Mild cognitive impairment: Memory complaints (preferably qualified by an informant) and memory impairment relative to the patient's age and education, but preserved general cognitive function and intact activities of daily living (ADL). On MMSE, the patients generally score in the range of 26 to 28. It is the precursor to several types of dementia, including neurodegenerative (e.g. Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies), vascular dementia and dementia caused by neoplasms, normal pressure hydrocephalus and metabolic factors.

Progression of dementia varies with the cause. Early symptoms include lapses in memory, reasoning and judgement. Most disorders like sadness, anger and frustration are common. Gradually, deficits in all higher mental functions become evident. Dysphasias, apraxias, agnosias, urinary incontienence and focal neurological deficits occur. In later stages, deterioration in personality, personal hygiene and self-care become evident. The person requires to be looked after by others. In advanced stages, the person is mute, lies on bed and succumbs to intercurrent infections.