Abstracts

Rationale: The differentiation between PNES (Psychogenic Non Epileptic Seizures) and ES (Epileptic Seizures) at the bedside continues to be diagnostically challenging. One of us (BJF) noted that patients with PNES may assume postures that facilitate motor behaviors or appear to reduce effort. This study was performed to determine if this behavior is useful in differentiating between PNES and ES. Methods: We evaluated 56 consecutive patients with epileptic and non-epileptic seizures for the presence or absence of a posture maintained or a behavior that intervenes to increase the comfort and, or reduce physical effort before, during or after a paroxysmal behavioral event, using a single-blinded retrospective review of VEEG. We refer to this behavior as a position of convenience (POC). Independent comparisons of PNES (Psychogenic Non Epileptic Seizures) and ES (Epileptic Seizures) were made for the first and last recorded attack of each epilepsy monitoring admission. The presence or absence of POC was analyzed before, during and after each event. POC before the event was identified if a change in position occurred less than 45 seconds prior to the event. POC after the event was identified as a change in position that occured less than 1 minute following the attack. Results: Movement towards a POC before an event did not differentiate between PNES and ES (p=0.5511; Chi square analysis) when evaluating first recorded events, but did show a significantly increased likelihood of PNES for last recorded attacks (p=0.0188). The presence of POC’s during an event increased the likelihood of PNES at the time of the first attack (p= 0.0131) and last recorded attack (p=0.0001). Movement toward a POC after an event was associated with the diagnosis of ES (p < 0.0001) both for the first and last recorded attacks. Conclusions: The presence or absence of the POC may be useful in differentiating PNES from ES. Variations in the occurrence of auras, fatigue and medication withdrawal between the first and last recorded attacks may help to explain why POC prior to the first attack failed to reach statistical significance. Further evaluation of POC in the differential diagnosis of PNES, ES and other paroxysmal behavioral disorders is warranted.