A group of epilepsy syndromes with a presumed genetic origin, no structural abnormalities on imaging, onset in childhood or adolescence, and generally good response to treatment.
| Feature | Description |
|---|---|
| Etiology | Genetic (no structural or metabolic cause identified) |
| Age of Onset | Childhood to adolescence |
| EEG Findings | Generalized 3 Hz spike-and-wave (absence); polyspike-and-wave (myoclonic) |
| MRI | Normal |
| Cognitive Development | Normal |
| Treatment Response | Generally good; may require lifelong medication |
1. Childhood Absence Epilepsy (CAE) • Onset: 4–10 years • Seizures: Frequent typical absences (staring, eyelid flutter, unresponsiveness) • EEG: 3 Hz spike-and-wave • Prognosis: Often remits in adolescence • Treatment: Ethosuximide, Valproate
2. Juvenile Absence Epilepsy (JAE) • Onset: 10–17 years • Seizures: Absence seizures ± generalized tonic-clonic seizures (GTCS) • EEG: 3–4 Hz generalized spike-and-wave • Prognosis: May persist into adulthood • Treatment: Valproate, Lamotrigine
3. Juvenile Myoclonic Epilepsy (JME) • Onset: 12–18 years • Seizures: Myoclonic jerks, often after waking; GTCS ± absence seizures • EEG: 4–6 Hz polyspike-and-wave • Prognosis: Lifelong condition; high relapse if treatment is stopped • Treatment: Valproate, Levetiracetam, Lamotrigine
4. Epilepsy with Generalized Tonic-Clonic Seizures Alone (EGTCSA) • Onset: Adolescence • Seizures: Only GTCS, often triggered by sleep deprivation or alcohol • EEG: Generalized polyspike discharges • Treatment: Valproate, Levetiracetam
🚫 Drugs to Avoid in IGE: Carbamazepine, Phenytoin, Oxcarbazepine, Gabapentin These may worsen absence or myoclonic seizures.
In clinical practice, there is a prevailing notion that photosensitivity mostly occurs in children with epilepsy (CWE) with idiopathic generalized epilepsy.
van Win et al. investigated the distribution of epilepsy types and etiology in photosensitive children and the associations with specific clinical and electroencephalogram (EEG) variables.
In this retrospective cohort study, clinical data were acquired from all children that showed photosensitivity during systematic intermittent photic stimulation (IPS), over a 10-year interval at a tertiary level Children's Hospital, Winnipeg. Patient demographics, EEG findings, and clinical data and symptoms during IPS were abstracted. Classification of diagnoses using the International League Against Epilepsy (ILAE) 2017 guidelines was done by an expert panel.
Seventy-eight photosensitive children were identified. Forty (51.3%) had generalized epilepsy (idiopathic: 27, structural: 2, other: 11) compared with 19 (24.4%) focal (idiopathic: 1, structural: 2, other: 16), 8 (10.3%) combined focal and generalized (structural: 4, other: 4), and 11 (14.1%) unknown epilepsy (other: 11); (χ2 (3) = 32.1, p = .000). Self-sustaining or outlasting photo paroxysmal responses (PPRs) occurred in association with all epilepsy types; however, the EEGs of focal CWE without treatment comprised almost solely of PPRs which outlasted the stimulus (8/10), in contrast to only 8/17 of focal CWE with treatment and to 13/26 of generalized epilepsy without treatment. Most frequency intervals in individual patients were less under treatment: a decrease in standardized photosensitivity range (SPR) was seen in 5 CWE, an increase in 2, and no change in 1 during treatment. Both CWE with focal and generalized epilepsy showed abnormal activity on EEG during hyperventilation (40% vs 65.7%). Thirteen out of 14 CWE with clinical signs during IPS had independent spontaneous epileptiform discharges (SEDs) in the EEG recording.
Photosensitivity occurs in all types of epilepsy rather than in idiopathic generalized epilepsy alone. Surprisingly, there is a tendency for focal epilepsy to be associated with self-sustaining PPRs, especially when no treatment is used. Treatment tends to make the PPR more self-limiting and decrease the SPR. There is a tendency that clinical signs during IPS occur in EEGs in individuals with SEDs 1).
Idiopathic generalized epilepsy (IGE) is a brain network disease, but the location of this network and its relevance for treatment remain unclear. Ji et al. combine the locations of brain abnormalities in IGE (131 coordinates from 21 studies) with the human connectome to identify an IGE network. We validate this network by showing alignment with structural brain abnormalities previously identified in IGE and brain areas activated by generalized epileptiform discharges in simultaneous electroencephalogram-functional magnetic resonance imaging. The topography of the IGE network aligns with brain networks involved in motor control and loss of consciousness consistent with generalized seizure semiology. To investigate therapeutic relevance, we analyze data from 21 patients with IGE treated with deep brain stimulation (DBS) for generalized seizures. Seizure frequency reduced a median 90% after DBS and stimulation sites intersect an IGE network peak in the centromedian nucleus of the thalamus. Together, this study helps unify prior findings in IGE and identify a brain network target that can be tested in clinical trials of brain stimulation to control generalized seizures 2).