Abstracts

Rationale: Psychogenic non-epileptic spells (PNES) are paroxysmal motor, sensory or autonomic disturbances that resemble epileptic seizure, but lack corresponding abnormal electrical activity in the brain. The potential iatrogenic effects of inappropriate treatment for PNES include being subject to multiple imaging studies as well as adverse effects of anticonvulsants inappropriately prescribed.  While definitive diagnosis of PNES is made via video EEG (vEEG) monitoring, there is limited data available to guide physicians as to when to suspect PNES and to refer for vEEG monitoring.  In the present study, we assessed the association between the demographic and clinical characteristics of patients with PNES and the frequency of brain imaging prior to the diagnosis with vEEG. Methods: This is a retrospective chart review of adult patients diagnosed with PNES at the University of Nebraska Medical Center. The demographic parameters, psychiatric co-morbidities and utilization of relevant medications in these patients were examined. The segments of the diagnostic continuous vEEG were reviewed for semiology and classified into the categories as either hyper- or paucikinetic movements; the latter category included those with non-motor symptoms. The event categories were adapted from the previously published semiologic classification of PNES. The frequency of the brain imaging tests prior to the definitive diagnosis was assessed and correlated with the semiological category and gender. The patients with co-existing epilepsy were excluded. Results: Fifty-five out of 560 patients monitored with vEEG in 2015-2016 were diagnosed with PNES. This group included 17 male (31%) and 38 female (69%) patients with the median age of 35 years at PNES diagnosis. The movements associated with PNES events were regarded as paucikinetic in 38 patients (69%) and hyperkinetic in 17 patients (31%). There was no difference in the distribution of the PNES semiology between the two sexes (p=0.27; chi-square test). Brain imaging tests, including CT head and MRI of the brain were performed at least once in 83% of patients and 4 times or more in 13 % prior to the definitive diagnosis. There was a significant association between the frequency of brain imaging tests and sex (p=0.04; Fisher exact test). Specifically, the proportion of males referred to complete 4 or more brain scans was higher by 25% than that of females. There was no association between the frequency of imaging tests and PNES semiology (p=0.51, Fisher exact test). Interestingly, patients with paucikinetic movements tended to have higher number of comorbid psychiatric disorders as compared to the patients with hyperkinetic events (p=0.09; Wilcoxon rank test). Conclusions: These data suggest that the frequency of brain imaging obtained prior to the definitive diagnosis of PNES is influenced by sex but is unaffected by semiology of the events. Therefore, the diagnosis of probable PNES in male patients should be promptly confirmed with vEEG to avoid unjustified imaging tests. Funding: None