Modification of slow cortical potentials in patients with refractory epilepsy: A controlled outcome study

Purpose: To compare self-regulation of low-frequency EEG components (slow c ortical potentials, SCPs) with other methods of seizure control for patient s with drug refractory partial epilepsy and to separate the real anticonvul sive effect from placebo effects. Methods: Results of a treatment program of SCP self-regulation (experimenta l group) are compared with two groups of patients, one of which learned sel f-control of respiratory parameters (end-tidal CO, and respiration rate: RE S group); the other received medication with new anticonvulsive drugs (AEDs ) in combination with psychosocial counseling (MED group). Clinical, cognit ive, behavioral, and personality measures were assessed before and after tr eatment. In addition, to control for placebo responses, patients repeatedly estimated their beliefs in the efficiency of the respective treatment, the ir satisfaction and expectations, and the quality of the relationship with their therapists. Results: SCP and MED groups showed a significant decrease of seizure freque ncy, but the RES group did not. Clear positive changes in the sociopsycholo gical adjustment were obtained in all three groups, with the maximal improv ement being attained in the RES group. Conclusions: All kinds of therapy result in considerable improvement of pat ients' emotional state, which may in part be due to potential placebo effec ts: however, this improvement is not related to the quality of the therapeu tic effect proper (i.e., seizure reduction). Traditional double-blind contr ol group designs are inappropriate for behavioral interventions or treatmen ts with psychoactive pharmacologic drugs. Rather, specific tests can be dev eloped to control the placebo effect and to separate it from the genuine th erapeutic effects.