Apparent shift in visual field preference after unilateral stroke.
Patients with either a left- or a right-hemisphere stroke lesion scored higher in tasks of word-picture matching and of nonverbal shape matching when information was presented tachistoscopically (120 msec) to the visual field (VF) projecting to their undamaged hemisphere. Left-hemisphere stroke patients (n = 13) were dissociated from right-hemisphere stroke patients (n = 15) by low word recognition from memory and by low right VF but nearly normal left VF accuracy in word-picture matching or shape matching; the former appeared to rely upon processing of word meaning by the right hemisphere. In contrast, right-stroke patients had higher right than left VF scores in both tasks, and their discrimination of nonverbal shapes via the right VF was not different from that of controls (n = 15). Preferred processing by the VF projecting to the undamaged hemisphere appeared as a shift in perceptual asymmetry but may indicate, in support of a "direct access" model, that each hemisphere responds more or less efficiently to word and to nonverbal shape discriminations.
Riege
W H
WH
Sepulveda VA Medical Center, CA 91343.
Metter
E J
EJ
Hanson
W R
WR
D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology; D002561:Cerebrovascular Disorders / Q000503:physiopathology* / Q000523:psychology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D014794:Visual Fields; D014796:Visual Perception / Q000502:physiology*