Aikia 1992

Methods	Randomised, double‐blinded, parallel‐group trial conducted in Finland 2 treatment arms: OXC and PHT
Participants	Adult participants with newly diagnosed epilepsy and "normal intellectual capacity" with a minimum of 2 seizures in the last 2 years or 1 seizure and an epileptiform EEG Number randomised: OXC = 19, PHT = 18 Number completed and included in analysis: OXC = 14, PHT = 15 (see Notes) 11 male participants (38%) out of 29 included participants 21 participants with partial epilepsy (72%) out of 29 included participants Mean age of included participants (SD): OXC = 33.6 (14) years, PHT = 32.7 (12.5) years
Interventions	Monotherapy with OXC or PHT 4‐ to 8‐week titration period followed by a maintenance phase of 12 months. Doses achieved not stated Range of follow‐up not stated
Outcomes	Neuropsychological assessment and cognitive functioning in 3 major areas at baseline, 6 months' and 12 months' follow‐up: Verbal learning and memory Sustained attention Simple psychomotor speed
Notes	Participants experiencing inadequate seizure control, adverse events or those who were non‐compliant were withdrawn from the trial and excluded from analysis (5 from OXC group and 3 from PHT group). Results presented only for 29 participants (OXC = 14 and PHT = 15) completing the trial Outcomes chosen for this review were not reported; contact could not be made with trial author to provide IPD
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were "randomly assigned" to treatment; no further information provided
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"The study followed a double blind design"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"The study followed a double blind design"; no further information provided about whether outcome assessor was blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT approach not taken: results reported only for 29 participants (OXC = 14 and PHT = 15) who completed 12‐month follow‐up. 8 participants experiencing inadequate seizure control, adverse events or those who were non‐compliant (OXC = 5 and PHT = 3) were excluded from analysis and results
Selective reporting (reporting bias)	Low risk	No protocol available and outcomes chosen for this review not reported. Neuropsychological and cognitive outcomes well reported and treatment withdrawal rates reported
Other bias	Low risk	None identified