The clock drawing test for the identification of responders to donepezil

Background: With new therapies available for Alzheimer's disease (AD), there is need for a brief sensitive screening instrument to predict response to therapy. The Clock test's use as a predictive tool for a therapeutic response to donepezil has not been previously reported. We hypothesize that initial scoring on the clock drawing test would predict response to donepezil after 1 year of therapy. Methods: Subjects were recruited from the Jewish General Hospital Memory Clinic using the following inclusion criteria: a diagnosis of AD, taking donepezil for a minimum of 4 months before the study, a Folstein Mini-Mental State Exam (MMSE), and the clock drawing test administered before the initiation of donepezil. Subjects were excluded if they had not completed at least 4 months of donepezil therapy, if their charts were incomplete, or if they were unwilling to be followed-up at the clinic. Demographic data abstracted from charts included age, sex, level of education, place of residence, presence or absence of a caregiver, medications, initial and subsequent functional status as measured by the Barthel and OARS scales, Folstein MMSE, and clock drawing tests. Results: Of the 45 subjects who met the inclusion criteria (26 females, 19 males), 6 men (31.5%) and 13 women (50%) worsened on their MMSE during the study period. There was a mildly predictive role of the initial clock score for a positive response to therapy. No such predictive value was found for initial MMSE, Barthel or OARS scores. Conclusions: Our data suggest a predictive role of the initial clock score for a positive response to therapy, as defined by a stable or improved MMSE score. Initial scores on the MMSE, Barthel and OARS were not as predictive. Our results are suggestive of a potentially useful clinical tool in the evaluation of treatment of early AD.