Distinct Clinical Phenotypes of Late Onset and Early Onset Epilepsies

Originally published in Epilepsia

Despite representing the most common and fastest-growing form of epilepsy in older adults, the clinical features of late-onset epilepsy (LOE) and how it differs from early-onset epilepsy (EOE) remain largely underexplored.

Researchers evaluated the characteristics and risk factors of LOE compared to EOE in a single-center, retrospective study that included individuals with clinically diagnosed epilepsy.

A cohort of older adults was identified and divided into two groups: LOE defined by epilepsy onset occurring at over 60 years of age and EOE when epilepsy onset was diagnosed at under 60 years of age. A total of 326 individuals were included.

The study found that LOE subjects were more likely to be employed/retired than unemployed/disabled, to have focal epilepsy, and to demonstrate cognitive impairment. Cognitive impairment developed after epilepsy onset in the majority of individuals in both groups.

Among the 284 individuals who underwent electroencephalography, epileptiform discharges or seizures were less frequent in LOE. Characteristics including intracranial hemorrhage, intracranial infarction, current alcohol use, former alcohol use, higher medical comorbidity burden, and lower body mass index were independently associated with LOE.

LOE also demonstrated significantly less temporal lobe involvement, a lower lifetime seizure burden, a lower rate of drug-resistant epilepsy, and less use of older generation and adjunctive ASMs compared with EOE. EOE and LOE represent distinct clinical phenotypes.

LOE is associated with greater focal epilepsy, cerebrovascular disease (stroke and hemorrhage), cognitive impairment, and overall higher medical comorbidity burden. Conversely, EOE reflects an epileptogenic disorder characterized by long-standing temporal lobe involvement, drug resistance, and higher ASM exposure.

Recognition of these distinctions may improve individualized diagnostic evaluation, cognitive screening, risk stratification, and therapeutic decision-making.

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