Sato 1982

Methods	Randomised double‐blind response ‐ conditional cross‐over study. VPS with PCB for 6 weeks followed by ESM with PCB for 6 weeks for one group. The other group followed the same regimen in a reverse order. Follow‐up 3 months.
Participants	45 naive and drug resistant participants aged 3 to 18 years with absence seizures (not specified if typical or atypical). 18 male.
Interventions	Drug naive participants were on monotherapy (ESM or VPS) while refractory to previous treatment participants were on polytherapy.
Outcomes	Reduction in seizure frequency as judged by 12‐hour EEG telemetry, 100% for drug naive and 80% for drug‐resistant participants.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported how patients were randomly assigned to treatments.
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Study was described as "double‐blinded" without further details.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Study was described as "double‐blinded" without further details.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Study was described as "double‐blinded" without further details.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	The study protocol is not available but it is clear that the published reports include all expected outcomes.