Object Perception Impairments Predict Instrumental Activities of Daily Living Dependence in Alzheimer's Disease

Abstract

This study examined the contribution of object perception and spatial localization to functional dependence among Alzheimer's disease (AD) patients. Forty patients with probable AD completed measures assessing verbal recognition memory, working memory, object perception, spatial localization, semantic knowledge, and global cognition. Primary caregivers completed a measure of activities of daily living (ADLs) that included instrumental and basic self-care subscales (i.e., IADLs and BADLs, respectively). Stepwise multiple regressions revealed that global cognition accounted for significant portions of variance among the ADL total, IADL, and BADL scores. However, when global cognition was removed from the model, object perception was the only significant cognitive predictor of the ADL total and IADL subscale scores, accounting for 18.5% and 19.3% of the variance, respectively. When considering multiple cognitive components simultaneously, object perception and the integrity of the inferotemporal cortex is important in the completion of functional abilities in general and IADLs in particular among AD patients. This research was supported by F32-AG022773 (ALJ), K23-MH065857 (RPH), K24-NS002140 (GG), and P30-AG013846 (BU ADC). A portion of these data served in partial fulfillment of the PhD requirements from Drexel University for Angela L. Jefferson under the research mentorship of Dr. Guila Glosser. Portions of these data were presented in October 2003 at the 23rd annual meeting of the National Academy of Neuropsychology, Dallas, TX, and in February 2004 at the 32nd annual meeting of the International Neuropsychological Society in Baltimore, MD. The authors wish to thank the physicians who supported recruitment efforts at Brown Medical School (i.e., Dr. Norman Gordon) and the University of Pennsylvania Medical Center (i.e., Drs. Chris Clark, Jason Karlawish, and Branch Coslett). The authors also wish to thank Ms. Jennifer Gallo (Drexel) and Mr. Jay Lawrence (Brown) for their data collection efforts. Lastly, the authors wish to thank Dr. Adam Brickman for his insightful comments on earlier versions of this manuscript.