Induction of psychogenic nonepileptic events: success rate influenced by prior induction exposure, ictal semiology, and psychological profiles.

PURPOSE

To evaluate whether certain preinduction clinical characteristics may influence the success rate of induction.

METHODS

We prospectively enrolled and attempted inductions on 51 patients who were suspected to have psychogenic nonepileptic events based on clinical grounds. In addition to careful examination of the reported ictal semiology, we administered a battery of four psychological instruments to our enrolled patients.

KEY FINDINGS

We found that among 42 cases of successful induction, 92.9% (n=39) of these cases were successfully induced on the first attempt (i.e., without prior induction exposure). We observed that induction showed significantly higher rate of success in cases that demonstrate: (1) hypermotor ictal semiology (p=0.029); (2) more prevalent self-reporting of uncommon cognitive and affective symptoms (p=0.035); or (3) higher tendency to rely on coping strategies of "instrumental support" (p=0.013) and "active coping" (p=0.027), when compared to noninducible cases.

SIGNIFICANCE

Singular administration of placebo induction on preselected patients with these clinical characteristics may reduce costs by shortening video electroencephalography-(EEG) monitoring sessions and improve the diagnostic yield of video-EEG even for patients with very infrequent events.