Author(s): CAREY, B., HILLMAN, C., PEELLE, J. , Institution: NORTHEASTERN UNIVERSITY , Country: UNITED STATES, Abstract-ID: 789

Introduction: Despite hearing loss being one of the top causes of years lived with disability, most audiological care focuses only on auditory processing deficits and neglects a key aspect of such impairments, understanding speech in background noise. Earlier research has shown that understanding speech in noise (SIN) requires not only increased listening effort but also an upregulation of executive processes. Similarly, prior work has found that higher fit individuals perform better on executive function tasks compared to their lower fit peers. Given that understanding SIN relies on executive functions and, in turn, higher cardiovascular fitness levels benefit executive function, we hypothesized that CRF would be associated with SIN performance.
Methods: We recruited 41 healthy adults ages 18-61. Our main dependent variable was intelligibility from a speech-in-noise task where they heard sentences in three different levels of noise (quiet, 0 dB SNR, -5 dB SNR) and had to repeat out loud what they heard. The percentage of correct words were calculated for each noise condition. Participants’ VO2max was measured using a modified Balke protocol and a median split was performed to bifurcate participants into lower and higher fitness groups. We conducted a 2 (fitness group) x 3 (noise condition) mixed ANOVA to investigate whether VO2max levels affect speech-in-noise performance.
Results: There was a marginally significant effect of fitness group F(1,39) = 3.63, p = 0.064, η2G = 0.063 such that higher fit participants trended towards performing better across noise conditions than their lower fit counterparts. There was also a significant effect of noise condition as participants performed worse with increased task difficultly (i.e. from quiet to -5 dB SNR), F(1.66, 64.1) = 383.59, p < 0.001, η2G = 0.734. Importantly, there was a significant fitness group x noise condition interaction, F(1.66, 64.1) = 383.59, p= 0.027, η2G = 0.029. Post hoc pairwise analyses with Bonferroni correction showed that the fitness groups’ differences on SIN performance depended on condition difficulty. At -5B SNR, the higher fit participants repeated significantly more correct words (M=58.36, SD=13.69) compared to lower fit participants (M=48.38, SD=14.99) t(39)=2.21, p=0.03, d=0.70. At 0 dB SNR, higher fit (M=86.29, SD=12.40) repeated more correct words than lower fit (M=80.16, SD= 11.24) participants, although group differences were non-significant t(39)=1.62, p=0.11, d=0.51. In the quiet condition, no group differences were observed.
Discussion: These novel findings suggest that higher fit individuals perform better in more difficult environments with noisy speech when listening effort is increased. Despite decades of research investigating why some listeners struggle in noise more than others, there remains a lack of beneficial interventions. Improving cardiorespiratory fitness may be a low-cost noninvasive way to bolster hearing health.