The Scale for the Assessment and Rating of Ataxia is a reliable and valid measure of ataxia, making it an appropriate primary outcome measure for clinical trials.
Our study suggests that spinocerebellar ataxia (SCA) 1, SCA2, and SCA3 share a number of common biologic properties, whereas SCA6 is distinct in that its phenotype is more determined by age than by disease-related factors.
Objective: To obtain quantitative data on the progression of the most common spinocerebellar ataxias (SCAs) and identify factors that influence their progression, we initiated the EUROSCA natural history study, a multicentric longitudinal cohort study of 526 patients with SCA1, SCA2, SCA3, or SCA6. We report the results of the 1-and 2-year follow-up visits. Methods:As the primary outcome measure we used the Scale for the Assessment and Rating of Ataxia (SARA, 0-40), and as a secondary measure the Inventory of Non-Ataxia Symptoms (INAS, 0-16) count. Results:The annual increase of the SARA score was greatest in SCA1 (2.18 Ϯ 0.17, mean Ϯ SE) followed by SCA3 (1.61 Ϯ 0.12) and SCA2 (1.40 Ϯ 0.11). SARA progression in SCA6 was slowest and nonlinear (first year: 0.35 Ϯ 0.34, second year: 1.44 Ϯ 0.34). Analysis of the INAS count yielded similar results. Larger expanded repeats and earlier age at onset were associated with faster SARA progression in SCA1 and SCA2. In SCA1, repeat length of the expanded allele had a similar effect on INAS progression. In SCA3, SARA progression was influenced by the disease duration at inclusion, and INAS progression was faster in females.
Alexander disease (AD) in its typical form is an infantile lethal leucodystrophy, characterized pathologically by Rosenthal fibre accumulation. Following the identification of glial fibrillary acidic protein (GFAP) gene as the causative gene, cases of adult-onset AD (AOAD) are being described with increasing frequency. AOAD has a different clinical and neuroradiological presentation with respect to early-onset AD, as abnormalities are mainly concentrated in the brainstem^spinal cord junction. We report detailed clinical and genetic data of 11 cases of AOAD, observed over a 4 -year period, and a review of the previously reported 25 cases of genetically confirmed AOAD. In our series, onset occurred as late as age 62, and up to 71 in an affected deceased relative. Most cases appeared sporadic, but family history may be misleading.The most frequent symptoms were related to bulbar dysfunctionçwith dysarthria, dysphagia, dysphonia (seven patients)ç, pyramidal involvement (seven patients) and cerebellar ataxia (seven patients). Four patients had palatal myoclonus. Sleep disorders were also observed (four cases). Bulbar symptoms, however, were infrequent at onset and two symptomatic patients had an almost pure pyramidal involvement. Two subjects were asymptomatic. Misdiagnosis at presentation was frequent and MRI was instrumental in suggesting the correct diagnosis by showing, in all cases, mild to severe atrophy of the medulla oblongata extending caudally to the cervical spinal cord. In ten patients, molecular studies revealed six novel missense mutations and three previously reported changes in GFAP. The last typical patient carried no definitely pathogenic mutation, but a missense variant (p.D157N), supposedly a rare polymorphism. Revision of the literature and the present series indicate that the clinical picture is not specific, but AOAD must be considered in patients of any age with lower brainstem signs.When present, palatal myoclonus is strongly suggestive. Pyramidal involvement, cerebellar ataxia and urinary disturbances are common. Less frequent findings include sleep disorders and dysautonomia. Fluctuations may occur. The course is variable, usually slowly progressive and less severe than the AD forms with earlier onset. AOAD is more common than previously thought and might even be the most common form of AD. The diagnosis is strongly suggested by MRI and confirmed by GFAP gene analysis.Keywords: Alexander disease; GFAP; brainstem diseases; medulla oblongata atrophy; palatal myoclonus Abbreviations: AD = Alexander disease; AOAD = adult-onset AD; FLAIR = fluid-attenuated inversion recovery; GFAP = glial fibrillary acidic protein
While both the Scale for the Assessment and Rating of Ataxia and the SCA Functional Index (SCAFI) (and its 9-hole pegboard component) had favorable measurement precision, the clinical relevance of SCAFI and 9-hole pegboard score changes warrants further exploration. The EQ-5D visual analogue scale proved insufficient for longitudinal assessment, but validly reflected patients' impression of change.
To evaluate the efficacy of treatments in spinocerebellar ataxias (SCAs), appropriate clinical scales are required. This study evaluated metric properties of the International Cooperative Ataxia Rating Scale (ICARS) in 156 SCA patients and 8 controls. ICARS was found to be a reliable scale satisfying accepted criteria for interrater reliability, test-retest reliability, and internal consistency. Although validity testing was limited, we found evidence of validity of ICARS when ataxia disease stages and Barthel index were used as external criteria. On the other hand, our study revealed two major problems associated with the use of ICARS. First, the redundant and overlapping nature of several items gave rise to a considerable number of contradictory ratings. Second, a factorial analysis showed that the rating results were determined by four different factors that did not coincide with the ICARS subscales, thus questioning the justification of ICARS subscore analysis in clinical trials.
The proposed functional measures and their composite SCAFI have favorable properties to assess patients with spinocerebellar ataxia.
BACKGROUND AND PURPOSE:In recent years, the discovery that mutations in the glial fibrillary acidic protein gene (GFAP) were responsible for Alexander disease (AD) brought recognition of adult cases. The purpose of this study was to demonstrate that MR imaging allows identification of cases of AD with adult onset (AOAD), which are remarkably different from infantile cases.
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