Changes in left temporal interictal epileptiform activity during and after the performance of cognitive tasks are reported in an 18-year-old male with intractable complex partial seizures evaluated at the Radcliffe Infirmary, Oxford, UK. Epileptiform discharges were suppressed or enhanced depending on the nature and timing of the tasks. A posterior temporal spike focus occurred only during rest periods that followed verbal tasks. The mean left mid-to-anterior temporal spike count was halved during verbal tasks compared to the count during visuo-spatial tasks. A relatively low rate of right-sided temporal discharges was unchanged during or after the performance of tasks. 
COMMENT. Activation or suppression of EEG focal spike discharges in relation to psychological testing may have a role in the medical treatment of certain children with reading and other learning disabilities as well as the assessment of patients before and after surgery for epilepsy.