Recurrent seizures in patients with dementia: frequency, seizure types, and treatment outcome

Patients with a primary neurodegenerative disorder associated with cognitive impairment are at increased risk for epilepsy. The goal of the present study was to characterize seizure type(s), etiological diagnosis of dementia, electroencephalogram (EEG) and imaging findings, and response to antiepileptic drug (AED) therapy in these individuals.

A retrospective study was performed identifying patients in the Mayo Alzheimer Disease Patient Registry (ADPR) and Alzheimer Disease Research Center (ADRC) who were classified as having dementia and epilepsy from 1986 to 2006. Multiple clinical parameters were extracted from patient charts and evaluated to characterize the primary neurodegenerative disorder and seizure outcomes.

Sixty-three of the 1738 ADPR and ADRC patients (3.6%) had epilepsy. Twenty-four of the 63 patients were excluded because of insufficient information regarding their epilepsy. The remaining 39 patients were analyzed. Twenty-eight of the 63 patients (72%) experienced complex partial seizures. Head MRI was performed in 35 patients (90%). Fourteen patients (36%) had MRI-identified structural lesions that included remote stroke and prior intracerebral hemorrhage. EEGs were obtained in 29 patients (74%). Fifteen patients (38%) had epileptiform discharges. Overall, it was found that 79% had an excellent response to AED therapy. Approximately one-third of the patients had dose-related side effects from an AED.

The present study indicated that most individuals with the comorbidity of epilepsy and dementia have complex partial seizures that may be adequately controlled on AED therapy. The long-term effect of seizure activity on the neurodegenerative disorder is unknown.