This chapter deals with the pathological, physiological and clinical features of dementia. It discusses the occurrence of epilepsy, diagnostic tests and management of Alzheimer disease (AD) and other neurodegenerative diseases. AD is the most common cause of dementia, accounting for more than half of all dementia patients. Epilepsy is diagnosed as a rule after two or more spontaneous seizures. Advanced age increases the risk of both epilepsy and dementia. The dementing process may cause a selective loss of inhibitory neurons that encourages the formation of epileptogenic foci producing seizures. Neuropsychological evaluation is helpful in evaluating for type of dementia. Treatment is usually initiated after a second seizure. The mainstay of epilepsy treatment in the patient with dementia is anticonvulsant medication. Antiepileptic drugs can even be used as a hypnotic, especially if most seizures are nocturnal, but again the decrease in alertness can easily outweigh the benefits.