Electrophysiological and behavioural study of localisation in presence of noise

Objective: 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. Design: The speech token/da/was presented in a multi-deviant oddball paradigm in quiet and in presence of speech babble at þ5 dB SNR. The deviants were presented at locations that differed from the standard by 30_, 60_ and 90_. Study sample: Sixteen normal hearing adults between the age range of 18–35 years participated in the study. Results: 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. Conclusions: Under the stimulus paradigm and measures employed in this study, localisation ability as effectively sampled appeared resistant to speech babble interference.