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Psychogenic Non-epileptic Seizures (PNES) Across the Age Span
Psychogenic non-epileptic seizures (PNES) are sudden, involuntary changes in behavior, sensation, motor activity, cognitive processing (including consciousness), and/or autonomic function linked to a dysfunction in the processing of psychological or social distress which, unlike epileptic seizures, are not related to electrographic ictal discharges and cannot be explained by other neurological or medical conditions. PNES are also called non-epileptic events, non-epileptic attacks, pseudoseizures, psychogenic seizures, dissociative seizures; we will use the term ‘psychogenic non-epileptic seizures’ and the abbreviation PNES in this review.
Prevalence and Impact of PNES
In the United States alone, it is estimated that 300,000 to 400,000 individuals suffer from PNES ; it is also estimated that about a quarter of patients referred to tertiary epilepsy centers actually have PNES . The lifetime cost of treating NES for individual patients was estimated at $100,000 in 1998 . PNES significantly impact quality of life, even when compared to epilepsy [3,4]. Frequently mistaken for epilepsy at onset, diagnosis is usually delayed on average for 7 years . The benefit of early recognition is not only economical, but it can have profound impact on the patient’s quality of life, can help identify and address unresolved emotional problems and can reduce iatogrenic complications including misuse of anti-epileptic drugs and other medical interventions that can lead to serious complications .
Video-EEG monitoring that captures a typical event with no electrographic findings suggestive of epilepsy can help establish the diagnosis and is considered the ‘gold standard’ in PNES diagnosis. Without negative electrographic findings during a typical event in video-EEG, the specificity of diagnosing PNES by history alone is established at 50% .
There is no ‘pathognomonic’ or diagnostic clinical sign or symptom that can reliably distinguish epileptic from non-epileptic events, although some signs could be ‘suggestive’ of PNES (such as thrashing movements of the entire body, opistotonic (back-arching) posturing of the trunk, moaning and crying , stuttering , out-of-phase oscillatory movements , eyelid closure especially at the onset of the event , longer duration, lack of post-ictal confusion , sterterous post-ictal breathing ). Special consideration in the differential diagnosis should be given to frontal hypermotor seizures, which can present with unusual semiological characteristics, might not show helpful ictal electrographic discharges on EEG and hence can be confused with PNES . PNES should also be distinguished from other physiological paroxysms (such as cardiogenic and noncardiogenic syncope, transient ischemic attacks, atypical migraine presentations, narcolepsy, parasomnias, intermittent movement disorders, etc).
Risk Factors and Diagnostic Conceptualization
Several biological and psychosocial predisposing, precipitating, and perpetuating factors have been described as contributing to the multifactorial background of patients with PNES . Numerous studies have linked PNES to a high prevalence of comorbid psychiatric conditions such as mood disorders, anxiety disorders, post-traumatic stress disorder, somatoform disorders, dissociative disorders and cluster B personality disorders [14-18]. History of trauma-related events  is a predisposing factor for PNES and lifetime rates of physical and/or sexual abuse range from 50% to 77%  in adults with PNES. In addition to the psychiatric comorbidities, diverse neurological factors have been documented in PNES individuals (history of mild head injuries, neuropsychological deficits, comorbid epilepsy, intellectual disability, etc) adding to the complexity and heterogeneity of their presentation [21-25]. Onset of new illnesses, life events, relationship conflicts, exposure to certain medications are examples of factors that can help precipitate PNES in already vulnerable individuals, while illness representations, interpersonal relational style and other cognitive and behavioral factors can contribute to the perpetuation of PNES [26, 27].
While these factors are relevant for diagnostic and treatment considerations, none of them alone are sufficient to explain the development, precipitation or continuation of the events and it is their multifactorial interaction that might facilitate the expression of PNES.
The ‘psychogenic’ nature of PNES implies that the events are considered an expression that the body and mind have in response to emotionally relevant information; in many cases, the emotionally distressing factors remain outside of the awareness of the patient. The fact that the events or attacks are psychogenic does not imply that they are voluntarily fabricated. The events are outside of the patient’s control. The DSM-IV-TR classifies PNES as a form of conversion disorder (itself, a form of somatoform disorder) .
Presentation of Diagnosis and Treatment
Once the existence of PNES is established, discussing the findings with the patient and, when pertinent, with his or her family, is the first therapeutic step. An important task in the presentation of the diagnosis is emphasizing what PNES are rather than, and in addition to, what they are not. In about 10% of patients, PNES resolve with an explanation of the problem. It has also been shown that longer-term outcome is better in PNES patients who accept that they have PNES than those who continue to think that they have epilepsy, and who are likely to remain heavy users of health care services. Some forms of normalization of the patient’s illness experience have positive effects on psychosocial outcome (such as giving explanations linking physical and psychological factors based on the patients’ experience) while other forms have been found to be harmful (basic reassurance, reporting negative test results, giving negative results and generic explanations) .
Event reduction (in both frequency and severity), improvements in quality of life and social functioning, decrease in use of antiepileptic drugs, medical utilization and iatrogenic complications, as well as addressing psychiatric comorbidities should be considered equally important goals of treatment .
Evidence-based treatment approaches for PNES are limited due to the small number of studies, small samples and open-label design . A promising approach that has shown evidence of efficacy in open-label studies is cognitive-behavioral therapy (CBT) [31, 32], a manualized, time-limited form of psychotherapy. Individualized psychological treatment based on each patient’s presentation and comorbidities should also be considered . Psychiatric comobordities commonly encountered in PNES usually necessitate pharmacological treatment and a small open-label, uncontrolled study found a reduction in PNES frequency with the antidepressant sertraline .
PNES constitute an important differential diagnosis in individuals who present with seizures, particularly when seizures are poorly controlled. The delay in diagnosis and treatment is costly to patients and society. The gold standard for diagnosis is capturing a typical event during v-EEG monitoring; specific forms of epilepsy and certain physiological paroxysms need to be ruled out. Several biological and psychosocial risk factors have been identified as contributing to the multifactorial background on which PNES present. PNES are classified as a conversion disorder and considered an expression of emotional distress. Treatment is aimed at reducing the events, improving quality of life, minimizing iatrogenic complications and addressing comorbid psychiatric conditions. Cognitive-behavioral psychotherapy has shown efficacy at reducing PNES frequency in small, uncontrolled trials and is considered the cornerstone of treatment.
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