WHEN SHOULD INDUCTION PROTOCOLS BE USED IN THE DIAGNOSTIC EVALUATION OF PATIENTS WITH PAROXYSMAL EVENTS

Purpose: To determine the timing of spontaneous psychogenic nonepilept ic events (PNEE) during video-EEG telemetry (VEEG), and the need to us e induction protocols (IP). Methods: We studied 100 consecutive patien ts (75 females, 25 males) admitted to our inpatient VEEG unit from Jul y 1994 to June 1996 for differential diagnosis of paroxysmal events. W e recorded the time to the first diagnostic spontaneous event, identif ied by the patient or a family member as typical. Episodes were classi fied as PNEE, physiologic nonepileptic events (PhysNEE), and epileptic seizures (ES). Results: The mean duration of VEEG was 74 +/- SD 54.1 h. In 82 patients, a diagnostic event occurred spontaneously. The firs t event was an ES in 22 patients, a PNEE in 53, and a PhysNEE in 7. Th e time to first diagnostic event was significantly shorter for PNEE th an for ES [15.0 +/- SD 16.3 h (range 5 min to 58 h) vs. 28.6 +/- SD 34 .0 h (range 1-110 h) F = 15.621, p < 0.0001]. In the first 24 h, 77.4% of the patients with PNEE had an event. By 48 h, all but 2 (96.2%) ha d had diagnostic events. After the first 58 h of monitoring, all patie nts with PNEE experienced a spontaneous diagnostic event. Conclusion. Spontaneous events can be expected to occur within 48 h in most patien ts with PNEE. Therefore, if IP are to be used as a diagnostic tool, we suggest that they be withheld during the initial 48 h of VEEG monitor ing.