A systematic review of adults with Dravet syndrome

Dravet Syndrome (DS) is a rare and severe infantile-onset epileptic encephalopathy. DS research focuses mainly on children. We did a systematic review, completed on January 18^th, 2021, examining the number of clinical DS studies. We show that there are 208 studies on children exclusively, 28 studies on adults exclusively, and 116 studies involving adults and children combined. This 7:1 ratio of children to adult studies exclusively shows the dearth of research that addresses long-term natural history of DS into adulthood. Through this systematic review, we examine the most up-to-date information in DS adults as it pertains to seizures, electroencephalogram, imaging, treatment, motor abnormalities, cognitive and social behavior outcomes, cardiac abnormalities, sleep disturbances, diagnosis in adults, and mortality. Overall, the frequency of seizures increases in the first decade of life and then myoclonic, atypical absences and focal seizures with impaired awareness tend to decrease in frequency or even disappear in adulthood. Adults tend to have a notable reduction in status epilepticus, especially after 30 years of age. Parkinsonian features were seen in patients as young as 19 years old and are more severe in older patients, suggesting a progression of the parkinsonian symptoms. In adulthood, patients continue to present with behavior problems, associated with a lower health-related quality of life. The leading reported cause of death in DS adults is Sudden Unexpected Death in Epilepsy (SUDEP). Further studies in older adults are needed to understand the long-term outcomes of patients with DS.