Clinical importance of mimics

Psychogenic nonepileptic seizures (PNES) represent a common diagnostic problem in routine neurologic practice and consist of paroxysmal, time-limited alterations in motor, sensory, autonomic, and/or cognitive signs and symptoms that are not accompanied by ictal epileptiform activity. Estimates vary but most published data suggest that about 20% patients referred to epilepsy centers for recurrent refractory seizures have PNES. Moreover, disease duration prior to establishing the diagnosis of PNES may be very long, which illustrates that PNES are usually not missed but are misclassified and inappropriately treated for a long time as epilepsy. Most PNES patients fulfill the diagnostic criteria of conversion/dissociative disorders, addressing the diagnosis towards a psychiatric – rather than neurological - domain. Notably, advanced neuroimaging studies revealed abnormalities of the sensori-motor network and its connections in patients with psychogenic movement disorders, providing a unifying pathomechanism that may underlie both these conditions for an organic brain disorder. The clinical scenario of PNES is further complicated by the co-occurrence of several psychopathological diseases, frequently reactive to traumatic events. A large body of evidence suggests that experiences of trauma are closely linked to PNES and a significant proportion of patients report sexual abuse. Likewise, there is evidence that dissociative and depressive symptoms in PNES patients are linked to a positive history of sexual abuse. Overall, identifying these key risk factors highlight the importance of considering different psychotherapeutic approaches on the basis of the particular subgroup of patients with PNES.