Sound localization in hemispherectomized patients.
In order to precisely evaluate the consequences of cortical damage on free-field sound localization in humans, the present study examined response accuracy to auditory targets in three hemispherectomized patients and IQ-matched controls. Listeners reported sound location by pointing with their dominant hand to the apparent sound location in an anechoic chamber. Two conditions were tested: (i) localization of a fixed-sound source and (ii) localization of the beginning and the end of a simulated moving stimulus. In both conditions, the responses of the patients were less accurate than those of the controls in the hemifield contralateral to their removed hemisphere. Moreover, the single-case analyses revealed that the performances obtained with fixed sources were generally more precise than those obtained with moving sources. This result is discussed in terms of a differential involvement of cortical and subcortical pathways in the processing of stationary and moving sounds. Finally, the age at surgery and the post-surgical interval were related with the magnitude of the deficits, suggesting the possible influences of functional reorganization and cerebral plasticity.
Poirier
P
P
Groupe de Recherche en Neuropsychologie Expérimentale, Université de Montréal, Québec, Canada.
Lassonde
M
M
Villemure
J G
JG
Geoffroy
G
G
Lepore
F
F
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001925:Brain Damage, Chronic / Q000503:physiopathology / Q000523:psychology; D002540:Cerebral Cortex / Q000503:physiopathology; D002541:Cerebral Decortication; D003337:Corpus Callosum / Q000503:physiopathology / Q000601:surgery; D004292:Dominance, Cerebral / Q000502:physiology*; D004827:Epilepsy / Q000503:physiopathology / Q000523:psychology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology; D011183:Postoperative Complications / Q000503:physiopathology* / Q000523:psychology; D011571:Psychoacoustics; D011597:Psychomotor Performance / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*