The clock drawing test as a valid screening method for mild cognitive impairment

To validate the Clock Drawing Test (CDT) as a screening method for detecting mild cognitive impairment (MCI) and to find the appropriate scoring protocol and its cutoff point, we compared the sensitivity and specificity of three CDT protocols. Subjects included 219 outpatients with memory complaints, who were attending the geriatric memory clinic. Cahn's protocol, with a cutoff point of 7, was more successful at differentiating clinically diagnosed MCI subjects from normal elderly individuals, with higher sensitivity (74.7%) and specificity (75.6%), than were the other protocols. The CDT, as a handy screening method, may be useful for clinicians to reliably identify subjects with MCI, and it may contribute to early detection of dementia.