Evolution of Clinical Outcome Measures and Biomarkers in Sporadic Adult-Onset Degenerative Ataxia.

BACKGROUND: Sporadic adult-onset ataxias without known genetic or acquired cause are subdivided into multiple system atrophy of cerebellar type (MSA-C) and sporadic adult-onset ataxia of unknown etiology (SAOA). OBJECTIVES: To study the differential evolution of both conditions including plasma neurofilament light chain (NfL) levels and magnetic resonance imaging (MRI) markers. METHODS: SPORTAX is a prospective registry of sporadic ataxia patients with an onset >40 years. Scale for the Assessment and Rating of Ataxia was the primary outcome measure. In subgroups, blood samples were taken and MRIs performed. Plasma NfL was measured via a single molecule assay. Regional brain volumes were automatically measured. To assess signal changes, we defined the pons and middle cerebellar peduncle abnormality score (PMAS). Using mixed-effects models, we analyzed changes on a time scale starting with ataxia onset. RESULTS: Of 404 patients without genetic diagnosis, 130 met criteria of probable MSA-C at baseline and 26 during follow-up suggesting clinical conversion to MSA-C. The remaining 248 were classified as SAOA. At baseline, NfL, cerebellar white matter (CWM) and pons volume, and PMAS separated MSA-C from SAOA. NfL decreased in MSA-C and did not change in SAOA. CWM and pons volume decreased faster, whereas PMAS increased faster in MSA-C. In MSA-C, pons volume had highest sensitivity to change, and PMAS was a predictor of faster progression. Fulfillment of possible MSA criteria, NfL and PMAS were risk factors, CWM and pons volume protective factors for conversion to MSA-C. CONCLUSIONS: This study provides detailed information on differential evolution and prognostic relevance of biomarkers in MSA-C and SAOA. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Clinical Features and Neuroimaging Findings of Neuropil Antibody-Positive Idiopathic Sporadic Ataxia of Unknown Etiology.

Idiopathic sporadic ataxia (ISA) is the clinical term for nonfamilial ataxia with adult-onset and a slowly progressive course. However, immune-mediated cerebellar ataxia cannot be completely excluded from ISA. The current study investigated the neuropil antibodies against cell-surface antigens and clarified the clinical features and neuroimaging findings of patients with these antibodies. Using tissue-based immunofluorescence assays (TBAs), we examined antibodies against the cerebellum in serum samples from 67 patients who met the ISA diagnostic criteria, including 30 patients with multiple system atrophy with predominant cerebellar features (MSA-C) and 20 patients with hereditary ataxia (HA), and 18 healthy control subjects. According to the TBA results, we divided subjects into three groups: subjects positive for neuropil antibodies, subjects positive for intracellular antibodies only, and subjects negative for antibodies. We compared clinical features and neuroimaging findings in ISA patients among these three groups. The prevalence of neuropil antibodies in ISA (17.9%) was significantly higher than that in MSA-C (3.3%), HA (0%), or healthy subjects (0%). The neuropil antibody-positive ISA patients showed pure cerebellar ataxia more frequently than the other ISA patients. Two neuropil antibody-positive patients showed significant improvement of cerebellar ataxia after immunotherapy. We detected neuropil antibodies in 17.9% of ISA patients. Characteristic clinical features of neuropil antibody-positive ISA patients were pure cerebellar ataxia. Some cases of neuropil antibody-positive ISA responded to immunotherapy.

Genetic ataxias: update on classification and diagnostic approaches.

Ataxia encompasses a large group of rare disorders characterized by irregular movements, decreased coordination, imbalance, kinetic tremor, wide-based stance, and dysarthria. Evaluating ataxia can be challenging considering the volume of disorders and their complex pathologies involving diverse genetic and clinical factors. This is a comprehensive review of the genetic ataxia literature, presenting updated guidelines for differential diagnosis. Age, time course, and family history provide initial guidance for evaluation of ataxia. As genetic testing is increasingly utilized, new genes are discovered and phenotypes for existing disorders are expanded. This review assists physicians by offering a diagnostic roadmap for suspected hereditary ataxia based on the current literature.

Prominent White Matter Involvement in Multiple System Atrophy of Cerebellar Type.

BACKGROUND: Sporadic degenerative ataxia patients fall into 2 major groups: multiple system atrophy with predominant cerebellar ataxia (MSA-C) and sporadic adult-onset ataxia (SAOA). Both groups have cerebellar volume loss, but little is known about the differential involvement of gray and white matter in MSA-C when compared with SAOA. OBJECTIVES: The objective of this study was to identify structural differences of brain gray and white matter between both patient groups. METHODS: We used magnetic resonance imaging to acquire T1-weighted images and diffusion tensor images from 12 MSA-C patients, 31 SAOA patients, and 55 healthy controls. Magnetic resonance imaging data were analyzed with voxel-based-morphometry, tract-based spatial statistics, and tractography-based regional diffusion tensor images analysis. RESULTS: Whole-brain and cerebellar-focused voxel-based-morphometry analysis showed gray matter volume loss in both patient groups when compared with healthy controls, specifically in the cerebellar areas subserving sensorimotor functions. When compared with controls, the SAOA and MSA-C patients showed white matter loss in the cerebellum, whereas brainstem white matter was reduced only in the MSA-C patients. The tract-based spatial statistics revealed reduced fractional anisotropy within the pons and cerebellum in the MSA-C patients both in comparison with the SAOA patients and healthy controls. In addition, tractography-based regional analysis showed reduced fractional anisotropy along the corticospinal tracts in MSA-C, but not SAOA. CONCLUSION: Although in our cohort extent and distribution of gray and white matter loss were similar between the MSA-C and SAOA patients, magnetic resonance imaging data showed prominent microstructural white matter involvement in the MSA-C patients that was not present in the SAOA patients. Our findings highlight the significance of microstructural white matter changes in the differentiation between both conditions. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Cardiovascular autonomic testing in the work-up of cerebellar ataxia: insight from an observational single center study.

BACKGROUND: Cerebellar ataxias are a heterogeneous group of disorders of both genetic and non-genetic origin. In sporadic cases, two entities are recognized: multiple system atrophy of cerebellar type (MSA-C) and SAOA (sporadic adult-onset ataxia). The presence of severe cardiovascular autonomic failure reliably distinguishes MSA-C from other ataxias, but it may appear only late in the disease course. OBJECTIVE: To evaluate the diagnostic yield of cardiovascular autonomic function tests in the work-up of cerebellar ataxia. METHODS: We applied a cardiovascular autonomic tests battery in consecutive patients with neurodegenerative cerebellar ataxia and matched healthy controls. We recorded the presence of both orthostatic hypotension (OH) and blood pressure falls non-fulfilling the criteria of OH (non-OH BP). Sporadic cases were followed-up for an eventual conversion to MSA-C. RESULTS: Forty-two patients were recruited, 19 of whom with sporadic disease (2 probable MSA-C, 6 possible MSA-C, 11 SAOA). Sporadic and hereditary cases showed no difference concerning ataxia severity at baseline. At head-up tilt, non-OH BP falls were detected in nine patients, but not in controls. This finding was significantly more frequent in sporadic cases (p = 0.006) and was detected in five out of seven patients that during follow-up converted to possible/probable MSA-C. Findings at standing test were normal in four out of nine cases with non-OH BP falls at head-up tilt. CONCLUSIONS: A complete cardiovascular autonomic battery with head-up tilt can detect early signs of BP dysregulation which may be missed at bed-side tests, thus warranting its application in the first line work-up of cerebellar ataxias.

Idiopathic cerebellar ataxia (IDCA): Diagnostic criteria and clinical analyses of 63 Japanese patients.

Cortical cerebellar atrophy (CCA) and multiple system atrophy with predominant cerebellar ataxia (MSA-C) are the two major forms of adult-onset sporadic ataxia. Contrary to MSA-C, there are neither diagnostic criteria nor neuroimaging features pathognomonic for CCA. Therefore, it is assumed that the category of CCA in the Japanese national registry include heterogeneous cerebellar ataxic disorders. To refine this category in more detail, we here used a clinical-based term, "idiopathic cerebellar ataxia (IDCA)", and proposed its diagnostic criteria. We collected 346 consecutive patients with the core features of the criteria (sporadic, insidious-onset and slowly progressive cerebellar ataxia in adults, and cerebellar atrophy on brain imaging). Of these, 212 (61.3%) were diagnosed with probable or possible MSA, and 30, who did not meet the diagnostic criteria for MSA at examination, were also excluded because of MRI findings suggestive of MSA. Twenty two were proven to have hereditary spinocerebellar ataxias by genetic testing, and 19 had secondary ataxias. Finally, the remaining 63 (18.2%) were diagnosed with IDCA. The mean (standard deviation) age at onset was 57.2 (10.8) years. Of these, 25 (39.7%) showed pure cerebellar ataxia, and the remaining 38 (60.3%) had some of extracerebellar features including abnormal tendon reflexes (46.0%), positive Babinski sign (9.5%), sensory disturbance (12.7%), cognitive impairment (9.5%), and involuntary movements (7.9%). Our results show that IDCA refined by the diagnostic criteria still includes clinically and genetically heterogeneous ataxic disorders. More extensive genetic analyses will be of significance for further clarification of this group.

C9ORF72 repeat expansion is not detected in sporadic ataxia patients in mainland China.

Expansion of a GGGGCC hexanucleotide repeat in the gene C9ORF72 is a common pathogenic mutation in families with autosomal dominant frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). In order to understand whether pathogenic GGGGCC expansions of C9ORF72 are associated with spinocerebellar ataxia (SCA) in mainland China, we performed an experiment to determine the prevalence of pathogenic hexanucleotide expansions of C9ORF72 in a large cohort of Chinese Han patients with SCA. 411 sporadic patients with SCA and 314 healthy controls were screened for pathogenic hexanucleotide expansions of C9ORF72 utilizing a repeat primed polymerase chain reaction assay. However, no pathological repeat expansion of C9ORF72 was detected in either patients or controls. We therefore conclude that an expansion in C9ORF72 may not play a significant role in SCA in our cohort. However, more studies are needed to draw conclusions for the general population.

Gluten Sensitivity - A Potentially Reversible Cause of Progressive Cerebellar Ataxia and Myoclonus - A Case Report.

Gluten sensitivity is an umbrella term used for diverse clinical manifestations occurring as a result of abnormal immunological reactivity to dietary gluten in genetically susceptible individuals. Celiac disease is the most well-known but not the only manifestation of gluten sensitivity. Myoclonus with Ataxia is a rare manifestation of gluten sensitivity and should be considered in the differential diagnosis of all patients with idiopathic sporadic ataxia. The presence of gluten-related immune markers in normal population however complicates the reliable diagnosis of gluten related neurological disorders and clinical improvement on gluten free diet can serve as a diagnostic tool for this disease. We report a case of sporadic progressive cerebellar ataxia with myoclonus with positive antigliadin antibodies, which improved with a trial of gluten free diet. This case highlights an important diagnostic and therapeutic principle in management of late onset idiopathic ataxia.

Peripheral nerve involvement in hereditary cerebellar and multisystem degenerative disorders.

Hereditary ataxias (HA) encompass an increasing number of degenerative disorders characterized by progressive cerebellar ataxia usually accompanied by extracerebellar semeiology including peripheral nerve involvement. Classically, HA were classified according to their pathological hallmark comprising three main forms: (1) spinal form predominantly with degeneration of spinocerebellar tracts, posterior columns, and pyramidal tracts (Friedreich's ataxia, FA); (2) olivopontocerebellar atrophy (OPCA); and (3) cortical cerebellar atrophy (CCA). In the 1980s Harding proposed a clinico-genetic classification based upon age of onset, modality of transmission, and clinical semeiology. The main categories in this classification were as follows: (1) early onset cerebellar ataxia (EOCA) with age of onset below 25 years and usually with autosomal recessive (AR) transmission (this group encompasses FA and syndromes different from FA); (2) autosomal dominant cerebellar ataxia (ADCA) with adult onset and with either cerebellar-plus syndrome or pure cerebellar semeiology; and (3) idiopathic late onset onset cerebellar ataxia (ILOCA). With the advent of molecular genetics, the nosology of HA has been in a state of constant flux. At present EOCA comprises at least 17 genotypes (designated with the acronym of ARCA derived from AR cerebellar ataxia), whereas under the umbrella of ADCA 30 genotypes have been reported. In this chapter we will review peripheral nerve involvement in classical pathological entities (OPCA and CCA), ARCA, ADCA, and ILOCA paying special attention to the most prevalent syndromes in each category. As a general rule, nerve involvement is relatively common in any form of ataxia except ILOCA, the most common pattern being either sensory or sensorimotor neuronopathy with a dying-back process. An exception to this rule is AR spastic ataxia of Charlevoix-Saguenay where nerve conduction studies show the characteristic pattern of intermediate neuropathy implying that sacsin mutation causes both axonal and Schwann cell dysfunction.

Estudio de las ataxias esporádicas de comienzo en el adulto en el Hospital de Clínicas de Montevideo - Uruguay / Study of sporadic ataxias of adult onset in Hospital de Clínicas de Montevideo - Uruguay / Estudo de ataxias esporádicas de aparecimento de adultos no Hospital de Clínicas de Montevidéu - Uruguai

Resumen: Introducción: El diagnóstico etiológico de las ataxias esporádicas de comienzo en el adulto (AECA) es un desafío clínico pues sus causas posibles son múltiples. No existen en el país estudios a este respecto. Objetivo: Describir las características clínicas, imagenológicas y etiológicas de los pacientes con AECA. Métodos: Estudio prospectivo observacional de los pacientes con AECA que consultaron en el Hospital de Clínicas de Montevideo desde abril de 2010 a marzo de 2014. Se realizó una evaluación clínico-paraclínica protocolizada para llegar al diagnóstico etiológico. Resultados: Se incluyeron 36 pacientes. En 20 de ellos se logró demostrar una etiología definida, siendo las más frecuentes la degeneración cerebelosa alcohólica y la paraneoplásica. La mayoría de los casos en quienes se instauró un tratamiento de dicha etiología lograron un cese de la progresión o mejoría de los síntomas. Discusión y Conclusiones: El estudio protocolizado de los pacientes con AECA logra el diagnóstico etiológico en más de 50% de los casos. Aún así un 44% de los pacientes quedan sin etiología demostrada, principalmente por la incapacidad de acceder a estudios genéticos. Los factores que más se asocian a encontrar una etiología adquirida demostrada fueron: rápida progresión, síndrome vermiano puro y franca asimetría del cuadro.

Abstract: Introduction: Etiological diagnosis of Sporadic Ataxia of Adult Onset (SAAO) is a clinical challenge because its possible causes are multiple. There are no studies of SAAO in our country. Objective: To describe the clinical, imaging and etiological characteristics of patients with SAAO. Methods: Prospective observational study of patients with SAAO who consulted at Hospital de Clínicas de Montevideo from April 2010 to March 2014. A protocolized clinical-paraclinical evaluation was performed to reach the etiological diagnosis. Results: Thirty-six patients were included. In 20 of them an acquired definite etiology was demonstrated. The most frequent were alcoholic and paraneoplastic cerebellar degeneration . The majority of cases in which a treatment of this etiology was instituted resulted in a cessation of the progression or improvement of symptoms. Discussion and Conclusions: The protocolized study of patients with SAAO achieves the etiological diagnosis in more than 50% of the cases. Still, 44% of patients remained without proven etiology, mainly due to the inability to access genetic studies. The factors that are most associated with finding a proven acquired etiology were: rapid progression, pure vermis syndrome and frank asymmetry of symptoms.

Resumo: Introdução: O diagnóstico etiológico da ataxia esporádica do início do adulto (AECA) é um desafio clínico porque suas possíveis causas são múltiplas. Não há estudos neste país. Objetivo: Descrever as características clínicas, imagiológicas e etiológicas de pacientes com AECA. Métodos: estudo prospectivo observacional de pacientes com AECA que consultou no Hospital de Clínicas de Montevidéu de abril de 2010 a março de 2014. Foi realizada uma avaliação clínico-paraclínica para alcançar o diagnóstico etiológico. Resultados: Foram incluídos trinta e seis pacientes. Em 20 deles, foi possível demonstrar uma etiologia definida, sendo a mais frequente a degeneração cerebelar alcoólica e a degeneração paraneoplásica. A maioria dos casos em que o tratamento desta etiologia foi instituído resultou na cessação da progressão ou melhora dos sintomas. Discussão e Conclusões: O estudo protocolizado de pacientes com AECA atinge o diagnóstico etiológico em mais de 50% dos casos. Ainda assim, 44% dos pacientes estão sem etiologia comprovada, principalmente devido à incapacidade de acessar estudos genéticos. Os fatores mais associados com a obtenção de uma etiologia comprovada foram: progressão rápida, síndrome do vermimus puro e assimetria franca da condição.

Adult onset sporadic ataxias: a diagnostic challenge / Ataxias esporadicas de inicio no adulto: um desafio diagnostico

Patients with adult onset non-familial progressive ataxia are classified in sporadic ataxia group. There are several disease categories that may manifest with sporadic ataxia: toxic causes, immune-mediated ataxias, vitamin deficiency, infectious diseases, degenerative disorders and even genetic conditions. Considering heterogeneity in the clinical spectrum of sporadic ataxias, the correct diagnosis remains a clinical challenge. In this review, the different disease categories that lead to sporadic ataxia with adult onset are discussed with special emphasis on their clinical and neuroimaging features, and diagnostic criteria.

Pacientes com ataxia progressiva que se inicia na idade adulta, e sem histórico familiar da doença, são classificados no grupo das ataxias esporádicas. Existem várias categorias de doenças que podem se manifestar com ataxia esporádica, tais como: causas tóxicas, ataxias imunomediadas, deficiência de vitaminas, doenças infecciosas, doenças degenerativas e até mesmo condições genéticas. Considerando a heterogeneidade no espectro clínico das ataxias esporádicas, a definição da etiologia constitui um desafio diagnóstico. Neste artigo de revisão, realizamos uma discussão sobre as diferentes categorias de doenças que causam ataxia com início na idade adulta sem histórico familiar, com ênfase nas características clínicas, aspectos de imagem e critérios diagnósticos.