Definition of "Dementia"

deterioration of intellectual faculties resulting from a disorder of the brain and often accompanied by emotional disturbance; disorders include senile dementia of the Alzheimer's type, multi-infarct dementia, reversible dementia, progressive neurological disorders, alcohol-induced dementia, serious and persistent mental illness, spinal cord injury, developmental disability, brain injury. Alzheimer's disease accounts for approximately 60% of cases of organic dementia in the elderly and multi-infarct dementia comprises approximately 25% of the cases of dementia in the elderly.