Feasibility of the Speech Intelligibility Index in Turkish‑speaking Adults with Sensorineural Hearing Loss

Objective: The speech intelligibility index (SII) quantifies the proportion of speech that is audible to a listener.Its predictive accuracy is based on the acoustic and phonetic properties of the language it uses.Our study evaluated the feasibility of using the English-based SII for Turkish-speaking individuals with sensorineural hearing loss, comparing younger and older adults.Methods: In this retrospective cross-sectional study, 161 participants (68 younger adults and 93 older adults) with bilateral sensorineural hearing loss were included.Hearing thresholds, word recognition scores (WRS), and SII values were analyzed.Non-parametric statistical analyses, including the Wilcoxon signed-rank test for paired comparisons, Mann-Whitney U test for group differences, Spearman's rank correlation for associations, and Fisher Z-test with bootstrap analysis to compare correlation coefficients were conducted to evaluate differences and relationships among audiological measures.Results: Significant positive correlations were found between SII and WRS in both age groups (r=0.73 for younger adults; r=0.65-0.70 for older adults).Older adults had higher high-frequency thresholds and lower WRS (p