A diagnosis of dementia requires a medical history; physical examination, including neurological examination); and appropriate laboratory tests.
Taking a thorough medical history involves gathering information about the onset, duration, and progression of symptoms; any possible risk factors for dementia, such as a family history of the disorder or other neurological disease; history of stroke; and alcohol or other drug (prescription or over-the-counter) use.
The American Psychiatric Association has established two generally accepted criteria for the diagnosis of dementia: (1) erosion of recent and remote memory and (2) impairment of one or more of the following functions:
- Language: misuse of words or inability to remember and use words correctly (i.e., aphasia)
- Motor activity: unable to perform motor activities even though physical ability remains intact (i.e., apraxia)
- Recognition: unable to recognize objects, even though sensory function is intact (i.e., agnosia)
- Executive function: unable to plan, organize, think abstractly
Symptoms often develop gradually and show a progressive deterioration in function.