A patient presenting with chapeau de gendarme and three phase-ictal EEG pattern: Suggesting a focus in the interhemispheric fissure.

An 8-year-old autistic boy had daily seizures that caused staring, arm stiffening, and a distinctive mouth shape. These were initially mistaken for autism-related behaviors. Special brain wave tests revealed the seizures came from a specific brain area. Common seizure medications didn't work, but a medication called lacosamide stopped the seizures for over three years. This shows the importance of proper testing to identify seizure types in autistic children.

This case report describes an 8-year-old boy with autism spectrum disorder who experienced daily seizures characterized by the 'chapeau de gendarme' sign (distinctive mouth positioning) and a specific three-phase EEG pattern. The seizures were initially misdiagnosed as behavioral issues related to autism. Video-EEG monitoring at age 11 revealed a unique pattern suggesting seizures originating from the interhemispheric fissure cortex. Traditional anti-seizure medications (valproate, levetiracetam) were ineffective, but lacosamide successfully controlled seizures over three years.

The authors propose that the combination of these clinical and EEG features may serve as markers for this specific seizure type and location.

Clinicians should carefully evaluate seizure-like episodes in autistic children rather than attributing them to behavioral issues. Detailed EEG analysis may help identify specific seizure foci. Lacosamide may be considered when conventional anti-seizure medications fail in similar cases.

Single case report with no sample size provided. Findings cannot be generalized without replication in larger studies. Limited follow-up data and no comparison group. Represents preliminary evidence requiring validation through controlled studies.

We report a pediatric case of frontal lobe epilepsy with seizures characterized by the "chapeau de gendarme (CdG)" sign and a three phase-ictal scalp EEG (3Ph-EEG) pattern, suggesting a seizure focus in the interhemispheric fissure (IHF) cortex. An 8-year-old boy with autism spectrum disorder (ASD) presented with daily episodes of impaired consciousness, staring, and bilateral tonic posturing of the upper limbs, accompanied by stiffening and drooping of both corners of the mouth. These episodes were initially misdiagnosed as behavioral disturbances in patients with ASD. Video-scalp EEG at age 11 revealed a 3Ph-EEG pattern: 1) brief β bursts in the left frontal region; 2) diffuse attenuation; and 3) rhythmic activity evolving from β to δ frequencies over the left fronto-centro-parietal regions.

Seizure semiology and EEG findings were consistent with a seizure focus in the anterior IHF cortex, including the cingulate gyrus. Although valproate and levetiracetam were ineffective, lacosamide (LCM) effectively controlled the seizures, and its efficacy was sustained over a 3-year follow-up period. The combination of CdG and 3Ph-EEG patterns may serve as clinical and electrophysiological markers for seizures originating in the frontal IHF cortex. Therefore, LCM may be an effective treatment option for such cases.

This case underscores the importance of detailed seizure semiology and EEG interpretation for accurate localization.