Psychogenic non-epileptic seizures: an overview on terminology, epidemiology and diagnostic features

Psychogenic non-epileptic seizures (PNES) are paroxysmal events which may be misdiagnosed as epileptic seizures. However, unlike epileptic seizures, PNES are not caused by an excessive and hypersynchronous electrical activity in the brain and therefore are not accompanied by ictal electroencephalographic changes; they are common disorders, considered as an involuntary response to emotional, physical, psychological or social distress. This review focuses on terminology, epidemiology, and diagnostic difficulties encountered by physicians facing with this condition. It also provides a comprehensive overview of the diagnostic accuracy values (sensitivity and specificity) for clinical signs commonly used to support the diagnosis of PNES. The differential diagnosis between PNES and epileptic seizures may represent a diagnostic challenge, complicated by the coexistence of both conditions in some patients (up to 50%). The diagnostic delay for PNES is worrisome as a correct and prompt diagnosis is essential for an adequate therapy and to prevent unnecessary, costly and potentially harmful drug treatment. The diagnostic “gold standard” is a video-EEG recording of the paroxysmal event. Several physical signs have different sensitivity and specificity values in the differential diagnosis between PNES and epileptic seizures, but the diagnosis should never be driven by any single clinical sign alone. In doubtful cases, diagnosis should be carefully reconsidered checking event description and semiology at each visit, and not forgetting the possibility of a coexistence of both epilepsy and PNES.