Spatial localization deficits and auditory cortical dysfunction in schizophrenia.
BACKGROUND
Schizophrenia is associated with deficits in the ability to discriminate auditory features such as pitch and duration that localize to primary cortical regions. Lesions of primary vs. secondary auditory cortex also produce differentiable effects on ability to localize and discriminate free-field sound, with primary cortical lesions affecting variability as well as accuracy of response. Variability of sound localization has not previously been studied in schizophrenia.


METHODS
The study compared performance between patients with schizophrenia (n = 21) and healthy controls (n = 20) on sound localization and spatial discrimination tasks using low frequency tones generated from seven speakers concavely arranged with 30° separation.


RESULTS
For the sound localization task, patients showed reduced accuracy (p = 0.004) and greater overall response variability (p = 0.032), particularly in the right hemifield. Performance was also impaired on the spatial discrimination task (p = 0.018). On both tasks, poorer accuracy in the right hemifield was associated with greater cognitive symptom severity. Better accuracy in the left hemifield was associated with greater hallucination severity on the sound localization task (p = 0.026), but no significant association was found for the spatial discrimination task.


CONCLUSIONS
Patients show impairments in both sound localization and spatial discrimination of sounds presented free-field, with a pattern comparable to that of individuals with right superior temporal lobe lesions that include primary auditory cortex (Heschl's gyrus). Right primary auditory cortex dysfunction may protect against hallucinations by influencing laterality of functioning.
Perrin
Megan A
MA
Schizophrenia Research Center, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, United States. map2005@columbia.edu
Butler
Pamela D
PD
DiCostanzo
Joanna
J
Forchelli
Gina
G
Silipo
Gail
G
Javitt
Daniel C
DC
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001303:Auditory Cortex / Q000503:physiopathology*; D016022:Case-Control Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013017:Sound Localization; D013028:Space Perception