Abstracts

Rationale: Ring chromosome 20 ring syndrome [r(20)] is characterized by a peculiar electroclinical phenotype consisting of focal seizures and non convulsive status epilepticus (NCSE), cognitive impairment, behavioural problems and absence of a consistent pattern of dysmorphology. Over than 60 cases have been reported till now, but the semeiological features of seizures of these patients are not yet fully described. Methods: We reviewed the clinical and video-EEG data of all our patients with [r(20)] in order to define clinical characteristics of seizures at epilepsy onset and during follow-up. We performed several video-EEG (VEEG) monitoring and sleep recordings in each patient. Results: Five patients (4 females, 1 male), aged 8 to 29 years (mean age 17 years) were evaluated. Mean age at epilepsy onset was 7 years (range 4 - 10 years ). All patients except one showed new-onset fears, which appeared concomitantly with seizures, as well as terrifying hallucinations. Video-EEG recordings allowed us to study both the clinical semeiology and the electrical pattern of the seizures. The most common ictal symptoms during wakefulness seizures were motor arrest, staring, frightened expression, oral and/or gestural automatism, often associated with a tonic component and aphasia persisting for a variable time. During sleep seizures presenting symptoms were sudden arousal, head-raising movements, frightened staring, cycling and speech arrest. The electrical pattern of these seizures was characterized by the sudden onset of low-voltage, fast, bilateral EEG activity predominant over the frontal regions. Seizures in the older patients were characterized by staring, autonomic modifications and eyelids myoclonias. The EEG pattern consisted of a theta rhythmic activity followed by spike and waves complexes predominant in the frontal areas. NCSE was recorded in 3 patients: this status was associated with bilateral spike waves and slow spike waves over the frontal regions, which lasted for variable times and was correlated to a modification of the alertness and various degree of cognitive impairment. Conclusions: Epilepsy definition in [r(20)] syndrome still reserve many unexplored areas and could bring interesting insights for epileptologic and genetic studies. In our group of patients, a common characteristic is the occurrence of sudden fears and terrifying hallucinations, concomitantly with the epilepsy onset, that should be considered as part of the ictal symptoms and could be helpful for early diagnosis. Besides, the whole electroclinical features of seizures strongly support the hypothesis of an involvement of frontal lobes.