The clock test, also called the clock draw test, is one of several tests used to determine if a patient suffers from dementia, including Alzheimer's disease. At least two common versions of the clock test exist, and the choice to use a particular test is solely based on the preference of the test administrator.
The test takes approximately 10 minutes and can be scored immediately. It is widely used in physician offices, clinics and hospitals whenever a patient's mental faculties are in question.
According to research published in the "Journal of Geriatric Psychiatry and Neurology," people who score poorly on the clock test usually have deficits in semantic memory, which is the portion of memory associated with words, knowledge and understanding. According to the Alzheimer Research Forum, the clock test is "best used in combination with other cognitive assessment instruments. It cannot stand alone to diagnose dementia or any other ailment.
The steps of administering the test follow.
The Patient Is Asked to Draw a Clock
Step 1 varies by specific test. In one variety, a 4-inch-diameter circle is drawn for the patient. He is then asked to draw a clock. In another variety, the patient must also draw the circle. In each variety of the test, the patient is scored on correct placement and sequence of the numbers 1 through 12.
The Patient Is Tested for Ability to Read a Clock
Step 2 also varies by specific test. In one variety, the patient is asked to make the clock read "10 minutes after 11:00." In the second variety, the patient is asked to draw a time on the clock (if he does not spontaneously do so). He is then asked to write the correct time on the piece of paper. For each variety of test, points are given for correctness.
The Results Are Evaluated in Context With Other Findings
A perfect score on the clock test varies from 7 to 10, depending on which test is used. A score of 2 or more points below a perfect score is considered abnormal. In conjunction with laboratory results, clinical examination and other psychological tests, such as the Mini Mental Status Examination, the professional uses the score from the clock test to make a diagnosis of dementia, delirium or other illness. Often, the test is repeated on a later day to monitor for improvement in condition.
What to Do if You Are Concerned
If you have concerns as to whether a loved one has dementia, schedule an examination with a primary care provider, geriatrician or psychiatrist. The clock test should not be administered by anyone other than a medical or mental health professional.
References
- "Psychiatric Times"; 10-Point Clock Test Screens for Cognitive Impairment in Clinic and Hospital Settings; Peter J. Manos, M.D., Ph.D.; Oct. 12, 1998
- "Journal of Geriatric Psychiatry and Neurology"; Clock Test Deficits Are Associated With Semantic Memory Impairment in Alzheimer Disease; Thomas Leyhe et al.; Dec. 1, 2009
- Alzheimer Research Forum: Neuropsychological Testing--Clock Draw Test
