreased in phase B. No change was observed in the mediolateral sway path length. The combination of anodal ctDCS and physical therapy may decrease COG sway in patients with cerebellar ataxia in the closed-eyes standing condition, and its effect may be greater in the anteroposterior direction.

Ataxic hemiparesis: a narrative review for clinical practice in rehabilitation

BACKGROUND

Ataxic hemiparesis (AH) is a well-recognized clinical lacunar stroke syndrome, characterized by paresis with ataxia on the same side of the body. It affects patients with stroke involving the basal ganglia, pons, internal capsule, corona radiata, and thalamus. In the past, lacunar syndrome denotes good functional recovery with low mortality and morbidity rate. However, recent evidence suggests AH has an association with more debilitating outcomes in the long term.

OBJECTIVE

To provide a comprehensive narrative review of published literatures on the topics related with AH and update clinical practice including rehabilitation.

METHODS

Literature review was performed by using the keywords "Subcortical Ataxia," "Lacunar Stroke," "Diaschisis", and "Ataxic Hemiparesis" on PubMed and Google Scholar Engines from 1978 to 2022. All papers published in English were reviewed and manual search of references from retrieved literature was performed for other relevant articles.

RESULTS

A comprehensive review was carried out on the following topics: neuroanatomical localization, pathogenesis, clinical features and clinical assessment scales, pharmacological and non-pharmacological modalities for ataxia treatment, prognosis, and outcome.

CONCLUSION

AH imposes significant challenges on stroke survivors when it comes to remediation of balance and coordination. It is associated with increased risk of mortality, stroke recurrence, and dementia. Though application of the concept of neuroplasticity and the utilization of repetitive transcranial magnetic stimulation have shown early promising results, further research is needed to establish the practice guidelines for rehabilitation of patients with AH.

Physical Therapy and Aminopyridine for Downbeat Nystagmus Syndrome: A Case Report

BACKGROUND AND PURPOSE

Individuals with downbeat nystagmus (DBN) syndrome present with DBN, dizziness, blurred vision, and unsteady gait. Pharmacological intervention with 4-aminopyridine (4-AP) may be effective in improving oculomotor function, but there is minimal evidence to date that it improves gait. This suggests the possible benefit of combining pharmacotherapy with physical therapy to maximize outcomes. This case report documents improvements in gait and balance after physical therapy and aminopyridine (AP) in an individual with DBN syndrome.

CASE DESCRIPTION

The patient was a 70-year-old man with a 4-year history of worsening dizziness and imbalance, diagnosed with DBN syndrome. He demonstrated impaired oculomotor function, dizziness, and imbalance, which resulted in falls and limited community ambulation.

INTERVENTION

The patient completed a customized, tapered course of physical therapy over 6 months. Outcome measures included the 10-meter walk test, the Timed Up and Go (TUG), the Dynamic Gait Index (DGI), and the modified clinical test of sensory integration and balance.

OUTCOMES

Improvements exceeding minimal detectable change were demonstrated on the TUG and the DGI. Gait speed on the 10-meter walk test did not change significantly, but the patient was able to use a cane to ambulate in the community and reported no further falls.

DISCUSSION

Controlled studies are needed to explore the potential for AP to augment physical therapy in people with DBN syndrome. Physical therapists are encouraged to communicate with referring medical providers about the use of AP as pharmacotherapy along with physical therapy for individuals with DBN syndrome.

Effect of a Home-Base Core Stability Exercises in Hereditary Ataxia. A Randomized Controlled Trial. A Pilot Randomized Controlled Trial

BACKGROUND

Core stability exercises (CSE) have been shown to be effective in improving trunk function in several neurological diseases, but the evidence is scarce on Hereditary Ataxias (HA).

OBJECTIVE

To evaluate the effectiveness of a 5-week home-based CSE program in terms of ataxia severity, trunk function, balance confidence, gait speed, lower limb motor function, quality of life, health status and falls rate in HA individuals at short- and long-term.

METHODS

This is an assessor-blind randomized controlled clinical trial parallel group 1:1. The individuals were divided in experimental group (EG) performed standard care in addition to CSE, and control group (CG) performed standard care alone. The CSE home-program was conducted 1-h/day, 5-day/week for 5-week. The assessment was performed at baseline, endpoint (5-week), and follow-up (10-week). The primary outcomes were ataxia severity assessed by the Scale for the Assessment and Rating of Ataxia and trunk function assessed by Spanish-version of Trunk Impairment Scale 2.0. The secondary outcomes were balance confidence assessed by Activities-specific Balance Confidence (ABC), gait speed by 4-meter walk test (4-MWT), the lower limb motor function by 30-s sit-to-stand, quality of life by EuroQol 5-dimension 5-level (EQ-5D-5L), health-status by EQ-5D and falls rate.

RESULTS

Twenty-three HA individuals were recruited (51.8 ± 11.10 years). Statistically significant group-time interaction was shown in ABC (F:5.539; P = 0.007), EQ-5D-5L Total (F:4.836; P = 0.013), EQ 5D (F:7.207; P = 0.006).

CONCLUSIONS

No statistical differences between groups for ataxia severity and trunk function were observed. However, were differences for balance confidence, gait speed, quality of life, and falls rate in HA individuals.

Content Validity of the Modified Functional Scale for the Assessment and Rating of Ataxia (f-SARA) Instrument in Spinocerebellar Ataxia

The functional Scale for the Assessment and Rating of Ataxia (f-SARA) assesses Gait, Stance, Sitting, and Speech. It was developed as a potentially clinically meaningful measure of spinocerebellar ataxia (SCA) progression for clinical trial use. Here, we evaluated content validity of the f-SARA. Qualitative interviews were conducted among individuals with SCA1 (n = 1) and SCA3 (n = 6) and healthcare professionals (HCPs) with SCA expertise (USA, n = 5; Europe, n = 3). Interviews evaluated symptoms and signs of SCA and relevance of f-SARA concepts for SCA. HCP cognitive debriefing was conducted. Interviews were recorded, transcribed, coded, and analyzed by ATLAS.TI software. Individuals with SCA1 and 3 reported 85 symptoms, signs, and impacts of SCA. All indicated difficulties with walking, stance, balance, speech, fatigue, emotions, and work. All individuals with SCA1 and 3 considered Gait, Stance, and Speech relevant f-SARA concepts; 3 considered Sitting relevant (42.9%). All HCPs considered Gait and Speech relevant; 5 (62.5%) indicated Stance was relevant. Sitting was considered a late-stage disease indicator. Most HCPs suggested inclusion of appendicular items would enhance clinical relevance. Cognitive debriefing supported clarity and comprehension of f-SARA. Maintaining current abilities on f-SARA items for 1 year was considered meaningful for most individuals with SCA1 and 3. All HCPs considered meaningful changes as stability in f-SARA score over 1-2 years, 1-2-point change in total f-SARA score, and deviation from natural history. These results support content validity of f-SARA for assessing SCA disease progression in clinical trials.

Structural Validity of the Mini-Balance Evaluation Systems Test in Individuals With Spinocerebellar Ataxia: A Rasch Analysis Study

OBJECTIVE

To examine the structural validity of the Mini-Balance Evaluation Systems Test (Mini-BESTest) in individuals with spinocerebellar ataxia (SCA).

DESIGN

Methodological research on data gathered in a cross-sectional study. A Rasch analysis was conducted (partial credit model).

SETTING

Inpatients in a hospital rehabilitation setting.

PARTICIPANTS

A pooled sample of patients with SCA (N=65 [total 110 data]; 23 women, 42 men; mean±SD age 63.1±9.9y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We evaluated the Mini-BESTest's category structure, unidimensionality, and measurement accuracy (0: unable to perform or requiring help to 2: normal performance).

RESULTS

The Mini-BESTest rating scale fulfilled the category functioning criteria. The analysis of the standardized Rasch residuals showed the scale's unidimensionality, but there were 7 item pairs indicating local dependence. All of the items fit the underlying scale construct (dynamic balance), with the exception of item #1, "Sit to stand," which was an underfit. The Mini-BESTest demonstrated adequate reliability (person separation reliability=.87) and separated the patients into 5 strata. The item-difficulty measures ranged from -4.49 to 2.02 logits, and the person ability-item difficulty matching was very good (the mean of person ability=-.07 logits and the mean of item difficulty=.00). No floor or ceiling effects were detected. The keyform identified items with small (#11, "Walk with head turns, horizontal") and large (#3, "Stand on 1 leg") item thresholds.

CONCLUSIONS

The Mini-BESTest has a unidimensional balance assessment scale with good category structure and reliability even for individuals with SCA. However, it also has some inherent shortcomings such as fit statistics, local item dependencies, and item thresholds. The results obtained when the Mini-BESTest is administered to patients with cerebellar ataxia should, thus, be interpreted cautiously.

Glucocorticoid receptor-dependent therapeutic efficacy of tauroursodeoxycholic acid in preclinical models of spinocerebellar ataxia type 3

Spinocerebellar ataxia type 3 (SCA3) is an adult-onset neurodegenerative disease caused by a polyglutamine expansion in the ataxin-3 (ATXN3) gene. No effective treatment is available for this disorder, other than symptom-directed approaches. Bile acids have shown therapeutic efficacy in neurodegenerative disease models. Here, we pinpointed tauroursodeoxycholic acid (TUDCA) as an efficient therapeutic, improving the motor and neuropathological phenotype of SCA3 nematode and mouse models. Surprisingly, transcriptomic and functional in vivo data showed that TUDCA acts in neuronal tissue through the glucocorticoid receptor (GR), but independently of its canonical receptor, the farnesoid X receptor (FXR). TUDCA was predicted to bind to the GR, in a similar fashion to corticosteroid molecules. GR levels were decreased in disease-affected brain regions, likely due to increased protein degradation as a consequence of ATXN3 dysfunction being restored by TUDCA treatment. Analysis of a SCA3 clinical cohort showed intriguing correlations between the peripheral expression of GR and the predicted age at disease onset in presymptomatic subjects and FKBP5 expression with disease progression, suggesting this pathway as a potential source of biomarkers for future study. We have established a novel in vivo mechanism for the neuroprotective effects of TUDCA in SCA3 and propose this readily available drug for clinical trials in SCA3 patients.

Cerebellar, Not Nigrostriatal Degeneration Impairs Dexterity in Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) clinically manifests with either predominant nigrostriatal or cerebellopontine degeneration. This corresponds to two different phenotypes, one with predominant Parkinson's symptoms (MSA-P [multiple system atrophy-parkinsonian subtype]) and one with predominant cerebellar deficits (MSA-C [multiple system atrophy-cerebellar subtype]). Both nigrostriatal and cerebellar degeneration can lead to impaired dexterity, which is a frequent cause of disability in MSA.

OBJECTIVE

The aim was to disentangle the contribution of nigrostriatal and cerebellar degeneration to impaired dexterity in both subtypes of MSA.

METHODS

We thus investigated nigrostriatal and cerebellopontine integrity using diffusion microstructure imaging in 47 patients with MSA-P and 17 patients with MSA-C compared to 31 healthy controls (HC). Dexterity was assessed using the 9-Hole Peg Board (9HPB) performance.

RESULTS

Nigrostriatal degeneration, represented by the loss of cells and neurites, leading to a larger free-fluid compartment, was present in MSA-P and MSA-C when compared to HCs. Whereas no intergroup differences were observed between the MSAs in the substantia nigra, MSA-P showed more pronounced putaminal degeneration than MSA-C. In contrast, a cerebellopontine axonal degeneration was observed in MSA-P and MSA-C, with stronger effects in MSA-C. Interestingly, the degeneration of cerebellopontine fibers is associated with impaired dexterity in both subtypes, whereas no association was observed with nigrostriatal degeneration.

CONCLUSION

Cerebellar dysfunction contributes to impaired dexterity not only in MSA-C but also in MSA-P and may be a promising biomarker for disease staging. In contrast, no significant association was observed with nigrostriatal dysfunction. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A Novel de novo KIF1A Mutation in a Patient with Ataxia, Intellectual Disability and Mild Foot Deformity

Early-onset ataxias are often difficult to diagnose due to the genetic and phenotypic heterogeneity of patients. Whole exome sequencing (WES) is a powerful method for determining causative mutations of early-onset ataxias. We report a case in which a novel de novo KIF1A mutation was identified in a patient with ataxia, intellectual disability and mild foot deformity.A patient presented with sporadic forms of ataxia with mild foot deformity, intellectual disability, peripheral neuropathy, pyramidal signs, and orthostatic hypotension. WES was used to identify a novel de novo mutation in KIF1A, a known causative gene of neurodegeneration and spasticity with or without cerebellar atrophy or cortical visual impairment syndrome (NESCAVS).We report a novel phenotype of NESCAVS that is associated with a novel de novo missense mutation in KIF1A, which provides valuable information for the diagnosis of NESCAVS even in the era of WES. Early rehabilitation of patients with NESCAVS may prevent symptom worsening and improve the disease course.

Effectiveness of rehabilitation intervention in persons with Friedreich ataxia

Introduction

The relevance of rehabilitation in progressive neurological disorders, such as Friedreich's Ataxia (FRDA), has yet to be convincingly proven. FRDA is characterized by ataxia, loss of gait, scoliosis, cardiomyopathy, dysarthria and dysphagia, with reduced life expectancy. The disease onset is usually in adolescence, leading to progressive disability. Omaveloxolone has been recently approved as the first pharmacological treatment for FRDA in adults and adolescents aged 16 years and older. Regarding non-pharmacological therapies, neurorehabilitation is a valuable aid in addressing the symptoms and in maintaining the residual functioning. We performed a prospective observational cohort study to evaluate the efficacy of inpatient rehabilitation (IR) for people with FRDA.

Methods

A total of 42 individuals (29 adults and 13 children) with FRDA were recruited. There were 27 ambulant and 15 non-ambulant participants. The patients underwent IR of 3 and 4 weeks in children and adults, respectively. The IR treatment was designed to be applied within a multidisciplinary setting, so FRDA patients underwent, in addition to physiotherapy, also occupational therapy, practical manual activities and psychological support aiming to enhance transferable skills useful in the activities of daily living. The primary outcome was the Scale for the Assessment and Rating of Ataxia (SARA). Other measures were: Friedreich Ataxia Rating Scale (FARS) and Nine Hole Peg Test (NHPT). Furthermore, we used the 6 Minute Walk Test (6MWT), the Timed Up and Go (TUG) and the Berg Balance Scale (BBS) only on ambulant subjects. Outcomes were evaluated at baseline and at the end of the treatment.

Results

We report that the IR significantly improves motor performance and ataxia symptoms in patients with FRDA. Our study shows significant functional improvement in all the outcome measures used, except for NHPT bilaterally. FARS and SARA scores post-IR are significatively reduced when compared (p < 0.001).

Discussion

We demonstrate that IR programs in FRDA can provide a meaningful clinical improvement in terms of outcome measures. These findings could be useful when approaching progressive neurological disorders.

Injury of the Vestibulocerebellar Tract and Signs of Ataxia in Patients with Cerebellar Stroke

BACKGROUND

The vestibulocerebellar tract (VCT) is responsible for maintaining balance, spatial orientation, and coordination. Damage to the vestibular system is accompanied by symptoms of balance disorder or ataxia. This study aimed to compare cerebellar dysfunction according to VCT damage in patients with cerebellar stroke.

METHODS

Six patients with cerebellum injury were recruited. This study measured ataxia and hand function related to visuomotor integration and manual dexterity using the Purdue pegboard test. The primary and bilateral secondary VCTs were reconstructed to investigate the integrity of pathways using diffusion tensor imaging (DTI).

RESULTS

The ataxia sign was positive in five patients (83%) at onset. In the result of the pegboard test, all patients had hand dysfunction in the dominant hand (100%). Likewise, all patients also had non-dominant hand dysfunction (100%). On the DTI tractography, the left and right primary VCTs of the patients demonstrated a 25% injury rate. Furthermore, the injury rates of ipsilateral and contralateral secondary VCTs were 50% and 58%.

CONCLUSIONS

Ataxia is related to secondary VCTs, and hand dysfunction is also related to VCTs. Therefore, we believe that the current study will be helpful in evaluating and providing a clinical intervention strategy for patients with ataxia and hand dysfunction following cerebellar injury.

The S-Factor, a New Measure of Disease Severity in Spinocerebellar Ataxia: Findings and Implications

Spinocerebellar ataxias (SCAs) are progressive neurodegenerative disorders, but there is no metric that predicts disease severity over time. We hypothesized that by developing a new metric, the Severity Factor (S-Factor) using immutable disease parameters, it would be possible to capture disease severity independent of clinical rating scales. Extracting data from the CRC-SCA and READISCA natural history studies, we calculated the S-Factor for 438 participants with symptomatic SCA1, SCA2, SCA3, or SCA6, as follows: ((length of CAG repeat expansion - maximum normal repeat length) /maximum normal repeat length) × (current age - age at disease onset) × 10). Within each SCA type, the S-Factor at the first Scale for the Assessment and Rating of Ataxia (SARA) visit (baseline) was correlated against scores on SARA and other motor and cognitive assessments. In 281 participants with longitudinal data, the slope of the S-Factor over time was correlated against slopes of scores on SARA and other motor rating scales. At baseline, the S-Factor showed moderate-to-strong correlations with SARA and other motor rating scales at the group level, but not with cognitive performance. Longitudinally the S-Factor slope showed no consistent association with the slope of performance on motor scales. Approximately 30% of SARA slopes reflected a trend of non-progression in motor symptoms. The S-Factor is an observer-independent metric of disease burden in SCAs. It may be useful at the group level to compare cohorts at baseline in clinical studies. Derivation and examination of the S-factor highlighted challenges in the use of clinical rating scales in this population.

Interrater Reliability of the Scale for the Assessment and Rating of Ataxia, Berg Balance Scale, and Functional Independence Measure Motor Domain in Individuals With Hereditary Cerebellar Ataxia

OBJECTIVE

To determine the interrater reliability of the Scale for the Assessment and Rating of Ataxia (SARA), Berg Balance Scale (BBS), and motor domain of the FIM (m-FIM) administered by physiotherapists in individuals with a hereditary cerebellar ataxia (HCA).

DESIGN

Participants were assessed by 1 of 4 physiotherapists. Assessments were video-recorded and the remaining 3 physiotherapists scored the scales for each participant. Raters were blinded to each other's scores.

SETTING

Assessments were administered at 3 clinical locations in separate states in Australia.

PARTICIPANTS

Twenty-one individuals (mean age=47.63 years; SD=18.42; 13 male and 8 female) living in the community with an HCA were recruited (N=21).

MAIN OUTCOME MEASURES

Total and single-item scores of the SARA, BBS, and m-FIM were examined. The m-FIM was conducted by interview.

RESULTS

Intraclass coefficients (2,1) for the total scores of the m-FIM (0.92; 95% confidence interval [CI], 0.85-0.96), SARA (0.92; 95% CI, 0.86-0.96), and BBS (0.99; 95% CI, 0.98-0.99) indicated excellent interrater reliability. However, there was inconsistent agreement with the individual items, with SARA item 5 (right side) and item 7 (both sides) demonstrating poor interrater reliability and items 1 and 2 demonstrating excellent reliability.

CONCLUSIONS

The m-FIM (by interview), SARA, and BBS have excellent interrater reliability for use when assessing individuals with an HCA. Physiotherapists could be considered for administration of the SARA in clinical trials. However, further work is required to improve the agreement of the single-item scores and to examine the other psychometric properties of these scales.

Inborn Errors of Metabolism with Ataxia: Current and Future Treatment Options

A number of hereditary ataxias are caused by inborn errors of metabolism (IEM), most of which are highly heterogeneous in their clinical presentation. Prompt diagnosis is important because disease-specific therapies may be available. In this review, we offer a comprehensive overview of metabolic ataxias summarized by disease, highlighting novel clinical trials and emerging therapies with a particular emphasis on first-in-human gene therapies. We present disease-specific treatments if they exist and review the current evidence for symptomatic treatments of these highly heterogeneous diseases (where cerebellar ataxia is part of their phenotype) that aim to improve the disease burden and enhance quality of life. In general, a multimodal and holistic approach to the treatment of cerebellar ataxia, irrespective of etiology, is necessary to offer the best medical care. Physical therapy and speech and occupational therapy are obligatory. Genetic counseling is essential for making informed decisions about family planning.

Responsiveness of the Scale for the Assessment and Rating of Ataxia and Natural History in 884 Recessive and Early Onset Ataxia Patients

OBJECTIVE

The Scale for the Assessment and Rating of Ataxia (SARA) is the most widely applied clinical outcome assessment (COA) for genetic ataxias, but presents metrological and regulatory challenges. To facilitate trial planning, we characterize its responsiveness (including subitem-level relations to ataxia severity and patient-focused outcomes) across a large number of ataxias, and provide first natural history data for several of them.

METHODS

Subitem-level correlation and distribution-based analysis of 1,637 SARA assessments in 884 patients with autosomal recessive/early onset ataxia (370 with 2-8 longitudinal assessments) were complemented by linear mixed effects modeling to estimate progression and sample sizes.

RESULTS

Although SARA subitem responsiveness varied between ataxia severities, gait/stance showed a robust granular linear scaling across the broadest range (SARA < 25). Responsiveness was diminished by incomplete subscale use at intermediate or upper levels, nontransitions ("static periods"), and fluctuating decreases/increases. All subitems except nose-finger showed moderate-to-strong correlations to activities of daily living, indicating that metric properties-not content validity-limit SARA responsiveness. SARA captured mild-to-moderate progression in many genotypes (eg, SYNE1-ataxia: 0.55 points/yr, ataxia with oculomotor apraxia type 2: 1.14 points/yr, POLG-ataxia: 1.56 points/yr), but no change in others (autosomal recessive spastic ataxia of Charlevoix-Saguenay, COQ8A-ataxia). Whereas sensitivity to change was optimal in mild ataxia (SARA < 10), it substantially deteriorated in advanced ataxia (SARA > 25; 2.7-fold sample size). Use of a novel rank-optimized SARA without subitems finger-chase and nose-finger reduces sample sizes by 20 to 25%.

INTERPRETATION

This study comprehensively characterizes COA properties and annualized changes of the SARA across and within a large number of ataxias. It suggests specific approaches for optimizing its responsiveness that might facilitate regulatory qualification and trial design. ANN NEUROL 2023;94:470-485.

Advances in cerebellar disorders: pre-clinical models, therapeutic targets, and challenges

INTRODUCTION

Cerebellar ataxias (CAs) represent neurological disorders with multiple etiologies and a high phenotypic variability. Despite progress in the understanding of pathogenesis, few therapies are available so far. Closing the loop between preclinical studies and therapeutic trials is important, given the impact of CAs upon patients' health and the roles of the cerebellum in multiple domains. Because of a rapid advance in research on CAs, it is necessary to summarize the main findings and discuss future directions.

AREAS COVERED

We focus our discussion on preclinical models, cerebellar reserve, the therapeutic management of CAs, and suitable surrogate markers. We searched Web of Science and PubMed using keywords relevant to cerebellar diseases, therapy, and preclinical models.

EXPERT OPINION

There are many symptomatic and/or disease-modifying therapeutic approaches under investigation. For therapy development, preclinical studies, standardization of disease evaluation, safety assessment, and demonstration of clinical improvements are essential. Stage of the disease and the level of the cerebellar reserve determine the goals of the therapy. Deficits in multiple categories and heterogeneity of CAs may require disease-, stage-, and symptom-specific therapies. More research is needed to clarify how therapies targeting the cerebellum influence both basal ganglia and the cerebral cortex, poorly explored domains in CAs.

Effects of non-invasive brain stimulation for degenerative cerebellar ataxia: a protocol for a systematic review and meta-analysis

INTRODUCTION

To date, the medical and rehabilitation needs of people with degenerative cerebellar ataxia (DCA) are not fully met because no curative treatment has yet been established. Movement disorders such as cerebellar ataxia and balance and gait disturbance are common symptoms of DCA. Recently, non-invasive brain stimulation (NIBS) techniques, including repetitive transcranial magnetic stimulation and transcranial electrical stimulation, have been reported as possible intervention methods to improve cerebellar ataxia. However, evidence of the effects of NIBS on cerebellar ataxia, gait ability, and activity of daily living is insufficient. This study will aim to systematically evaluate the clinical effects of NIBS on patients with DCA.

METHODS AND ANALYSIS

We will conduct a preregistered systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We will include randomised controlled trials to assess the effects of NIBS on patients with DCA. The primary clinical outcome will be cerebellar ataxia, as measured by the Scale for Assessment and Rating of Ataxia and the International Cooperative Ataxia Rating Scale. The secondary outcomes will include gait speed, functional ambulatory capacity and functional independence measure, as well as any other reported outcomes that the reviewer considers important. The following databases will be searched: PubMed, Cochrane Central Register of Controlled Trials, CINAHL and PEDro. We will assess the strength of the evidence included in the studies and estimate the effects of NIBS.

ETHICS AND DISSEMINATION

Because of the nature of systematic reviews, no ethical issues are anticipated. This systematic review will provide evidence on the effects of NIBS in patients with DCA. The findings of this review are expected to contribute to clinical decision-making towards selecting NIBS techniques for treatment and generating new clinical questions to be addressed.

PROSPERO REGISTRATION NUMBER

CRD42023379192.

Targeting Ion Channels and Purkinje Neuron Intrinsic Membrane Excitability as a Therapeutic Strategy for Cerebellar Ataxia

In degenerative neurological disorders such as Parkinson's disease, a convergence of widely varying insults results in a loss of dopaminergic neurons and, thus, the motor symptoms of the disease. Dopamine replacement therapy with agents such as levodopa is a mainstay of therapy. Cerebellar ataxias, a heterogeneous group of currently untreatable conditions, have not been identified to have a shared physiology that is a target of therapy. In this review, we propose that perturbations in cerebellar Purkinje neuron intrinsic membrane excitability, a result of ion channel dysregulation, is a common pathophysiologic mechanism that drives motor impairment and vulnerability to degeneration in cerebellar ataxias of widely differing genetic etiologies. We further propose that treatments aimed at restoring Purkinje neuron intrinsic membrane excitability have the potential to be a shared therapy in cerebellar ataxia akin to levodopa for Parkinson's disease.

Home Aerobic Training for Cerebellar Degenerative Diseases: a Randomized Controlled Trial

Balance training has shown some benefits in cerebellar ataxia whereas the effects of aerobic training are relatively unknown. To determine whether a phase III trial comparing home aerobic to balance training in ambulatory patients with cerebellar ataxia is warranted, we conducted a single-center, assessor-blinded, randomized controlled trial. Nineteen subjects were randomized to aerobic training and 17 subjects to balance training. The primary outcome was improvement in ataxia as measured by the Scale for the Assessment and Rating of Ataxia (SARA). Secondary outcomes included safety, training adherence, and balance improvements. There were no differences between groups at baseline. Thirty-one participants completed the trial, and there were no training-related serious adverse events. Compliance to training was over 70%. There was a mean improvement in ataxia symptoms of 1.9 SARA points (SD 1.62) in the aerobic group compared to an improvement of 0.6 points (SD 1.34) in the balance group. Although two measures of balance were equivocal between groups, one measure of balance showed greater improvement with balance training compared to aerobic training. In conclusion, this 6-month trial comparing home aerobic versus balance training in cerebellar ataxia had excellent retention and adherence to training. There were no serious adverse events, and training was not interrupted by minor adverse events like falls or back pain. There was a significant improvement in ataxia symptoms with home aerobic training compared to balance training, and a phase III trial is warranted. Clinical trial registration number: NCT03701776 on October 8, 2018.

Rehabilitation effects in idiopathic normal pressure hydrocephalus: a randomized controlled trial

BACKGROUND

Gait-balance disturbances are core symptoms of idiopathic normal pressure hydrocephalus (iNPH). However, the rehabilitation effects of cerebrospinal fluid (CSF) shunting along with other treatment or no further treatment (natural course [NC]) for iNPH are unknown.

OBJECTIVES

This study evaluated whether dynamic equilibrium gait training (DEGT) can improve gait-balance functions after CSF shunting of patients with iNPH compared to standard exercise (SE) and NC. Furthermore, it investigated the incidence of falls.

METHODS

A total of 70 patients with iNPH who underwent CSF shunting were randomly assigned to 6 weeks of DEGT (n = 23), 6 weeks of SE (n = 23), or NC (n = 24). Evaluation was performed at baseline (preoperatively) and at 1 week, 7 weeks (postintervention), and 6 months postoperatively (follow-up). Outcomes were measured using the functional gait assessment (FGA), 10-m walk test, timed up-and-go test, life-space assessment (LSA), and fall incidence.

RESULTS

A total of 65 participants completed the study. During the intention-to-treat analysis, the DEGT group demonstrated significant recovery of gait-balance functions according to only the FGA at postintervention and follow-up compared to the SE and NC groups; however, recovery of the SE group did not differ from that of the NC group. The DEGT group had a significantly lower fall incidence than the other groups at follow-up. Significantly better LSA results were observed for all groups at follow-up compared to baseline; however, no difference in LSA results were observed between groups.

CONCLUSIONS

DEGT in addtion to CSF shunting can facilitate the recovery of gait-balance function and reduce the fall incidence of iNPH patients.

Effects of Intensive Exercise on Cognitive Dysfunction in Patients With Pure Cerebellar Degeneration: A Single-Arm Pilot Study

Objective To clarify the profile of cognitive dysfunction and the effects of intensive exercise in spinocerebellar degeneration (SCD).Methods We enrolled 60 healthy controls and 16 patients with purely cerebellar type SCD without gait disturbance or organic changes other than cerebellar changes. To assess cognitive function, we evaluated the participants using the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Montreal Cognitive Assessment-Japanese (MoCA-J) at admission and after intensive exercise.Results Compared to the controls, SCD patients showed significant cognitive decline. As a result of intensive exercise, significant improvements in motor and cognitive functions were observed: the MMSE score improved from 27.7±1.9 to 29.0±1.3 points (p<0.001); the FAB score improved from 14.8±2.2 to 15.8±2.0 points (p=0.002); and the MoCA-J score improved from 24.6±2.2 to 26.7±1.9 points (p<0.001). For sub-scores, significant improvements were noted in serial 7, lexical fluency, motor series, and delayed recall.Conclusion Our study indicates that intensive exercise can be effective not only for motor dysfunction but also for cognitive dysfunction (Clinical Trial Registration No. UMIN-CTR: UMIN000040079).

Objective Assessment of Upper-Extremity Motor Functions in Spinocerebellar Ataxia Using Wearable Sensors

The study presents a novel approach to objectively assessing the upper-extremity motor symptoms in spinocerebellar ataxia (SCA) using data collected via a wearable sensor worn on the patient's wrist during upper-extremity tasks associated with the Assessment and Rating of Ataxia (SARA). First, we developed an algorithm for detecting/extracting the cycles of the finger-to-nose test (FNT). We extracted multiple features from the detected cycles and identified features and parameters correlated with the SARA scores. Additionally, we developed models to predict the severity of symptoms based on the FNT. The proposed technique was validated on a dataset comprising the seventeen (n = 17) participants' assessments. The cycle detection technique showed an accuracy of 97.6% in a Bland-Altman analysis and a 94% accuracy (F1-score of 0.93) in predicting the severity of the FNT. Furthermore, the dependency of the upper-extremity tests was investigated through statistical analysis, and the results confirm dependency and potential redundancies in the upper-extremity SARA assessments. Our findings pave the way to enhance the utility of objective measures of SCA assessments. The proposed wearable-based platform has the potential to eliminate subjectivity and inter-rater variabilities in assessing ataxia.

Monitoring gait at home with radio waves in Parkinson's disease: A marker of severity, progression, and medication response

Parkinson's disease (PD) is the fastest-growing neurological disease in the world. A key challenge in PD is tracking disease severity, progression, and medication response. Existing methods are semisubjective and require visiting the clinic. In this work, we demonstrate an effective approach for assessing PD severity, progression, and medication response at home, in an objective manner. We used a radio device located in the background of the home. The device detected and analyzed the radio waves that bounce off people's bodies and inferred their movements and gait speed. We continuously monitored 50 participants, with and without PD, in their homes for up to 1 year. We collected over 200,000 gait speed measurements. Cross-sectional analysis of the data shows that at-home gait speed strongly correlates with gold-standard PD assessments, as evaluated by the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III subscore and total score. At-home gait speed also provides a more sensitive marker for tracking disease progression over time than the widely used MDS-UPDRS. Further, the monitored gait speed was able to capture symptom fluctuations in response to medications and their impact on patients' daily functioning. Our study shows the feasibility of continuous, objective, sensitive, and passive assessment of PD at home and hence has the potential of improving clinical care and drug clinical trials.

Activation of TrkB-Akt signaling rescues deficits in a mouse model of SCA6

Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease resulting in motor coordination deficits and cerebellar pathology. Expression of brain-derived neurotrophic factor (BDNF) is reduced in postmortem tissue from SCA6 patients. Here, we show that levels of cerebellar BDNF and its receptor, tropomyosin receptor kinase B (TrkB), are reduced at an early disease stage in a mouse model of SCA6 (SCA684Q/84Q). One month of exercise elevated cerebellar BDNF expression and improved ataxia and cerebellar Purkinje cell firing rate deficits. A TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), likewise improved motor coordination and Purkinje cell firing rate and elevated downstream Akt signaling. Prolonged 7,8-DHF administration persistently improved ataxia when treatment commenced near disease onset but was ineffective when treatment was started late. These data suggest that 7,8-DHF, which is orally bioavailable and crosses the blood-brain barrier, is a promising therapeutic for SCA6 and argue for the importance of early intervention for SCA6.

Explainable artificial intelligence based on feature optimization for age at onset prediction of spinocerebellar ataxia type 3

Existing treatments can only delay the progression of spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) after onset, so the prediction of the age at onset (AAO) can facilitate early intervention and follow-up to improve treatment efficacy. The objective of this study was to develop an explainable artificial intelligence (XAI) based on feature optimization to provide an interpretable and more accurate AAO prediction. A total of 1,008 affected SCA3/MJD subjects from mainland China were analyzed. The expanded cytosine-adenine-guanine (CAG) trinucleotide repeats of 10 polyQ-related genes were genotyped and included in related models as potential AAO modifiers. The performance of 4 feature optimization methods and 10 machine learning (ML) algorithms were compared, followed by building the XAI based on the SHapley Additive exPlanations (SHAP). The model constructed with an artificial neural network (ANN) and feature optimization of Crossing-Correlation-StepSVM performed best and achieved a coefficient of determination (R2) of 0.653 and mean absolute error (MAE), root mean square error (RMSE), and median absolute error (MedianAE) of 4.544, 6.090, and 3.236 years, respectively. The XAI explained the predicted results, which suggests that the factors affecting the AAO were complex and associated with gene interactions. An XAI based on feature optimization can improve the accuracy of AAO prediction and provide interpretable and personalized prediction.

The Outcomes of an Individualized Physical Therapy Program in CALFAN Syndrome: A Case Report

PURPOSE

This case report investigated the effectiveness of an individualized physical therapy program in CALFAN syndrome.

CASE DESCRIPTION

A 13-year-old girl participated in physical therapy, which included trunk stabilization, balance training, and functional exercises for 12 weeks.

ASSESSMENTS

The International Cooperative Ataxia Rating Scale; Trunk Impairment Scale; Pediatric Quality of Life Inventory; Functional Independence Measure for Children; Quick Disability of the Arm, Shoulder, and Hand Questionnaire; 9-Hole Peg Test; and Cobb measurement were used as outcome measures.

RESULTS

Positive changes were observed in the International Cooperative Ataxia Rating Scale; Quick Disability of the Arm, Shoulder, and Hand Questionnaire; Pediatric Quality of Life Inventory; Trunk Impairment Scale; Functional Independence Measure; and the 9-Hole Peg Test. The Cobb angle was increased by 2° in the thoracic region and reduced by 11° in the lumbar region.

CONCLUSIONS

Physical therapy improved quality of life, functional independence, trunk control, and upper extremity performance.

WHAT THIS ADDS TO EVIDENCE

This case report is the first to support the effectiveness of physical therapy for a child with CALFAN syndrome.

Consensus Paper: Strengths and Weaknesses of Animal Models of Spinocerebellar Ataxias and Their Clinical Implications

Spinocerebellar ataxias (SCAs) represent a large group of hereditary degenerative diseases of the nervous system, in particular the cerebellum, and other systems that manifest with a variety of progressive motor, cognitive, and behavioral deficits with the leading symptom of cerebellar ataxia. SCAs often lead to severe impairments of the patient's functioning, quality of life, and life expectancy. For SCAs, there are no proven effective pharmacotherapies that improve the symptoms or substantially delay disease progress, i.e., disease-modifying therapies. To study SCA pathogenesis and potential therapies, animal models have been widely used and are an essential part of pre-clinical research. They mainly include mice, but also other vertebrates and invertebrates. Each animal model has its strengths and weaknesses arising from model animal species, type of genetic manipulation, and similarity to human diseases. The types of murine and non-murine models of SCAs, their contribution to the investigation of SCA pathogenesis, pathological phenotype, and therapeutic approaches including their advantages and disadvantages are reviewed in this paper. There is a consensus among the panel of experts that (1) animal models represent valuable tools to improve our understanding of SCAs and discover and assess novel therapies for this group of neurological disorders characterized by diverse mechanisms and differential degenerative progressions, (2) thorough phenotypic assessment of individual animal models is required for studies addressing therapeutic approaches, (3) comparative studies are needed to bring pre-clinical research closer to clinical trials, and (4) mouse models complement cellular and invertebrate models which remain limited in terms of clinical translation for complex neurological disorders such as SCAs.

Preliminary Study of Vibrotactile Feedback during Home-Based Balance and Coordination Training in Individuals with Cerebellar Ataxia

Intensive balance and coordination training is the mainstay of treatment for symptoms of impaired balance and mobility in individuals with hereditary cerebellar ataxia. In this study, we compared the effects of home-based balance and coordination training with and without vibrotactile SA for individuals with hereditary cerebellar ataxia. Ten participants (five males, five females; 47  ±  12 years) with inherited forms of cerebellar ataxia were recruited to participate in a 12-week crossover study during which they completed two six-week blocks of balance and coordination training with and without vibrotactile SA. Participants were instructed to perform balance and coordination exercises five times per week using smartphone balance trainers that provided written, graphic, and video guidance and measured trunk sway. The pre-, per-, and post-training performance were assessed using the Scale for the Assessment and Rating of Ataxia (SARA), SARAposture&gait sub-scores, Dynamic Gait Index, modified Clinical Test of Sensory Interaction in Balance, Timed Up and Go performed with and without a cup of water, and multiple kinematic measures of postural sway measured with a single inertial measurement unit placed on the participants’ trunks. To explore the effects of training with and without vibrotactile SA, we compared the changes in performance achieved after participants completed each six-week block of training. Among the seven participants who completed both blocks of training, the change in the SARA scores and SARAposture&gait sub-scores following training with vibrotactile SA was not significantly different from the change achieved following training without SA (p>0.05). However, a trend toward improved SARA scores and SARAposture&gait sub-scores was observed following training with vibrotactile SA; compared to their pre-vibrotacile SA training scores, participants significantly improved their SARA scores (mean=−1.21, p=0.02) and SARAposture&gait sub-scores (mean=−1.00, p=0.01). In contrast, no significant changes in SARA scores and SARAposture&gait sub-scores were observed following the six weeks of training without SA compared to their pre-training scores immediately preceding the training block without vibrotactile SA (p>0.05). No significant changes in trunk kinematic sway parameters were observed as a result of training (p>0.05). Based on the findings from this preliminary study, balance and coordination training improved the participants’ motor performance, as captured through the SARA. Vibrotactile SA may be a beneficial addition to training regimens for individuals with hereditary cerebellar ataxia, but additional research with larger sample sizes is needed to assess the significance and generalizability of these findings.

Participation and Functional Independence in Adults With Recessive Spastic Ataxia of Charlevoix-Saguenay

Background. Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a progressive disorder where upper and lower extremities motor performances may bring participation restriction. Purpose. To document participation in adults with ARSAC and explore associations with motor performances. Method. Twenty-eight participants took part in the study. Participation was assessed using the LIFE-H. Motor performance was assessed using several outcomes including the SARA, LEMOCOT, Berg Balance Scale, 10-Meter Walk Test, and Finger-to-nose Test. Findings. Participation was significantly lower in the wheelchair user subgroup. Also, for 29 activities out of 77, at least 15% of participants reported severely disrupted participation. Participation was correlated with upper and lower limbs coordination, walking ability, balance, disease severity, and fine dexterity (Spearman r = .41–0.85, p < .03). Implications. Results showed significant participation restrictions and suggest that interventions aiming to improve or compensate upper and lower limbs functions could help to decrease disease burden.

Cognitive and Physical Intervention in Metals’ Dysfunction and Neurodegeneration

Metals—especially iron, copper and manganese—are important elements of brain functions and development. Metal-dysregulation homeostasis is associated with brain-structure damage to the motor, cognitive and emotional systems, and leads to neurodegenerative processes. There is more and more evidence that specialized cognitive and motor exercises can enhance brain function and attenuate neurodegeneration in mechanisms, such as improving neuroplasticity by altering the synaptic structure and function in many brain regions. Psychological and physical methods of rehabilitation are now becoming increasingly important, as pharmacological treatments for movement, cognitive and emotional symptoms are limited. The present study describes physical and cognitive rehabilitation methods of patients associated with metal-induced neurotoxicity such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease and Wilson’s disease. In our review, we describe physical (e.g., virtual-reality environments, robotic-assists training) and psychological (cognitive training, cognitive stimulation, neuropsychological rehabilitation and cognitive-behavioral and mindfulness-based therapies) methods, significantly improving the quality of life and independence of patients associated with storage diseases. Storage diseases are a diverse group of hereditary metabolic defects characterized by the abnormal cumulation of storage material in cells. This topic is being addressed due to the fact that rehabilitation plays a vital role in the treatment of neurodegenerative diseases. Unfortunately so far there are no specific guidelines concerning physiotherapy in neurodegenerative disorders, especially in regards to duration of exercise, type of exercise and intensity, as well as frequency of exercise. This is in part due to the variety of symptoms of these diseases and the various levels of disease progression. This further proves the need for more research to be carried out on the role of exercise in neurodegenerative disorder treatment.

Effects of therapeutic exercise on disease severity, balance, and functional Independence among individuals with cerebellar ataxia: A systematic review with meta-analysis

BACKGROUND

Balance impairments are common in cerebellar ataxia. Exercises are beneficial in this population.

OBJECTIVE

Explore the benefits of therapeutic exercises on disease severity, balance and functional independence in cerebellar ataxia.

METHODS

Databases were searched from inception until July 2021. Methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale and the Newcastle-Ottawa Scale (NOS); and quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool.

RESULTS

Twenty-six studies were included and eight studies of low to high PEDro methodological quality were meta-analyzed. 'Low' to 'moderate' GRADE quality evidence supports the use of therapeutic exercises to reduce disease severity, assessed using the Scale for the Assessment and Rating of Ataxia [weighted mean difference (WMD): -3.3; 95% confidence interval (95%CI): -3.7, -2.8; p < .01]; and improve balance, assessed using the Berg Balance Scale (WMD: 2.6; 95%CI: 1.1, 4.2; p < .01). The effect of therapeutic exercises on functional independence was insignificant (WMD: 1.6; 95%CI: -1.5, 4.6; p = .31).

CONCLUSION

Low to moderate evidence from studies of low to high methodological quality provides some support for therapeutic exercises for reducing disease severity among non-hereditary degenerative cerebellar ataxia and improving balance among acquired cerebellar ataxia. Exercises did not benefit functional independence. Additional studies of large sample size and high methodological quality are necessary to substantiate these findings.

Case Report: Late-Onset Autosomal Recessive Cerebellar Ataxia Associated With SYNE1 Mutation in a Chinese Family

Autosomal recessive cerebellar ataxia type 1 (ARCA-1), also known as autosomal recessive spinocerebellar ataxia type 8 (SCAR8), is caused by spectrin repeat containing nuclear envelope protein 1 (SYNE1) gene mutation. Nesprin-1, encoded by SYNE1, is widely expressed in various tissues, especially in the striated muscle and cerebellum. The destruction of Nesprin-1 is related to neuronal and neuromuscular lesions. It has been reported that SYNE1 gene variation is associated with Emery-Dreifuss muscular dystrophy type 4, arthrogryposis multiplex congenita, SCAR8, and dilated cardiomyopathy. The clinical manifestations of SCAR8 are mainly characterized by relatively pure cerebellar ataxia and may be accompanied by upper and/or lower motor neuron dysfunction. Some affected people may also display cerebellar cognitive affective syndrome. It is conventionally held that the age at the onset of SCAR8 is between 6 and 42 years (the median age is 17 years). Here, we report a pedigree with SCAR8 where the onset age in the proband is 48 years. This case report extends the genetic profile and clinical features of SCAR8. A new pathogenic site (c.7578del; p.S2526Sfs*8) located in SYNE1, which is the genetic cause of the patient, was identified via whole exome sequencing (WES).

Rehabilitation in patients with cerebellar ataxias

ABSTRACT Cerebellar ataxias comprise a heterogeneous group of diseases characterized by motor and non-motor symptoms, which can be acquired, degenerative, or have a genetic cause, such as spinocerebellar ataxias (SCA). Usually, the genetic and neurodegenerative forms of cerebellar ataxias present a progressive and inevitable worsening of the clinical picture so that rehabilitation treatment is fundamental. Rehabilitation treatment includes physical therapy, respiratory therapy, speech, voice and swallowing therapy, occupational therapy, and new technologies, such as the use of exergames. The current treatment of patients with cerebellar ataxias, especially neurodegenerative forms, genetic or not, should include these different forms of rehabilitation, with the main objective of improving the quality of life of patients.

Tai Chi for Dynamic Balance Training Among Individuals with Cerebellar Ataxia: An Assessor-Blinded Randomized-Controlled Trial

Objective: To evaluate the immediate and long-term effects of 12 weeks of Tai Chi training on dynamic balance and disease severity among individuals with cerebellar ataxia (CA).

Design: An assessor-blinded, two-arm, parallel-group randomized-controlled trial was conducted among 24 participants with CA. Participants were randomized to receive either Tai Chi intervention (n = 12) or usual care (n = 12). Dynamic balance was assessed using the Berg Balance Scale (BBS), Scale for the Assessment and Rating of Ataxia (SARA) balance sub-component of the SARA (SARAbal), Sensory Organization Test, and Limits of Stability test. Disease severity was assessed using the SARA and health-related quality of life using the EuroQol visual analog scale. Assessments were completed at baseline (week 0: T1), postintervention (week 12: T2), and at the end of the 24-week (week 36: T3) follow-up period.

Interventions: The 8-form Tai Chi exercise was delivered in 60-min sessions, three times a week for 12 weeks. Participants were asked to complete an unsupervised home Tai Chi exercise program over the next 24 weeks. Participants in the usual care control group completed all study measures but did not receive any intervention.

Results: Compared with the usual care control group, after 12 weeks of Tai Chi training, the experimental group demonstrated beneficial effects for dynamic balance assessed using the BBS (mean difference [MD]: 4, 95% confidence interval [CI]: −1.06 to 8.71) and the SARAbal (MD: −1.33, 95% CI: −2.66 to 2.33). The effect size ranged from small to large. The benefits gained were not sustained after 24 weeks during the follow-up assessment. Tai Chi did not benefit disease severity and health-related quality of life in this population.

Conclusion: Some evidence supports the immediate beneficial effects of 12 weeks of Tai Chi training on the dynamic balance among individuals with CA.

Australia New Zealand Clinical Trials Registry (ACTRN12617000327381).

The protective role of exercise against age-related neurodegeneration

Endurance exercise is a widely accessible, low-cost intervention with a variety of benefits to multiple organ systems. Exercise improves multiple indices of physical performance and stimulates pronounced health benefits reducing a range of pathologies including metabolic, cardiovascular, and neurodegenerative disorders. Endurance exercise delays brain aging, preserves memory and cognition, and improves symptoms of neurodegenerative pathologies like Amyotrophic Lateral Sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, and various ataxias. Potential mechanisms underlying the beneficial effects of exercise include neuronal survival and plasticity, neurogenesis, epigenetic modifications, angiogenesis, autophagy, and the synthesis and release of neurotrophins and cytokines. In this review, we discuss shared benefits and molecular pathways driving the protective effects of endurance exercise on various neurodegenerative diseases in animal models and in humans.

Current and Emerging Treatment Modalities for Spinocerebellar Ataxias

INTRODUCTION

Spinocerebellar ataxias (SCA) are a group of rare neurodegenerative diseases that dramatically affect the lives of affected individuals and their families. Despite having a clear understanding of SCA's etiology, there are no current symptomatic or neuroprotective treatments approved by the FDA.

AREAS COVERED

Research efforts have greatly expanded the possibilities for potential treatments, including both pharmacological and non-pharmacological interventions. Great attention is also being given to novel therapeutics based in gene therapy, neurostimulation, and molecular targeting. This review article will address the current advances in the treatment of SCA and what potential interventions are on the horizon.

EXPERT OPINION

SCA is a highly complex and multifaceted disease family with the majority of research emphasizing symptomatic pharmacologic therapies. As pre-clinical trials for SCA and clinical trials for other neurodegenerative conditions illuminate the efficacy of disease modifying therapies such as AAV-mediated gene therapy and ASOs, the potential for addressing SCA at the pre-symptomatic stage is increasingly promising.

Rehabilitation in movement disorders: From basic mechanisms to clinical strategies

Movement disorders encompass a variety of conditions affecting the nervous system at multiple levels. The pathologic processes underlying movement disorders alter the normal neural functions and could lead to aberrant neuroplastic changes and to clinical phenomenology that is not expressed only through mere motor symptoms. Given this complexity, the responsiveness to pharmacologic and surgical therapies is often disappointing. Growing evidence supports the efficacy of neurorehabilitation for the treatment of movement disorders. Specific form of training involving both goal-based practice and aerobic training could drive and modulate neuroplasticity in order to restore the circuitries dysfunctions and to achieve behavioral gains. This chapter provides an overview of the alterations expressed in some movement disorders in terms of clinical signs and symptoms and plasticity, and suggests which ones and why tailored rehabilitation strategies should be adopted for the management of the different movement disorders.

Occupational Therapy and the IMPACT Act: Part 1. A Systematic Review of Evidence for Fall Prevention and Reduction, Community Discharge and Reintegration, and Readmission Prevention Interventions

IMPORTANCE

Interventions that prevent falls, facilitate discharge after hospitalization, and reduce hospital readmissions assist occupational therapy practitioners in demonstrating professional value, improving quality, and reducing costs.

OBJECTIVE

In this systematic review, we address three outcome areas of the Improving Medicare Post-Acute Care Transformation (IMPACT) Act of 2014: prevention and reduction of falls, facilitation of community discharge and reintegration, and prevention of hospital readmission.

DATA SOURCES

We conducted a search of the literature published between 2009 and 2019. Study Selection and Data Collection: We developed operational definitions to help us identify articles that answered the search question for each outcome area. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

FINDINGS

We found 53 articles that address the three outcome areas. Regarding the prevention and reduction of falls, low strength of evidence is available for interventions focusing on a single fall risk and for customized interventions addressing multiple risks. Moderate strength of evidence supports structured community fall risk prevention interventions. Low strength of evidence was found for community discharge and reintegration interventions that include physical activity and educational programming. Low to moderate strength of evidence was found for readmission prevention interventions for patients with four types of condition. Conclusion and Relevance: Several intervention themes in the three outcome areas of interest are supported by few studies or by studies with a moderate risk of bias. Additional research is needed that supports the value of occupational therapy interventions in these outcome areas. What This Article Adds: Our study provides important insights into the state of the evidence related to occupational therapy interventions to address three outcome areas of the IMPACT Act.

Occupational Therapy and the IMPACT Act: Part 1. A Systematic Review of Evidence for Fall Prevention and Reduction, Community Discharge and Reintegration, and Readmission Prevention Interventions

IMPORTANCE

Interventions that prevent falls, facilitate discharge after hospitalization, and reduce hospital readmissions assist occupational therapy practitioners in demonstrating professional value, improving quality, and reducing costs.

OBJECTIVE

In this systematic review, we address three outcome areas of the Improving Medicare Post-Acute Care Transformation (IMPACT) Act of 2014: prevention and reduction of falls, facilitation of community discharge and reintegration, and prevention of hospital readmission.

DATA SOURCES

We conducted a search of the literature published between 2009 and 2019. Study Selection and Data Collection: We developed operational definitions to help us identify articles that answered the search question for each outcome area. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

FINDINGS

We found 53 articles that address the three outcome areas. Regarding the prevention and reduction of falls, low strength of evidence is available for interventions focusing on a single fall risk and for customized interventions addressing multiple risks. Moderate strength of evidence supports structured community fall risk prevention interventions. Low strength of evidence was found for community discharge and reintegration interventions that include physical activity and educational programming. Low to moderate strength of evidence was found for readmission prevention interventions for patients with four types of condition. Conclusion and Relevance: Several intervention themes in the three outcome areas of interest are supported by few studies or by studies with a moderate risk of bias. Additional research is needed that supports the value of occupational therapy interventions in these outcome areas. What This Article Adds: Our study provides important insights into the state of the evidence related to occupational therapy interventions to address three outcome areas of the IMPACT Act.

Motor training-related brain reorganization in patients with cerebellar degeneration

Cerebellar degeneration progressively impairs motor function. Recent research showed that cerebellar patients can improve motor performance with practice, but the optimal feedback type (visual, proprioceptive, verbal) for such learning and the underlying neuroplastic changes are unknown. Here, patients with cerebellar degeneration (N = 40) and age‐ and sex‐matched healthy controls (N = 40) practiced single‐joint, goal‐directed forearm movements for 5 days. Cerebellar patients improved performance during visuomotor practice, but a training focusing on either proprioceptive feedback, or explicit verbal feedback and instruction did not show additional benefits. Voxel‐based morphometry revealed that after training gray matter volume (GMV) was increased prominently in the visual association cortices of controls, whereas cerebellar patients exhibited GMV increase predominantly in premotor cortex. The premotor cortex as a recipient of cerebellar efferents appears to be an important hub in compensatory remodeling following damage of the cerebro‐cerebellar motor system.

Pharmacological and non-pharmacological management of spinocerebellar ataxia: A systematic review

Spinocerebellar ataxias (SCA) comprise a rare, genetic subgroup within the degenerative ataxias and are dominantly inherited, with up to 48 recognized genetic subtypes. While an updated review on the management of degenerative ataxia is published recently, an evidence-based review focussed on the management of SCA is lacking. Here, we reviewed the pharmacological and non-pharmacological management of SCA by conducting a systematic review on Medline Ovid and Scopus. Of 29,284 studies identified, 47 studies (pharmacological: n = 25; non-pharmacological: n = 22) that predominantly involved SCA patients were included. Twenty studies had a high risk of bias based on the Cochrane's Collaboration risk of bias tool. As per the European Federation of Neurological Societies 2004 guideline for therapeutic intervention, the remaining 27 studies were of Class I (n = 4) and Class II (n = 23) evidence. Only two therapies had Level A recommendations for the management of ataxia symptoms: riluzole and immediate in-patient neurorehabilitation. Ten therapies had Level B recommendations for managing ataxia symptoms and require further investigations with better study design. These include high dose valproate acid, branched-chain amino acid, intravenous trehalose; restorative rehabilitation using cycling regimen and videogame; and cerebellar stimulations using transcranial direct current stimulation and transcranial magnetic stimulation. Lithium and coaching on psychological adjustment received Level B recommendation for depressive symptoms and quality of life, respectively. Heterogeneous study designs, different genotypes, and non-standardized clinical measures alongside short duration and small sample sizes may hamper meaningful clinical translation. Therefore, rating of recommendations only serve as points of reference.

Gait training with a wearable curara® robot for cerebellar ataxia: a single-arm study

Background

Ataxic gait is one of the most common and disabling symptoms in people with degenerative cerebellar ataxia. Intensive and well-coordinated inpatient rehabilitation improves ataxic gait. In addition to therapist-assisted gait training, robot-assisted gait training has been used for several neurological disorders; however, only a small number of trials have been conducted for degenerative cerebellar ataxia. We aimed to validate the rehabilitative effects of a wearable “curara®” robot developed in a single-arm study of people with degenerative cerebellar ataxia.

Methods

Twenty participants with spinocerebellar ataxia or multiple system atrophy with predominant cerebellar ataxia were enrolled. The clinical trial duration was 15 days. We used a curara® type 4 wearable robot for gait training. We measured the following items at days 0, 7, and 14: Scale for the Assessment and Rating of Ataxia, 10-m walking time (10 mWT), 6-min walking distance (6 mWD), and timed up and go test. Gait parameters (i.e., stride duration and length, standard deviation of stride duration and length, cadence, ratio of the stance and swing phases, minimum and maximum knee joint angles, and minimum and maximum hip joint angles) were obtained using a RehaGait®. On days 1–6 and 8–13, the participants were instructed to conduct gait training for 30 ± 5 min with curara®. We calculated the improvement rate as the difference of values between days 14 and 0 divided by the value on day 0. Differences in the gait parameters were analyzed using a generalized linear mixed model with Bonferroni’s correction.

Results

Data from 18 participants were analyzed. The mean improvement rate of the 10 mWT and 6 mWD was 19.0% and 29.0%, respectively. All gait parameters, except the standard deviation of stride duration and length, improved on day 14.

Conclusions

Two-week RAGT with curara® has rehabilitative effects on gait function comparable to those of therapist-assisted training. Although the long-term effects after a month of RAGT with curara® are unclear, curara® is an effective tool for gait training of people with degenerative ataxia.

Trial registration jRCT, jRCTs032180164. Registered: 27 February 2019; retrospectively registered. https://jrct.niph.go.jp/en-latest-detail/jRCTs032180164.

Pallidal degenerations and related disorders: an update

Neurodegenerative disorders involving preferentially the globus pallidus, its efferet and afferent circuits and/or related neuronal systems are rare. They include a variety of both familial and sporadic progressive movement disorders, clinically manifesting as choreoathetosis, dystonia, Parkinsonism, akinesia or myoclonus, often associated with seizures, mental impairment and motor or cerebellar symptoms. Based on the involved neuronal systems, this heterogenous group has been classified into several subgroups: "pure" pallidal atrophy (PPA) and extended forms, pallidonigral and pallidonigrospinal degeneration (PND, PNSD), pallidopyramidal syndrome (PPS), a highly debatable group, pallidopontonigral (PPND), nigrostriatal-pallidal-pyramidal degeneration (NSPPD) (Kufor-Rakeb syndrome /KRS), pallidoluysian degeneration (PLD), pallidoluysionigral degeneration (PLND), pallidoluysiodentate atrophy (PLDA), the more frequent dentatorubral-pallidoluysian atrophy (DRPLA), and other hereditary multisystem disorders affecting these systems, e.g., neuroferritinopathy (NF). Some of these syndromes are sporadic, others show autosomal recessive or dominant heredity, and for some specific gene mutations have been detected, e.g., ATP13A2/PARK9 (KRS), FTL1 or ATP13A2 (neuroferritinopathy), CAG triple expansions in gene ATN1 (DRPLA) or pA152T variant in MAPT gene (PNLD). One of the latter, and both PPND and DRPLA are particular subcortical 4-R tauopathies, related to progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and frontotemporal lobe degeneration-17 (FTLD-17), while others show additional 3-R and 4-R tauopathies or TDP-43 pathologies. The differential diagnosis includes a large variety of neurodegenerations ranging from Huntington and Joseph-Machado disease, tauopathies (PSP), torsion dystonia, multiple system atrophy, neurodegeneration with brain iron accumulation (NBIA), and other extrapyramidal disorders. Neuroimaging data and biological markers have been published for only few syndromes. In the presence of positive family histories, an early genetic counseling may be effective. The etiology of most phenotypes is unknown, and only for some pathogenic mechanisms, like polyglutamine-induced oxidative stress and autophagy in DRPLA, mitochondrial dysfunction induced by oxidative stress in KRS or ferrostasis/toxicity and protein aggregation in NF, have been discussed. Currently no disease-modifying therapy is available, and symptomatic treatment of hypo-, hyperkinetic, spastic or other symptoms may be helpful.

Amelioration of motor and nonmotor symptoms in cortical cerebellar atrophy and multiple system atrophy-cerebellar type by inpatient rehabilitation: a retrospective study

Sporadic spinocerebellar degenerative diseases such as multiple system atrophy (cerebellar type) and cortical cerebellar atrophy typically present with cerebellar ataxia. Multiple system atrophy is characterized by ataxia, with parkinsonism, dysautonomia and neuropsychiatric symptoms, resulting in reduced quality of life. Effects of physical rehabilitation focused on motor symptoms with ataxia in nonmultiple system atrophy patients have been reported; however, without addressing concomitant nonmotor symptoms. Here, we examined the motor, nonmotor and quality of life effects of inpatient physical rehabilitation in 15 multiple systems atrophy and nine cortical cerebellar atrophy patients without dementia. Rehabilitation involved a 4-week hospitalization with physical, occupational and speech therapy. The following assessments were conducted at admission and discharge: the scale for the assessment and rating of ataxia for ataxia; Montreal cognitive assessment for cognition, hospital anxiety and depression scale for emotion and medical outcomes study short-form for health-related quality of life. Data were analyzed for statistical significance (P < 0.05) using the Wilcoxon signed-rank test. In patients with multiple system atrophy, rehabilitation significantly improved ataxia, cognition with mild cognitive impairment (73.3%) and health-related quality of life; however, patients with depression (86.7%) showed no improvement in emotional health and quality of life. Similar effects on motor and nonmotor symptoms were observed in patients with cortical cerebellar atrophy. This suggests that inpatient rehabilitation could not only improve motor and nonmotor functions, but also the quality of life in patients with spinocerebellar degenerative disease.

Physiology of Cerebellar Reserve: Redundancy and Plasticity of a Modular Machine

The cerebellum is endowed with the capacity for compensation and restoration after pathological injury, a property known as cerebellar reserve. Such capacity is attributed to two unique morphological and physiological features of the cerebellum. First, mossy fibers that convey peripheral and central information run mediolaterally over a wide area of the cerebellum, resulting in the innervation of multiple microzones, commonly known as cerebellar functional units. Thus, a single microzone receives redundant information that can be used in pathological conditions. Secondly, the circuitry is characterized by a co-operative interplay among various forms of synaptic plasticity. Recent progress in understanding the mechanisms of redundant information and synaptic plasticity has allowed outlining therapeutic strategies potentiating these neural substrates to enhance the cerebellar reserve, taking advantage of the unique physiological properties of the cerebellum which appears as a modular and potentially reconfiguring brain structure.

Phase I Single-Blinded Randomized Controlled Trial Comparing Balance and Aerobic Training in Degenerative Cerebellar Disease

INTRODUCTION

Primary deficits in individuals with cerebellar degeneration include ataxia, unstable gait, and incoordination. Balance training is routinely recommended to improve function whereas little is known regarding aerobic training.

OBJECTIVE

To determine the feasibility of conducting a randomized trial comparing balance and aerobic training in individuals with cerebellar degeneration.

DESIGN

Assessor blinded randomized control phase I trial.

SETTING

Assessments in medical center, home training.

PARTICIPANTS

Twenty participants with cerebellar degeneration were randomized to home balance or aerobic training.

INTERVENTION

Aerobic training consisted of 4 weeks of stationary bicycle training, five times per week for 30-minute sessions. Home balance training consisted of performing the same duration of easy, moderate, and/or hard exercises.

OUTCOME MEASURES

Scale for the Assessment and Rating of Ataxia (SARA), maximal oxygen consumption (VO2 max), Dynamic Gait Index, Timed Up and Go, gait speed.

RESULTS

All 20 participants completed assigned training with no major adverse events. Seven of each group attained target training duration, frequency, and intensity. Although both groups had significant improvements in ataxia severity, balance, and gait measures, there were greater improvements in individuals who performed aerobic training in ataxia severity and maximal oxygen consumption when compared to balance training. The effect size for these outcome measures was determined to be large, indicating a phase II trial comparing the benefits of aerobic and balance training was feasible and required 26 participants per group. Improvements in SARA score and VO2 max remained in the aerobic training group at 3 months posttraining, but these improvements were trending back to baseline. In contrast, all balance group measures for pretraining and 3 months posttraining were statistically similar.

CONCLUSIONS

A phase II trial comparing balance and aerobic training in individuals with cerebellar degeneration is feasible. Benefits trended back toward baseline after training stopped, although benefits of longer duration exercise programs still need to be determined.

Balance and physical functioning in Spinocerebellar ataxias 3 and 10

OBJECTIVES

Limitations of functional capacity and balance are common features of the natural history of spinocerebellar ataxias (SCA). However, their onset and progression patterns differ according to subtype. The aim of our study was to compare physical functionality and balance parameters in SCA10 and SCA3 patients, correlating with clinical variables.

MATERIALS & METHODS

Cross-sectional study evaluating ninety-five SCA patients (60 with SCA3 and 35 with SCA10) with validated scales for functional independence, balance and the severity of signs and symptoms.

RESULTS

The groups were similar in terms of age and gender, and results were adjusted for age at symptom onset. The SCA10 patients had better results for balance and functional independence (p < 0.007). They also had lower scores for disease severity (p < 0.0002) and the subitems gait (p < 0.0005), posture (p < 0.0021) and sitting balance (p < 0.0008). Symptom progression in both groups was similar for patients with a disease duration of up to ten years, but there was a more marked decline in SCA3 patients after this period.

CONCLUSIONS

We have shown that disease progression as assessed by balance and physical functioning is slower in SCA10 patients than SCA3 patients, particularly after 10 years of disease. These findings are important as they can help to characterize the disease, assisting in the development of new therapies and rehabilitation programs.