What do systematic reviews say?

Short‐term (within 1 month) percentage change (improvement) in overall speech production · people with speech disorder resulting from hereditary ataxias

Short‐term (within 1 month) change in isolated movement, objective and subjective measures of speech production Wessel 1995: Mean syllable duration during rapid‐syllable repetition task. Scale from: 1 to 500. Shorter durations are better. · people with speech disorder resulting from hereditary ataxias

Short‐term (within 1 month) change in quality of life scores related to communication as measured by validated communication assessments · people with speech disorder resulting from hereditary ataxias

Longer‐term (minimum 1 month) change in generic quality of life scores · people with speech disorder resulting from hereditary ataxias

Adverse effects (during the study) · people with speech disorder resulting from hereditary ataxias

Longer‐term burdens (minimum 1 month) (for example, demands on caregivers, frequency of tests, restrictions on lifestyle) · people with speech disorder resulting from hereditary ataxias

Economic outcomes · people with speech disorder resulting from hereditary ataxias