Sensory Changes

Changes in sensory abilities with aging, especially vision, are obvious. Those over the age of 40 are quite familiar with increasing difficulty in focusing on close stimuli, which often makes reading of small print laborious (Kosnik et al., 1988). Less obvious changes include diminished ability to see in dim light, decreased color discrimination, and increased visual processing time (Bieliauskas, 2001; Cavanaugh and Blanchard-Fields, 2002). Similar changes take place in auditory abilities and other senses, including somesthesia, balance, taste, and olfaction (Cavanaugh and Blanchard-Fields, 2002). There are also major declines in the ability of humans to identify odors after age 65 although women and nonsmokers retain the ability to identify odors better (Doty, 2001).

The implications of changes in sensory function for studies for dementia and cognitive changes in aging are twofold. First, the ability to perform cognitive tasks is dependent on the ability to receive, appreciate, and process basic sensory information accurately. One cannot be expected to perform a task involving spatial skills if one's vision is faulty, as documented in many studies (Cavanaugh and Blanchard-Fields, 2002). Second, in some cases sensory-perceptual functions include simple cognitive functions. Odor identification, for example, involves recall of information and matching of stimuli, in addition to basic sensation. Interestingly, a standardized odor identification test developed by Doty and colleagues has been found to be highly sensitive to AD and other dementias (Doty, 2001; McCaffery et al., 2000).

0 0

Post a comment