Self-regulation of slow cortical potential and seizure suppression by scalp electroencephalography: Early prediction of therapeutic efficacy

Objective: Seizure suppression using the neurofeedback (NFB) method by self-regulation of scalp-recorded slow cortical potential (SCP) is effective for patients with refractory focal epilepsy. However, the prolonged training period required prevents it from wider implementation as the standard treatment in clinical practice. Therefore, we examined whether it would be appropriate to shorten the training period, in spite of the small number of patients. Methods: 12 patients participated the NFB training. 1 course of NFB training consisted of 35 sessions divided into 2 phases. After each phase we evaluated whether each patient acquired NFB control, and seizure reduction was assessed compared to that before training. Results: Of 11 patients who completed the first training phase, 4 showed reduced post-training seizure frequency, of whom 3 could regulate the SCP polarity (NFB control). Of the remaining 7, 2 acquired NFB control during the second training phase but seizure frequency did not decrease. Furthermore, the other 5 did not acquire NFB control, and seizure frequency did not decrease. Conclusions: Patients who acquired NFB control within a short period, i.e., 3 weeks, were more likely to exhibit a lower post-training seizure frequency. Significance: SCP self-regulation can be acquired within a short period and is associated with seizure reduction.