What are psychogenic nonepileptic seizures (PNES)?

Psychogenic Non-Epileptic Seizures (PNES)

Psychogenic non-epileptic seizures (PNES) are episodes that resemble epileptic seizures but are not associated with abnormal electrical activity in the brain and are instead caused by psychological processes. 1, 2

Definition and Classification

PNES are classified as:

• In ICD-10: Dissociative disorders
• In DSM-IV: Somatoform disorders 3

They represent a form of conversion disorder where psychological distress manifests as physical symptoms that mimic epileptic seizures.

Epidemiology

• Prevalence: 10-30% of patients referred to epilepsy centers have PNES 3
• Demographics:
  • 65-80% are young females 3
  • A subgroup of older men has been recently identified 3
  • Higher prevalence in people with intellectual disabilities 4
• Comorbidity: The prevalence of epilepsy in PNES patients is higher than in the general population 3

Clinical Presentation and Distinguishing Features

PNES can be distinguished from epileptic seizures by several characteristic features:

During the attack (eyewitness observations):

• Eyes often closed during unconsciousness (vs. typically open in epilepsy) 5
• Pelvic thrusting movements 5
• Eye fluttering 5
• Longer duration of apparent loss of consciousness (10-30 minutes) 5
• Asymmetrical, asynchronous movements 5
• Movements beginning after onset of loss of consciousness 5
• Repeated waxing and waning in intensity and changes in nature of movement 5

Other distinguishing features:

• Normal EEG during a typical seizure event (gold standard diagnostic criterion) 1, 2
• Tongue biting is rare, and when present, typically affects the tip rather than lateral sides 5
• Absence of post-ictal confusion that is typical in epileptic seizures

Etiology and Risk Factors

PNES development is associated with:

• History of trauma or abuse 1
• Comorbid psychiatric disorders (depression, anxiety, other somatoform disorders) 1, 3
• Previous or concurrent conversion symptoms 1
• Neurobiological factors: Some patients show cognitive impairment and subtle structural/functional brain abnormalities 2
• Head injury may contribute to pathogenesis 3
• Right hemisphere brain pathology has been associated with PNES 3

Diagnostic Approach

Gold Standard:

• Video-EEG monitoring during a typical event 2, 3, 6
  • Shows normal electrical activity during seizure-like behavior

Diagnostic Challenges:

• Mean latency between manifestations and diagnosis: approximately 7 years 3
• Many patients receive incorrect epilepsy diagnosis and unnecessary anticonvulsant treatment 3
• Complex partial seizures of frontal origin can present similarly to PNES 3

Common Diagnostic Pitfalls

• Assuming all seizure-like events in psychiatric patients are psychogenic 1
• Missing dual diagnosis of epilepsy and PNES (occurs in approximately 10-30% of cases) 6
• Relying solely on clinical characteristics, which lack sensitivity 3
• Overreliance on biochemical markers (neuron-specific enolase, prolactin, creatine kinase) which are not reliable for validation 3

Management Approach

1. Clear communication of diagnosis to the patient is essential 3
2. Multidisciplinary approach:
   • Neurologist follow-up remains important even after diagnosis 3
   • Psychiatric treatment for comorbidities 3
   • Psychological interventions, particularly Cognitive Behavioral Therapy (CBT) 1
3. Medication management:
   • Supervised withdrawal of antiepileptic medications when appropriate 1
   • Pharmacological interventions for psychiatric comorbidities 2

Prognosis

• Even after correct diagnosis, a high proportion of patients continue to have seizures 3
• Nearly half of patients who become seizure-free remain unproductive 3
• Many continue to have symptoms of psychopathology including other somatoform, depressive, and anxiety disorders 3
• Seizure remission alone is not a comprehensive measure of medical or psychosocial outcome 3

Special Populations

PNES in Patients with Epilepsy:

Compared to patients with PNES alone, those with both PNES and epilepsy show:

• Younger age
• Higher percentage of spontaneously activated events
• Shorter disease duration
• Longer time to PNES diagnosis
• Lower percentage lost at follow-up 6

PNES in Intellectual Disability:

• Intellectual disability is a risk factor for developing PNES
• Often presents with complex needs requiring multidisciplinary care 4

PNES represents a significant diagnostic and therapeutic challenge that is costly to patients and healthcare systems. Further research is needed to better understand this condition and develop more effective treatment approaches.