Association among Extended High-Frequency Hearing, Speech Perception in Noise, and Auditory Temporal-Spectral Processing in Adults with Normal Hearing: A Cross-Sectional Study.

Speech comprehension relies on temporal and spectral processing, which can be impaired by background noise. Traditional pure-tone audiometry in standard frequencies has limitations in predicting speech understanding under such conditions. Extended High Frequencies (EHFs) contribute to audibility and speech recognition. This study aims to investigate the correlation between EHF hearing, auditory temporal-spectral processing, and speech comprehension in background noise, and to analyze the factors influencing speech perception in noise ability in adults with normal hearing, emphasizing the importance of EHF evaluation in clinical settings. This cross-sectional study included 44 participants with normal auditory function. The participants underwent high-frequency audiometry, the Quick speech-in-noise (SIN) test for SIN comprehension evaluation, the Gap in Noise (GIN) test for temporal resolution assessment, and the Spectral-Temporally Modulated Ripple Test (SMRT) for spectral resolution examination. The study found a significant correlation between mean EHF thresholds and SNR loss in both common (P-value = 0.019) and high-frequency (P-value = 0.033) words lists. However, no significant correlations were observed between mean EHF thresholds and mean GIN thresholds, GIN percentage of correct answers, or SMRT results. Regression analysis revealed that EHF thresholds significantly contribute to predicting SNR loss. Our findings demonstrate a correlation between EHF thresholds and SIN performance but not with spectro-temporal resolution. However, significant associations between spectro-temporal resolution and SIN performance were observed. Combining these assessments may enhance the prediction of SIN difficulties, facilitating targeted rehabilitation strategies.