Forgetting rate and interference effects on a verbal memory distractor task in patients with temporal lobe epilepsy.

To investigate interference effects in lateralized temporal lobe epilepsy (TLE), we compared 79 patients with left (n = 43) or right (n = 36) TLE and 33 healthy controls on a verbal memory distractor task (VMDT) structured according to the Brown-Peterson paradigm. The subjects were also administered a selective reminding procedure (SRP) for verbal learning, a word fluency test (WFT) and the Wisconsin Card Sorting test (WCST) for "frontal" functions. On the VMDT, left TLE patients were significantly impaired as compared to right TLE patients and controls. This impaired performance correlated with the severity of learning and short-term memory deficit but not with deficits on the WFT or the WCST. Our data suggest that lateralized epileptic discharges may affect the function played by the medial temporal lobe in inhibiting interference, thus contributing to the material-specific memory deficit of TLE patients.