Digital Outcomes of Upper Limb Ataxia Capture Meaningful Longitudinal Change and Treatment Response.

Background: Digital-motor outcomes promise better responsiveness than clinician-reported outcomes in ataxia trials. However, their patient meaningfulness and sensitivity to change remain to be demonstrated, particularly in the upper limb domain.

Objectives: Validation of quantitative motor (Q-Motor) assessment for upper limb ataxia against patient-reported outcomes and regarding sensitivity to both longitudinal and treatment-induced change, the latter in n-of-1 treatment settings.

Multifeature quantitative motor assessment of upper limb ataxia including drawing and reaching.

Objective: Voluntary upper limb movements are an ecologically important yet insufficiently explored digital-motor outcome domain for trials in degenerative ataxia. We extended and validated the trial-ready quantitative motor assessment battery "Q-Motor" for upper limb movements with clinician-reported, patient-focused, and performance outcomes of ataxia.

Methods: Exploratory single-center cross-sectional assessment in 94 subjects (46 cross-genotype ataxia patients; 48 matched controls), comprising five tasks measured by force transducer and/or position field: Finger Tapping, diadochokinesia, grip-lift, and-as novel implementations-Spiral Drawing, and Target Reaching.