Abstracts

Rationale: Eighty to ninety percent of individuals with Angelman Syndrome have epilepsy, and sleep disturbances have been described clinically in 20 – 80%. Although epilepsy is thought to exacerbate sleep problems, the effect of a seizure disorder on sleep has rarely been studied in this population. The relationship of seizure type, frequency and severity to sleep disorders, and the medications used to treat them, have never been studied in a cohort greater than 109.Methods: An online survey was conducted through the Angelman Syndrome Foundation to characterize the presentation and treatment of epilepsy in Angelman Syndrome. The Behavioral Evaluation of Disorders of Sleep questionnaire (BEDS, Schreck 1997/1998) was additionally offered to respondents to assess the prevalence of sleep disorders. The relationship of a sleep disorder to genetic subtype, epilepsy and seizure severity was evaluated, as well as the use of medications to treat both seizure and sleep disorders.Results: 386 respondents completed the BEDS questionnaire in addition to the epilepsy survey. Eighty-four percent of BEDS respondents indicated that their child or family member had epilepsy, and sleep disturbances were described by 44%. Of those indicating a sleep disorder, 79% had epilepsy, and 69% of those describing both epilepsy and sleep problems had multiple seizure types. Complex partial, absence, generalized tonic-clonic and atonic seizures were associated with disorders of sleep, and the frequency of seizures was directly related. Previous research findings were confirmed by comparison of the relative frequency of sleep disorders within each genetic subtype. Angelman Syndrome resulting from a maternal deletion generally presents a more severe phenotype, including a higher incidence of sleep disorders. Conversely, sleep disorders were less common in the more mildly affected phenotype of uniparental disomy. The two most commonly described problems affecting sleep patterns were apnea (has trouble breathing, or stops breathing), and expressive sleep disturbances (wakes up screaming, or walks in sleep). Across all factors of sleep disturbance, average scores were higher for those with epilepsy than without.Conclusions: Although the causal relationship remains unclear, sleep disturbances in Angelman Syndrome appear to show an association with the presence and severity of epilepsy, as well as multiple seizure types. The clinical presentation of Angelman Syndrome resulting from a maternal deletion includes a higher incidence of sleep disorders than other genetic subtypes. Medications used to treat these disorders are also examined.