Abstracts

Rationale: Psychogenic non-epileptic seizure (PNES) is a distinct clinical entity with clinical manifestations similar to epileptic seizure (ES) but without abnormal electrical brain discharges. PNES remains a diagnostic challenge for clinicians with the rate of misdiagnosis reported as high as 30%. Although video electroencephalography (V-EEG) is the gold standard for differentiating the two conditions, it is not readily available at all centers. Previous studies have focused on ictal characteristics that can be helpful in differentiating PNES and ES. However, there is only limited data in the literature regarding postictal characteristics of PNES that may help to differentiate between the two. In this study, we aimed to compare the duration of ictal and postictal recovery in ES and PNES patients and to explore the existence of any correlation between these two parameters in each group. Methods: Medical records of 465 patients admitted to EMU at the Upstate University Hospital from January 2012 to December 2015 were reviewed. Those with the discharge diagnosis of mixed ES and PNES, seizures related to physiological etiologies such as hypoglycemia, indeterminate discharge diagnosis, and no captured seizures were excluded. Postictal recovery duration was defined as the interval between the end of ictal period and either the first correct answer to postictal orientation questions or to the first followed command. Ictal and postictal recovery durations were calculated in each group and statistical analysis was performed. Results: 61 patients with PNES and 138 captured seizures, and 42 patients with ES and 66 captured seizures met the inclusion criteria. The two groups did not differ significantly in age and gender. Mean ictal duration in ES (105.4 ± 102.9 secs) was significantly shorter than PNES group (175.4 ± 169.6 secs) (p<=0.001). On the other hand, mean postictal recovery duration, by first correct orientation answer criteria, was significantly longer in ES (139.5 ± 185.6 secs) than PNES group (77.7 ± 128.9 secs) (p = 0.006). Similarly, mean postictal recovery duration, by first followed command criteria, was significantly longer in ES (141.1 ± 192.1 seconds) than PNES group (85.7± 136.3 secs) (p=0.019). Despite the shorter mean duration of ictal and longer mean duration of postictal in the ES group, there was no significant correlation between the ictal duration and intervals to the first correct orientation answer (r=0.1, p=0.385) or to the first followed command (r=0.1, p=0.228). However, we found a relatively stronger correlation in PNES with correlation coefficient between ictal duration and the two mentioned interval parameters being r=0.34 (p<0.001) and r=0.39 (p<0.001), respectively. Conclusions: We found a stronger quantitative correlation between ictal and postictal recovery durations in PNES compared to ES group. In other words, it does not seem that recovery from the postictal confusion is necessarily longer in those ES patients who had longer seizures. On the other hand, observation of relatively longer period of recovery associated with some of the longer seizures in the PNES group raises the question of whether these group of patients, unconsciously, also attempt to portray a severe form of their condition to the observers by exhibiting a prolonged recovery period. In addition, significantly longer ictal duration in PNES supports the previous reports that prolonged seizures more likely represent PNES than ES. Further studies are warranted for confirmation and implication of our findings. Funding: None