A COMPARISON OF CLOCK AND PENTAGON DRAWING IN ALZHEIMERS-DISEASE

Clock drawing is described as a novel, easily administered bedside mea sure of cognitive function. We examined from 77 ambulant elderly perso ns meeting NINCDS criteria for Alzheimer's disease their drawings of c lock faces and overlapping pentagons. Interrater reliability for two p reviously published scoring scales for clocks and a devised ordinal sc ale for overlapping pentagons was high. There was moderate correlation with their total scores on the CAMCOG and Mini Mental State Exam (MMS E). However, a considerable number of patients scored within the norma l range on all three drawing scales. A third (23/77) on clock drawing demonstrated their only abnormality at setting the time to 10 to 11 in stead of the requested 10 past 11. For the clock drawing test to be us ed as a rapid screening instrument for Alzheimer's disease in the comm unity an accurately drawn clock face must include the correct position of the hands. The pentagon test either alone or in combination did no t enhance the accuracy of the clock test.