Advanced Alzheimer's disease is a risk factor for late-onset seizures.

To determine the role of Alzheimer's disease as a causative factor for late-onset epilepsy, 44 subjects with mild senile dementia of the Alzheimer type and 58 healthy control subjects were examined over a 90-month period for the development of focal or generalized seizure activity (excluding myoclonus). At entry, all subjects were free of prior seizures and other neurologic, medical, and psychiatric disorders with the potential to impair cognition. Although no control subject developed seizures during the study period, 7 subjects with senile dementia of the Alzheimer type had at least one documented seizure. All 7 subjects had progressed to the severe stage of dementia by the time of the first seizure. Seizures were generalized tonic-clonic in type and were unassociated with clinical or (in 3 subjects) neuropathologic evidence for epileptogenic factors other than Alzheimer's disease. We conclude that advanced Alzheimer's disease alone may be an important risk factor for new-onset seizures in older adults.