Neuropsychological Domains Altered at the Early Stage of Cognitive Decline

Abstract

Objective: A neuropsychological battery is a gold standard for thorough cognitive evaluation. However, it could not be used as a screening test due to its long inspection time and high cost. This study is conducted to identify specific cognitive subdomains that alter even at the early stage of cognitive decline. Methods: Neuropsychological battery results of 575 persons who visited memory clinic were analysed. We classified stages of cognitive decline according to Clinical Dementia Rating (CDR) and CDR-Sum of boxes (CDR-SB). To explore which subdomains can sensitively distinguish normal cognition from the early cognitive impairment, we used Variable Importance in Projection (VIP) in addition to analysis of covariance. Results: We found that scores in subdomain tests such as Rey Complex Figure Test immediate and delayed recall successfully differentiate persons with CDR 0 from those with CDR 0.5 and also persons with CDR-SB 0 from those with CDR-SB 0.5 as indicated by VIP values greater than 1. Conclusion: These results suggest that alterations in visuospatial memory function might be a sensitive sign reflecting the early cognitive decline. The combination of only a few subtests could be also used as a reliable and sensitive screening tool to detect early cognitive impairment.