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Dissociating neglect from visual scanning deficits
672
Abstracts from the 19th Annual Meeting
diovascular measures to demonstrate dynamic cerebral laterality for low- and highhostile participants. Group testing at a large state university, yielded the experimental groups composed of high-hostile and low-hostile male participants (n = 30). Cardiovascular data suggest decreased right-cerebral activation (increased left-cerebral activation) following the verbal listening task and greater right-cerebral activation following the cognitive affective stressor. As expected, significant main effects of Trial were found on HR, SBP, and DBP. Specifically, participants demonstrated decreased cardiovascular arousal after the verbal dichotic listening tasks. The purpose of the second experiment was to demonstrate dynamic cerebral lateralization to physical stress by comparing high- and low-hostile individuals' cardiovascular reactivity and bilateral sensory recognition preference following stress. Further, this experiment was designed to replicate the first experiment with a physical stressor (instead of an affective stressor) and through the visual modality (instead of the auditory modality). Stress was induced via a physical task (cold pressor stressor). This experiment utilized a physical stressor condition, the tachistoscopic presentation of dual-concurrent phonemes to the left and right visual fields, and cardiovascular measures to demonstrate dynamic cerebral laterality for low- and high-hostile participants. Group testing at a large state university, yielded the experimental groups composed of high-hostile and low-hostile male participants (n = 30). Cardiovascular data (HR, SBP, and DBP) collected during this experiment may suggest decreased right-cerebral activation (increased left-cerebral activation) following the tachistoscopic task and greater right-cerebral activation following the painful cold pressor stressor. As expected, significant main effects of Trial were found on HR, SBP, and DBP. Specifically, participants demonstrated decreased arousal after the physical stressor.
Connor, B., Humphreys, G., & Wing, A. Dissociating Neglect From Visual Scanning Deficits. We present the case of a 51-year-old male with aneurysm in the right cerebral artery in 1992 and subsequent damage to right fronto-temporo-parietal areas. He originally presented to the University of Birmingham Psychology Department in October 1996, with a variety of cognitive deficits including: left visual neglect, left extinction, poor visual localization, as well as other nonvisual cognitive problems. However, after 2+ years of participating as a research subject in visual task experiments, including a variety of line bisection tasks, recent paper and pencil testing and computerized line bisection tasks reveal little left neglect but an ongoing visual scanning defect. On a cancellation task omissions were equally distributed in the left and right visual fields, while on a cluttered page of lines to bisect there were 6/21 omissions in the left visual field on plain lines and lines bounded by stimulus endpoints, but no omissions in the right visual field. On the other hand, in the line bisection task, mean error on all lines was 1.9 mm left of center. Maximum error was 11 mm left of center on any single line, with 6/21 plain and 8/21 bounded lines bisected left of center. Similarly, on a computerized task involving moving a vertical line from either the left or right side of the screen to the midpoint of a single 8-cm line presented in the center of the screen, all stimulus types (plain and bounded lines) showed a leftward bias, with no statistically significant difference in bisection error regardless of stimulus type or visual cueing from left or right. As has previously been shown in a study of sustained attention training for unilateral neglect, these results suggest that, for some individuals with left neglect, learning a leftward compensatory strategy when it is superimposed on a nonlateralized attentional deficit, can result in a right neglect, without addressing the underlying visual scanning defect.
Abstracts from the 19th Annual Meeting
diovascular measures to demonstrate dynamic cerebral laterality for low- and highhostile participants. Group testing at a large state university, yielded the experimental groups composed of high-hostile and low-hostile male participants (n = 30). Cardiovascular data suggest decreased right-cerebral activation (increased left-cerebral activation) following the verbal listening task and greater right-cerebral activation following the cognitive affective stressor. As expected, significant main effects of Trial were found on HR, SBP, and DBP. Specifically, participants demonstrated decreased cardiovascular arousal after the verbal dichotic listening tasks. The purpose of the second experiment was to demonstrate dynamic cerebral lateralization to physical stress by comparing high- and low-hostile individuals' cardiovascular reactivity and bilateral sensory recognition preference following stress. Further, this experiment was designed to replicate the first experiment with a physical stressor (instead of an affective stressor) and through the visual modality (instead of the auditory modality). Stress was induced via a physical task (cold pressor stressor). This experiment utilized a physical stressor condition, the tachistoscopic presentation of dual-concurrent phonemes to the left and right visual fields, and cardiovascular measures to demonstrate dynamic cerebral laterality for low- and high-hostile participants. Group testing at a large state university, yielded the experimental groups composed of high-hostile and low-hostile male participants (n = 30). Cardiovascular data (HR, SBP, and DBP) collected during this experiment may suggest decreased right-cerebral activation (increased left-cerebral activation) following the tachistoscopic task and greater right-cerebral activation following the painful cold pressor stressor. As expected, significant main effects of Trial were found on HR, SBP, and DBP. Specifically, participants demonstrated decreased arousal after the physical stressor.
Connor, B., Humphreys, G., & Wing, A. Dissociating Neglect From Visual Scanning Deficits. We present the case of a 51-year-old male with aneurysm in the right cerebral artery in 1992 and subsequent damage to right fronto-temporo-parietal areas. He originally presented to the University of Birmingham Psychology Department in October 1996, with a variety of cognitive deficits including: left visual neglect, left extinction, poor visual localization, as well as other nonvisual cognitive problems. However, after 2+ years of participating as a research subject in visual task experiments, including a variety of line bisection tasks, recent paper and pencil testing and computerized line bisection tasks reveal little left neglect but an ongoing visual scanning defect. On a cancellation task omissions were equally distributed in the left and right visual fields, while on a cluttered page of lines to bisect there were 6/21 omissions in the left visual field on plain lines and lines bounded by stimulus endpoints, but no omissions in the right visual field. On the other hand, in the line bisection task, mean error on all lines was 1.9 mm left of center. Maximum error was 11 mm left of center on any single line, with 6/21 plain and 8/21 bounded lines bisected left of center. Similarly, on a computerized task involving moving a vertical line from either the left or right side of the screen to the midpoint of a single 8-cm line presented in the center of the screen, all stimulus types (plain and bounded lines) showed a leftward bias, with no statistically significant difference in bisection error regardless of stimulus type or visual cueing from left or right. As has previously been shown in a study of sustained attention training for unilateral neglect, these results suggest that, for some individuals with left neglect, learning a leftward compensatory strategy when it is superimposed on a nonlateralized attentional deficit, can result in a right neglect, without addressing the underlying visual scanning defect.