Clinical characteristics and treatment responses in new-onset epilepsy in the elderly

Epidemiologic studies have shown that the incidence of epilepsy is the highest in the elderly population. Because the elderly constitutes the most rapidly growing population, epilepsy in this group is an important health issue worldwide. To identify the characteristics of epilepsy in the elderly, we reviewed our experience at a tertiary referral center in Japan.

We searched all electronic medical records of the past 6 years at the epilepsy clinic of the hospital affiliated to our University-affiliated hospital. We defined an elderly person as an individual aged 65 years and above. All patients underwent history and physical examinations, 3T magnetic resonance imaging and/or computer tomography, and electroencephalogram (EEG). The diagnosis of epilepsy, age of onset, etiology, and antiepileptic medication were recorded.

We identified 70 patients who developed epilepsy after the age of 65 years. The mean age of seizure onset was 73.1 years and 52.9% patients were males. Complex partial seizures (CPS) without secondarily generalization (n=33, 47.1%) were most frequent. The most frequent diagnosis was temporal lobe epilepsy (n=50, 71.4%). Etiological diagnosis was possible in nearly 50% patients, including those with cerebrovascular disease. A clear cause of epilepsy was not found (i.e., non-lesional epilepsy) in 52.8% patients. Interictal EEG revealed focal epileptiform discharges in 72.9% (n=51) patients. Of the 54 patients who were followed more than 1 year, 42 patients (77.8%) were on antiepileptic monotherapy and 52 patients (96.3%) had been seizure-free for more than 1 year.

The most frequent diagnosis in our cohort of elderly persons with new-onset epilepsy was temporal lobe epilepsy. Non-lesional temporal lobe epilepsy was not uncommon. Epileptogenecity was relatively low in elderly patients and they responded well to antiepileptic medication.