Abstracts

Rationale: Various psychiatric disorders can be associated with psychogenic non-epileptic seizure (PNES), including post-traumatic stress disorder (PTSD). Some studies have particularly noted higher prevalence of trauma and PTSD in PNES patients compared to epilepsy patients. Other studies have identified different semiologic clusters in PNES patients. However, there are limited data regarding the correlation of the etiologies of PNES with the above semiologic manifestations, particularly among the veteran population. Methods: This is a retrospective study utilizing chart review of veterans admitted to the video-EEG monitoring unit at the Michael E. DeBakey VA Medical Center in Houston, TX from January 1, 2000 to April 14, 2009. Patients with video-EEG confirmed PNES were included in the study and their records were reviewed for semiology of their PNES and the presence of an established diagnosis of PTSD. Patients were divided into 2 major groups based on their PNES characteristics: 1) Hypermotor: with major motor symptoms such generalized limb movements, pelvic thrusting and head movements; 2) Hypomotor: with altered responsiveness with negative (loss of function), or only mild motor symptoms. Patients with PTSD were categorized into 2 groups: 1) Combat-related (CR) PTSD; 2) Non-combat related (NCR) PTSD. Results: Out of 79 patients with video-EEG confirmed PNES, 25 (31.65%) had a concomitant diagnosis of PTSD. PTSD in 12 patients was related to CR events and in another 12 was related to NCR trauma. In the CR group, 8.33% (n=1) manifested with predominantly hypermotor and 91.67% (n=11) with predominantly hypomotor features. In the NCR group, hypermotor features were observed in 58.33% (n=7) and hypomotor features in 41.67% (n=5). Comparison of PNES characteristics in the two PTSD groups with 2-tailed Fisher’s exact test was statistically significant (p=0.0272) (table1). 1 PTSD patient had equal dominance of hypermotor and hypomotor features and was not included in the analysis. There was an expected gender difference between the 2 PTSD groups: 100% of patients with CR PTSD were male. However, we did not find any statistically significant relationship between gender and predominant semiology of PNES among the non-PTSD patients using a 2-tailed Fisher’s exact test (p=0.1359) (table 2). Females make up about 1/3 of our non-PTSD group. Conclusions: This study suggests that etiology of PTSD may have an effect on the semiologic presentation of PNES. While the underlying mechanisms are unclear, we hypothesize that the predominance of hypomotor features in PNES patients with CR PTSD represents a dissociative state utilized as a subconscious defensive mechanism - an “escape” from the exceedingly undesirable reality of past combat experiences. The NCR group reflects a wider spectrum of underlying psychodynamics, hence manifesting with roughly equal distributions of hyermotor and hypomotor PNES symptoms. Although our CR group consisted of males only, we did not find any statistically significant relationship between gender and PNES semiology among non-PTSD group which consisted of about 1/3 female.