The Relationship Between Spectral Resolution and Spectro-Temporal Resolution with Speech Perception in Noise in Individuals with Normal Hearing and Cochlear Hearing Loss

Abstract

Aim and Objectives: The present study aimed to measure the relationship between spectral resolution, spectro-temporal resolution, and speech perception in noise in individuals with normal hearing and cochlear hearing loss. The thresholds were compared across the three measures for the subjects with normal hearing and cochlear hearing loss. The spectral resolution (SRt) and spectro-temporal resolution (STRt) ability were assessed at 500, 1000, 2000, and 4000 Hz and were correlated with speech perception in noise ability (SNR-50). Methods: Two groups of adults were considered in the study. Group I consisted of individuals with normal hearing, and Group II consisted of individuals with cochlear hearing loss. All the participants had undergone a spectral resolution ability test using the notch noise method (500, 1000, 2000, and 4000 Hz test frequencies), a spectro-temporal resolution ability test using the spectro-temporal ripple test (500, 1000, 2000, and 4000 Hz test frequencies), and speech perception in noise ability. Results and Discussion: The cochlear hearing loss group was found to have significantly poorer thresholds than the normal hearing group for SRt, STRt, and SPIN-SNR-50. Correlation of SRt and STRt with SNR-50 was done, and found that the SRt and STRt at all four frequencies correlated with SNR-50 in individuals with normal hearing. Still, SRt was significantly correlated with STRt at 500, 1000, 2000, and 4000 Hz test frequencies. However, SNR-50 correlated with SRt only for 500 and 2000 Hz test frequencies. Like SRt, SNR-50 correlated with STRt at only 500 and 2000 Hz test frequencies. Conclusion: The individuals with cochlear hearing loss exhibited significantly poorer thresholds in spectral resolution, spectro-temporal resolution, and speech perception in noise abilities compared to those with normal hearing. The correlations indicate that spectral and spectro-temporal resolution abilities are related to speech perception in noise in normal hearing individuals across all tested frequencies. However, for individuals with cochlear hearing loss, significant correlations between speech perception in noise and spectral resolution were only observed at 500 and 2000 Hz. These results show the importance of both spectral and spectro-temporal processing in understanding speech in noisy environments, particularly highlighting the challenges faced by individuals with cochlear hearing loss.