Abstracts

Rationale: Hand stereotypies is a necessary criteria for Rett syndrome diagnosis, stereotypies are usually midline although can be asymmetric and include, washing, rubbing, tapping and other. Seizures of various types including simple motor seizures are described in more than 70% of patients and focal and generalized epileptiform activity is even more common. We are describing and discussing a new observation of a "movement disorder" in Rett syndrome patients which on first glance was considered as stereotypy but because of its unique character and synchronous abnormal EEG correlate have to be differently defined. Further analysis of this phenomenon components may shed light on the origin of stereotypies in Rett syndrome Methods: In our national Rett syndrome clinic that follows more than 150 patients we have identified 4 girls with this "unique" phenomenon. Clinical and video EEG features with specific observer manipulation of these 4 girls with typical and atypical (preserved speech variant) Rett syndrome is presented and reviewed Results: In 4 girls with MECP2 mutation proven Rett syndrome we have noticed very frequent episodes of awake unilateral hand tapping which appears only when touching surface and completely disappear by gentle hand holding or removing hand from surface. This behavior was found to be synchronous with onset and arrest of contra lateral central spikes on EEG during V-EEG recording, did not respond to acute or chronic anti convulsant treatment and partially remitted spontaneously after few months. Conclusions: The phenomena described and analyzed is unique and was never described before. It is not fully consistent with stereotypy neither with reflex motor seizure.EEG features may also be considered as giant evoked potentials. Its analysis may shed some light on the pathophysiology of the still unexplained hand stereotypies in Rett syndrome.