A Comparison of Auditory Perception in Hearing-Impaired and Normal Hearing Listeners: An Auditory Scene Analysis Study

Background: Auditory scene analysis (ASA) is the process by which the auditory system separates individual sounds in natural-world situations. ASA is a key function of auditory system, and contributes to speech discrimination in noisy backgrounds. It is known that sensorineural hearing loss (SNHL) detrimentally affects auditory function in complex environments, but relatively few studies have focused on the influence of SNHL on higher level processes which are likely involved in auditory perception in different situations. Objectives: The purpose of the current study was to compare the auditory system ability of normally hearing and SNHL subjects using the ASA examination. Materials and Methods: A total of 40 right-handed adults (age range: 18 - 45 years) participated in this study. The listeners were divided equally into control and mild to moderate SNHL groups. ASA ability was measured using an ABA-ABA sequence. The frequency of the "A" was kept constant at 500, 1000, 2000 or 4000 Hz, while the frequency of the "B" was set at 3 to 80 percent above the "A" tone. For ASA threshold detection, the frequency of the B stimulus was decreased until listeners reported that they could no longer hear two separate sounds. Results: The ASA performance was significantly better for controls than the SNHL group; these differences were more obvious at higher frequencies. We found no significant differences between ASA ability as a function of tone durations in both groups. Conclusions: The present study indicated that SNHL may cause a reduction in perceptual separation of the incoming acoustic information to form accurate representations of our acoustic world.