The influence of age and hearing loss on thresholds measured using the TFS-AF test

The upper limit of sensitivity to binaural temporal fine structure (TFS) is around 1400 Hz. Higher values have been reported when keeping interaural phase differences fixed and varying the frequency adaptively, as in the adaptive-frequency TFS test [TFS-AF, Füllgrabe et al., Int J Audiol, 56, 926–935]. The probability of TFS-AF thresholds exceeding 1400 Hz, and the influence of age and hearing threshold were assessed.

TFS-AF thresholds from 277 participants across five studies were re-analysed as a function of Age, low-frequency pure-tone average threshold (PTL; 250, 500, 1000 and 2000 Hz), and high-frequency pure-tone average threshold (PTH; 6000 and 8000 Hz). The 95% confidence intervals on TFS-AF thresholds were computed. The effects of Age and Hearing threshold on the TFS-AF thresholds were assessed using a multiple-regression model.

The bootstrapped 95% confidence interval for this dataset around the median was 1030 to 1122 Hz, similar to that predicted by Monte Carlo simulation. This range was affected by Age and PTL. Regression modelling showed that the occurrence rate of TFS-AF thresholds exceeding 1400 Hz increased with younger Age and better PTL.

TFS-AF thresholds exceeding 1400 Hz are more likely for lower ages and better hearing thresholds.