CHANGES IN PATTERNS OF INTELLIGENCE TEST PERFORMANCE ASSOCIATED WITH HOMONYMOUS VISUAL FIELD DEFECTS

Abstract

The Wechsler-Bellevue Intelligence Scale was administered to 19 braindamaged patients with right homonymous visual field defects, 19 braindamaged patients with left homonymous visual field defects, 19 braindamaged patients without visual field defects, and 19 non-brain-damaged patients without visual field defects. The groups were roughly matched in age and education. The control group was significantly superior to the 3 brain-damaged groups in Verbal IQ, Performance IQ, and Full-Scale IQ. There was no significant difference among the 3 braindamaged groups in Full-Scale IQ, and the brain-damaged group without visual field defects did not differ significantly from the groups with visual field defects in Verbal IQ or Performance IQ. However, the brain-damaged group with right visual field defects was significantly lower in Verbal IQ than the brain-damaged group with left visual field defects, and the group with left visual field defects was significantly lower in Performance IQ than the group with right visual field defects. The same pattern of results was obtained when subtest scores were individually analyzed. The selective impairment of abilities as a function of the laterality of the homonymous visual field defect was apparently associated with the involvement of the left, hemisphere in right homonymous visual field defects, and with involvement of the right hemisphere in left homonymous visual field defects. The similarity of test performance of the brain-damaged group without visual field defects to that of the brain-damaged groups with visual field defects suggested that the loss of vision in one part of each eye did not produce any appreciable impairment of performance in addition to the impairment resulting from associated brain damage, even on subtests that required the correct perception of complex visual stimuli.