Auditory lateralization in schizophrenia--mismatch negativity and behavioral evidence of a selective impairment in encoding interaural time cues.
OBJECTIVE
Behavioural evidence suggests that individuals with schizophrenia may exhibit impairment in the encoding of cues to sound location. There are three primary cues used by the auditory system to locate the position of a sound in space: interaural differences in the arrival-time (ITD), phase (IPD), and the loudness (ILD) of the sound at the two ears. The goal in this study was to obtain an electrophysiological index of preattentive detection of change in sound lateralization created by these cues.


METHODS
The amplitude of mismatch negativity (MMN) was measured in 18 individuals with schizophrenia and 19 healthy comparison subjects to changes in sound lateralization produced by interaural temporal cues (ITD and IPD) and interaural loudness cues (ILD). Performance was also investigated on a target detection task, where targets were defined by ITD, IPD, or ILD cues.


RESULTS
Individuals with schizophrenia had reduced MMN amplitudes and decreased hit rates when deviants were created by interaural temporal cues, but not when loudness cues were used.


CONCLUSIONS
Results from both the MMN and behavioural task revealed a selective impairment in the use of temporal cues to sound lateralization in individuals with schizophrenia.


CONCLUSIONS
This finding supports previous research that suggests impairment in the encoding of the temporal information in schizophrenia.
Matthews
Natasha
N
School of Psychology, University of Newcastle, Callaghan, NSW 2308, Australia. Natasha.matthews@newcastle.edu.au
Todd
Juanita
J
Budd
Timothy W
TW
Cooper
Gavin
G
Michie
Patricia T
PT
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000704:Analysis of Variance; D003265:Contingent Negative Variation / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology*; D012559:Schizophrenia / Q000503:physiopathology*; D013017:Sound Localization / Q000502:physiology*