Comprehensive systematic review summary: Treatment of cerebellar motor dysfunction and ataxia: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

The Effects of Exergame on Postural Control in Individuals with Ataxia: a Rater-Blinded, Randomized Controlled, Cross-over Study

Exergame trainings might have therapeutic value in ataxic patients. The aim of this study was to investigate the effect of exergame training with an exercise program on postural control by comparing it with traditional balance and coordination exercise program. Nineteen patients were randomly allocated to two groups. In the first group, exergame training and an exercise program (EEP) were applied together for the first 8 weeks; after 10 weeks washout, a conventional exercise program (CEP) was applied for the second 8 weeks. In the second group, the CEP was applied first followed by the EEP. Outcome measures were Limits of Stability test (LoS), International Classification Ataxia Ratio Scale (ICARS), Berg Balance Scale (BBS), and Timed-Up and Go test with a cognitive task (TUG-C), Reactive postural control and sensory orientation subscales of the Mini-BESTest. Seventeen patients (mean age ± SD, 32.53 ± 11.07 years) completed the study. ICARS, BBS scores improved only after EEP (p < 0.05). While there was no change in the RT and MVL parameters of the LoS test after EEP, the MXE, EPE, and DCL parameters improved significantly (p < 0.05). The MXE and MVL parameters of LoS improved after CEP (p < 0.05). There were no significant improvements in the Mini-BESTest's reactive postural control and sensory orientation subscale scores after both EEP and CEP (p > 0.05). The results of the present study demonstrated that exergame training can be used as a complementary training option in physiotherapy to improve postural control in patients with ataxia. ClinicalTrial.gov Identifier: NCT03607058.

[Adult-onset ataxias]

Adult-onset ataxias are clinically and etiologically heterogeneous disorders affecting the cerebellum and its afferent and efferent connections. Early symptoms are usually a progressive ataxia of gait and stance, followed by limb ataxia, cerebellar dysarthria and oculomotor disturbances. In addition, various neurological and non-neurological symptoms may occur. Hereditary, acquired, and sporadic degenerative ataxias are distinguished. A detailed medical history and clinical examination as well as cranial magnetic resonance imaging are essential for the diagnostic work-up; however, specific biochemical or genetic tests are often required to make a definitive diagnosis. Besides rehabilitative therapies, specific drugs or dietary recommendations are available for some types of ataxia. An early and precise diagnosis is important to avoid redundant diagnostics and for counselling of patients and their relatives.

A Variation in FGF14 Is Associated with Downbeat Nystagmus in a Genome-Wide Association Study

Downbeat nystagmus (DBN) is a frequent form of acquired persisting central fixation nystagmus, often associated with other cerebellar ocular signs, such as saccadic smooth pursuit or gaze-holding deficits. Despite its distinct clinical features, the underlying etiology of DBN often remains unclear. Therefore, a genome-wide association study (GWAS) was conducted in 106 patients and 2609 healthy controls of European ancestry to identify genetic variants associated with DBN. A genome-wide significant association (p < 5 × 10^-8) with DBN was found for a variation on chromosome 13 located within the fibroblast growth factor 14 gene (FGF14). FGF14 is expressed in Purkinje cells (PCs) and a reduction leads to a decreased spontaneous firing rate and excitability of PCs, compatible with the pathophysiology of DBN. In addition, mutations in the FGF14 gene cause spinocerebellar ataxia type 27. Suggestive associations (p < 1 × 10^-05) could be detected for 15 additional LD-independent loci, one of which is also located in the FGF14 gene. An association of a region containing the dihydrofolate reductase (DHFR) and MutS Homolog 3 (MSH3) genes on chromosome 5 was slightly below the genome-wide significance threshold. DHFR is relevant for neuronal regulation, and a dysfunction is known to induce cerebellar damage. Among the remaining twelve suggestive associations, four genes (MAST4, TPPP, FTMT, and IDS) seem to be involved in cerebral pathological processes. Thus, this GWAS analysis has identified a potential genetic contribution to idiopathic DBN, including suggestive associations to several genes involved in postulated pathological mechanisms of DBN (i.e., impaired function of cerebellar PCs).

[Less common, but clinically important episodic vertigo syndromes]

Die Differentialdiagnostik der selteneren, episodischen Schwindelsyndrome kann im klinischen Alltag eine Herausforderung darstellen, insbesondere wenn sie keine im Intervall messbaren Befunde in der neuro-ophthalmologischen oder -otologischen Routinediagnostik hinterlassen. Ursächlich für diese episodischen Schwindelsyndrome können physiologische Reaktionen aufgrund intersensorischer Inkongruenzen oder angeborene bzw. erworbene neuroanatomische/neurophysiologische Varianten sein, die zu vestibulären Reizsyndromen führen. In dieser Übersicht fokussieren wir auf die folgenden, aus unserer Sicht wichtigen vestibulären Syndrome: Bewegungskrankheit, Mal de Debarquement Syndrom, Visuelle Höhenintoleranz, Vestibularisparoxysmie, Zervikaler Schwindel, Episodische Ataxie Typ II und Syndrome eines dritten mobilen Fensters wie das Syndrom der Dehiszenz des superioren Bogengangs. Die Ausprägung reicht von milden Symptomen mit geringer Belastung bis hin zu schweren Krankheitsbildern mit relevanter Alltagseinschränkung. Sie können vom Kindes- oder Jugendalter bis ins Senium auftreten, teilweise mit abweichender Symptomatik. Durch gezielte Anamnese und ggf. erweiterte vestibuläre Diagnostik in einem spezialisierten Zentrum lassen sich diese Syndrome oft klar herausarbeiten und einer erfolgreichen Therapie zuführen.

Placebo response in degenerative cerebellar ataxias: a descriptive review of randomized, placebo-controlled trials

Placebo response in degenerative cerebellar ataxias (CAs) has never been studied despite the large number of randomized controlled trials (RCTs) that have been conducted. In this descriptive review, we aimed to examine the placebo response in patients with CAs. We performed a literature search on PubMed for RCTs on CAs that were published from 1977 to January 2020 and collected data on the changes from the baseline to the endpoint on various objective ataxia-associated clinical rating scales. We reviewed 56 clinical trials, finally including 35 parallel-group studies and excluding 21 cross-over studies. The included studies were categorized as follows: (1) studies showing significant improvements in one or more ataxia scales in the placebo groups (n = 3); (2) studies reporting individual placebo responders with improvements in one or more ataxia scales in the placebo groups (n = 5)-the overall proportion of placebo responders was 31.9%; (3) studies showing mean changes in the direction of improvement in at least one ataxia scale in the placebo groups, though not statistically significant (n = 19); (4) studies showing no placebo response in any of the ataxia scales in the placebo groups (n = 4); (5) studies where data on the placebo groups were unavailable (n = 9). This review demonstrated the placebo response in patients with CAs on various objective ataxia scales. Our study emphasizes that the placebo response should be considered when designing, analyzing, and interpreting clinical trials and in clinical practice in CA patients.

Morning Walk®-Assisted Gait Training Improves Walking Ability and Balance in Patients with Ataxia: a Randomized Controlled Trial

This study aimed to investigate walking ability and balance improvement of patients with ataxia caused by brain lesions after end-effector type robot (Morning Walk^®)-assisted gait training. This study randomly assigned 19 patients to one of two groups: 30 minutes of Morning Walk^® training with 1 hour of conventional physiotherapy (Morning Walk^® group; n = 10) or 1.5 hours of conventional physiotherapy (Control group; n = 9). Five treatment sessions per week were given for 3 weeks. The primary outcomes were walking ability and balance, which were assessed by the functional ambulation category (FAC) and Berg Balance Scale (BBS), respectively. The secondary outcomes included 10-meter Walk Test (10mWT), Rivermead Mobility Index (RMI), Motricity Index (MI), and Modified Barthel Index (MBI). At baseline, there was no statistically significant difference between the two groups except MBI. After the treatment, the Morning Walk^® group showed significant improvement in the FAC, BBS, 10mWT, RMI and MBI. The control group showed significant improvement in the BBS, 10mWT, RMI and MBI. Inter-group comparison demonstrated that the ∆FAC, ∆10mWT and ∆RMI of the Morning Walk^® group were significantly higher than those of the control group. Our results suggest that the patients with ataxia receiving Morning Walk^®-assisted gait training might improve greater in walking ability and balance than those trained with conventional physiotherapy.

Rehabilitation Treatment of Motor Dysfunction Patients Based on Deep Learning Brain-Computer Interface Technology

In recent years, brain-computer interface (BCI) is expected to solve the physiological and psychological needs of patients with motor dysfunction with great individual differences. However, the classification method based on feature extraction requires a lot of prior knowledge when extracting data features and lacks a good measurement standard, which makes the development of BCI. In particular, the development of a multi-classification brain-computer interface is facing a bottleneck. To avoid the blindness and complexity of electroencephalogram (EEG) feature extraction, the deep learning method is applied to the automatic feature extraction of EEG signals. It is necessary to design a classification model with strong robustness and high accuracy for EEG signals. Based on the research and implementation of a BCI system based on a convolutional neural network, this article aims to design a brain-computer interface system that can automatically extract features of EEG signals and classify EEG signals accurately. It can avoid the blindness and time-consuming problems caused by the machine learning method based on feature extraction of EEG data due to the lack of a large amount of prior knowledge.

Autosomal Recessive Cerebellar Ataxias With Elevated Alpha-Fetoprotein: Uncommon Diseases, Common Biomarker

alpha-Fetoprotein (AFP) is a biomarker of several autosomal recessive cerebellar ataxias (ARCAs), especially ataxia telangiectasia (AT) and ataxia with oculomotor apraxia (AOA) type 2 (AOA2). More recently, slightly elevated AFP has been reported in AOA1 and AOA4. Interestingly, AOA1, AOA2, AOA4, and AT are overlapping ARCAs characterized by oculomotor apraxia, with oculocephalic dissociation, choreo-dystonia, and/or axonal sensorimotor neuropathy, in addition to cerebellar ataxia with cerebellar atrophy. The genetic backgrounds in these disorders play central roles in nuclear maintenance through DNA repair [ATM (AT), APTX (AOA1), or PNKP (AOA4)] or RNA termination [SETX (AOA2)]. Partially discriminating thresholds of AFP have been proposed as a way to distinguish between ARCAs with elevated AFP. In these entities, elevated AFP may be an epiphenomenon as a result of liver transcriptional dysregulation. AFP is a simple and reliable biomarker for the diagnosis of ARCA in performance and interpretation of next-generation sequencing. Here, we evaluated clinical, laboratory, imaging, and molecular data of the group of ARCAs that share elevated AFP serum levels that have been described in the past two decades. © 2020 International Parkinson and Movement Disorder Society.

Update on the Treatment of Ataxia: Medication and Emerging Therapies

While rehabilitation therapies always help patients with ataxia, there are currently no FDA-approved treatments for ataxia. Medications are available to treat symptoms that may complicate an ataxic illness, e.g., tremor, myoclonus, dystonia, and rigidity, which are discussed elsewhere in this volume. Spasticity, pain, fatigue, depression, sleep disturbances, cognitive decline, and bowel and bladder dysfunction, if they occur, all have multiple available drugs and therapies for symptomatic use. There is also an extensive literature on off-label uses of various medications to improve imbalance. The pipeline of emerging therapies for symptomatic and possible disease-modifying management of ataxia gives hope that we will soon see the first of many FDA-approved drugs for ataxic illnesses.

Effects of cerebellar transcranial magnetic stimulation on ataxias: A randomized trial

INTRODUCTION

Cerebellar ataxia remains a neurological symptom orphan of treatment interventions, despite being prevalent and incapacitating. We aimed to study, in a double-blind design, whether cerebellar modulation could improve ataxia.

METHODS

We included patients with diagnosis of spinocerebellar ataxia type 3, multiple systems atrophy cerebellar type, or post-lesion ataxia. Patients received five sessions each of sham and active cerebellar 1 Hz deep repetitive transcranial magnetic stimulation in randomized order. Our primary outcome was the decrease in the Scale for the Assessment and Rating of Ataxia when comparing phases (active x sham). Secondary outcomes measures included the International Cooperative Ataxia Rating Scale, and other motor, cognitive, and quality of life scales. This study was registered at clinicaltrials.gov (protocol NCT03213106).

RESULTS

Twenty-four patients aged 29-74 years were included in our trial. After active stimulation, the Scale for the Assessment and Rating of Ataxia score was significantly lower than the score after sham stimulation [median (interquartile range) of 10.2 (6.2, 16.2) versus 12.8 (9.6, 17.8); p = 0.002]. The International Cooperative Ataxia Rating Scale score also improved after active stimulation versus sham [median (interquartile range) of 29.0 (21.0, 43.5) versus 32.8 (22.0, 47.0); p = 0.005]. Other secondary outcomes were not significantly modified by stimulation. No patient presented severe side effects, and nine presented mild and self-limited symptoms.

CONCLUSIONS

Our protocol was safe and well-tolerated. These findings suggest that cerebellar modulation may improve ataxic symptom and provide reassurance about safety for clinical practice.

Episodic Ataxias: Faux or Real?

The term Episodic Ataxias (EA) was originally used for a few autosomal dominant diseases, characterized by attacks of cerebellar dysfunction of variable duration and frequency, often accompanied by other ictal and interictal signs. The original group subsequently grew to include other very rare EAs, frequently reported in single families, for some of which no responsible gene was found. The clinical spectrum of these diseases has been enormously amplified over time. In addition, episodes of ataxia have been described as phenotypic variants in the context of several different disorders. The whole group is somewhat confused, since a strong evidence linking the mutation to a given phenotype has not always been established. In this review we will collect and examine all instances of ataxia episodes reported so far, emphasizing those for which the pathophysiology and the clinical spectrum is best defined.

Non-Invasive Cerebellar Stimulation in Neurodegenerative Ataxia: A Literature Review

Cerebellar ataxias are a heterogenous group of degenerative disorders for which we currently lack effective and disease-modifying interventions. The field of non-invasive brain stimulation has made much progress in the development of specific stimulation protocols to modulate cerebellar excitability and try to restore the physiological activity of the cerebellum in patients with ataxia. In light of limited evidence-based pharmacologic and non-pharmacologic treatment options for patients with ataxia, several different non-invasive brain stimulation protocols have emerged, particularly employing repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) techniques. In this review, we summarize the most relevant rTMS and tDCS therapeutic trials and discuss their implications in the care of patients with degenerative ataxias.

Effect of rovatirelin in patients with cerebellar ataxia: two randomised double-blind placebo-controlled phase 3 trials

OBJECTIVE

To investigate the efficacy of rovatirelin, a thyrotropin-releasing hormone analogue, for ataxias in patients with spinocerebellar degeneration (SCD).

METHODS

Two multicentre, randomised, double-blind, placebo-controlled phase 3 studies (KPS1301, KPS1305) enrolled patients with predominant cerebellar ataxia, including SCA6, SCA31 or cortical cerebellar atrophy. KPS1301 enrolled patients with truncal ataxia and KPS1305 enrolled patients with truncal and limb ataxia. Each study included 4 weeks of pretreatment, a 28-week or 24-week treatment period and 4 weeks of follow-up. Patients were randomised (1:1:1) to rovatirelin (1.6 or 2.4 mg) or placebo in KPS1301, and randomised (1:1) to rovatirelin 2.4 mg or placebo in KPS1305. The primary endpoint was change in Scale for the Assessment and Rating of Ataxia (SARA) total scores. Pooled analysis was performed in patients who met the SARA recruitment criteria of KPS1305.

RESULTS

From October 2013 to May 2014, KPS1301 enrolled 411 patients; 374 were randomised to rovatirelin 1.6 mg (n=125), rovatirelin 2.4 mg (n=126) or placebo (n=123). From November 2016 to August 2017, KPS1305 enrolled 241 patients; 203 were randomised to rovatirelin 2.4 mg (n=101) or placebo (n=102). The primary endpoint showed no significant difference between rovatirelin and placebo in these two studies. In the pooled analysis (n=278), the difference between rovatirelin 2.4 mg (n=140) and placebo (n=138) was -0.61 (-1.64 vs -1.03; 95% CI -1.16 to -0.06; p=0.029) in the adjusted mean change in the SARA total score.

CONCLUSIONS

Rovatirelin is a potentially effective treatment option for SCD.

TRIAL REGISTRATION NUMBER

NCT01970098; NCT02889302.

Relationship between ataxia and inferior cerebellar peduncle injury in patients with cerebral infarct

INTRODUCTION

The inferior cerebellar peduncle (ICP) is a major neural tract in the cerebellum and is involved in coordination of movement and proprioceptive; therefore, ICP injury can be accompanied by poor coordination of movement, including ataxia. In this study, using diffusion tensor tractography (DTT), we investigated the relationship between ataxia and ICP injury in patients with cerebral infarct.

METHODS

We recruited 14 stroke patients with ataxia after the onset of stroke and 12 normal subjects. The Score of Assessment and Rating of Ataxia (SARA) was used to evaluate ataxia. The values of fractional anisotropy (FA), apparent diffusion coefficient, and fiber number (FN) of the ICP were measured for the diffusion tensor imaging parameters.

RESULTS

Significant differences were observed in the FA and FN values of the ICP in the affected hemisphere between the patient and control groups (P < .05). In addition, the FN value of the ICP in the affected hemisphere showed a negative correlation with SARA (r = -0.538, P < .05). However, parameters of the ICP in the unaffected hemisphere or the FN value in the unaffected hemisphere showed no correlation with SARA (P > .05).

CONCLUSION

We found that the ataxia severity was closely related to the severity of ICP injury in patients with cerebral infarct. Our results suggest that evaluation of the ICP using DTT would be useful for patients with ataxia after cerebral infarct.

Ataxia

PURPOSE OF REVIEW

This article reviews the symptoms, laboratory and neuroimaging diagnostic tests, genetics, and management of cerebellar ataxia.

RECENT FINDINGS

Recent advances in genetics have led to the identification of novel genetic causes for ataxia and a more comprehensive understanding of the biological pathways critical for normal cerebellar function. When these molecular pathways become dysfunctional, patients develop cerebellar ataxia. In addition, several ongoing clinical trials for Friedreich ataxia and spinocerebellar ataxia will likely result in novel symptomatic and disease-modifying therapies for ataxia. Antisense oligonucleotides for spinocerebellar ataxias associated with CAG repeat expansions might be a promising therapeutic strategy.

SUMMARY

Cerebellar ataxias include heterogeneous disorders affecting cerebellar function, leading to ataxic symptoms. Step-by-step diagnostic workups with genetic investigations are likely to reveal the underlying causes of ataxia. Some disease-specific therapies for ataxia exist, such as vitamin E for ataxia with vitamin E deficiency and thiamine for Wernicke encephalopathy, highlighting the importance of recognizing these forms of ataxia. Finally, genetic diagnosis for patients with ataxia will accelerate clinical trials for disease-modifying therapy and will have prognostic value and implications for family planning for these patients.

Is the walk ratio a window to the cerebellum in multiple sclerosis? A structural magnetic resonance imaging study

BACKGROUND AND PURPOSE

Existing research studies have demonstrated a relationship between magnetic resonance imaging (MRI) neuroimaging measures and walking speed in people with multiple sclerosis (PwMS). However, to date there are no data as to the brain structures involved in gait coordination and control in PwMS. Therefore, the aim of our study was to investigate the association between walk ratio, an indicator of gait coordination, and related brain structures in PwMS.

METHODS

A brain MRI was performed by a 3.0-T MR scanner in conjunction with a volumetric analysis based on three-dimensional T1-weighted images. Regions of interest were volumes of the hippocampus, amygdala, putamen, caudate, pallidum, thalamus, cerebellum and the corpus callosum regions. Walking speed and walk ratio, defined as step length divided by step rate, was measured whilst walking on an electronic walkway.

RESULTS

In all, 343 PwMS (41.1 ± 13.4 years, 69.1% female, median Expanded Disability Status Scale 2.5) were included in the study. A significant association was found between the left cerebellum volume and walk ratio after controlling for age, gender, total cranial volume and disability; R²  = 0.379, P = 0.002. A similar association was found between the right cerebellum volume and walk ratio, R²  = 0.364, P = 0.002. No correlations were observed between walk ratio and the thalamus, basal ganglia, hippocampus, amygdala and the corpus callosum volumes. No association was found between walking speed and all brain measures.

CONCLUSIONS

The walk ratio should be considered when evaluating and assessing PwMS presenting with ataxia. Furthermore, it is also hypothesized that a low walk ratio indicates a lower cerebellum volume in the MS population.

Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2

The effective therapeutic treatment and the disease-modifying therapy for spinocerebellar ataxia type 2 (SCA2) (a progressive hereditary disease caused by an expansion of polyglutamine in the ataxin-2 protein) is not available yet. At present, only symptomatic treatment and methods of palliative care are prescribed to the patients. Many attempts were made to study the physiological, molecular, and biochemical changes in SCA2 patients and in a variety of the model systems to find new therapeutic targets for SCA2 treatment. A better understanding of the uncovered molecular mechanisms of the disease allowed the scientific community to develop strategies of potential therapy and helped to create some promising therapeutic approaches for SCA2 treatment. Recent progress in this field will be discussed in this review article.

What is the best way to keep walking and moving around for individuals with Machado-Joseph disease? A scoping review through the lens of Aboriginal families with Machado-Joseph disease in the Top End of Australia

OBJECTIVES

Machado-Joseph disease (MJD) is the most common spinocerebellar ataxia worldwide. Prevalence is highest in affected remote Aboriginal communities of the Top End of Australia. Aboriginal families with MJD from Groote Eylandt believe 'staying strong on the inside and outside' works best to keep them walking and moving around, in accordance with six key domains that form the 'Staying Strong' Framework. The aim of this current study was to review the literature to: (1) map the range of interventions/strategies that have been explored to promote walking and moving around (functional mobility) for individuals with MJD and; (2) align these interventions to the 'Staying Strong' Framework described by Aboriginal families with MJD.

DESIGN

Scoping review.

DATA SOURCES

Searches were conducted in July 2018 in MEDLINE, EMBASE, CINAHL, PsychINFO and Cochrane Databases.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed studies that (1) included adolescents/adults with MJD, (2) explored the effects of any intervention on mobility and (3) included a measure of mobility, function and/or ataxia were included in the review.

RESULTS

Thirty studies were included. Few studies involved participants with MJD alone (12/30). Most studies explored interventions that aligned with two 'Staying Strong' Framework domains, 'exercising your body' (n=13) and 'searching for good medicine' (n=17). Few studies aligned with the domains having 'something important to do' (n=2) or 'keeping yourself happy' (n=2). No studies aligned with the domains 'going country' or 'families helping each other'.

CONCLUSIONS

Evidence for interventions to promote mobility that align with the 'Staying Strong' Framework were focused on staying strong on the outside (physically) with little reflection on staying strong on the inside (emotionally, mentally and spiritually). Findings suggest future research is required to investigate the benefits of lifestyle activity programmes that address both physical and psychosocial well-being for families with MJD.

Cerebellar transcranial direct current stimulation in spinocerebellar ataxia type 3 (SCA3-tDCS): rationale and protocol of a randomized, double-blind, sham-controlled study

BACKGROUND

Spinocerebellar ataxia type 3 (SCA3) is the most common subtype among the autosomal dominant cerebellar ataxias, a group of neurodegenerative disorders for which currently no disease-specific therapy is available. Evidence-based options for symptomatic treatment of ataxia are also limited. Recent investigations in a heterogeneous group of hereditary and acquired ataxias showed promising, prolonged effects of a two-week course with daily sessions of cerebellar anodal transcranial direct current stimulation (tDCS) on ataxia severity, gait speed, and upper limb dexterity. The aim of the SCA3-tDCS study is to further examine whether tDCS improves ataxia severity and various (cerebellar) non-motor symptoms in a homogeneous cohort of SCA3 patients and to explore the time course of these effects.

METHODS/DESIGN

An investigator-initiated, double-blind, randomized, sham-controlled, single-center trial will be conducted. Twenty mildly to moderately affected SCA3 patients (Scale for the Assessment and Rating of Ataxia score between 3 and 20) will be included and randomly assigned in a 1:1 ratio to either cerebellar anodal tDCS or sham cerebellar tDCS. Patients, investigators, and outcome assessors are unaware of treatment allocation. Cerebellar tDCS (20 min, 2 mA, ramp-up and down periods of 30 s each) will be delivered over ten sessions, distributed in two groups of five consecutive days with a two-day break in between. Outcomes are assessed after a single session of tDCS, after the tenth stimulation (T1), and after three, six, and twelve months. The primary outcome measure is the absolute change of the SARA score between baseline and T1. In addition, effects on a variety of other motor and neuropsychological functions in which the cerebellum is known to be involved will be evaluated using quantitative motor tests, static posturography, neurophysiological measurements, cognitive assessment, and questionnaires.

DISCUSSION

The results of this study will inform us whether repeated sessions of cerebellar anodal tDCS benefit SCA3 patients and whether this form of non-invasive stimulation might be a novel therapeutic approach to consider in a neurorehabilitation setting. Combined with two earlier controlled trials, a positive effect of the SCA3-tDCS study will encourage implementation of this intervention and stimulate further research in other SCAs and heredodegenerative ataxias.

TRIAL REGISTRATION

NL7321 , registered October 8, 2018.

Sleep spindles and K-complex activities are decreased in spinocerebellar ataxia type 2: relationship to memory and motor performances

BACKGROUND

Sleep spindles and K-complexes are electroencephalographic hallmarks of non-rapid eye movement (non-REM) sleep that provide valuable information into brain functioning, plasticity and sleep functions in normal and pathological conditions. However, they have not been systematically investigated in spinocerebellar ataxias (SCA). To close this gap, the current study was carried out to quantify sleep spindles and K-complexes in SCA2 and to assess their relationship with clinical and molecular measures, as well as with memory and attention/executive functioning.

METHODS

In this study, 20 SCA2 patients, 20 preclinical carriers and 20 healthy controls underwent whole-night polysomnographic (PSG) recordings as well as sleep interviews, ataxia scoring and neuropsychological assessments. Sleep spindles and K-complexes were automatically detected during non-REM sleep stage 2 (N2). Their densities were evaluated as events/minute.

RESULTS

Compared to controls, sleep spindle density was significantly reduced in SCA2 patients and preclinical subjects. By contrast, K-complex density was specifically and significantly decreased only in SCA2 patients. Reduced spindle activity correlated with measures of verbal memory, whereas reduced K-complex activity correlated with age, ataxia severity and N3 sleep percentage in SCA2 patients.

CONCLUSIONS

Findings document an impairment of N2 sleep microstructure in SCA2 already in prodromal stages, suggesting an early involvement of thalamo-cortical and/or cortical circuits underlying the generation of sleep spindles and K-complexes. Thus, sleep spindle density may serve as useful biomarker for deficits of neural plasticity mechanisms underlying verbal memory alterations in patients. It may also serve as promising outcome measure in further therapeutical trials targeting memory decline in SCA2. With regard to K-complexes, they have potential usefulness as marker of sleep protection.

Spinocerebellar ataxia

The spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of autosomal dominantly inherited progressive disorders, the clinical hallmark of which is loss of balance and coordination accompanied by slurred speech; onset is most often in adult life. Genetically, SCAs are grouped as repeat expansion SCAs, such as SCA3/Machado-Joseph disease (MJD), and rare SCAs that are caused by non-repeat mutations, such as SCA5. Most SCA mutations cause prominent damage to cerebellar Purkinje neurons with consecutive cerebellar atrophy, although Purkinje neurons are only mildly affected in some SCAs. Furthermore, other parts of the nervous system, such as the spinal cord, basal ganglia and pontine nuclei in the brainstem, can be involved. As there is currently no treatment to slow or halt SCAs (many SCAs lead to premature death), the clinical care of patients with SCA focuses on managing the symptoms through physiotherapy, occupational therapy and speech therapy. Intense research has greatly expanded our understanding of the pathobiology of many SCAs, revealing that they occur via interrelated mechanisms (including proteotoxicity, RNA toxicity and ion channel dysfunction), and has led to the identification of new targets for treatment development. However, the development of effective therapies is hampered by the heterogeneity of the SCAs; specific therapeutic approaches may be required for each disease.

Genetics, Mechanisms, and Therapeutic Progress in Polyglutamine Spinocerebellar Ataxias

Autosomal dominant cerebellar ataxias (ADCAs) are a group of neurodegenerative disorders characterized by degeneration of the cerebellum and its connections. All ADCAs have progressive ataxia as their main clinical feature, frequently accompanied by dysarthria and oculomotor deficits. The most common spinocerebellar ataxias (SCAs) are 6 polyglutamine (polyQ) SCAs. These diseases are all caused by a CAG repeat expansion in the coding region of a gene. Currently, no curative treatment is available for any of the polyQ SCAs, but increasing knowledge on the genetics and the pathological mechanisms of these polyQ SCAs has provided promising therapeutic targets to potentially slow disease progression. Potential treatments can be divided into pharmacological and gene therapies that target the toxic downstream effects, gene therapies that target the polyQ SCA genes, and stem cell replacement therapies. Here, we will provide a review on the genetics, mechanisms, and therapeutic progress in polyglutamine spinocerebellar ataxias.

Long term at-home treatment with transcranial direct current stimulation (tDCS) improves symptoms of cerebellar ataxia: a case report

BACKGROUND

Progressive cerebellar ataxia is a neurodegenerative disorder without effective treatment options that seriously hinders quality of life. Previously, transcranial direct current stimulation (tDCS) has been demonstrated to benefit cerebellar functions (including improved motor control, learning and emotional processing) in healthy individuals and patients with neurological disorders. While tDCS is an emerging therapy, multiple daily sessions are needed for optimal clinical benefit. This case study tests the symptomatic benefit of remotely supervised tDCS (RS-tDCS) for a patient with cerebellar ataxia.

METHODS

We report a case of a 71-year-old female patient with progressive cerebellar ataxia, who presented with unsteady gait and balance impairment, treated with tDCS. tDCS was administered using our RS-tDCS protocol and was completed daily in the patient's home (Monday - Friday) with the help of a trained study technician. tDCS was paired with 20 min of simultaneous cognitive training, followed by 20 min of physical exercises directed by a physical therapist. Stimulation consisted of 20 min of 2.5 mA direct current targeting the cerebellum via an anodal electrode and a cathodal electrode placed over the right shoulder. The patient completed baseline and treatment end visits with neurological, cognitive, and motor (Lafayette Grooved Pegboard Test, 25 ft walk test and Timed Up and Go Test) assessments.

RESULTS

The patient successfully completed sixty tDCS sessions, 59 of which were administered remotely at the patient's home with the use of real time supervision as enabled by video conferencing. Mild improvement was observed in the patient's gait with a 7% improvement in walking speed, which she completed without a walking-aid at treatment end, which was in stark contrast to her baseline assessment. Improvements were also achieved in manual dexterity, with an increase in pegboard scores bilaterally compared to baseline.

CONCLUSIONS

Results from this case report suggest that consecutively administered tDCS treatments paired with cognitive and physical exercise hold promise for improving balance, gait, and manual dexterity in patients with progressive ataxia. Remotely supervised tDCS provides home access to enable the administration over an extended period. Further controlled study in a large group of those with cerebellar ataxia is needed to replicate these findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03049969 . Registered 10 February 2017- Retrospectively registered.

Therapy of episodic ataxias: case report and review of the literature

Episodic ataxias (EAs) are characterized by recurrent, discrete episodes of vertigo and ataxia. EA1 and EA2 are the two most common forms. In the interictal interval, myokymia is typically present in EA1, whereas EA2 patients present with interictal nystagmus. Specific pharmacological therapies are available for EA1 and especially EA2. We briefly discuss the case of an Italian young man with EA2, with a novel de novo CACNA1A mutation, who in our opinion is particularly illustrative for introducing the therapeutic approach. Acetazolamide could fully suppress EA episodes in our patient. We also provide a perspective review of the topic. 4-Aminopyridine is another valid treatment option. For EA1 (and for rarer EAs), the therapeutic possibilities are more limited. Carbamazepine is probably the treatment of choice for EA1, but the optimal treatment plan is unknown. A better understanding of the molecular processes involved in the mediation of EAs will lead to more specific and efficacious therapies for this still elusive group of disorders.

The Comprehensive Management of Cerebellar Ataxia in Adults

PURPOSE OF REVIEW

In this review, we present the multidisciplinary approach to the management of the many neurological, medical, social, and emotional issues facing patients with cerebellar ataxia.

RECENT FINDINGS

Our holistic approach to treatment, developed over the past 25 years in the Massachusetts General Hospital Ataxia Unit, is centered on the compassionate care of the patient and their family, empowering them through engagement, and including the families as partners in the healing process. We present the management of ataxia in adults, beginning with establishing an accurate diagnosis, followed by treatment of the multiple symptoms seen in cerebellar disorders, with a view to maximizing quality of life and effectively living with the consequences of ataxia. We discuss the importance of a multidisciplinary approach to the management of ataxia, including medical and non-medical management and the evidence base that supports these interventions. We address the pharmacological treatment of ataxia, tremor, and other associated movement disorders; ophthalmological symptoms; bowel, bladder, and sexual symptoms; orthostatic hypotension; psychiatric and cognitive symptoms; neuromodulation, including deep brain stimulation; rehabilitation including physical therapy, occupational therapy and speech and language pathology and, as necessary, involving urology, psychiatry, and pain medicine. We discuss the role of palliative care in late-stage disease. The management of adults with ataxia is complex and a team-based approach is essential.

Repetitive Transcranial Magnetic Stimulation in Spinocerebellar Ataxia: A Pilot Randomized Controlled Trial

Spinocerebellar ataxia (SCA) is a neurodegenerative disorder caused by dysfunction of the cerebellum and its connected neural networks. There is currently no cure for SCA and symptomatic treatment remains limited. We aimed here to examine the effects of a repetitive transcranial magnetic stimulation (rTMS) targeting the cerebellum on clinical impression, postural control and gait in patients with SCA. In this randomized, double-blinded and sham-controlled study, 20 individuals aged 18-75 years with SCA confirmed by genetic testing completed rTMS or sham intervention comprising 20 sessions of MRI-guided stimulation over the cerebellum. Baseline assessments included the Standard Ataxia Rating Assessment (SARA), the 9-hole peg test of manual dexterity, the Timed Up-and-Go (TUG) test, standing postural control with eyes-open and eyes-closed, and gait. Immediate (within 1-week) and 1-month follow-ups were completed. Intervention compliance was high (19 ± 2 of 20 sessions) and no rTMS-related adverse events were reported. rTMS, compared to sham, was associated with greater percent improvement in SARA total score from baseline to the 1-month follow-up (p = 0.008). Secondary analyses of individual SARA items revealed that rTMS improved performance within the "stance" sub-score only (p = 0.002). This functional change was accompanied by improvement to several objective metrics of postural sway during eyes-open and eyes-closed standing (p < 0.008). rTMS did not influence the 9-hole peg test, TUG, or gait kinematics. A 20-session rTMS intervention is safe and feasible for those with SCA. Additional research is warranted to confirm the observed longer-term benefits of this intervention on standing postural control. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01975909.

Recognizing and treating atypical Parkinson disorders

Though less common than Parkinson's disease (PD), the atypical Parkinson disorders such as such as dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration are increasingly recognized and important to distinguish from PD. Atypical or "Parkinson-plus" disorders are multisystem disorders and generally progress more rapidly and respond poorly to current therapies compared to PD. Recent advances in our understanding of the pathophysiology of these disorders, however, have generated new interest in the development of novel diagnostics and disease-modifying therapeutics aimed at identifying and treating these disorders. In this review we discuss the clinical approach to the atypical Parkinson disorders and the recent developments in diagnostic and research criteria that take into account the phenotypic heterogeneity and advances in our understanding of the pathophysiology of these disorders.

Recent advances in understanding dominant spinocerebellar ataxias from clinical and genetic points of view

Abstract

Spinocerebellar ataxias (SCAs) are rare types of cerebellar ataxia with a dominant mode of inheritance. To date, 47 SCA subtypes have been identified, and the number of genes implicated in SCAs is continually increasing. Polyglutamine (polyQ) expansion diseases

( ATXN1/SCA1, ATXN2/SCA2, ATXN3/SCA3, CACNA1A/SCA6, ATXN7/SCA7, TBP/SCA17, and ATN1/DRPLA) are the most common group of SCAs. No preventive or curative treatments are currently available, but various therapeutic approaches, including RNA-targeting treatments, such as antisense oligonucleotides (ASOs), are being developed. Clinical trials of ASOs in SCA patients are already planned. There is, therefore, a need to identify valid outcome measures for such studies. In this review, we describe recent advances towards identifying appropriate biomarkers, which are essential for monitoring disease progression and treatment efficacy. Neuroimaging biomarkers are the most powerful markers identified to date, making it possible to reduce sample sizes for clinical trials. Changes on brain MRI are already evident at the premanifest stage in SCA1 and SCA2 carriers and are correlated with CAG repeat size. Other potential biomarkers have also been developed, based on neurological examination, oculomotor study, cognitive assessment, and blood and cerebrospinal fluid analysis. Longitudinal studies based on multimodal approaches are required to establish the relationships between parameters and to validate the biomarkers identified.

A randomized controlled pilot trial of game-based training in individuals with spinocerebellar ataxia type 3

Exergames are interactive video games used for exercise and may have therapeutic value in people with degenerative ataxia. The purpose of this study was to investigate potential effects of exergaming training on cerebellar ataxia in people with spinocerebellar ataxia type 3 (SCA3). Nine individuals with SCA3 were recruited and randomized to either exergaming or conventional group for a 4-week training period. The severity of ataxia was measured as the primary outcome by the Scale for the Assessment and Rating of Ataxia (SARA) and by the directional control of the limit of stability test. The secondary outcomes included upper-limb function and gait performance. After training, participants in the exergaming group had a significant decrease in the total SARA score and the gait-posture SARA subscore. Participants in the conventional training group did not show a significant improvement in selected outcome measures after the 4-week training period. No significant difference was found between groups for any of these measures. Our results suggested that the exergaming training program significantly decreased ataxia. These results support implementation of exergaming training for people with SCA3.