Dementia diagnosis at the earlier stages is important to prevent the fast progression of the disease. Earlier diagnosis helps start the treatment early, which eventually helps the patient to live quality life longer. Dementia diagnosis needs medical history including appropriate laboratory tests coupled with physical examination and neurological examination.

When the doctors take a thorough medical history at the time of dementia diagnosis, relevant information regarding the onset of the disease, duration of the disease and the sighs and symptoms of the disease are taken. It is also analyzed if there are any particular risk factors for developing dementia .

According to American Psychiatric Association (APA), there are primarily two major criteria for dementia diagnosis - (A) wearing down of remote and recent memory and (B) impairment of four important functions including language, motor activity, recognition and executive function.

In the language function, it is analyzed if there is any prominent impaired speech or inability to remember appropriate words. In the motor activity function, it is analyzed if there is any impairment in the motor activities while there is no problem in physical activities.

In the recognition function, it is thoroughly observed if the patient is unable to recognize objects or person. In the executive function, it is analyzed if there is any impairment in the area of decision making, planning and judgment. Impairment of any two or more areas can be a warning signs for dementia onset.

Apart from the diagnosis structure designed by American Psychiatric Association, differential diagnosis is also common for dementia diagnosis. The practitioners must not get confused between delirium and dementia during their diagnostic observations. While delirium is temporary and severe mental disturbance, dementia progresses slowly over time.

Delirium may also develop as a counterpart of other infectious disease. Once the patients get relief from the infectious disease, they get relief from the delirium as well. So the diagnostic experts must be aware of the possibilities of delirium during dementia diagnosis.