Digital Measures of Postural Sway Quantify Balance Deficits in Spinocerebellar Ataxia.

BACKGROUND: Maintaining balance is crucial for independence and quality of life. Loss of balance is a hallmark of spinocerebellar ataxia (SCA). OBJECTIVE: The aim of this study was to identify which standing balance conditions and digital measures of body sway were most discriminative, reliable, and valid for quantifying balance in SCA. METHODS: Fifty-three people with SCA (13 SCA1, 13 SCA2, 14 SCA3, and 13 SCA6) and Scale for Assessment and Rating of Ataxia (SARA) scores 9.28 ± 4.36 and 31 healthy controls were recruited. Subjects stood in six test conditions (natural stance, feet together and tandem, each with eyes open [EO] and eyes closed [EC]) with an inertial sensor on their lower back for 30 seconds (×2). We compared test completion rate, test-retest reliability, and areas under the receiver operating characteristic curve (AUC) for seven digital sway measures. Pearson's correlations related sway with the SARA and the Patient-Reported Outcome Measure of Ataxia (PROM ataxia). RESULTS: Most individuals with SCA (85%-100%) could stand for 30 seconds with natural stance EO or EC, and with feet together EO. The most discriminative digital sway measures (path length, range, area, and root mean square) from the two most reliable and discriminative conditions (natural stance EC and feet together EO) showed intraclass correlation coefficients from 0.70 to 0.91 and AUCs from 0.83 to 0.93. Correlations of sway with SARA were significant (maximum r = 0.65 and 0.73). Correlations with PROM ataxia were mild to moderate (maximum r = 0.56 and 0.34). CONCLUSION: Inertial sensor measures of extent of postural sway in conditions of natural stance EC and feet together stance EO were discriminative, reliable, and valid for monitoring SCA. © 2024 International Parkinson and Movement Disorder Society.

Abnormal vestibular-evoked myogenic potentials as a risk factor for unpredicted falls in spinocerebellar ataxia: a preliminary study.

OBJECTIVE: This study aimed to correlate the symptoms and signs with the findings of laboratory vestibular function tests in patients with spinocerebellar ataxia (SCA). METHOD: We retrospectively recruited 26 patients with SCA (9 men, median age: 52, age range: 21-67). Assessments included Dizziness Handicap Inventory, EuroQoL Five-Dimension, symptom questionnaires manifesting during walking in daily life, the Scale for the Assessment and Rating of Ataxia (SARA), and vestibular function tests including 3D video-oculography, video head impulse test, subjective visual vertical, and cervical and ocular vestibular evoked myogenic potentials (VEMP). RESULTS: Cross-analyses revealed that the patients with VEMP abnormalities showed higher SARA (p = 0.014) and prevalence of unpredictable falls (p = 0.046). The patients with SCA1 more frequently had unpredictable falls (75%, p = 0.038) and VEMP abnormalities (88%, p = 0.001) compared to SCA2 (29% falls, 17% VEMP abnormalities) and SCA6 (no falls or VEMP abnormalities). CONCLUSION: Abnormal VEMPs are strongly associated with unpredicted falls in patients with SCA, particularly in those with SCA1. Impaired processing of otolithic information may contribute to falls in SCAs, and VEMP may help identifying the patients with a risk for unpredicted falls and preventing fall-related injuries in SCA. Limited number of patients with lower SARA scores warrant further confirmatory studies.

Bidirectional Transcription at the PPP2R2B Gene Locus in Spinocerebellar Ataxia Type 12.

BACKGROUND: Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by expansion of a CAG repeat in the PPP2R2B gene. OBJECTIVE: In this study, we tested the hypothesis that the PPP2R2B antisense (PPP2R2B-AS1) transcript containing a CUG repeat is expressed and contributes to SCA12 pathogenesis. METHODS: Expression of PPP2R2B-AS1 transcript was detected in SCA12 human induced pluripotent stem cells (iPSCs), iPSC-derived NGN2 neurons, and SCA12 knock-in mouse brains using strand-specific reverse transcription polymerase chain reaction. The tendency of expanded PPP2R2B-AS1 (expPPP2R2B-AS1) RNA to form foci, a marker of toxic processes involving mutant RNAs, was examined in SCA12 cell models by fluorescence in situ hybridization. The apoptotic effect of expPPP2R2B-AS1 transcripts on SK-N-MC neuroblastoma cells was evaluated by caspase 3/7 activity. Western blot was used to examine the expression of repeat associated non-ATG-initiated translation of expPPP2R2B-AS1 transcript in SK-N-MC cells. RESULTS: The repeat region in the PPP2R2B gene locus is bidirectionally transcribed in SCA12 iPSCs, iPSC-derived NGN2 neurons, and SCA12 mouse brains. Transfected expPPP2R2B-AS1 transcripts induce apoptosis in SK-N-MC cells, and the apoptotic effect may be mediated, at least in part, by the RNA secondary structure. The expPPP2R2B-AS1 transcripts form CUG RNA foci in SK-N-MC cells. expPPP2R2B-AS1 transcript is translated in the alanine open reading frame (ORF) via repeat-associated non-ATG translation, which is diminished by single-nucleotide interruptions within the CUG repeat and MBNL1 overexpression. CONCLUSIONS: These findings suggest that PPP2R2B-AS1 contributes to SCA12 pathogenesis and may therefore provide a novel therapeutic target for the disease. © 2023 International Parkinson and Movement Disorder Society.

Integrated genome and transcriptome analyses reveal the mechanism of genome instability in ataxia with oculomotor apraxia 2.

Mutations in the SETX gene, which encodes Senataxin, are associated with the progressive neurodegenerative diseases ataxia with oculomotor apraxia 2 (AOA2) and amyotrophic lateral sclerosis 4 (ALS4). To identify the causal defect in AOA2, patient-derived cells and SETX knockouts (human and mouse) were analyzed using integrated genomic and transcriptomic approaches. A genome-wide increase in chromosome instability (gains and losses) within genes and at chromosome fragile sites was observed, resulting in changes to gene-expression profiles. Transcription stress near promoters correlated with high GCskew and the accumulation of R-loops at promoter-proximal regions, which localized with chromosomal regions where gains and losses were observed. In the absence of Senataxin, the Cockayne syndrome protein CSB was required for the recruitment of the transcription-coupled repair endonucleases (XPG and XPF) and RAD52 recombination protein to target and resolve transcription bubbles containing R-loops, leading to genomic instability. These results show that transcription stress is an important contributor to SETX mutation-associated chromosome fragility and AOA2.

Novel KCND3 Variant Underlying Nonprogressive Congenital Ataxia or SCA19/22 Disrupt KV4.3 Protein Expression and K+ Currents with Variable Effects on Channel Properties.

KCND3 encodes the voltage-gated potassium channel KV4.3 that is highly expressed in the cerebellum, where it regulates dendritic excitability and calcium influx. Loss-of-function KV4.3 mutations have been associated with dominant spinocerebellar ataxia (SCA19/22). By targeted NGS sequencing, we identified two novel KCND3 missense variants of the KV4.3 channel: p.S347W identified in a patient with adult-onset pure cerebellar syndrome and p.W359G detected in a child with congenital nonprogressive ataxia. Neuroimaging showed mild cerebellar atrophy in both patients. We performed a two-electrode voltage-clamp recording of KV4.3 currents in Xenopus oocytes: both the p.G345V (previously reported in a SCA19/22 family) and p.S347W mutants exhibited reduced peak currents by 50%, while no K+ current was detectable for the p.W359G mutant. We assessed the effect of the mutations on channel gating by measuring steady-state voltage-dependent activation and inactivation properties: no significant alterations were detected in p.G345V and p.S347W disease-associated variants, compared to controls. KV4.3 expression studies in HEK293T cells showed 53% (p.G345V), 45% (p.S347W) and 75% (p.W359G) reductions in mutant protein levels compared with the wildtype. The present study broadens the spectrum of the known phenotypes and identifies additional variants for KCND3-related disorders, outlining the importance of SCA gene screening in early-onset and congenital ataxia.

Spinocerebellar ataxia Type 7: clinical and genetic study of a new Moroccan family (case report).

Spinocerebellar ataxia type 7 (SCA7) is a rare autosomal dominant neurodegenerative disease. Its clinical presentation is a progressive cerebellar ataxia associated with cone and retinal dystrophy. The CAG repeat expansion in the ataxin-7 gene (ATXN7) causes spinocerebellar ataxia type 7 - a mutation that results in the degeneration of the brain stem cells, retina and cerebellum. We report in this study the clinical and genetic features of a new Moroccan family of SCA7, from the South of Morocco. We performed the molecular genetic testing to confirm the diagnosis of SCA7. The objective of this study is to report a new Moroccan case of SCA7 and to illustrate the role of the geneticist in the diagnosis, management and development of genetic counseling of SCA7 disease.

Motor and cognitive outcomes of cerebello-spinal stimulation in neurodegenerative ataxia.

Cerebellar ataxias represent a heterogeneous group of disabling disorders characterized by motor and cognitive disturbances, for which no effective treatment is currently available. In this randomized, double-blind, sham-controlled trial, followed by an open-label phase, we investigated whether treatment with cerebello-spinal transcranial direct current stimulation (tDCS) could improve both motor and cognitive symptoms in patients with neurodegenerative ataxia at short and long-term. Sixty-one patients were randomized in two groups for the first controlled phase. At baseline (T0), Group 1 received placebo stimulation (sham tDCS) while Group 2 received anodal cerebellar tDCS and cathodal spinal tDCS (real tDCS) for 5 days/week for 2 weeks (T1), with a 12-week (T2) follow-up (randomized, double-blind, sham controlled phase). At the 12-week follow-up (T2), all patients (Group 1 and Group 2) received a second treatment of anodal cerebellar tDCS and cathodal spinal tDCS (real tDCS) for 5 days/week for 2 weeks, with a 14-week (T3), 24-week (T4), 36-week (T5) and 52-week follow-up (T6) (open-label phase). At each time point, a clinical, neuropsychological and neurophysiological evaluation was performed. Cerebellar-motor cortex connectivity was evaluated using transcranial magnetic stimulation. We observed a significant improvement in all motor scores (scale for the assessment and rating of ataxia, international cooperative ataxia rating scale), in cognition (evaluated with the cerebellar cognitive affective syndrome scale), in quality-of-life scores, in motor cortex excitability and in cerebellar inhibition after real tDCS compared to sham stimulation and compared to baseline (T0), both at short and long-term. We observed an addon-effect after two repeated treatments with real tDCS compared to a single treatment with real tDCS. The improvement at motor and cognitive scores correlated with the restoration of cerebellar inhibition evaluated with transcranial magnetic stimulation. Cerebello-spinal tDCS represents a promising therapeutic approach for both motor and cognitive symptoms in patients with neurodegenerative ataxia, a still orphan disorder of any pharmacological intervention.

Focal dystonia in a case of SYNE1 spastic-ataxia: Expanding the phenotypic spectrum.

Synaptic nuclear envelope protein-1 (SYNE1) related cerebellar ataxia also called ARCA1 or SCAR8, manifests as a relatively pure cerebellar ataxia or with additional neurological involvement. Dystonia is rarely seen in SYNE1 ataxia and to the best of our knowledge, there are only three reports of dystonia in patients with SYNE1 ataxia. This report describes a 22-year-old woman with chronic progressive spastic-ataxia of 3-year duration with additional focal dystonia of the right upper limb. Patient had cerebellar atrophy on MRI brain and a novel pathogenic homozygous variant in exon 74 of the SYNE1 gene (p.Gln4047Ter).

Cognitive impairment and its neuroimaging correlates in spinocerebellar ataxia 2.

INTRODUCTION: Cognitive impairment (CI) is reported but is poorly explored in spinocerebellar ataxia 2 (SCA2). This study was undertaken to evaluate and classify cognitive impairment in patients with SCA2 and to identify their grey matter (GM) correlates. METHODS: We evaluated the neurocognitive profile of 35 SCA2 and 30 age-, gender- and education-matched healthy controls using tests for attention, executive functions, learning and memory, language and fluency, and visuomotor constructive ability. Patients were classified into SCA2 with and without CI based on normative data from population and healthy controls. Furthermore, patients with CI were sub-classified based on the number of impaired domains into multi-domain CI (≥3 domains; MDCI) and limited domain CI (≤2 domains; LDCI). The underlying GM changes were identified using voxel based morphometry. RESULTS: The mean age at onset, duration of disease, and ataxia score was 28.7 ± 8.51 years, 66.7 ± 44.1 months, and 16.1 ± 4.9 points, respectively. CI was present in 71.4% of SCA2 subjects (MDCI: 42.7%; LDCI: 28.5%). Patients with CI had significant atrophy of the posterior cerebellum, sensorimotor cortex, and superior frontal gyrus (FWE p-value <0.05). Patients with MDCI had significant GM atrophy of the angular gyrus compared to LDCI (FWE p-value <0.05). CONCLUSION: Patients with CI had significant GM involvement of the posterior cerebellum and frontal lobe, suggestive of impairment in the cerebello-fronto-cortical circuitry.

Spinocerebellar ataxia type 14: refining clinicogenetic diagnosis in a rare adult-onset disorder.

OBJECTIVES: Genetic variant classification is a challenge in rare adult-onset disorders as in SCA-PRKCG (prior spinocerebellar ataxia type 14) with mostly private conventional mutations and nonspecific phenotype. We here propose a refined approach for clinicogenetic diagnosis by including protein modeling and provide for confirmed SCA-PRKCG a comprehensive phenotype description from a German multi-center cohort, including standardized 3D MR imaging. METHODS: This cross-sectional study prospectively obtained neurological, neuropsychological, and brain imaging data in 33 PRKCG variant carriers. Protein modeling was added as a classification criterion in variants of uncertain significance (VUS). RESULTS: Our sample included 25 cases confirmed as SCA-PRKCG (14 variants, thereof seven novel variants) and eight carriers of variants assigned as VUS (four variants) or benign/likely benign (two variants). Phenotype in SCA-PRKCG included slowly progressive ataxia (onset at 4-50 years), preceded in some by early-onset nonprogressive symptoms. Ataxia was often combined with action myoclonus, dystonia, or mild cognitive-affective disturbance. Inspection of brain MRI revealed nonprogressive cerebellar atrophy. As a novel finding, a previously not described T2 hyperintense dentate nucleus was seen in all SCA-PRKCG cases but in none of the controls. INTERPRETATION: In this largest cohort to date, SCA-PRKCG was characterized as a slowly progressive cerebellar syndrome with some clinical and imaging features suggestive of a developmental disorder. The observed non-ataxia movement disorders and cognitive-affective disturbance may well be attributed to cerebellar pathology. Protein modeling emerged as a valuable diagnostic tool for variant classification and the newly described T2 hyperintense dentate sign could serve as a supportive diagnostic marker of SCA-PRKCG.

Cognitive impairment in spinocerebellar ataxia type 12.

INTRODUCTION: Cognitive impairment has now been recognised to be present in patients with several of spinocerebellar ataxias (SCAs). Cognitive impairment in patients with spinocerebellar ataxia type 12 has not been evaluated. OBJECTIVE: To evaluate the cognitive impairment in patients diagnosed with spinocerebellar ataxia type 12 (SCA12). METHODS: We conducted a cross sectional study and enrolled 30 (20 male and 10 female) genetically confirmed SCA12 patients and 30 healthy, age, gender and education matched individuals as controls. Cognitive domains were tested using a battery of validated neurocognitive tests. RESULT: Mean age of patients was 51.6 ± 8.0 years and mean disease duration was 5.3 ± 3.0 years. Mean International Cooperative Ataxia Rating Scale (ICARS) score was 29.8 ± 12.5. SCA 12 patients scored significantly lower than controls in executive function and new learning ability. Other tested cognitive domains were also affected but did not reach statistical significance. Age, age at onset, severity of ataxia, disease duration and CAG repeat length did not correlate with cognitive impairment. CONCLUSION: Cognitive impairment is a part of the spectrum of SCA12 and is characterized by dysfunction in executive function and new learning ability even early in the course of disease.

Molecular and electrophysiological features of spinocerebellar ataxia type seven in induced pluripotent stem cells.

Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disease caused by a polyglutamine repeat expansion in the ATXN7 gene. Patients with this disease suffer from a degeneration of their cerebellar Purkinje neurons and retinal photoreceptors that result in a progressive ataxia and loss of vision. As with many neurodegenerative diseases, studies of pathogenesis have been hindered by a lack of disease-relevant models. To this end, we have generated induced pluripotent stem cells (iPSCs) from a cohort of SCA7 patients in South Africa. First, we differentiated the SCA7 affected iPSCs into neurons which showed evidence of a transcriptional phenotype affecting components of STAGA (ATXN7 and KAT2A) and the heat shock protein pathway (DNAJA1 and HSP70). We then performed electrophysiology on the SCA7 iPSC-derived neurons and found that these cells show features of functional aberrations. Lastly, we were able to differentiate the SCA7 iPSCs into retinal photoreceptors that also showed similar transcriptional aberrations to the SCA7 neurons. Our findings give technical insights on how iPSC-derived neurons and photoreceptors can be derived from SCA7 patients and demonstrate that these cells express molecular and electrophysiological differences that may be indicative of impaired neuronal health. We hope that these findings will contribute towards the ongoing efforts to establish the cell-derived models of neurodegenerative diseases that are needed to develop patient-specific treatments.

In vivo analysis of the spontaneous firing of cerebellar Purkinje cells in awake transgenic mice that model spinocerebellar ataxia type 2.

Cerebellar Purkinje cells (PCs) fire spontaneously in a tonic mode, although the precision of this pacemaking activity is disturbed in many abnormal conditions involving cerebellar atrophy, such as many spinocerebellar ataxias (SCAs). In our previous studies we used the single-unit extracellular recording method to analyze spontaneous PC firing in vivo in the anesthetized SCA2-58Q transgenic mice. We realized that PCs from aging SCA2-58Q mice fire much less regularly compared to PCs from their wild type (WT) littermates and this abnormal activity can be reversed with an intraperitoneal (i. p.) injection of SK channel-positive modulator chlorzoxazone (CHZ). Here we used the same single-unit extracellular recording method to analyze the spontaneous firing in vivo in awake SCA2-58Q transgenic mice. For this purpose, we used the Mobile HomeCage (Neurotar, Finland) floating platform to immobilize the experimental animal's head during the recording sessions. We discovered that generally PCs from awake animals fired much more frequently and much less regularly than previously observed PCs from anesthetized animals. In vivo recordings from awake SCA2/WT mice revealed that complex spikes, which are generated by PCs in reply to the excitation coming by climbing fibers, as well as simple spikes, were much less frequent in SCA2 mice compared to their WT littermates. To test the effect of the SK channel positive modulation on the PCs firing activity in awake SCA2 mice and also the effect on their motor coordination, we started the CHZ trial in these mice. We discovered that the long-term i. p. injections of CHZ did not affect the spike generation in SCA2-58Q mice, however, they did recover the precision of this spontaneous pacemaking activity. Furthermore, we also showed that treatment with CHZ alleviated the age-dependent motor impairment in SCA2-58Q mice. We propose that the lack of precision in PC spike generation might be a key cause for the progression of ataxic symptoms in different SCAs and that the activation of calcium-activated potassium channels, including SK channels, can be used as a potential way to treat SCAs on the physiological level of the disease.

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.

Lower urinary tract and bowel dysfunction in spinocerebellar ataxias.

BACKGROUND: Little information is available in spinocerebellar ataxias (SCAs) regarding pelvic organ symptoms. The aim of this study was to characterize the lower urinary tract (LUT) and bowel dysfunction in autosomal dominant spinocerebellar ataxias. METHODS: Patients with confirmed SCAs attending a tertiary care service were approached about LUT and bowel complaints, and completed validated questionnaires: urinary symptom profile (USP), Qualiveen-Short form, International Prostate Symptom Score, and Neurogenic Bowel Dysfunction Score. SCA3 and SCA7 patients with urological complaints additionally underwent urodynamic studies (UDS). Patients' characterization included demographic, clinical (Scale for the Assessment and Rating of Ataxia (SARA), Inventory of Non-Ataxia Signs (INAS)), and genetic variables. Descriptive and comparative analyses were performed. RESULTS: Fifty-one patients participated: SCA1 (n = 4), SCA2 (n = 11), SCA3 (n = 13), SCA6 (n = 17), and SCA7 (n = 6). The prevalence of self-reported LUT symptoms was 60.8% (n = 31), whereas LUT symptoms was reported in 86.3%(n = 44) using the USP. Both storage and voiding symptoms were reported, urinary frequency and urgency being the most frequent (n = 34, 68%). Although LUT symptoms were most often classed as mild (n = 27, 61.4%), they impacted QoL in 38 patients (77.6%). Of these, 21 (55.3%) were not on pharmacological treatment for urinary dysfunction. Most common abnormalities in UDS (n = 14) were detrusor overactivity (storage phase) and detrusor underactivity (voiding phase). Bowel symptoms were less common (31.4%, n = 16) and of mild severity. CONCLUSION: LUT symptoms are prevalent in SCA patients and impact QoL, whereas bowel symptoms tend to be mild. These symptoms are overlooked by patients and physicians due to the complexity of neurological involvement in SCA, and therefore a multidisciplinary management approach should be adopted.

Family history as a clue to the diagnosis of orofacial abnormal movements in a 30-year-old man.

A 30-year-old man presented with a two-year history of involuntary movements in the face and mouth. Movements progressively worsened during the previous six months. Born from non-consanguineous parents, he had normal developmental milestones and his past medical history was unremarkable. The patient did not take any medication or had a history of illicit drug use. Family history was positive for unsteady gait of unknown cause. Neurological examination disclosed isolated orofacial dystonia affecting the face, particularly his mouth and eyes, resembling Meige's syndrome. Dystonic closure of eyelids and dystonic contractions of orbicularis oris and platysma were particularly visible while patient was talking. The Montreal Cognitive Assessment score was 30. There were no other movement disorders or other abnormalities in neurological examination. Of note, cerebellar examination as well as gait assessment were normal.

Longitudinal Analysis of the Relation Between Clinical Impairment and Gray Matter Degeneration in Spinocerebellar Ataxia Type 7 Patients.

Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disease characterized by progressive ataxia and retinal degeneration. Previous cross-sectional studies show a significant decrease in the gray matter of the cerebral cortex, cerebellum, and brainstem. However, there are no longitudinal studies in SCA7 analyzing whole-brain degeneration and its relation to clinical decline. To perform a 2-year longitudinal characterization of the whole-brain degeneration and clinical decline in SCA7, twenty patients underwent MRI and clinical evaluations at baseline. Fourteen completed the 2-year follow-up study. A healthy-matched control group was also included. Imaging analyses included volumetric and cortical thickness evaluation. We measured the cognitive deterioration in SCA7 patients using MoCA test and the motor deterioration using the SARA score. We found statistically significant differences in the follow-up compared to baseline. Imaging analyses showed that SCA7 patients had severe cerebellar and pontine degeneration compared with the control group. Longitudinal follow-up imaging analyses of SCA7 patients showed the largest atrophy in the medial temporal lobe without signs of a progression of cerebellar and pontine atrophy. Effect size analyses showed that MRI longitudinal analysis has the largest effect size followed by the SARA scale and MoCA test. Here, we report that it is possible to detect significant brain atrophy and motor and cognitive clinical decline in a 2-year follow-up study of SCA7 patients. Our results support the hypothesis that longitudinal analysis of structural MRI and MOCA tests are plausible clinical markers to study the natural history of the disease and to design treatment trials in ecologically valid contexts.

Central motor conduction time in spinocerebellar ataxia: a meta-analysis.

The dominantly inherited spinocerebellar ataxias (SCAs) are a large class of neurodegenerative diseases. Transcranial magnetic stimulation has been used to evaluate the function of the pyramidal tract, and central motor conduction time (CMCT) is one index used to detect pyramidal tract dysfunction. We conducted a comprehensive search of PubMed, Embase and Web of Science. Eight eligible studies were included in the meta-analysis. For upper limb CMCT, the mean difference (95% confidence interval (CI)) between the combined SCA group and the control group was 2.24 [1.76-2.72], while the mean differences (95% CIs) between the subtypes and the control group were as follows: 4.43 [3.58-5.28] for SCA1, 0.25 [-0.15,0.65] for SCA2, 1.04 [-0.37,2.46] for SCA3 and 0.49 [-0.29,1.28] for SCA6. Additionally, SCA1 significantly differed from SCA2 and SCA3 in terms of CMCT (P=0.0006 and P=0.010, respectively). We also compared lower limb CMCT between the SCA2 and control groups. The mean difference (95% CI) was 6.58 [4.49-8.67], which was clearly statistically significant. The differences in CMCT values among different subtypes suggests diverse pathological mechanisms. In general, CMCT is a promising objective index to judge the severity of disease deserving further investigation.

The Impact of Compulsivity and Impulsivity in Cerebellar Ataxia: A Case Series.

Background: The cerebellum has recently been identified to have a key role in reward processing, and individuals with ataxia have been found to be more impulsive and compulsive as part of cerebellum-related cognitive and behavioral disturbances. Case Report: We reported five individuals with cerebellar ataxia who demonstrate impulsive and compulsive behaviors, including hobbyism, gambling, and compulsive medication use, to illustrate that these symptoms can be highly disabling. Discussion: These five cases provide examples of behavioral symptoms in cerebellar ataxia. Further investigations of the pathomechanism of these symptoms will advance our understanding of the cerebellum in cognition and behavior.