Dementia, just like mild cognitive impairment (MCI), is not a diagnosis, but rather a “stage” or “severity” of the cognitive impairment due to some underlying medical conditions. It is further divided into mild, moderate and severe stages. If dementia is caused by Alzheimer’s disease (AD), it is called dementia due to AD. Similarly if dementia is caused by head injury, it is called dementia due to head injury.
Dementia is defined as the stage at which cognitive impairment has progressed in severity to the point where it is interfering with well-learned activities of daily life, such as shopping, cooking, driving, managing finances, managing the house, doing yard work, home repairs, and so on. Examples of cognitive impairment often seen during the dementia stage are: