Distinguishing epileptic seizures from psychogenic non-epileptic seizures in real-world practice

The differentiation between epileptic seizures and psychogenic non-epileptic seizures (PNES) remains one of the most clinically challenging tasks in neurology and psychiatry. Misdiagnosis is common, often leading to years of inappropriate anti-epileptic treatment, persistent disability, and significant psychosocial burden.

PNES is best conceptualized under:

• Functional Neurological Symptom Disorder
• Dissociative Neurological Symptom Disorder

These are involuntary conditions, not consciously produced behaviors.

🔍 1. The Gold Standard: Video EEG Monitoring

Why it matters

The only definitive way to differentiate is:

👉 Simultaneous video + EEG recording during an event

Interpretation

• Epileptic seizure: Clear ictal epileptiform activity
• PNES: Normal EEG during apparent seizure

Clinical nuance

• Some frontal lobe seizures may have subtle EEG changes → interpret cautiously
• Always correlate clinical semiology + EEG

🧪 2. Bedside Clinical Elicitation Tests

These are supportive tools, not diagnostic in isolation.

🔹 Eye Closure & Resistance

• Epilepsy: Eyes usually open or non-resistant
• PNES: Eyes tightly closed, active resistance to opening

👉 Suggests preserved voluntary control

🔹 Eyelash / Corneal Reflex

• Lightly touch eyelashes
  • Epilepsy: No blink during generalized seizure
  • PNES: Blink or avoidance

🔹 Drop Arm Test

• Lift arm and drop over face
  • Epilepsy: Falls freely (may hit face)
  • PNES: Avoidance → hand deviates

👉 Indicates protective motor control

🔹 Pain Response

• Nail bed pressure / trapezius squeeze
  • Epilepsy: No purposeful response
  • PNES: Withdrawal or organized reaction

🔹 Suggestibility / Interruption

• Calm verbal suggestion or distraction
  • PNES: Episode may reduce or stop
  • Epilepsy: No interruption

⚠️ Use ethically; avoid deception

⚡ 3. Semiology: Pattern Recognition

This is where clinical expertise becomes critical.

🔹 Onset

• Epilepsy: Sudden
• PNES: Gradual, often emotionally triggered

🔹 Motor Activity

• Epilepsy: Stereotyped, rhythmic, synchronous
• PNES: Asynchronous, irregular, variable

🔹 Duration

• Epilepsy: Typically 30 sec – 2 min
• PNES: Often prolonged (>2–5 min), fluctuating

🔹 Characteristic Movements

• Pelvic thrusting: More common in PNES
• Side-to-side head shaking: Suggestive of PNES
• Opisthotonus-like postures: May be seen in PNES

🔹 Tongue Bite

• Epilepsy: Lateral border
• PNES: Tip of tongue (if present)

🔹 Incontinence

• Epilepsy: Common
• PNES: Rare

🔹 Post-Ictal State

• Epilepsy: Confusion, drowsiness, headache
• PNES: Rapid recovery, emotional expression

🧪 4. Laboratory Markers (Adjuncts Only)

🔹 Serum Prolactin (10–20 min post-event)

• Elevated in:
  • Generalized tonic-clonic seizures
  • Complex partial seizures
• Usually normal in PNES

⚠️ Limitations:

• Not useful for absence seizures
• False positives/negatives occur

🔹 Creatine Kinase (CK)

• May rise after true seizures due to muscle breakdown
• Typically normal in PNES

🧠 5. Key Clinical Red Flags for PNES

• Long, dramatic, fluctuating episodes
• Occur in presence of others
• Eyes tightly closed
• Preserved awareness intermittently
• Poor response to anti-epileptic drugs
• Clear psychological stressors

⚠️ 6. Critical Clinical Caveats

🔸 Coexistence

• 10–20% patients may have both epilepsy and PNES

🔸 Avoid premature labeling

• Mislabeling as “fake” → therapeutic rupture

🔸 Always rule out:

• Frontal lobe epilepsy
• Syncope
• Movement disorders

🧩 7. Integrative Understanding

🛠️ 8. Treatment Implications

Epilepsy

• Anti-epileptic drugs
• Neurological follow-up

PNES

• Psychoeducation (crucial first step)
• Trauma-focused therapy / CBT
• Address comorbid depression, anxiety

👉 Early correct diagnosis significantly improves outcomes

📌 One-Line Clinical Wisdom

👉 “EEG confirms, but semiology guides suspicion.”

✍️ About the Author

Dr. Srinivas Rajkumar T, MD (AIIMS), DNB, MBA (BITS Pilani)
Consultant Psychiatrist & Neurofeedback Specialist

At the Mind & Memory Clinic, Apollo Clinic Velachery (Opp. Phoenix Mall), I routinely evaluate complex presentations including dissociative disorders, PNES, ADHD, and cognitive disorders using a combination of:

• Detailed clinical assessment
• Objective tools (including neurocognitive testing and QEEG where indicated)
• Evidence-based, individualized treatment planning

If you or your patient is struggling with unclear seizure-like episodes or treatment-resistant symptoms, a structured evaluation can help arrive at the right diagnosis and avoid years of unnecessary treatment.

✉ srinivasaiims@gmail.com 📞 +91-8595155808