Negative potential shifts and the prediction of the outcome of neurofeedback therapy in epilepsy

About two-thirds of epilepsy patients who learn to control their slow corti cal potential shifts (SCP) reduce their seizure rate, but the remaining thi rd does not demonstrate clinical improvement. In the present study, this fi nding was replicated in a group of 27 patients with focal epilepsy. We foun d that patients who consistently produced larger negative SCP in all condit ions during the first phase of treatment, showed no decrease in seizure fre quency during the six-month follow-up, as compared with the three-month bas eline phase. The large negative SCP explained about one-third of the varian ce of the clinical outcome. Age, medication, seizure history, or the locali zation of focus were found to be unrelated to clinical improvement. (C) 199 9 Elsevier Science IreIand Ltd. All rights reserved.