A 39-year-old man presented to an epilepsy clinic with four months history of brief, recurrent episodes of intense fear and déjà vu lasting 3–10 seconds. The events were stereotyped, with preserved awareness and full recall. He reported that they occurred exclusively during periods of psychological stress and could be anticipated or seemingly provoked. They reliably occurred during his daily runs when passing a specific church, and he reported being able to “bring them on” when anxious or focusing on the sensation.
His background was marked by significant psychosocial stressors, including bereavement, financial loss, housing instability, fertility difficulties, and occupational stress related to restrictions on his work as a professional bus driver. During the initial clinic consultation, a habitual event was observed. This was characterised by sudden distress, head turning, and bilateral down turning of the angles of the mouth, lasting approximately 10 seconds, with preserved awareness and complete post-event recall. His partner confirmed the episode was typical.
MRI head was normal. Routine and sleep-deprived EEGs demonstrated non-specific fronto-temporal slow wave activity and intermixed sharpened waves without definitive epileptiform discharges, and no habitual events were captured. As there was a clinical suspicion of seizures based on the observed semiology, a treatment trial with levetiracetam was suggested but discontinued by the patient due to perceived increased frequency of events. Despite the apparent situational triggers and reported volitional control, the brief stereotypical motor semiology maintained suspicion for focal epilepsy.
Inpatient video-EEG telemetry captured multiple habitual episodes, confirming their epileptic nature. The clinical semiology was characterised by ictal pouting (the Chapeau de Gendarme sign) with subtle impaired awareness, auto-motor behaviour, autonomic features, and motor involvement of the left upper and lower limbs, suggesting seizure onset in the right frontal region. Although the most prominent ictal EEG changes occurred after clinical onset, evolving epileptiform activity was predominantly observed over the right anterior temporal and fronto-polar regions. EEG changes preceding the clinical onset arose from the same region, consistent with the observed semiology.
Systematic review evidence associates the Chapeau de Gendarme sign with mesial frontal epilepsy, particularly involving the anterior cingulate cortex, though moderate evidence links it to a broader network including insulo-opercular and temporal regions.
This case highlights how situational triggers, apparent self-induction, and psychosocial stress may be subjectively perceived by patients and confound the clinical diagnosis of epileptic seizures, underscoring the importance of detailed semiological analysis and video telemetry in MRI-negative focal epilepsy.
