BACKGROUND The Scale for the Assessment and Rating of Ataxia (SARA) is a commonly used scale measuring the severity of cerebellar ataxia and is a candidate for outcome measurement in foreseeable clinical trials in Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS). Documenting its psychometric properties in this population will accelerate clinical trial readiness. The objectives of this study were to document the content and construct validity, the internal consistency, and to explore the 2-year responsiveness and the 4-year interpretability of the SARA in ARSACS. METHODS The first phase of the study consisted of an international Delphi survey to document the content validity. The second phase consisted of a methodological study from the secondary analysis of a longitudinal study to document the construct validity in 69 participants. Responsiveness to change and interpretability of the SARA was explored among a sub-sample of participants (n = 32 and n = 16, respectively). RESULTS The SARA demonstrates adequate content validity with possible influence of pyramidal and/or neuropathic involvement. It demonstrates excellent construct validity (rs = 0.77-0.95) and internal consistency (Cronbach's α = 0.89). The responsiveness to change was not significant, and the interpretation of change score increased by 1.9 ± 2.5 falling below the minimal detectable change threshold of 3.06. CONCLUSIONS The SARA has shown evidences of adequate content validity and excellent construct validity in ARSACS. Responsiveness to change and interpretability will need to be further documented among a larger sample over a longer period of time.

中文翻译：

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记录共济失调评估和评分量表的心理测量特性，以促进 Charlevoix-Saguenay 常染色体隐性痉挛性共济失调的试验准备

背景共济失调评估和评定量表（SARA）是测量小脑共济失调严重程度的常用量表，是夏洛瓦-萨格奈常染色体隐性痉挛性共济失调（ARSACS）可预见临床试验结果测量的候选量表。在这一人群中记录其心理测量特性将加速临床试验的准备。本研究的目的是记录内容和结构效度、内部一致性，并探讨 ARSACS 中 SARA 的 2 年反应性和 4 年可解释性。方法 研究的第一阶段包括一项国际德尔菲调查，以记录内容有效性。第二阶段包括对纵向研究的二次分析进行的方法学研究，以记录 69 名参与者的结构有效性。在参与者的子样本（分别为 n = 32 和 n = 16）中探索了对 SARA 变化的响应和可解释性。结果 SARA 证明了足够的内容效度，可能受到锥体和/或神经病变的影响。它展示了出色的结构效度（rs = 0.77-0.95）和内部一致性（Cronbach's α = 0.89）。对变化的反应不显着，对变化评分的解释增加了 1.9 ± 2.5，低于 3.06 的最小可检测变化阈值。结论 SARA 在 ARSAC 中显示了足够的内容效度和优秀的结构效度的证据。