Intersecting pentagon copying and clock drawing test in mild and moderate Alzheimer's disease

Abstract

BackgroundIn Alzheimer's disease (AD) drawing and constructional abilities are impaired and worsen as the disease progresses. PurposeTo examine the feasibility of and develop a method for screening, diagnosis, and staging of dementia that can be quickly administered and interpreted in the clinical setting. MethodsThe study aims to describe a scoring mechanism of the intersecting pentagon copying (IPC) task based on the degree of drawing failure and pitted against the Mini-Mental State Examination (MMSE) and the clock drawing test (CDT), which is probably its most likely competitor for a small measure. This is a prospective cohort study of 91 probable dementia patients of the Alzheimer type referred to the geriatrician over a period of 3 years where the suitability of prescribing acetyl cholinesterase inhibitor is investigated. The patients were categorized as follows: 18 (20%) normal, 31 (34%) mild dementia, and 42 (46%) moderate dementia. The copying of the pentagon was part of the MMSE and these drawings were further scrutinized and a 10-point scoring method developed. Each IPC and CDT was blindly and independently rated by two geriatricians. ResultsThe MMSE and Clinical Dementia Rating were found to have very similar staging results. The IPC had some commonality with these measures for patients defined as normal in that most score 10/10 for the IPC. However, both mild and moderate dementia patients according to other measures have an overlapping range of scores on the IPC scoring method developed. The highest association for the IPC with the CDT was 0.68. IPC had a stronger correlation with the total MMSE than with the two shorter versions. ConclusionThe IPC seems to operate more as a screening tool rather than a dementia staging instrument and assists in identifying normal patients.