Structural Brain Correlates of Sleep Microstructure in Spinocerebellar Ataxia Type 2 and its Role on Clinical Phenotype.

The influence of brain atrophy on sleep microstructure in Spinocerebellar Ataxias (SCAs) has not been extensively explored limiting the use of these sleep traits as surrogate biomarkers of neurodegeneration and clinical phenotype. The objective of the study is to explore the relationship between sleep microstructure and brain atrophy in SCA2 and its role in the clinical phenotype. Fourteen SCA2 mutation carriers (7 pre-manifest and 7 manifest subjects) underwent polysomnographic, structural MRI, and clinical assessments. Particularly, markers of REM and non-REM sleep microstructure, measures of cerebellar and brainstem atrophy, and clinical scores were analyzed through correlation and mediation analyses. The sleep spindle activity exhibited a negative correlation with the number of trials required to complete the verbal memory test (VMT), and a positive correlation with the cerebellar volume, but the significance of the latter correlation did not survive multiple testing corrections. However, the causal mediation analyses unveiled that sleep spindle activity significantly mediates the association between cerebellar atrophy and VMT performance. Regarding REM sleep, both phasic EMG activity and REM sleep without atonia exhibited significant associations with pontine atrophy and disease severity measures. However, they did not demonstrate a causal mediation effect between the atrophy measures and disease severity. Our study provides evidence about the association of the pontocerebellar atrophy with sleep microstructure in SCA2 offering insights into the cerebellar involvement in cognition via the control of the sleep spindle activity. Therefore, our findings may help to understand the disease pathogenesis and to better characterize sleep microstructure parameters as disease biomarkers.Clinical trial registration number (TRN): No applicable.

Serum S100ß Levels Are Linked with Cognitive Decline and Peripheral Inflammation in Spinocerebellar Ataxia Type 2.

Experimental and clinical studies have indicated a potential role of the protein S100ß in the pathogenesis and phenotype of neurodegenerative diseases. However, its impact on spinocerebellar ataxia type 2 (SCA2) remains to be elucidated. The objective of the study is to determine the serum levels of S100ß in SCA2 and its relationship with molecular, clinical, cognitive, and peripheral inflammatory markers of the disease. Serum concentrations of S100ß were measured by enzyme-linked immunosorbent assay in 39 SCA2 subjects and 36 age- and gender-matched controls. Clinical scores of ataxia, non-ataxia symptoms, cognitive dysfunction, and some blood cell count-derived inflammatory indices were assessed. The SCA2 individuals manifested S100ß levels similar to the control group, at low nanomolar concentrations. However, the S100ß levels were directly associated with a better performance of cognitive evaluation within the SCA2 cohort. Moreover, the S100ß levels were inversely correlated with most peripheral inflammatory indices. Indeed, the neutrophil-to-lymphocyte ratio significantly mediated the effect of serum S100ß on cognitive performance, even after controlling for the ataxia severity in the causal mediation analysis. Our findings suggested that, within physiologic concentrations, the protein S100ß exerts a neuroprotective role against cognitive dysfunction in SCA2, likely via the suppression of pro-inflammatory mechanisms.

Peripheral Inflammation Links with the Severity of Clinical Phenotype in Spinocerebellar Ataxia 2.

BACKGROUND: The role of peripheral inflammation in spinocerebellar ataxia type 2 (SCA2) is unknown. OBJECTIVE: The objective of this study was to identify peripheral inflammation biomarkers and their relationship with the clinical and molecular features. METHODS: Blood cell count-derived inflammatory indices were measured in 39 SCA2 subjects and their matched controls. Clinical scores of ataxia, nonataxia, and cognitive dysfunction were assessed. RESULTS: The neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the Systemic Inflammation Index (SII), and the Aggregate Index of Systemic Inflammation (AISI) were significantly increased in SCA2 subjects compared with controls. The increases in PLR, SII, and AISI were even observed in preclinical carriers. NLR, PLR, and SII were correlated with the Scale for the Assessment and Rating of Ataxia speech item score rather than with the total score. The NLR and SII were correlated with the nonataxia and the cognitive scores. CONCLUSIONS: Peripheral inflammatory indices are biomarkers in SCA2, which may help to design future immunomodulatory trials and advance our understanding of the disease. © 2023 International Parkinson and Movement Disorder Society.

COVID-19 Impacts the Mental Health and Speech Function in Spinocerebellar Ataxia Type 2: Evidences from a Follow-Up Study.

Limited evidence suggests that the SARS-CoV-2 infection can accelerate the progression of neurodegenerative diseases, but this has been not verified in the spinocerebellar ataxias (SCA). The objective of this study is to assess the impact of COVID-19 on the mental health and motor features of SCA2. A follow-up study was carried out in 170 Cuban SCA2 subjects and 87 community controls between 2020 and 2021. All subjects underwent a structured questionnaire to assess the risks of exposure to COVID-19, the confirmation of COVID-19 diagnosis, and the Hospital Anxiety and Depression Scale (HADS). Moreover, 36 subjects underwent the Scale for the Assessment and Rating of ataxia (SARA). The risk of exposure to SARS-CoV-2 and the frequency of COVID-19 were similar between the ataxia cohort and the community controls. Within the ataxia group, significantly increased HADS scores existed at the 2nd visit in both groups, but this increase was more evident for the infected group regarding the depression score. Moreover, a significant within-group increase of SARA score was observed in the infected group but not the non-infected group, which was mainly mediated by the significant increase of the speech item score in the infected group. Similar results were observed within the subgroup of preclinical carriers. Our study identified no selective vulnerability nor protection to COVID-19 in SCA2, but once infected, the patients experienced a deterioration of mental health and speech function, even at preclinical disease stage. These findings set rationales for tele-health approaches that minimize the detrimental effect of COVID-19 on SCA2 progression and identify SCA2 individuals as clinical model to elucidate the link between SARS-CoV-2 infection and neurodegeneration.

An Exploratory Survey on the Care for Ataxic Patients in the American Continents and the Caribbean.

Little is known about access of rare disease carriers to health care. To increase this knowledge, the Pan American Hereditary Ataxia Network (PAHAN) conducted an exploratory survey about care for hereditary ataxias in American continents and the Caribbean. A questionnaire was sent to health professionals about the hereditary ataxias identified; access to care; and local teaching and research. The number of ataxics under current care per 100,000 inhabitants was subtracted from the expected overall prevalence of 6/100,000, to estimate the prevalence of uncovered ataxic patients. Local Human Development Indexes (HDI) were used to measure socio-economic factors. Twenty-six sites participated. Twelve sites had very high, 13 had high, and one site had medium HDI. Participants reported on 2239 and 602 patients with spinocerebellar ataxias and recessive forms under current care. The number of patients under current care per inhabitants varied between 0.14 and 12/100,000. The estimated prevalence of uncovered ataxic patients was inversely proportional to HDIs (rho = 0.665, p = 0.003). Access to diagnosis, pre-symptomatic tests, and rehabilitation were associated with HDIs. More and better molecular diagnostic tools, protocols and guidelines, and professional training for ataxia care were the top priorities common to all respondents. Evidence of inequalities was confirmed. Lower HDIs were associated with high potential numbers of uncovered ataxic subjects, and with lack of molecular diagnosis, pre-symptomatic testing, and rehabilitation. More and better diagnostic tools, guidelines, and professional training were priorities to all sites. PAHAN consortium might help with the last two tasks.

Erythropoietin in Spinocerebellar Ataxia Type 2: Feasibility and Proof-of-Principle Issues from a Randomized Controlled Study.

BACKGROUND: Several pieces of evidence have shown the neurotrophic effect of erythropoietin (EPO) and its introduction in the therapeutic practice of neurological diseases. However, its usefulness in the treatment of spinocerebellar ataxia type 2 (SCA2) has not been proven despite the fact that it is endogenously reduced in these patients. OBJECTIVE: The study aims to investigate the safety, tolerability, and clinical effects of a nasally administered recombinant EPO in SCA2 patients. METHODS: Thirty-four patients were enrolled in this double-blind, randomized, placebo-controlled, phase I-II clinical trial of the nasally administered human-recombinant EPO (NeuroEPO) for 6 months. The primary outcome was the change in the spinocerebellar ataxia functional index (SCAFI), while other motor, neuropsychological, and oculomotor measures were assessed. RESULTS: The 6-month changes in SCAFI score were slightly higher in the patients allocated to NeuroEPO treatment than placebo in spite of the important placebo effect observed for this parameter. However, saccade latency was significantly decreased in the NeuroEPO group but not in placebo. The frequency and severity of adverse events were similar between both groups, without evidences of hematopoietic activity of the drug. CONCLUSIONS: This study demonstrated the safety and tolerability of NeuroEPO in SCA2 patients after 6 months of treatments and suggested a small clinical effect of this drug on motor and cognitive abnormalities, but confirmatory studies are warranted. © 2022 International Parkinson and Movement Disorder Society.

Cognitive Decline Is Closely Associated with Ataxia Severity in Spinocerebellar Ataxia Type 2: a Validation Study of the Schmahmann Syndrome Scale.

The cerebellar cognitive affective syndrome scale (CCAS-S) was designed to detect specific cognitive dysfunctions in cerebellar patients but is scarcely validated in spinocerebellar ataxias (SCA). The objective of this study is to determine the usefulness of the CCAS-S in a Cuban cohort of SCA2 patients and the relationship of its scores with disease severity. The original scale underwent a forward and backward translation into Spanish language, followed by a pilot study to evaluate its comprehensibility. Reliability, discriminant, and convergent validity assessments were conducted in 64 SCA2 patients and 64 healthy controls matched for sex, age, and education. Fifty patients completed the Montreal Cognitive Assessment (MoCA) test. The CCAS-S showed an acceptable internal consistency (Cronbach's alpha = 0.74) while its total raw score and the number of failed tests showed excellent (ICC = 0.94) and good (ICC = 0.89) test-retest reliability, respectively. Based on original cut-offs, the sensitivity of CCAS-S to detect possible/probable/definite CCAS was notably high (100%/100%/91%), but specificities were low (6%/30/64%) because the decreased specificity observed in four items. CCAS-S performance was significantly influenced by ataxia severity in patients and by education in both groups. CCAS-S scores correlated with MoCA scores, but showed higher sensitivity than MoCA to detect cognitive impairments in patients. The CCAS-S is particularly useful to detect cognitive impairments in SCA2 but some transcultural and/or age and education-dependent adaptations could be necessary to improve its diagnostic properties. Furthermore, this scale confirmed the parallelism between cognitive and motor deficits in SCA2, giving better insights into the disease pathophysiology and identifying novel outcomes for clinical trials.

Weight loss is correlated with disease severity in Spinocerebellar ataxia type 2: a cross-sectional cohort study.

BACKGROUND: Body weight changes occur frequently during advanced stages of Spinocerebellar Ataxia type 2 (SCA2), nevertheless limited information exists on biomarkers of nutritional status of these patients. OBJECTIVE.: To assess changes in surrogate nutritional markers of SCA2 patients; to explore their associations with expanded CAG repeats and disease severity. METHODS: One-hundred-thirteen SCA2 patients and 50 healthy controls underwent a comprehensive anthropometrical and biochemical assessment protocol of the nutritional status. Neurological and genotype assessments were also performed. RESULTS: A decrease in weight, body mass index (BMI), cutaneous skinfold thickness, fat mass, arm muscle circumference, calf circumference and skeletal muscle mass was observed in SCA2 patients compared to the controls. The total/HDL cholesterol ratio was significantly reduced in patients. BMI was correlated with the age at onset. Overall, anthropometric measures were correlated with clinical markers of disease severity and were more evident in severe and moderate cases. CONCLUSIONS: Using anthropometric measures in the assessment of the nutritional status of SCA2 patients might provide hints about pathophysiological mechanisms that underlie metabolic abnormalities in SCA2. Anthropometric are close related with disease severity and progression, and trigger preventive therapies aimed to ameliorate weight loss and wasting in these patients.

Convolutional Neural Networks for Segmenting Cerebellar Fissures from Magnetic Resonance Imaging.

The human cerebellum plays an important role in coordination tasks. Diseases such as spinocerebellar ataxias tend to cause severe damage to the cerebellum, leading patients to a progressive loss of motor coordination. The detection of such damages can help specialists to approximate the state of the disease, as well as to perform statistical analysis, in order to propose treatment therapies for the patients. Manual segmentation of such patterns from magnetic resonance imaging is a very difficult and time-consuming task, and is not a viable solution if the number of images to process is relatively large. In recent years, deep learning techniques such as convolutional neural networks (CNNs or convnets) have experienced an increased development, and many researchers have used them to automatically segment medical images. In this research, we propose the use of convolutional neural networks for automatically segmenting the cerebellar fissures from brain magnetic resonance imaging. Three models are presented, based on the same CNN architecture, for obtaining three different binary masks: fissures, cerebellum with fissures, and cerebellum without fissures. The models perform well in terms of precision and efficiency. Evaluation results show that convnets can be trained for such purposes, and could be considered as additional tools in the diagnosis and characterization of neurodegenerative diseases.

Gene Therapy for Polyglutamine Spinocerebellar Ataxias: Advances, Challenges, and Perspectives.

Polyglutamine spinocerebellar ataxias (SCAs) comprise a heterogeneous group of six autosomal dominant ataxias caused by cytosine-adenine-guanine repeat expansions in the coding region of single genes. Currently, there is no curative or disease-slowing treatment for these disorders, but their monogenic inheritance has informed rationales for development of gene therapy strategies. In fact, RNA interference strategies have shown promising findings in cellular and/or animal models of SCA1, SCA3, SCA6, and SCA7. In addition, antisense oligonucleotide therapy has provided encouraging proofs of concept in models of SCA1, SCA2, SCA3, and SCA7, but they have not yet progressed to clinical trials. On the contrary, the gene editing strategies, such as the clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), have been introduced to a limited extent in these disorders. In this article, we review the available literature about gene therapy in polyglutamine SCAs and discuss the main technological and ethical challenges toward the prospect of their use in future clinical trials. Although antisense oligonucleotide therapies are further along the path to clinical phases, the recent failure of three clinical trials in Huntington's disease may delay their utilization for polyglutamine SCAs, but they offer lessons that could optimize the likelihood of success in potential future clinical studies. © 2021 International Parkinson and Movement Disorder Society.

Gait Variability in Spinocerebellar Ataxia Assessed Using Wearable Inertial Sensors.

BACKGROUND: Quantitative assessment of severity of ataxia-specific gait impairments from wearable technology could provide sensitive performance outcome measures with high face validity to power clinical trials. OBJECTIVES: The aim of this study was to identify a set of gait measures from body-worn inertial sensors that best discriminate between people with prodromal or manifest spinocerebellar ataxia (SCA) and age-matched, healthy control subjects (HC) and determine how these measures relate to disease severity. METHODS: One hundred and sixty-three people with SCA (subtypes 1, 2, 3, and 6), 42 people with prodromal SCA, and 96 HC wore 6 inertial sensors while performing a natural pace, 2-minute walk. Areas under the receiver operating characteristic curves (AUC) were compared for 25 gait measures, including standard deviations as variability, to discriminate between ataxic and normal gait. Pearson's correlation coefficient assessed the relationships between the gait measures and severity of ataxia. RESULTS: Increased gait variability was the most discriminative gait feature of SCA; toe-out angle variability (AUC = 0.936; sensitivity = 0.871; specificity = 0.896) and double-support time variability (AUC = 0.932; sensitivity = 0.834; specificity = 0.865) were the most sensitive and specific measures. These variability measures were also significantly correlated with the scale for the assessment and rating of ataxia (SARA) and disease duration. The same gait measures discriminated gait of people with prodromal SCA from the gait of HC (AUC = 0.610, and 0.670, respectively). CONCLUSIONS: Wearable inertial sensors provide sensitive and specific measures of excessive gait variability in both manifest and prodromal SCAs that are reliable and related to the severity of the disease, suggesting they may be useful as clinical trial performance outcome measures. © 2021 International Parkinson and Movement Disorder Society.

Prodromal Spinocerebellar Ataxia Type 2 Subjects Have Quantifiable Gait and Postural Sway Deficits.

BACKGROUND: The search for valid preclinical biomarkers of cerebellar dysfunction is a key research goal for the upcoming era of early interventional approaches in spinocerebellar ataxias. This study aims to describe novel preclinical biomarkers of subtle gait and postural sway abnormalities in prodromal spinocerebellar ataxia type 2 (pre-SCA2). METHODS: Thirty pre-SCA2 patients and their matched healthy controls underwent quantitative assessments of gait and postural sway using a wearable sensor-based system and semiquantitative evaluation of cerebellar features by SARA (Scale for the Assessment and Rating of Ataxia) score. RESULTS: Quantitative analysis of natural gait showed a significantly larger variability of the swing period, toe-off angle and toe-out angle in pre-SCA2, and larger mean coronal and transverse ranges of motion of the trunk at the lumbar location and of the sagittal range of motion of the trunk at the sternum location compared to controls. During tandem gait, pre-SCA2 subjects showed larger lumbar, trunk, and arm ranges of motion than controls. Postural sway analysis showed excessive body oscillation that was increased in tandem stance. Overall, these abnormalities were detected in pre-SCA2 patients without clinical evidence of abnormalities in SARA. The toe-off angle and swing time variability were significantly correlated with the time to ataxia onset, whereas the toe-off angle and transverse range of motion at trunk position during tandem gait were significantly associated with the SARA score. CONCLUSIONS: This study demonstrates early alteration of gait and postural sway control in prodromal SCA2 using a wearable sensor-based system. This offers new pathophysiological hints into this early disease stage and provides novel potential biomarkers for future clinical trials. © 2020 International Parkinson and Movement Disorder Society.

Impacts of the COVID-19 Pandemic on the Mental Health and Motor Deficits in Cuban Patients with Cerebellar Ataxias.

Although there are no convincing evidences of detrimental effect of SARS-CoV2 infection on the cerebellum, the COVID-19 pandemic could impact the life quality of patients with cerebellar ataxias, but few studies have addressed this concern. To assess the motor and mental health changes caused by the COVID-19 pandemics in Cuban patients with cerebellar ataxias, three hundred four patients with cerebellar ataxias and 167 healthy controls were interviewed for risks of exposure to COVID-19, and the self-perception of the pandemics' impact on the disease progression and on the mental health. All subjects underwent the Hospital Anxiety and Depression Scale. The patients reported low exposition to SARS-CoV2 infection, but one case was confirmed with a mild COVID-19. Overall, depressive and anxiety symptoms were significantly and marginally increased in patients, respectively, with higher scores in cases with severe and moderate ataxia. Positive patient's impression of psychopathological changes was associated to increased age, age at onset, and anxiety. Sixty-seven patients had a positive self-perception of ataxia progression, which was mainly influenced by higher anxiety scores but not by the adherence to at-home exercise programs. However, the practice of physical exercise was related with lower depression and anxiety scores, but this therapeutical effect was not significantly influenced by the disease stage. We demonstrated the negative effect of the COVID-19 pandemic on the mental and motor deficits in Cuban patients with cerebellar ataxias and the positive effect of the at-home physical exercise programs on their mental well-being. These findings give rationales to develop tele-medicine approaches to minimize these health impacts and to study the long-term effects of such sequelae and accordingly define their treatments.

EMG Rectification Is Detrimental for Identifying Abnormalities in Corticomuscular and Intermuscular Coherence in Spinocerebellar Ataxia Type 2.

Corticomuscular and intermuscular coherence (CMC, IMC) reflect connectivity between neuronal activity in the motor cortex measured by electroencephalography (EEG) and muscular activity measured by electromyography (EMG), or between activity in different muscles, respectively. There is an ongoing debate on the appropriateness of EMG rectification prior to coherence estimation. This work examines the effects of EMG rectification in CMC and IMC estimation in 20 spinocerebellar ataxia type 2 (SCA2) patients, 16 prodromal SCA2 gene mutation carriers, and 26 healthy controls during a repetitive upper or lower limb motor task. Coherence estimations were performed using the non-rectified raw EMG signal vs. the rectified EMG signal. EMG rectification decreases the level of significance of lower beta-frequency band CMC and IMC values in SCA2 patients and prodromal SCA2 mutation carriers vs. healthy controls, and also results in overall lower coherence values. EMG rectification is detrimental for beta-frequency band CMC and IMC estimation. One likely reason for this effect is distortion of coherence estimation in high-frequency signals, where the level of amplitude cancelation is high.

Founder Effects of Spinocerebellar Ataxias in the American Continents and the Caribbean.

Spinocerebellar ataxias (SCAs) comprise a heterogeneous group of autosomal dominant disorders. The relative frequency of the different SCA subtypes varies broadly among different geographical and ethnic groups as result of genetic drifts. This review aims to provide an update regarding SCA founders in the American continents and the Caribbean as well as to discuss characteristics of these populations. Clusters of SCAs were detected in Eastern regions of Cuba for SCA2, in South Brazil for SCA3/MJD, and in Southeast regions of Mexico for SCA7. Prevalence rates were obtained and reached 154 (municipality of Báguano, Cuba), 166 (General Câmara, Brazil), and 423 (Tlaltetela, Mexico) patients/100,000 for SCA2, SCA3/MJD, and SCA7, respectively. In contrast, the scattered families with spinocerebellar ataxia type 10 (SCA10) reported all over North and South Americas have been associated to a common Native American ancestry that may have risen in East Asia and migrated to Americas 10,000 to 20,000 years ago. The comprehensive review showed that for each of these SCAs corresponded at least the development of one study group with a large production of scientific evidence often generalizable to all carriers of these conditions. Clusters of SCA populations in the American continents and the Caribbean provide unusual opportunity to gain insights into clinical and genetic characteristics of these disorders. Furthermore, the presence of large populations of patients living close to study centers can favor the development of meaningful clinical trials, which will impact on therapies and on quality of life of SCA carriers worldwide.

Hereditary Ataxias in Cuba: A Nationwide Epidemiological and Clinical Study in 1001 Patients.

The prevalence estimations of hereditary ataxias are biased since most epidemiological studies are confined to isolated geographical regions and few nationwide studies are available. The study aims to assess the prevalence, distribution, and neurological features of the Cuban population with hereditary ataxias. A nationwide epidemiological study of hereditary ataxias was conducted in Cuba between March 2017 and June 2018. Patients were scheduled at the Cuban ataxia research center, various hospitals, or at their homes. Demographic and clinical variables were obtained through standardized questionnaires and validated clinical tools. Overall, 1001 patients were diagnosed with hereditary ataxias for a nationwide prevalence of 8.91 cases/100.000 inhabitants. Spinocerebellar ataxia type 2 (SCA2) was the commonest subtype, with highest prevalences at Holguín province (47.86/100.000), and a broad dissemination in the whole country. Most of neurological features were common between all SCA cohorts, but the frequencies of some of them varied between distinct subtypes. Within the SCA2 cohort, significant influences of long mutation size and higher disease duration over the muscle atrophy and oculomotor disorders were observed. Besides, higher disease durations were associated with resting tremor and dysphagia, whereas shorter disease durations were associated with hyperreflexia. The spreading of SCA2 to whole country and the documented raising of its prevalence set the rationales for higher-scope medical care and research strategies, supported in collaborative research networks. The wide epidemiological, clinical, and genetic characterization of this founder SCA2 population identifies this homogeneous cohort as an attractive source for the development of future clinical-genetic and therapeutic researches.

Involvement of the Auditory Pathway in Spinocerebellar Ataxia Type 7.

BACKGROUND: Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant disorder caused by a mutation in the ATXN7 gene. The involvement of the brainstem auditory pathway in pathogenesis of this disease has not been systematically assessed. AIM: To determine involvement of the brainstem auditory pathway in SCA7 patients and its relationship to clinical features of the disease. METHODS: In this case-control study, brainstem auditory-evoked potentials (BAEPs) were assessed in 12 SCA7 patients with clinical and molecular diagnosis, compared to 2 control groups of 16 SCA2 patients and 16 healthy controls. RESULTS: SCA7 patients exhibited significant prolongation of I-wave and III-wave latencies, whereas SCA2 patients showed increased latencies for III and V waves and I-III interpeak interval. SCA7 patients with larger I-wave latencies exhibited larger CAG repeats, earlier onset age, and higher SARA scores, but in SCA2 cases, these were not observed. CONCLUSIONS: BAEP tests revealed functional involvement of the auditory pathway in SCA7 (mainly at) peripheral portions, which gave new insights into the disease physiopathology different from SCA2 and may unravel distinct pathoanatomical effects of polyQ expansions in the central nervous system. SIGNIFICANCE: These findings offer important insights into the distinctive disease mechanisms in SCA7 and SCA2, which could be useful for differential diagnosis and designing specific precision medicine approaches for both conditions.

Automated Detection of Presymptomatic Conditions in Spinocerebellar Ataxia Type 2 Using Monte Carlo Dropout and Deep Neural Network Techniques with Electrooculogram Signals.

Application of deep learning (DL) to the field of healthcare is aiding clinicians to make an accurate diagnosis. DL provides reliable results for image processing and sensor interpretation problems most of the time. However, model uncertainty should also be thoroughly quantified. This paper therefore addresses the employment of Monte Carlo dropout within the DL structure to automatically discriminate presymptomatic signs of spinocerebellar ataxia type 2 in saccadic samples obtained from electrooculograms. The current work goes beyond the common incorporation of this special type of dropout into deep neural networks and uses the uncertainty derived from the validation samples to construct a decision tree at the register level of the patients. The decision tree built from the uncertainty estimates obtained a classification accuracy of 81.18% in automatically discriminating control, presymptomatic and sick classes. This paper proposes a novel method to address both uncertainty quantification and explainability to develop reliable healthcare support systems.

Neurorehabilitation Improves the Motor Features in Prodromal SCA2: A Randomized, Controlled Trial.

BACKGROUND: The search for early interventions is a novel approach in spinocerebellar ataxias, but there are few studies supporting this notion. This article aimed to assess the efficacy of neurorehabilitation treatment in prodromal spinocerebellar ataxia type 2. METHODS: Thirty spinocerebellar ataxia type 2 preclinical carriers were enrolled in a randomized, controlled trial using neurorehabilitation. The intervention in the treated group was 4 hours per day, 5 days per week for 12 weeks, emphasizing static balance, gait, and limb coordination. The control group did not receive rehabilitation. The primary outcome measure was the time for 5-m tandem gait over the floor. Secondary outcomes included other timed tests with increased motor complexity, as well as the scores of the SARA and the Inventory of Non-ataxia Symptoms. RESULTS: The times for 5-m tandem gait over the floor and the mattress were significantly reduced only in the rehabilitated group. Moreover, the times upholding the tandem stance over a mattress and the seesaw were notably increased only in this group. Likewise, the finger-nose and the heel-shin tests were improved in the rehabilitated group alone. The SARA score and the count of nonataxia symptoms were unchanged. CONCLUSIONS: This rehabilitation program improves the subtle gait, postural and coordinative deficits in prodromal spinocerebellar ataxia type 2, which provided novel hints about the preservation of motor learning and neural plasticity mechanisms in early disease stages, leading chances for other interventional approaches in this and other spinocerebellar ataxias. © 2019 International Parkinson and Movement Disorder Society.

Effects of Physical Rehabilitation in Patients with Spinocerebellar Ataxia Type 7.

Today, neurorehabilitation has become in a widely used therapeutic approach in spinocerebellar ataxias; however, there are scarce powerful clinical studies supporting this notion, and these studies require extension to other specific SCA subtypes in order to be able to form conclusions concerning its beneficial effects. Therefore, in this study, we perform for the first time a case-control pilot randomized, single-blinded, cross-sectional, and observational study to evaluate the effects of physical neurorehabilitation on the clinical and biochemical features of patients with spinocerebellar ataxia type 7 (SCA7) in 18 patients diagnosed with SCA7. In agreement with the exercise regimen, the participants were assigned to groups as follows: (a) the intensive training group, (b) the moderate training group, and (c) the non-training group (control group).We found that both moderate and intensive training groups showed a reduction in SARA scores but not INAS scores, compared with the control group (p < 0.05). Furthermore, trained patients exhibited improvement in the SARA sub-scores in stance, gait, dysarthria, dysmetria, and tremor, as compared with the control group (p < 0.05). No significant improvements were found in daily living activities, as revealed by Barthel and Lawton scales (p > 0.05). Patients under physical training exhibited significantly decreased levels in lipid-damage biomarkers and malondialdehyde, as well as a significant increase in the activity of the antioxidant enzyme PON-1, compared with the control group (p < 0.05). Physical exercise improved some cerebellar characteristics and the oxidative state of patients with SCA7, which suggest a beneficial effect on the general health condition of patients.