Discriminating between epileptic and nonepileptic events: The utility of hypnotic seizure induction

Purpose: To determine the validity of the Hypnotic Induction Profile (HIP) followed by seizure induction during continuous video-electroencephalograph ic (EEG) monitoring to discriminate between epileptic (EE) and nonepileptic events (NEE). Methods: Eighty-two patients admitted to the Stanford Comprehensive Epileps y Center for differential diagnosis of seizure-like events were evaluated. Exclusion criteria included inability or refusal to complete the HIP, lack of a "typical" event, an IQ <70, present evidence of psychosis, or a physio logical cause for NEE. Sixty-nine patients met these criteria. while underg oing continuous video-EEG monitoring, the patient completed an HIP, an inve ntory designed to measure the degree of hypnotizability, An attempt was the n made to induce the patient's typical events under hypnosis by using a spl it-screen technique. An event without an EEG correlate was thought to repre sent an NEE. A diagnosis of NEE was made independently by the neurology tea m and was compared with results obtained with the hypnotic evaluation. Results: Results for patients with EE were compared with those with NEE and a group consisting of both EE/NEE. All patients with NEE were then contras ted with the EE group. HIP scores for the EE patients indicated lower hypno tizability than the NEE group and were statistically significant when NEE p atients and those with NEE/EE were combined. The sensitivity of seizure ind uction in the diagnosis of NEE was 77%, with a specificity of 95%. Conclusions: The HIP coupled with seizure induction is a useful technique t o aid in the diagnosis of patients with NEE. It is sensitive and specific, and it may provide the patient with a useful behavioral tool to control NEE s. It may also furnish a conduit for long-term treatment.