Methods: Two female patients underwent a prolonged video EEG 24 h as part of their epilepsy assessment. Results: In both cases, the EEG showed a very peculiar and stereotypical pattern of bilateral synchronous spikes at about Hz.
This activity was present during wakefulness and highly activated at sleep onset and in NREM sleep, which could show nearly continuous spike activity.
This activity dramatically decreased in REM sleep and after awakening. This pattern of "dents de scie" sawtooth spikes maintained the same morphology throughout the entire EEG recording.
In both patients, the spikes were favored by passive eye closure. During wakefulness, the spikes could evolve into atypical absences while keeping the same "dents de scie" pattern.
Neither patient had tonic or myoclonic seizures at the time of the EEG assessment. Both were moderately retarded, and neither one had a typical DS gait disorder. Previous EEG recordings of case 1 performed at 9. Conclusions: Both patients have a similar electro-clinical phenotype. This "dents de scie" pattern appears to be very specific and could be pathognomonic in a subgroup of young adults with DS.
