Temporal Dynamics of the Scale for the Assessment and Rating of Ataxia in Spinocerebellar Ataxias.

BACKGROUND: The Scale for the Assessment and Rating of Ataxia (SARA) is the reference clinical scale to assess the severity of cerebellar ataxia. In the context of upcoming therapeutic trials, a reliable clinical outcome is needed to assess the efficiency of treatments. OBJECTIVE: The aim is to precisely assess and compare temporal dynamics of SARA and a new f-SARA. METHODS: We analyzed data from four cohorts (EUROSCA, RISCA, CRC-SCA, and SPATAX) comprising 1210 participants and 4092 visits. The linearity of the progression and the variability were assessed using an ordinal Bayesian mixed-effect model (Leaspy). We performed sample size calculations for therapeutic trials with different scenarios to improve the responsiveness of the scale. RESULTS: Seven of the eight different items had a nonlinear progression. The speed of progression was different between most of the items, with an average time for a one-point increase from 3.5 years [3.4; 3.6] (median, 95% credible interval) for the fastest item to 11.4 [10.9; 12.0] years. The total SARA score had a linear progression with an average time for a one-point increase of 0.95 [0.92; 0.98] years. After removing the four last items and rescaling all items from 0 to 4, variability increased and progression was slower and thus would require a larger sample size in a future therapeutic trial. CONCLUSION: Despite a heterogeneous temporal dynamics at the item level, the global progression of SARA was linear. Changing the initial scale deteriorates the responsiveness. This new information about the temporal dynamics of the scale should help design the outcome of future clinical trials. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Validating Automated Segmentation Tools in the Assessment of Caudate Atrophy in Huntington's Disease.

Background: Neuroimaging shows considerable promise in generating sensitive and objective outcome measures for therapeutic trials across a range of neurodegenerative conditions. For volumetric measures the current gold standard is manual delineation, which is unfeasible for samples sizes required for large clinical trials. Methods: Using a cohort of early Huntington's disease (HD) patients (n = 46) and controls (n = 35), we compared the performance of four automated segmentation tools (FIRST, FreeSurfer, STEPS, MALP-EM) with manual delineation for generating cross-sectional caudate volume, a region known to be vulnerable in HD. We then examined the effect of each of these baseline regions on the ability to detect change over 15 months using the established longitudinal Caudate Boundary Shift Integral (cBSI) method, an automated longitudinal pipeline requiring a baseline caudate region as an input. Results: All tools, except Freesurfer, generated significantly smaller caudate volumes than the manually derived regions. Jaccard indices showed poorer levels of overlap between each automated segmentation and manual delineation in the HD patients compared with controls. Nevertheless, each method was able to demonstrate significant group differences in volume (p < 0.001). STEPS performed best qualitatively as well as quantitively in the baseline analysis. Caudate atrophy measures generated by the cBSI using automated baseline regions were largely consistent with those derived from a manually segmented baseline, with STEPS providing the most robust cBSI values across both control and HD groups. Conclusions: Atrophy measures from the cBSI were relatively robust to differences in baseline segmentation technique, suggesting that fully automated pipelines could be used to generate outcome measures for clinical trials.

Assessment of Ataxia Rating Scales and Cerebellar Functional Tests: Critique and Recommendations.

BACKGROUND: We assessed the clinimetric properties of ataxia rating scales and functional tests, and made recommendations regarding their use. METHODS: A systematic literature search was conducted to identify the instruments used to rate ataxia symptoms. The identified rating scales and functional ability tests were reviewed and ranked by the panel as "recommended," "suggested," or "listed" for the assessment of patients with discrete cerebellar disorders, using previously established criteria. RESULTS: We reviewed 14 instruments (9 rating scales and 5 functional tests). "Recommended" rating scales for the assessment of symptoms severity were: for Friedreich's ataxia, the Friedreich's Ataxia Rating Scale, the International Cooperative Ataxia Rating Scale (ICARS), and the Scale for the Assessment and Rating of Ataxia (SARA); for spinocerebellar ataxias, ICARS and SARA; for ataxia telangiectasia: ICARS and SARA; for brain tumors, SARA; for congenital disorder of glycosylation-phosphomannomutase-2 deficiency, ICARS; for cerebellar symptoms in multiple sclerosis, ICARS; for cerebellar symptoms in multiple system atrophy: Unified Multiple System Atrophy Rating Scale and ICARS; and for fragile X-associated tremor ataxia syndrome, ICARS. "Recommended" functional tests were: for Friedreich's ataxia, Ataxia Functional Composite Score and Composite Cerebellar Functional Severity Score; and for spinocerebellar ataxias, Ataxia Functional Composite Score, Composite Cerebellar Functional Severity Score, and SCA Functional Index. CONCLUSIONS: We identified some "recommended" scales and functional tests for the assessment of patients with major hereditary ataxias and other cerebellar disorders. The main limitations of these instruments include the limited assessment of patients in the more severe end of the spectrum and children. Further research in these populations is warranted. © 2020 International Parkinson and Movement Disorder Society.

Standardized Assessment of Hereditary Ataxia Patients in Clinical Studies.

BACKGROUND: Hereditary ataxias are a heterogeneous group of degenerative diseases of the cerebellum, brainstem, and spinal cord. They may present with isolated ataxia or with additional symptoms going beyond cerebellar deficits. There are an increasing number of clinical studies with the goal to define the natural history of these disorders, develop biomarkers, and investigate therapeutic interventions. Especially, early and preclinical disease stages are currently of particular interest. METHODS AND RESULTS: Evidence-based, we review standards for sampling and storage of biomaterials, clinical and neuropsychological assessment, as well as neurophysiology and neuroimaging and recommendations for standardized assessment of ataxia patients in multicenter studies. CONCLUSIONS: DNA, RNA, serum, and, if possible, cerebrospinal fluid samples should be processed following established standards. Clinical assessment in ataxia studies must include use of a validated clinical ataxia scale. There are several validated clinical ataxia scales available. There are no instruments that were specifically designed for assessing neuropsychological and psychiatric symptoms in ataxia disorders. We provide a list of tests that may prove valuable. Quantitative performance tests have the potential to supplement clinical scales. They provide additional objective and quantitative information. Posturography and quantitative movement analysis-despite valid approaches-require standardization before implemented in multicenter studies. Standardization of neurophysiological tools, as required for multicenter interventional trials, is still lacking. Future multicenter neuroimaging studies in ataxias should implement quality assurance measures as defined by the ADNI or other consortia. MRI protocols should allow morphometric analyses.

Reliability and factor structure of the Short Problem Behaviors Assessment for Huntington's disease (PBA-s) in the TRACK-HD and REGISTRY studies.

The authors report the inter-rater reliability and factor structure of the Short Problem Behaviors Assessment (PBA-s), a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. Video recordings of 410 PBA-s interviews were rescored by an independent rater, and Cohen's kappa calculated to assess inter-rater reliability. The mean kappa was 0.74 for severity and 0.76 for frequency scores, whereas weighted kappa (allowing scores to differ by 1 point) was 0.94 for severity and 0.92 for frequency scores. The results of factor analysis were consistent with previous studies using other measures. The authors conclude that the PBA-s is a reliable measure.

Annual change in Friedreich's ataxia evaluated by the Scale for the Assessment and Rating of Ataxia (SARA) is independent of disease severity.

BACKGROUND: The objective of the study was to evaluate the sensitivity to change of the Scale for the Assessment and Rating of Ataxia (score, 0-40) in Friedreich's ataxia. METHODS: This was a follow-up study in adult patients with genetically confirmed Friedreich's ataxia evaluated at least twice (minimum interval, 6 months). Participants were outpatients at the Center for Neurogenetics of the Pitie-Salpêtrière Hospital in Paris. RESULTS: We included 84 patients; 60% had 3 or more evaluations. The mean score on first assessment was 22.7 ± 9, and the mean follow-up was 1.84 ± 1.10 years. The mean increase was 1.36 ± 2.3 points/year; this variation was not significantly linked to factors known to influence disease severity such as age at onset, disease duration, GAA expansion length, and wheelchair use. CONCLUSIONS: In adult Friedreich's ataxia patients the Scale for the Assessment and Rating of Ataxia can detect annual changes independently of disease severity. In future therapeutic trials no patient stratification is globally required.

Quantitative assessment of the evolution of cerebellar signs in spinocerebellar ataxias.

BACKGROUND: Responsive ataxia rating scales are essential for determining outcome measures in clinical trials. METHODS: We evaluated the responsiveness over time of the composite cerebellar functional severity score, a quantitative score measuring cerebellar ataxia in 133 patients with autosomal dominant cerebellar ataxias (ADCA), which were prospectively evaluated at inclusion and after one-year of follow-up. A more responsive tool was developed, the Cerebellar Functional Severity score writing, incorporating the writing test at dominant hand to the Cerebellar Functional Severity score. RESULTS: Within the one-year follow-up period, the Cerebellar Functional Severity score and its writing version increased significantly and the Scale for the Assessment and Rating of Ataxia decreased significantly reflecting increased severity of the cerebellar symptoms. The Cerebellar Functional Severity score writing responsiveness was best in genotypes SCA1, 2, and 3 compared with the other genotypes (effect size = 0.196, standardized response mean (SRM) = 0.624 versus effect size = -0.051, SRM = -0.150). The Cerebellar Functional Severity score writing used as an outcome measure would require only 163 SCA1, 2, or 3 patients per group in a two-arm interventional trial for a 50% reduction in progression and 80% of power. DISCUSSION: Our study demonstrates that the Cerebellar Functional Severity score and Cerebellar Functional Severity score writing are responsive quantitative scores for evaluating sensitivity to change in ADCA patients and can be used as outcome measures in clinical trials, especially when targeting genotypes SCA1, 2 and 3.