Prevalence of epilepsy among people with intellectual disabilities: A systematic review

• Review of 48 studies on prevalence in people with intellectual disabilities.
• Pooled estimate 22.2% (95% CI 19.6–25.1) for general samples.
• Prevalence increased with increasing level of intellectual disability.
• Pooled estimate 12.4% (95% CI 9.1–16.7) for people with Down syndrome.
• Prevalence increased with age in people with Down syndrome.

PurposeEpilepsy is more common in people with intellectual disabilities than in the general population. However, reported prevalence rates vary widely between studies. This systematic review aimed to provide a summary of prevalence studies and estimates of prevalence based on meta-analyses.MethodStudies were identified via electronic searches using Medline, Cinahl and PsycINFO and cross-citations. Information extracted from studies was tabulated. Prevalence rate estimates were pooled using random effects meta-analyses and subgroup analyses were conducted.ResultsA total of 48 studies were included in the tabulation and 46 studies were included in meta-analyses. In general samples of people with intellectual disabilities, the pooled estimate from 38 studies was 22.2% (95% CI 19.6–25.1). Prevalence increased with increasing level of intellectual disability. For samples of people with Down syndrome, the pooled estimate from data in 13 studies was 12.4% (95% CI 9.1–16.7), decreasing to 10.3% (95% CI 8.4–12.6) following removal of two studies focusing on older people. Prevalence increased with age in people with Down syndrome and was particularly prevalent in those with Alzheimer's/dementia.ConclusionEpilepsy is highly prevalent in people with intellectual disabilities. Services must be equipped with the skills and information needed to manage this condition.