Epilepsy in adult patients with Down syndrome: a clinical-video EEG study.

Patients with Down syndrome are now living longer and the overall prevalence of epilepsy is increasing, however, full characterisation of epilepsy in adult age is still incomplete. We describe the electroclinical characteristics of epilepsy in 22 adult patients with Down syndrome (11 males, 11 females), with a mean age of 46 years (range: 28-64 years), followed at the Epilepsy Centre, San Paolo Hospital in Milan. Mean age at epilepsy onset was 36.8 years (range: 6-60 years). Nine out of 22 patients had focal epilepsy, while nine had late-onset myoclonic epilepsy. In four patients, epilepsy was unclassified. The EEG pattern of our patients was characterised by a progressive slowing of the background activity with sharp-and-slow waves with frontal predominance. In the patients diagnosed with late-onset myoclonic epilepsy, the EEGs showed generalised polyspike waves. Three subjects had an episode of myoclonic status epilepticus at the beginning or in the course of the disorder. After the first descriptions of late-onset myoclonic epilepsy by Genton and Paglia (1994), this is one of the largest patient cohorts reported. Our data confirm that epilepsy in adult patients with Down syndrome presents peculiar electroclinical characteristics which should be recognized early as prompt, effective treatment may be beneficial. [Published with video sequences].