Late‐onset epileptic seizures in adults with Down syndrome are linked to Alzheimer’s disease

Abstract

AbstractBackgroundIndividuals with Down syndrome have a high risk of epilepsy and this risk increases with age. We aimed to determine the prevalence and characteristics of epileptic seizures and their link with symptomatic Alzheimer’s disease (AD).MethodPopulation‐based observational longitudinal study from the Down Alzheimer Neuroimaging Initiative. All adults with Down syndrome underwent a neurological and neuropsychological evaluation that included a structured questionnaire on epilepsy. Participants were classified as asymptomatic, prodromal AD or AD dementia patients. A subgroup had an electroencephalogram performed.ResultWe recruited 810 adults with Down syndrome, of whom 66.9% were asymptomatic, 7.2% had prodromal AD and 25.9% AD dementia. 143 (17.65%) had a history of epileptic seizures with a median age of onset of 41.20 years and a bimodal distribution (modes at 1 and 51 years). Clinical AD was associated with a higher risk of epileptic seizures: prevalence of 9.4% in asymptomatic individuals vs 28.04% in prodromal AD and 53.40% in AD dementia patients. Generalized tonic‐clonic seizures and myoclonic seizures were the most frequent seizure type, especially in patients with symptomatic AD. Epilepsy was associated with an earlier AD dementia diagnosis (p=0.016) and lower age at death (p=0.025).ConclusionSymptomatic AD is associated with a high risk of epileptic seizures in DS. Epilepsy in the context of Down syndrome associated Alzheimer´s disease shortens survival.