Some effects of feedback on epilepsy in man

Application of feedback techniques in epilepsy have included attempts to augment certain frequencies in the EEG (12-14 Hz; 6- 12 Hz) or to decrease paroxysmal EEG discharges. Over 6 yr we have employed contingency and random feedback of focal and generalized EEG discharges in 27 patients (age 19.8 ± 11.16, M. 11); EEG discharges triggered auditory, peripheral nerve or visual stimuli and the patients were instructed to try various maneuvers to increase or decrease the numbers of discharges; feedback sessions involved 20 min control, feedback and post-feedback epochs every 2 wk. Dosages of medications were kept constant during these studies and serum levels of medications were assessed regularly. No patient could increase the numbers of paroxysmal EEG discharges at will. One patient experienced increased seizures with triggered but not random auditory feedback with improvement in seizures and EEG during somatosensory feedback. The most dramatic improvement in a patient involved complete cessation of seizures with disappearance of paroxysmal discharges in the EEG after 18 mth of feedback and this improvement has persisted for 3 yr. The immediate effects of feedback on paroxysmal EEG discharges did not correlate with the reductions in clinical seizures, but an aura developed in 8 of 11 patients who showed marked improvement in numbers of clinical seizures; decreases in paroxysmal EEG discharges often followed reductions in seizures. There were progressive effects of contingency feedback sessions over the course of 1 to 2 yr; such techniques can be combined with direct neurostimulation in an attempt to develop pacemaker control of seizures in man.