Electrophysiological and behavioural study of localisation in presence of noise

The ability to determine the location of the sound source is often important for effective communication. However, it is not clear how the localisation is affected by background noise. In the current study, localisation in quiet versus noise was evaluated in adults both behaviourally, and using MMN and P3b.

The speech token/da/was presented in a multi-deviant oddball paradigm in quiet and in presence of speech babble at +5 dB SNR. The deviants were presented at locations that differed from the standard by 30°, 60° and 90°.

Sixteen normal hearing adults between the age range of 18-35 years participated in the study.

The results showed that participants were significantly faster and more accurate at identifying deviants presented at 60° and 90° as compared to 30°. Neither reaction times nor electrophysiological measures (MMN/P3b) were affected by the background noise. The deviance magnitude (30°, 60° and 90°) did not affect the MMN amplitude, but the smaller deviant (30°) generated P3b with smaller amplitude.

Under the stimulus paradigm and measures employed in this study, localisation ability as effectively sampled appeared resistant to speech babble interference.