The Effect of Stimulus Audibility on the Relationship between Pure-Tone Average and Speech Recognition in Noise Ability.

Background: The literature presents conflicting reports on the relationship between pure-tone threshold average and speech recognition in noise ability.

Purpose: The purpose of this retrospective study and meta-analysis was to determine the effect of stimulus audibility on the relationship between speech recognition in noise ability and bilateral pure-tone average (BPTA).

Research Design: Pure-tone threshold and Hearing in Noise Test (HINT) data from two data sets were evaluated. The HINT data from both data sets were divided into groups with complete and partial audibility of the HINT stimuli delivered at 65 dBA.

Study Sample: Normal and hearing-impaired participants were included in this retrospective study. For data set 1 (n = 215), a relatively weak relationship had been found between HINT thresholds and BPTA. For data set 2 (n = 55), a relatively strong relationship had been found between HINT thresholds and BPTA. For data set 1, only 10% of the participants had partial audibility of the HINT stimuli. For data set 2, 16% of the participants had partial audibility of the HINT stimuli.

Data Collection And Analysis: Pure-tone thresholds and HINT data were obtained from published and unpublished studies. HINT data were collected in a simulated soundfield environment under headphones using the standard HINT protocol. Statistical analyses included descriptive statistics, correlations, and a two-way analysis of variance (ANOVA), and multiple regression.

Results: A two-way ANOVA followed by post hoc analyses revealed a greater difference between the data sets for the Noise Front thresholds obtained with partial rather than complete audibility of the stimuli. A weak and nonsignificant relationship was found between BPTA versus HINT Noise Front thresholds for complete audibility data (r = 0.060, p = 0.356) and a strong relationship was found for the partial audibility data (r = 0.863, p < 0.001).

Conclusions: The proportion of partial audibility data in a given data set may influence the relative strength of the relationship between BPTA and HINT Noise Front thresholds. This brings into question the convention of using pure-tone average as a predictor of speech recognition in noise ability.