The Effect of Environmental Noise on Consonant Perception in Individual With Normal Hearing: A Prospective Observational Study

This study was done to identify the effect that environmental noises have on consonant perception of individuals with normal hearing sensitivity. The objectives were to find out the effect of white noise and environmental noises on consonant identification and to find the effect of noises on consonant features. Adult with normal hearing in both ears whose mother tongue was Odia were included. Initially the participants underwent pure tone audiometry, speech audiometry, immittance audiometry to confirm their normal hearing, good speech identification scores and normal middle ear function. For consonant identification test, the presentation level was 40 dB sensation level with reference to speech recognition threshold for all subjects. Consonant identification test was carried out in white noise and real environmental noises (traffic noise, classroom noise, park noise, restaurant noise) at 0 dB signal to noise ratio (SNR) and at + 5 dB (SNR). The results showed that at + 5 dB SNR condition all subjects were able to get 80% and above consonant identification (CI) scores irrespective of type of noise used for stimulus while at 0 dB SNR, the mean scores ranged from 75.5% (restaurant noise) to 84% (traffic noise). At + 5 dB SNR only in restaurant noise the CI scores were low as compared to those in white noise. At 0 dB SNR, the scores were low for both the test conditions of park noise and that of restaurant noise. Different types of noisy environments can affect consonant perception which can affect speech intelligibility.