[Psychogenic non epileptic seizures: a review]

Abstract

Objective: This paper summarizes the recent literature on the phenomena of psychogenic non epileptic seizures (PNES). DEFINITION AND EPIDEMIOLOGY: PNES are, as altered movement, sensation or experience, similar to epilepsy, but caused by a psychological process. Although in the ICD-10, PNES belong to the group of dissociative disorders, they are classified as somatoform disorders in the DSM-IV. That represents a challenging diagnosis: the mean latency between manifestations and diagnosis remains as long as 7 years. It has been estimated that between 10 and 30% of patients referred to epilepsy centers have paroxysmal events that despite looking like epileptic episodes are in fact non-epileptic. Many pseudo epileptic seizures have received the wrong diagnosis of epilepsy being treated with anticonvulsants. The prevalence of epilepsy in PNES patients is higher than in the general population and epilepsy may be a risk factor for PNES. It has been considered that 65 to 80% of PNES patients are young females but a new old men subgroup has been recently described. POSITIVE DIAGNOSIS AND PSYCHIATRIC COMORBIDITIES: Even if clinical characteristics of seizures were defined as important in the diagnosis algorithm, this point of view could be inadequate because of its lack of sensitivity. Because neuron-specific enolase, prolactin and creatine kinase are not reliable and able to validate the diagnosis, video electroencephalography monitoring (with or without provocative techniques) is currently the gold standard for the differential diagnosis of ES, and PNES patients with pseudoseizures have high rates of psychiatric disorders such as depression, anxiety, somatoform symptoms, dissociative disorders and post-traumatic stress disorder. We found evidence for correlations between childhood trauma, history of childhood abuse, PTSD, and PNES diagnoses. PNES could also be hypothesized of a dissociative phenomena generated by childhood trauma.

Pathophysiology: Some authors report that PNES can be associated with a physical brain disorder playing a role in their development: head injury may contribute to the pathogenesis of PNES. New-onset psychogenic seizures after resective epilepsy surgery or other intracranial neurosurgery have been described. Recent studies found psychogenic seizure disorders associated with brain pathology in the right hemisphere, non specific interictal electroencephalography abnormalities, magnetic resonance imaging changes and neuropsychological deficits. However, complex partial seizures of frontal origin might present similar characteristics with PNES and could be confused with the latter.

Prognosis and treatment: There is actually no clear agreement as the best treatment plan for PNES patients. The PNES diagnosis has to be clearly communicated to the patient. Nevertheless, even after a correct diagnosis is made a high proportion of PNES patients continue to have seizures, serious disability and bad self-reported quality of life. Furthermore, seizure remission cannot be considered a comprehensive measure of medical or psychosocial outcome. Nearly half of the patients who become seizure free remain unproductive and many of these patients continue to have symptoms of psychopathology including other somatoform, depressive, and anxiety disorders. Even if psychiatric comorbidities have to be treated by a psychiatrist? who could also suggest a psychotherapy, in all cases the importance of a neurologist continuing to follow post-diagnosis PNES patients is essential.

Conclusions: PNES is a diagnostic and therapeutic challenge that is costly to patients and to society at large. Further studies are needed to understand this dissociative psychiatric disorder and to propose therapeutic guidelines.