Restoration of Central Programmed Movement Pattern by Temporal Electrical Stimulation-Assisted Training in Patients with Spinal Cerebellar Atrophy

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.

Can the ARAT Be Used to Measure Arm Function in People With Cerebellar Ataxia?

OBJECTIVE

For people with ataxia, there are validated outcome measures to address body function and structure (BFS) impairments and participation; however, no outcome measure exists for upper extremity (UE) activity level in this population. The purpose of this study was to determine whether the action research arm test (ARAT), a measure of UE activity validated for other neurological conditions, might be a useful outcome measure for capturing UE activity limitations in ataxia.

METHODS

A total of 22 participants with ataxia were evaluated to assess construct validity of the ARAT; 19 of the participants were included in the interrater reliability assessment. Participants received a neurologic examination and completed a battery of outcome measures, including the ARAT. ARAT performance was video recorded and scored by 4 additional raters.

RESULTS

For construct validity, Spearman rho showed a significant moderate relationship between the ARAT and BSF outcome measures. A small, nonsignificant relationship was noted for the ARAT and the participation measure. For interrater reliability, Spearman rho showed a large, significant relationship among all raters for the ARAT (range = .87-.94). High reliability was demonstrated using the intraclass correlation coefficient ([2,1] = .97).

CONCLUSION

The ARAT is moderately correlated with ataxia BFS outcome measures, but not with participation scores. The ARAT is a measure of UE activity, which is different from BFS and participation outcome measures. The ARAT was identified to have strong interrater reliability among raters with varying amounts of experience administering the ARAT. Thus, for the ataxic population, the ARAT may be useful for assessing UE activity limitations.

IMPACT

Ataxia can negatively affect reaching tasks; therefore, it is important to assess UE activity level in people with ataxia. Until this study, no outcome measure had been identified for this purpose.

LAY SUMMARY

People with ataxia may have difficulty with daily tasks that require reaching. The ARAT is an outcome measure that clinicians can use to assess UE activity limitations to help design a treatment program.

[Effect of physical rehabilitation in patients with hereditary spinocerebellar ataxia. A systematic review]

Evidence of the effectiveness of rehabilitation interventions in spinocerebellar ataxia is scarce and variable. OBJECTIVES: The aim of this systematic review was to gather the existing evidence on the effectiveness of these interventions. MATERIAL AND METHODS: To do this, we analysed all the clinical trials published to date and assessed their results in terms of improved balance, gait, and performance of daily activities after treatment. Significant improvements were found for posture (P<.008) and gait (P<.02), as well as a reduction in the scores for the SARAg&p subscale (gait and posture) and SCAFI 8MW index (gait speed) (P=.02). We also observed improvements in speech disorders (P=.02), depressive symptoms (P<.0001) and accidental falls (P<.005).

Consensus paper: Decoding the Contributions of the Cerebellum as a Time Machine. From Neurons to Clinical Applications

Time perception is an essential element of conscious and subconscious experience, coordinating our perception and interaction with the surrounding environment. In recent years, major technological advances in the field of neuroscience have helped foster new insights into the processing of temporal information, including extending our knowledge of the role of the cerebellum as one of the key nodes in the brain for this function. This consensus paper provides a state-of-the-art picture from the experts in the field of the cerebellar research on a variety of crucial issues related to temporal processing, drawing on recent anatomical, neurophysiological, behavioral, and clinical research.The cerebellar granular layer appears especially well-suited for timing operations required to confer millisecond precision for cerebellar computations. This may be most evident in the manner the cerebellum controls the duration of the timing of agonist-antagonist EMG bursts associated with fast goal-directed voluntary movements. In concert with adaptive processes, interactions within the cerebellar cortex are sufficient to support sub-second timing. However, supra-second timing seems to require cortical and basal ganglia networks, perhaps operating in concert with cerebellum. Additionally, sensory information such as an unexpected stimulus can be forwarded to the cerebellum via the climbing fiber system, providing a temporally constrained mechanism to adjust ongoing behavior and modify future processing. Patients with cerebellar disorders exhibit impairments on a range of tasks that require precise timing, and recent evidence suggest that timing problems observed in other neurological conditions such as Parkinson's disease, essential tremor, and dystonia may reflect disrupted interactions between the basal ganglia and cerebellum.The complex concepts emerging from this consensus paper should provide a foundation for further discussion, helping identify basic research questions required to understand how the brain represents and utilizes time, as well as delineating ways in which this knowledge can help improve the lives of those with neurological conditions that disrupt this most elemental sense. The panel of experts agrees that timing control in the brain is a complex concept in whom cerebellar circuitry is deeply involved. The concept of a timing machine has now expanded to clinical disorders.

Age related changes of the motor excitabilities and central and peripheral muscle strength

INTRODUCTION

The purpose was to investigate the age effects on central versus peripheral sources of strength, fatigue, and central neural excitabilities.

METHODS

42 healthy subjects were recruited as young group (23.73 ± 2.15 years; n = 26) and middle-aged group (57.25 ± 4.57 years; n = 16). Maximum voluntary contraction force (MVC), voluntary activation level (VA), and twitch force of quadriceps were evaluated to represent general, central, and peripheral strengths. Central and peripheral fatigue indexes were evaluated using femoral nerve electrical stimulation. Cortical excitabilities were evaluated using transcranial magnetic stimulation (TMS).

RESULTS

The middle-aged group had lower MVC and twitch force of quadriceps, but not VA, than young group. No between group differences were found in fatigue indexes. The cortical excitability in middle-aged group was different from young group in paired TMS with inter-stimulus interval of 7 ms.

CONCLUSION

The age-related strength loss at early stage was primarily caused by peripheral muscular strength. The deviation of central neural excitability can be detected but the activation level was not impaired in middle-age adults.