Diagnostic gap in genetic epilepsies: A matter of age

This study aimed to evaluate the access to advanced diagnostic tests in patients with epilepsy and intellectual disability, with special focus on genetics.

Patients with epilepsy and intellectual disability evaluated between 2016 and 2018 at the Epilepsy Unit of two hospitals in Madrid, Spain were included. The main inclusion criterion was an undetermined etiological diagnosis after clinical assessment, neuroimaging, and electroencephalogram (EEG).

Two hundred and five patients with epilepsy and intellectual disability were evaluated, with 124 fulfilling the inclusion criteria (mean age: 33.9 years). Regarding the etiological workup, advanced neuroimaging, prolonged video-EEG, and any type of genetic test had been performed in 58%, 41%, and 40%, respectively. An etiological diagnosis was reached in 18.5%. The workup was considered incomplete in 67%. Variables that showed the strongest association with an incomplete diagnostic workup in the multivariate analysis were current age and seizure freedom.

Despite the multiple implications of modern diagnostic techniques, especially genetic testing, there is a large proportion of patients with epilepsy and intellectual disability who do not have access to them. Older age and seizure freedom seem to be associated with the highest diagnostic gap.