Memory impairment in epileptic patients: selective effects of phenobarbital concentration.

Nineteen epileptic patients were tested first under medium (week 1) and then under high (week 2) therapeutic levels of phenobarbital. Relative to response times of 20 controls with equivalent practice but without medication, response times of patients in a short-term memory scanning task were strikingly slowed during week 2. However, increased phenobarbital did not slow responses in a task requiring access to information in long-term memory.