Affiliations: Department of Psychology, Bowdoin College, Brunswick,
ME, USA | Foundation for Blood Research, Scarborough, ME,
USA | Maine Medical Center, Portland, ME, USA
Note: [] Corresponding author: Daniel D. Kurylo, Psychology Department,
Brooklyn College CUNY, 2900 Bedford Avenue, Brooklyn, NY 11210, USA. Tel.: +1
718 951 5969; Fax: +1 718 951 4814; E-mail: [email protected]
Abstract: Alzheimer's disease (AD) is often accompanied by impaired object
recognition, thereby reducing the ability to recognize common objects and
familiar faces. Impaired recognition may stem from decreased efficacy in
integrating visual information. Studies of perceptual abnormalities in AD
indicate an impairment in organizing elements of the visual scene, thereby
confusing components of individual forms. This type of impairment is consistent
with the characteristics of neural loss, which impact cortical integration. To
examine the extent to which perceptual organization is impaired in AD,
psychophysical measurements were made of visual perceptual grouping based upon
spatial relationships in a group of AD patients and demographically matched
elderly control subjects. A comparison was also made between young and elderly
control subjects to evaluate the effects of aging on these capacities. Deficits
in perceptual organization were found for a subgroup of AD patients, which
corresponded to impairment on facial recognition. A less profound functional
decline was found for the elderly control group. The degree of impairment for
AD subjects did not correlate to level of dementia, but instead appears to be
idiosyncratic to individual patients. These results are consistent with
impaired integrative function in AD, the degree of which reflects individual
differences in the regional distribution of neuropathological changes.
