Some effects of advanced aging on the visual-language processing capacity of the left and right hemispheres: evidence from unilateral tachistoscopic viewing.
The present study investigated the effects of advanced aging on hemispheric organization for visual-linguistic processing. Lexical decision vocal-reaction times of geriatric subjects were measured for unilaterally presented concrete and abstract nouns in an attempt to obtain an index of differential left and right hemispheric processing ability. Results of an ANOVA procedure showed that reaction times were significantly faster when subjects were presented the stimulus items in their right visual fields, regardless of whether the item was a concrete or abstract word. An ANOVA procedure applied to the arcsine of the percentages of occurrence of false-positive and false-negative error types showed a significant interaction between the error type and visual field variables. Post hoc tests showed left visual field, false-positive errors occurred significantly more often than the remaining visual field, error type configurations. Finally, for the reaction time data, a significant correlation existed between the two visual fields for the concrete and abstract items. Collectively, such findings were consistent with a callosal relay model of neurolinguistic organization, suggesting that the right hemisphere's ability to perform lexical decisions was diminished in the present group of elderly subjects.
Rastatter
M P
MP
Bowling Green State University, College of Health and Human Services, OH 43403-0280.
McGuire
R A
RA
D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008959:Models, Neurological; D011603:Psychophysiology; D013060:Speech / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*