Assadi 2007.

Methods	Randomised, double‐blind, placebo‐controlled, cross‐over trial
Participants	20 individuals with SCA or Friedreich ataxia were recruited and 19 completed the protocol. Of these, 14 were genetically confirmed (4 Friedreich ataxia, 1 SCA1, 4 SCA2, 2 SCA3, 1 SCA6, 1 SCA17, 1 dentatorubral‐pallidoluysian atrophy (DRPLA)) and 6 were idiopathic. Participants had clinically symptomatic ataxia and either cerebellar or brainstem atrophy on imaging studies or genetic confirmation of a hereditary SCA
Interventions	Participants received either buspirone hydrochloride 30 mg twice daily or placebo for 12 weeks. A titration period was implemented in the 1st 2 weeks of each arm (10 mg buspirone twice daily in week 1; 20 mg buspirone twice daily in week 2). A 4‐week washout period followed the 1st treatment phase, after which participants were crossed into the alternative treatment arm
Outcomes	ICARS, which includes an 8‐point speech subscale, was used to evaluate clinical features at baseline and at the end of each treatment phase (12 weeks' duration). The speech subscale was not reported separately to the total ICARS score
Notes	Several participants (6/20) were diagnosed with an idiopathic type of cerebellar degeneration (without a confirmed genetic diagnosis) Mr and Mrs Dennis Culnan provided the funding for the study. The provider of buspirone and placebo is not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation is not clear
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment is not clear
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding of participants and personnel is not clear
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding of investigators at assessment is not clear
Selective reporting (reporting bias)	Low risk	All planned outcomes are reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	1 participant withdrew from the protocol after moving away from the treatment site
Other bias	Low risk	None identified