Unraveling the genetic landscape of undiagnosed cerebellar ataxia in Brazilian patients.

INTRODUCTION: Hereditary ataxias (HAs) encompass a diverse and genetically intricate group of rare neurodegenerative disorders, presenting diagnostic challenges. Whole-exome sequencing (WES) has significantly improved diagnostic success. This study aimed to elucidate genetic causes of cerebellar ataxia within a diverse Brazilian cohort. METHODS: Biological samples were collected from individuals with sporadic or familial cerebellar ataxia, spanning various ages and phenotypes, excluding common SCAs and Friedreich ataxia. RFC1 biallelic AAGGG repeat expansion was screened in all patients. For AAGGG-negative cases, WES targeting 441 ataxia-related genes was performed, followed by ExpansionHunter analysis for repeat expansions, including the recently described GGC-ZFHX3. Variant classification adhered to ClinGen guidelines, yielding definitive or probable diagnoses. RESULTS: The study involved 76 diverse Brazilian families. 16 % received definitive diagnoses, and another 16 % received probable ones. RFC1-related ataxia was predominant, with two definitive cases, followed by KIF1A (one definitive and one probable) and SYNE-1 (two probable). Early-onset cases exhibited higher diagnostic rates. ExpansionHunter improved diagnosis by 4 %.We did not detected GGC-ZFHX3 repeat expansion in this cohort. CONCLUSION: This study highlights diagnostic complexities in cerebellar ataxia, even with advanced genetic methods. RFC1, KIF1A, and SYNE1 emerged as prevalent mutations. ZFHX3 repeat expansion seem to be rare in Brazilian population. Early-onset cases showed higher diagnostic success. WES coupled with ExpansionHunter holds promise as a primary diagnostic tool, emphasizing the need for broader NGS accessibility in Brazil.

Optimising verbal fluency analysis in neurological patients with dysarthria: examples from Parkinson's disease and hereditary ataxia.

BACKGROUND: Verbal fluency tests (VFTs) are widely used to assess cognitive-linguistic performance in neurological diseases. However, the influence of dysarthria on performance in tests requiring oral responses is unclear in ataxia and Parkinson's disease. OBJECTIVES: To determine the impact of dysarthria on VFT performance and evaluate the validity and reliability of alternative methods for analyzing VFT data. METHOD: Trained raters evaluated dysarthria using VFT recordings in people with ataxia (N = 61) or Parkinson's disease (PD; N = 69). Total Correct Items scores and qualitative parameters (intrusions, ambiguous verbalizations, perseverations, and interjections) were compared across semantic, phonemic, and alternating fluency tasks. Disease severity was considered as a covariate in the regression model. RESULTS: VFT dysarthria ratings correlated with the benchmark (ground truth) dysarthria scores derived from a monologue. Ambiguous responses resulting from unclear speech impeded the rater's ability to determine if a response was correct. Regression analysis indicated that more severe dysarthria ratings predicted diminished scores in all three tasks (semantic fluency, phonemic fluency and alternating fluency) in the ataxia group. The contribution of disease severity to semantic, phonemic and alternating fluency was reduced substantially in the ataxia group after accounting for dysarthria severity in the model in both groups. CONCLUSIONS: Dysarthria severity can be estimated based on speech samples derived from VFT. Dysarthria can lead to lower total correct items and is associated with more ambiguous verbalizations in VFT. Dysarthria severity should be considered when interpreting VFT performance in common movement disorders.

Coexistence of multiple sclerosis and spinocerebellar ataxia type-8.

Cerebellar dysfunction is likely to cause severe and treatment-resistant disability in multiple sclerosis (MS). Certain spinocerebellar ataxia (SCA)-related alleles can increase MS susceptibility, and channel polymorphisms can impact disability measures. Following an index patient with the coexistence of MS and SCA Type-8 (SCA8) in the MS clinic, an institutional engine search for MS and hereditary ataxia coexistence was conducted but did not reveal any other cases. This extremely rare coexistence of MS and SCA8 in our index patient may be incidental; however, a yet-to-be-identified contribution of coexistent hereditary ataxia(s) to the susceptibility of a prominent progressive ataxia MS phenotype cannot be ruled out.

Natural History and Phenotypic Spectrum of GAA-FGF14 Sporadic Late-Onset Cerebellar Ataxia (SCA27B).

BACKGROUND: Heterozygous GAA expansions in the FGF14 gene have been related to autosomal dominant cerebellar ataxia (SCA27B-MIM:620174). Whether they represent a common cause of sporadic late-onset cerebellar ataxia (SLOCA) remains to be established. OBJECTIVES: To estimate the prevalence, characterize the phenotypic spectrum, identify discriminative features, and model longitudinal progression of SCA27B in a prospective cohort of SLOCA patients. METHODS: FGF14 expansions screening combined with longitudinal deep-phenotyping in a prospective cohort of 118 SLOCA patients (onset >40 years of age, no family history of cerebellar ataxia) without a definite diagnosis. RESULTS: Prevalence of SCA27B was 12.7% (15/118). Higher age of onset, higher Spinocerebellar Degeneration Functional Score, presence of vertigo, diplopia, nystagmus, orthostatic hypotension absence, and sensorimotor neuropathy were significantly associated with SCA27B. Ataxia progression was ≈0.4 points per year on the Scale for Assessment and Rating of Ataxia. CONCLUSIONS: FGF14 expansion is a major cause of SLOCA. Our natural history data will inform future FGF14 clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Nutritional status and eating habits of patients with hereditary ataxias: a case-control study.

INTRODUCTION: Hereditary Ataxias (HAs) comprise a wide spectrum of genetically determined neurodegenerative diseases with progressive ataxia as the main symptom. Few studies have evaluated nutritional profile in HA patients and most of these focused on specific ataxia subtypes. The objectives of this study were: (1) to investigate whether hereditary ataxias were associated with changes in energy expenditure, body composition and dietary intake; (2) to verify differences in these variables according to ataxia subtype, sex, age, and disease severity. METHODS: Thirty-eight hereditary ataxia patients from two neurology centers in Northeastern Brazil and 38 controls were evaluated. Body composition was assessed with bio-impedance analysis and dietary intake was estimated with a validated questionnaire (24-hour dietary recall). RESULTS: Mean body mass index (BMI) was lower in HA compared to controls (p = 0.032). Hereditary ataxia patients showed lower protein intake, higher frequency of dysphagia and higher incidence of nausea and diarrhea. The difference in average estimated caloric intake did not reach statistical significance (2359kcal ± 622 in patients × 2713kcal ± 804 in controls, p = 0.08). Disease severity measured by the SARA scale was not associated with BMI, nor was ataxia subtype (autosomal dominant × non-autosomal dominant ataxias). CONCLUSION: Hereditary ataxia patients have lower BMI compared to healthy controls. There was no difference in this cohort between dominant or non-dominant ataxia regarding BMI. Weight loss may be a common finding among hereditary ataxias and may affect the quality of life in these patients.

Translation, Cross-Cultural Adaptation, and Validation to Brazilian Portuguese of the Cerebellar Cognitive Affective/Schmahmann Syndrome Scale.

Cerebellar cognitive affective syndrome (CCAS) is characterized by deficits in executive functions, language processing, spatial orientation, and affect regulation in patients with cerebellar disease. The symptoms can occur isolated or along with motor and coordination symptoms. The aim of our study was to translate and culturally adapt the CCAS scale to Brazilian Portuguese and validate the scale in our population. We performed a cross-sectional study with patients with primary and secondary ataxia. The study included 111 individuals, aged between 20 and 80 years, of both genders, 20 without cognitive and/or affective complaints who participated in the pre-test phase, 40 with cerebellar disease (hereditary/neurodegenerative ataxia or acquired/secondary cerebellar ataxia), and 51 healthy controls with no evidence of cognitive impairment and no affective symptoms matched for sex, age, and educational level. The scale was translated, culturally adapted, and validated. Statistical analysis of the data was performed, with association tests, mean comparison, and ROC curve analysis. Based on the analysis of the ROC curve, optimal cutoff values ​were found for each subitem of the scale. The translated and adapted scale has good internal consistency, is reproducible, has good reliability, and has the potential to be a reliable tool for screening cognitive symptoms in patients with cerebellar disease.

Unravelling the etiology of sporadic late-onset cerebellar ataxia in a cohort of 205 patients: a prospective study.

BACKGROUND: Despite recent progress in the field of genetics, sporadic late-onset (> 40 years) cerebellar ataxia (SLOCA) etiology remains frequently elusive, while the optimal diagnostic workup still needs to be determined. We aimed to comprehensively describe the causes of SLOCA and to discuss the relevance of the investigations. METHODS: We included 205 consecutive patients with SLOCA seen in our referral center. Patients were prospectively investigated using exhaustive clinical assessment, biochemical, genetic, electrophysiological, and imaging explorations. RESULTS: We established a diagnosis in 135 (66%) patients and reported 26 different causes for SLOCA, the most frequent being multiple system atrophy cerebellar type (MSA-C) (41%). Fifty-one patients (25%) had various causes of SLOCA including immune-mediated diseases such as multiple sclerosis or anti-GAD antibody-mediated ataxia; and other causes, such as alcoholic cerebellar degeneration, superficial siderosis, or Creutzfeldt-Jakob disease. We also identified 11 genetic causes in 20 patients, including SPG7 (n = 4), RFC1-associated CANVAS (n = 3), SLC20A2 (n = 3), very-late-onset Friedreich's ataxia (n = 2), FXTAS (n = 2), SCA3 (n = 1), SCA17 (n = 1), DRPLA (n = 1), MYORG (n = 1), MELAS (n = 1), and a mitochondriopathy (n = 1) that were less severe than MSA-C (p < 0.001). Remaining patients (34%) had idiopathic late-onset cerebellar ataxia which was less severe than MSA-C (p < 0.01). CONCLUSION: Our prospective study provides an exhaustive picture of the etiology of SLOCA and clues regarding yield of investigations and diagnostic workup. Based on our observations, we established a diagnostic algorithm for SLOCA.

Ataxia with Ocular Apraxia Type 1 (AOA1) (APTX, W279* Mutation): Neurological, Neuropsychological, and Molecular Outlining of a Heterogenous Phenotype in Four Colombian Siblings.

Hereditary ataxias are a group of devastating neurological disorders that affect coordination of gait and are often associated with poor coordination of hands, speech, and eye movements. Ataxia with ocular apraxia type 1 (AOA1) (OMIM: 606,350.0006) is characterized by slowly progressive symptoms of childhood-onset and pathogenic mutations in APTX; the only known cause underpinning AOA1. APTX encodes the protein aprataxin, composed of three domains sharing homology with proteins involved in DNA damage, signaling, and repair. We present four siblings from an endogamic family in a rural, isolated town of Colombia with ataxia and ocular apraxia of childhood-onset and confirmed molecular diagnosis of AOA1, homozygous for the W279* p.Trp279Ter mutation. We predicted the mutated APTX with AlphaFold to demonstrate the effects of this stop-gain mutation that deletes three beta helices encoded by amino acid 270 to 339 rescinding the C2H2-type zinc fingers (Znf) (C2H2 Znf) DNA-binding, the DNA-repair domain, and the whole 3D structure of APTX. All siblings exhibited different ages of onset (4, 6, 8, and 11 years old) and heterogeneous patterns of dysarthria (ranging from absence to mild-moderate dysarthria). Neuropsychological evaluation showed no neurocognitive impairment in three siblings, but one sibling showed temporospatial disorientation, semantic and phonologic fluency impairment, episodic memory affection, constructional apraxia, moderate anomia, low executive function, and symptoms of depression. To our knowledge, this report represents the most extensive series of siblings affected with AOA1 in Latin America, and the genetic analysis completed adds important knowledge to outline this family's disease and general complex phenotype of hereditary ataxias.

Neuropsychological Profile of Hereditary Ataxias: Study of 38 Patients.

Hereditary ataxias are a heterogeneous group of disorders characterized by degeneration of the cerebellum and its connections. It is known that patients with ataxia can manifest a broad spectrum of motor symptoms; however, current research has emphasized the relevance of cognitive disturbances. The aim of this study is to analyze the presence of cognitive impairment in a heterogeneous cohort of patients with hereditary ataxia (HA). A group of 38 patients with HA of different etiologies and a matched group of 38 healthy controls were recruited and evaluated through a comprehensive battery of neuropsychological tests. The findings show a worse performance in ataxic patients on planning, visuospatial skills, naming, and Theory of Mind tasks, regardless their physical and psychological symptomatology. The influence of clinical status as well as functional ability-related variables on their performance were analyzed, showing that the level of disability and motor disturbances have a significant effect on verbal memory, verbal fluency, and working memory. These findings suggest that patients with HA can manifest cognitive and neuropsychiatric symptoms as part of their clinical features, which demands its inclusion for the diagnosis and management of the disease.

Genotype-phenotype correlations in ocular manifestations of Marinesco-Sjögren syndrome: Case report and literature review.

PURPOSE: This study aims to present a family with two children with MSS who presented with different ophthalmic features. We also aim to review MSS patients' ocular manifestations to provide a basis for future clinical trials and improve MSS patients' ophthalmologic care. CASE DESCRIPTION: Both patients presented with global developmental delay, microcephaly, cerebellar ataxia, and myopathy. The older sibling had developed bilateral cataracts at the age of six. Her 2 years younger sister interestingly showed bilateral hyperopic refractive error without cataracts yet. Mendeliome sequencing unraveled a novel homozygous frameshift mutation in the SIL1 gene (SIL1, NM_022464.5, c.1042dupG, p.E348Gfs*4), causing MSS. A systematic literature review revealed that cataracts appear in 96% of MSS cases with a mean onset at 3.2 years. Additional frequent ocular features were strabismus (51.6%) and nystagmus (45.2%). CONCLUSION: SIL1-related MSS is associated with marked clinical variability. Cataracts can develop later than neuromuscular features and cognitive signs. Since cataract is a relatively late finding, patients may refer to ophthalmologists for other reasons such as refractive errors, strabismus, or nystagmus. Molecular genetic testing for SIL1 is essential to facilitate early diagnosis in patients with suspected MSS.

Short-Term Effect of Intensive Speech Therapy on Dysarthria in Patients With Sporadic Spinocerebellar Degeneration.

Purpose The aim of this study was to investigate a structured approach for effective speech therapy (ST) for dysarthria and speech-related quality of life in patients with sporadic spinocerebellar degeneration (SCD), including cerebellar-type multiple-system atrophy and cerebellar cortical atrophy. Method Twenty-two patients with SCD (cerebellar-type multiple system atrophy, 15 patients; cerebellar cortical atrophy, seven patients) who underwent intensive ST were examined. Dysarthria was evaluated using the Scale for Assessment and Rating of Ataxia Speech Dysfunction, Assessment of Motor Speech for Dysarthria Articulation, oral diadochokinesis (OD), and Voice Handicap Index-10 (VHI-10). Respiratory muscle strength (inspiratory and expiratory pressure) and respiratory-phonatory coordination (maximum phonation time) were measured. Cognitive function was evaluated using the Montréal Cognitive Assessment and the word fluency test. Mood was evaluated using the Hospital Anxiety and Depression Scale. The relationships between dysarthria scales (particularly, VHI-10) and clinical data were analyzed using stepwise regression. The differences in outcomes after intensive ST were analyzed using the Wilcoxon signed-rank test. The alpha level (p) for statistical significance was set at .0125 by Bonferroni correction. Results For both pre- and post-ST, the patient's OD (p = .002) and maximum phonation time (p = .002) significantly improved, except for Speech Dysfunction scores of the Scale for Assessment and Rating of Ataxia (p = .705) and the VHI-10 (p = .018). The Assessment of Motor Speech for Dysarthria Articulation, OD, and inspiratory pressure were identified as independent variables of VHI-10 (adjusted R 2 = .820) for speech-related quality of life; no correlations among the Montréal Cognitive Assessment, word fluency test, and Hospital Anxiety and Depression Scale scores were observed. Conclusion OD and VHI-10 showed improvements due to changes in speech function and respiratory-phonatory coordination, justifying intensive ST treatment for dysarthria in patients with SCD.

Mediastinal tumor resection in a patient with spinocerebellar degeneration.

BACKGROUND: In spinocerebellar degeneration (SCD) patients, general and regional anesthesia may cause postoperative dysfunction of respiratory, nerve and muscle systems. We present the surgical case of thymoma developed in patient with SCD. CASE PRESENTATION: A 47-year-old woman with spinocerebellar degeneration was admitted because of a well-defined mass measuring 48 × 31 mm in anterior mediastinum. She showed limb, truncal, ocular, and speech ataxia; hypotonia; areflexia; sensory disturbances; and muscle weakness. Her eastern cooperative oncology group performance status was 4. Surgical resection was performed via video-assisted thoracic surgery and under general anesthesia only without epidural analgesia. The mass was diagnosed as type B1 thymoma without capsular invasion (Masaoka stage I). The patients got a good postoperative course by cooperation with anesthesiologists and neurologists in perioperative managements. She has been well over 3 years of follow-up. CONCLUSIONS: In conclusion, careful surgical and anesthesia management is essential for providing an uneventful postoperative course in patients with SCD. Especially, selection of minimal invasive approach and avoid diaphragmatic nerve damage are the most important points in surgical procedures.

[Expert consensus on the management strategy of patients with hereditary ataxia during prevention and control of novel coronavirus pneumonia epidemic].

Since December 2019, a series of highly infectious cases of unexplained pneumonia have been discovered in Wuhan, Hubei Province, which have been confirmed as '2019 corona virus disease' caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 virus can invade many human systems including the lungs. Patients with central nervous system involvement may show a series of neurological symptoms, which is easy to be misdiagnosed and neglected, thereby increasing the risk of SARS-CoV-2 transmission. Hereditary ataxia is a large group of neurodegenerative diseases with great clinical and genetic heterogeneity and high mortality and disability. In view of the seriousness of the COVID-19 epidemic, a series of prevention and control measures adopted by the government have restricted the follow-up, diagnosis and treatment of patients by the hospitals, which has a great impact on their mental and physical health. In order to standardize the management of patients during the prevention and control of COVID-19 epidemic, the Specialized Committee of Neurogenetics of the Neurophysician Branch of Chinese Medical Doctor Association has formulated this consensus, with an aim to help patients to overcome the difficulties and pass the epidemic prevention period safely.

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.

Frequency analyses of posturography using logarithmic translation.

Background: Power-spectral analysis of the centre of pressure (CoP) frequencies of posturography provides exponentially approximated distributions, whereas logarithmic translation enables linear approximation.Objectives: Frequency analyses were adopted for posturography of healthy subjects and patients with spinocerebellar degeneration (SCD) using logarithmic translation to determine its clinical usefulness for managing the elderly and patients with disequilibrium.Material and methods: We included 172 healthy subjects and 47 SCD patients. Posturography was performed with the eyes fixated and closed, with and without foam rubber. The power-spectral data of the CoP were obtained with the maximum entropy method. Power-spectral data were logarithmically translated for quantitative evaluation.Results: For teenagers, high-frequency fluctuations were dominant and attributable to proprioceptive compensation due to immature postural control. In elderly populations, the increased frequency in the lateral direction was characterised by three peaks indicating postural disturbances attributed to three sensory inputs. The disappearance of one peak in the anteroposterior fluctuation indicates a decrease in vestibular contribution. The foam rubber and the closed-eye condition enhanced fluctuations in two peaks. There were differences in power-spectral distributions of two peaks between the healthy subjects and SCD patients.Conclusions: Logarithmic power-spectral data distribution could provide an age- and disease-specific novel and visually-comprehensible parameter.

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.

Epilepsy in spinocerebellar ataxia type 8: a case report.

BACKGROUND: Spinocerebellar ataxia type 8 is an uncommon genetic condition and presents with gait disturbances, ataxia, dysarthria, nystagmus, and cognitive and psychiatric abnormalities. Seizures are extremely uncommon in the spinocerebellar ataxias and have been reported only once before in a patient with spinocerebellar ataxia type 8. This case report highlights the need to evaluate spells in patients with a known neurodegenerative or genetic disease to exclude seizures, and it stresses the importance of timely diagnosis and therapy. CASE PRESENTATION: The patient was a 22-year-old Caucasian woman with known spinocerebellar ataxia 8 since age 10 years. She was admitted to our hospital with new-onset left hemiparesis and encephalopathy in addition to chronic occurrence of multiple spells of confusion and oromanual automatisms with postictal lethargy. Testing confirmed that she was having recurrent seizures with episodes of nonconvulsive status epilepticus. Urgent treatment with antiepileptic therapy was initiated; her seizures resolved shortly thereafter, and her mental status improved. Her left hemiparesis has improved; she remains seizure-free; and she has returned to her baseline antiepileptic medications following physical therapy. CONCLUSIONS: Seizures have been reported extremely rarely in association with spinocerebellar ataxia 8, but they must be considered in the differential diagnosis of patients with spells of altered awareness, especially in those with a known neurodegenerative or genetic condition. Clinicoradiological correlation with symptoms can help expedite diagnosis and treatment. Expert consultation with epileptologists at the earliest signs can help establish the diagnosis quickly, minimize morbidity, and enhance recovery.

Genetic and clinical analyses of spinocerebellar ataxia type 8 in mainland China.

BACKGROUND: Spinocerebellar ataxia type 8 (SCA8) is a rare autosomal dominant neurodegenerative disease caused by CTA/CTG repeat expansion in the ATXN8/ATXN8OS gene. METHODS: To analyze the frequency and clinical characteristics of SCA8 patients in mainland China, we combined polymerase chain reaction (PCR) and triplet repeat-primed PCR (TRP-PCR) to detect the CTA/CTG expansion. We studied a cohort of 362 ataxia patients in which the other known causative genes had been previously excluded, from among 1294 index patients. Positive samples were validated by southern blotting. RESULTS: The CTA/CTG expansion was observed in six probands, accounting for approximately 0.46% (6/1294) in all patients, and 1.66% (6/362) in patients without definite molecular diagnosis. Clinically, aside from the typical SCA8 phenotype, some patients carrying the CTA/CTG expansion exhibited the cerebellar form of multisystem atrophy (MSA-C) and ataxia with paroxysmal kinesigenic dyskinesia (PKD). CONCLUSION: For the first time, we described the PKD phenotype in association with CTA/CTG expansion, suggesting that CTA/CTG expansion might play a role in the pathogenesis of paroxysmal dyskinesia symptoms.

The cerebellum improves the precision of antisaccades by a latency-duration trade-off.

The cerebellum adapts motor responses by controlling the gain of a movement, preserving its accuracy and by learning from endpoint errors. Adaptive behavior likely acts not only in the motor but also in the sensory, behavioral, and cognitive domains, thus supporting a role of cerebellum in monitoring complex brain performances. Here, we analyzed the relationship between saccade latency, duration and endpoint error of antisaccades in a group of 10 idiopathic cerebellar atrophy (ICA) patients compared to controls. The latency distribution was decomposed in a decision time and a residual time. Both groups showed a trade-off between duration and decision time, with a peak of entropy within the range of this trade-off where the information flow was maximized. In cerebellar patients, greater reductions of duration as the time of decision increased, were associated with a lower probability for a saccade to fall near the target, with a constant low entropy outside the optimal time window. We suggest a modulation of saccade duration, depending on the latency-related decision time (accumulation of sensory and motor evidences in favor of a goal-directed movement), normally adopted to perform efficient trajectories in goal-directed saccades. This process is impaired in cerebellar patients suggesting a role for the cerebellum in monitoring voluntary motor performance by controlling the movement onset until the ambiguity of planning is resolved.

Dysarthria Profiles in Adults With Hereditary Ataxia.

Purpose This preliminary study examined whether speech profiles exist for adults with hereditary ataxia based on 2 competing frameworks: a pattern of instability/inflexibility or a pattern of differential subsystem involvement. Method Four dysarthria experts rated the speech samples of 8 adults with dysarthria from hereditary ataxia using visual analog scales and presence/severity rating scales of speech characteristics. Speaking tasks included diadochokinetics, sustained phonation, and a monologue. Results Speech profiles aligned with the instability/inflexibility framework, with the pattern of instability being the most common. Speech profiles did not emerge for the majority of speakers using the differential subsystem framework. Conclusions The findings extend previous research on pure ataxic dysarthria and suggest a possible framework for understanding the speech heterogeneity associated with the ataxias. The predominance of the instability profile is consistent with the notion of impaired feedforward control in speakers with cerebellar disruption.