Abstracts

Patients with autosomal dominant lateral temporal lobe epilepsy (ADLTE) may have seizures precipitated by sound or speech. We have performed a clinical and EEG study of a speech-induced seizure in a patient with ADLTE caused by an LGI1 mutation. A 23 year old male belonging to a large pedigree with ADTLE caused by an LGI1 missense mutation (c136C[gt]T) was examined prior to antiepileptic drug therapy seven days after a first generalized tonic-clonic seizure (GTC). A detailed clinical history was obtained. A video-EEG recording with interrogative speech as activation procedure was performed. For several months the patient had experienced occasional episodes of loss of understanding when spoken to. The attacks particularly occurred when he was unprepared for being addressed and was required to give a reply. They lasted only a few seconds and often occurred when he was called to from a neighbouring room. The voices became distorted and he could not comprehend the meaning despite hearing the words. He denied that sudden onset of music or other sounds could precipitate such symptoms. The day after a late party, while parking his car, his girlfriend spoke to him. Her speech became unintelligible to him. He did not reply and had a GTC.
When resting after hyperventilation during EEG, he was suddenly asked for the names of his siblings. He answered immediately, and was then asked how he felt. By then, he had lost any understanding and described how syllables floated together with an echoing character. He uttered [ldquo]Now![rdquo], but could not remember this afterwards. He had a blank stare for some seconds, turned his head to the right and developed a GTC.
In the EEG, rhythmic 6 Hz activity built up in the frontotemporal areas starting on the left side at the time of his first reply with a later bilateral and posterior spreading. After about 20 seconds cerebral activity was concealed by muscle artefacts. Postictal slowing was symmetrical and no aphasia was noted on awakening. To our knowledge, this is the first video-EEG recorded seizure in LGI1-caused ADTLE. This peculiar seizure semiology and precipitating effect of speech may serve as a marker for identifying further individuals with this particular pheno- and genotype and may indicate that the LGI1 gene may have a physiological function connected to the human capacity for speech and language.