Abstracts

Rationale: While a small study has shown the high yield from induction of psychogenic nonepileptic seizures (PNES) without placebo (Benbadis et al., 2000), no study has directly compared the effectiveness of placebo vs. non-placebo techniques from the same performer. In this study, we aim to compare the success rates of provocative techniques with added saline injections (placebo) vs. the same provocative techniques without saline injections. Methods: We retrospectively reviewed the data on patients who were diagnosed with PNES in the Houston VA from 10/2009 until 4/2015. From 10/2009 to 3/2013, our center utilized provocative induction with saline injections. After 3/2013 to present, our center utilized provocative induction without saline injections. We examined the number of provocative induction attempts, the success of rates of induction, and the techniques of induction (photic stimulation, hyperventilation, verbal suggestion with saline injections vs. the same techniques without saline injections). All provocation inductions were performed or supervised by the same clinician (DKC). Results: Between 10/2009 to 3/2013, a total of 140 patients that underwent induction with saline injection, and 109 (77.8%) patients experienced successful reproduction of their habitual events of interest. Correspondingly, between 3/2013 and 4/2015, a total of 50 patients underwent induction without saline injection, and 29 (58%) patients experienced successful reproduction of their habitual events. The success rates between these 2 techniques were significantly different (p = 0.0118). Conclusions: The data shows that the addition of placebo (saline) can significantly contribute with higher success rate of induced events in patients with PNES. Consider the known ethical issues associated with the addition of placebo, we believe that it may be reasonable to initiate provocative induction without placebo at first. Should patients remain symptoms free, then subsequent addition of placebo during the course of the same induction procedure may lead to higher success rate. Funding: None.