Overview

• Most common IGE syndrome (~27% of all IGE; 5–10% of all epilepsies)
• Peak onset 12–18 years (range 10–24); slight female predominance
• Complex polygenic inheritance; family history of epilepsy in 30–50%
• Susceptibility genes: EFHC1, GABRA1, GABRD, CLCN2, BRD2 — genetic testing is NOT required for diagnosis
• ~70% concordance in monozygotic twins; diagnosis is clinical and electroclinical, not genetic
• Up to 30% misdiagnosed as focal epilepsy → placed on Na channel blockers → seizures worsen

Classic Triad

Triggers

• Sleep deprivation — single most potent trigger; nearly universal
• Alcohol — intoxication + associated sleep disruption
• Photic stimulation — PPR in 30–90%; TV, video games, flickering lights
• Stress and fatigue — examination periods, emotional stress
• Praxis-induced seizures — triggered by complex cognitive tasks (calculation, writing, decision-making) in up to 40% of JME patients
• Menstruation — catamenial worsening of myoclonus and GTC
• ASM noncompliance — common trigger in the adolescent population

EEG Findings

• Interictal: Irregular generalized 3.5–6 Hz polyspike-and-wave discharges; normal background
• Photoparoxysmal response (PPR): Present in 30–90%
• Focal-appearing features in 30–40% (often frontal) — do NOT indicate focal epilepsy; do not prescribe Na channel blockers
• Single routine EEG may be normal in 30–50% — sleep-deprived EEG increases yield
• Ictal myoclonic: Generalized polyspike-wave burst time-locked to myoclonic jerk

Frontal Lobe Hypothesis

• VBM shows gray matter volume reductions in frontal lobes and thalamus
• DTI reveals reduced fractional anisotropy in frontal white matter tracts and frontal-thalamic connections
• fMRI shows enhanced motor cortex-thalamus connectivity; disrupted default mode network
• Subtle executive dysfunction: impaired prospective memory, planning, mental flexibility
• Supports cortico-thalamic network model of generalized epilepsy

Treatment

Medications That WORSEN JME

• Carbamazepine / Oxcarbazepine — most common cause of treatment failure due to misdiagnosis as focal epilepsy
• Phenytoin — worsens myoclonus; ineffective for generalized seizures
• Vigabatrin — consistently worsens myoclonus and absence
• Gabapentin / Pregabalin — may exacerbate myoclonic and absence seizures
• Lamotrigine — can paradoxically worsen myoclonus in a subset of patients

Prognosis

• NOT self-limited — ILAE classifies JME as "not self-limited"
• Relapse rate >80–90% with ASM withdrawal, even after years of seizure freedom
• 80–90% achieve excellent control with appropriate ASMs
• 10–20% have drug-resistant seizures (usually persistent myoclonus)
• Some patients (<20%) may achieve seizure freedom off medication after the 4th–5th decade

Clinical Features

• Onset: 10–25 years; may present later than other IGEs
• GTC seizures as the sole seizure type — no clinically apparent myoclonus or absences
• GTC preferentially on awakening or after relaxation; infrequent (yearly or less)
• Triggers: sleep deprivation, alcohol, stress (same as JME)
• Normal neurological examination and cognition

EEG

• Generalized 3–5.5 Hz spike-wave or polyspike-wave discharges
• Interictal EEG normal in up to 50% — a single routine EEG has low sensitivity
• Sleep-deprived EEG or prolonged monitoring increases diagnostic yield

Key Differentiator: GTCA vs. Focal to Bilateral TLC

Treatment & Prognosis

• First-line: VPA, LEV, LTG
• Avoid: CBZ, PHT, VGB, GBP/PGB
• NOT self-limited — lifelong treatment generally required; high relapse with ASM withdrawal
• Diagnostic challenge: Video-EEG monitoring may be needed when interictal EEG is nondiagnostic; misdiagnosis as focal epilepsy leads to inappropriate Na channel blocker selection
• Lifestyle counseling (sleep hygiene, alcohol avoidance) is critical — triggers are identical to JME

Clinical Features

• Onset: Childhood (typically 2–14 years; peak 6–8 years); persists into adulthood
• Defining feature: Rapid (3–6 Hz) rhythmic eyelid jerking with upward eye deviation, triggered by eye closure
• Photosensitivity: Nearly 100% — PPR on EEG in virtually all patients
• Other seizures: GTC (~50%), myoclonic jerks, typical absences
• Self-induced seizures: Some patients intentionally trigger eyelid myoclonia via eye closure or hand waving near a light source — this is an epileptic phenomenon, not a behavioral disorder

EEG

• Eye closure sensitivity: Generalized polyspike-wave within 0.5–2 seconds of eye closure — the hallmark
• PPR nearly universal on IPS
• Interictal: generalized 3–6 Hz polyspike-wave; brief discharges easily overlooked

Treatment & Prognosis

• Drug-resistant in 40–50% — eyelid myoclonia is the hardest seizure type to control
• ASMs: VPA (most effective), LEV, LTG (caution: may worsen eyelid myoclonia in some), ETX (for absence component), clobazam as adjunct
• Avoid: CBZ, PHT, VGB, GBP/PGB
• NOT self-limited — eyelid myoclonia and photosensitivity persist lifelong
• Photosensitivity management: Blue-tinted lenses (Z1 lenses); ambient lighting; screen brightness reduction
• Classification note: ILAE 2022 places EEM as a childhood-onset epilepsy that may be associated with epileptic encephalopathy in some patients (when cognitive impairment develops)

ASM Selection by Seizure Type in IGE

General ASM Principles

• AVOID Na channel blockers (CBZ, OXC, PHT) in all IGEs — worsen absence, myoclonic, and atonic seizures
• AVOID vigabatrin, gabapentin, pregabalin, tiagabine — exacerbate generalized seizure types
• VPA is the broadest-spectrum and most effective ASM but teratogenic — use LEV or LTG first-line in women of childbearing potential
• In refractory IGE, consider combination therapy: VPA + LTG, LEV + VPA, or addition of PER

Overlap Syndromes

• CAE → JME in some patients as myoclonic jerks emerge in adolescence
• JAE/JME overlap: absences + myoclonus; classify based on predominant seizure type
• Phenotypic heterogeneity within families — proband may have JME while sibling has CAE
• IGE vs. GGE: if criteria for any specific IGE syndrome are not met, classify as GGE

Absence Status Epilepticus

• Presentation: Prolonged confusion, psychomotor slowing, or near-stupor in an IGE patient; subtle eyelid fluttering or perioral twitching may be the only motor signs
• Duration: May last hours to days if unrecognized
• EEG: Continuous or near-continuous generalized spike-wave (2.5–4 Hz)
• Common triggers: ASM noncompliance, switching from broad-spectrum to Na channel blocker, sleep deprivation, alcohol
• Treatment: IV benzodiazepines (lorazepam, diazepam) — highly effective with rapid resolution
• Prognosis: Excellent with appropriate treatment; no lasting cognitive sequelae