The Goal Attainment Scale in Spinocerebellar Ataxia Type 3: Exploration of Feasibility and Content Validity.

Progress in therapeutic development in spinocerebellar ataxia type 3 (SCA3) underscores the need for trial readiness and outcome measures that accurately reflect patient-relevant disease progression. The Goal Attainment Scale (GAS) has been proposed to capture interindividual variability within a unified, patient-centered metric. However, concerns about its feasibility and clinimetric properties have limited its use in clinical trials so far. This exploratory study assesses the feasibility and content validity of the GAS interview in SCA3. The GAS interview was conducted by a single assessor in 15 SCA3 patients at varying disease stages. Feasibility metrics and the content of goals, categorized according to International Classification of Functioning, Disability and Health (ICF) domains, were evaluated. For each patient, at least three goals were successfully set within the planned timeframe, averaging 9.2 min per goal. The presence of a caregiver was considered important for ensuring goal quality in patients with severe cognitive impairment. Most goals were related to balance issues (30.2%), followed by coordination of limb movements (11.1%) and visual function (11.1%). Balance-related goals were consistently ranked as most important by patients across all disease stages. Our findings support the feasibility and content validity of the GAS interview in SCA3, with goal content deemed relevant from both patient and clinician perspectives. The next step is to implement the GAS in a trial setting, accompanied by an evaluation of its clinimetric properties within that context.