The ten point clock test: a quick screen and grading method for cognitive impairment in medical and surgical patients

Abstract

Objective: The objective of this study was to evaluate the clinical utility of the ten point clock test in screening for and grading cognitive deficits in medical and surgical patients.

Method: The setting was the hospital and clinics of Virginia Mason Medical Center, a tertiary referral center. Consecutive samples of hospitalized patients, and clinic outpatients--with and without a dementia--were administered the ten point clock test as well as a number of other neuropsychological tests and measures of cognitive impairment.

Results: Clock scores correlated with neuropsychological test scores and with the mini-mental state examination. They were stable from rater to rater, and from day to day in stable patients. The mean clock score of elderly outpatient controls was 8.5, significantly different from the mean of 5.5 scored by patients with a dementia. A cut off score of seven identified 76 percent of outpatients with dementia and 78 percent of elderly controls. Clock scores correlated well with nurses' ratings of their inpatients' cognitive deficits (Spearman's rs = -0.61). The test was easy to administer, even to hospitalized patients.

Conclusions: The ten point clock test is reliable, valid, and useful as a quick screen and grading method for cognitive deficits in medical and surgical patients.