The AD8 is an 8-item questionnaire that distinguishes between people who have dementia and people who don't. It is considered an informant based assessment because instead of the patient being questioned, the patient's informant (usually a spouse, child, or non-family caregiver) is asked to assess whether there have been changes in the past few years in certain areas of cognition and functioning. These include memory, orientation, executive functioning, and interest in activities. The AD8 has a yes or no format and takes only 3 minutes or so to complete. As with any Alzheimer's test, the AD8 is a screening test and does not take the place of a thorough diagnostic work-up of Alzheimer's disease.
Scoring of the AD8
Scoring of the AD8 is extremely simple: two or more "yes" answers is strongly suggestive of dementia, with the test having a sensitivity of 85% and a specificity of 86%. Sensitivity refers to the test's accuracy in identifying individuals with the disease (i.e., persons with Alzheimer's test as positive). Specificity refers to the test's effectiveness in identifying people who do not have the disease (i.e., persons without the disease test as negative).
Usefulness of the AD8
In addition to its use as a screening test for Alzheimer's disease, the AD8 is especially useful as a way to involve the caregiver. Caregivers can complete the AD8 at home in the presence of their loved one and then bring the results to the appointment, which may help the clinician to more effectively diagnose and treat dementia.
Overall Advantages and Disadvantages of the AD8
The AD8 is a rapidly administered, reliable Alzheimer's test that can be performed at home or in other settings. It has an extremely simple scoring system, with two or more "yes" answers suggesting that further diagnostic tests are warranted. A disadvantage is that an informant may not be available.
Galvin JE, Rose CM, Powlishta KK, et al. the AD8. A brief informant interview to detect dementia. Neurology. 2005;65:559-564.