Age- and sex-related differences in the relationship between pure-tone audiometry and speech discrimination in a...

To characterize the relationship between pure-tone audiometry (PTA) and speech discrimination (SpD) in a Japanese cohort, focusing on the divergence of these metrics across age groups and biological sex.

We retrospectively analyzed cases who underwent both pure-tone audiometry and SpD testing at Yokosuka Kyosai Hospital between April 2007 and February 2025. To restrict the analysis to hearing loss attributable solely to age-related decline, cases were excluded if they had active external or middle ear disease, a history of inner ear or retrocochlear disorders, significant interaural differences, or an air - bone gap in PTA.

Of the 873 cases who underwent SpD testing, 317 cases (154 males, 163 females), comprising a total of 634 ears, met the inclusion criteria. Both PTA thresholds and SpD scores tended to worsen with age in both sexes. Female cases had significantly better pure-tone audiometry thresholds than males at 2000 Hz and higher. In cases with more severe PTA, the slope of the relationship between PTA and SpD scores was steeper in males than in females. The strongest correlation between pure-tone audiometry thresholds and SpD scores was observed at 1000 Hz in both sexes. SpD scores were significantly higher in females than in males among individuals aged 70 years and older.

SpD scores revealed age- and sex-dependent functional decline not captured by PTA alone. In this Japanese cohort, the 1000 Hz threshold was the strongest predictor of SpD collapse. Males exhibited steeper discrimination loss, suggesting sex-specific divergence in phonemic regression.