Measurement of Auditory Discrimination using the Mismatch Negativity (MMN) for the Healthy Youth in the Horizontal Plane / 听力学及言语疾病杂志

ABSTRACT

Objective To explore whether the changes of sound source in the horizontal azimuth can induce mismatch negativity (MMN) ,and quantify the minimal audible angle which could elicit the MMN and to find effec‐tive way to test human's ability of sound localization in the horizontal plane .Methods With the self developed sound localization device and Bio - logic auditory evoked potentiometer ,in the free field hearing tests were performed on 30 healthy young volunteers according to oddball stimulation sequence .We adopted 1 000 Hz pure tone as the stand‐ard stimuli , the change of sound source location as experimental models ,using minimum audible angle (MAA ) measure procedure ,sound localization test was conducted at 0° ,± 45° ,± 90°standard positions in the horizontal plane .MMN was obtained by subtracting the ERP of deviant stimuli from the ERP of standard stimuli .The latency and amplitude of each MMN were recorded .Results The MMAs of normal young people were recorded and normal values of latency and amplitude of MMN were obtained .The results of the sound localization test for the youth wereMAA(0°)= 2 .09 ± 1 .81° ,MAA( - 45°)= 3 .84 ± 1 .61° ,MAA (45°) = 3 .69 ± 2 .39° ,MAA ( - 90°) = 4 .41 ± 1 . 41° ,MAA(90°)= 4 .23 ± 3 .22° ,separately .There was a significant effect of the location of the deviant stimulus , with those presented at 90° eliciting larger peaks and longer latency period than those presented at 0° .Conclusion Our findings suggest that changes of sound position in the horizontal azimuth can induce mismatch negative waves , and MMN on the basis of MAA test procedure could be used to evaluate the ability of sound localization .