Hearing Loss and Cognitive Function: Baseline Findings From the Brazilian Longitudinal Study of Adult Health: ELSA-Brasil.

OBJECTIVE: Hearing loss (HL) has been associated with cognitive impairment in high-income countries. However, no study has investigated this association in low- and middle-income countries. Therefore, our aim was to investigate the association between cognitive function and HL in the Brazilian Longitudinal Study of Adult Health. DESIGN: Cross-sectional analysis of Longitudinal Study of Adult Health (ELSA-Brasil) with 802 individuals (35-74 years old). Hearing was measured using pure-tone audiometry. A pure-tone average (s) of thresholds at 500, 1000, 2000, and 4000 Hz was calculated. HL was defined as a PTA above 25 dB in the better ear or either ear, as a categorical variable. Cognitive performance was measured using the Consortium to Establish a Registry for Alzheimer's Disease word list memory test, the semantic and phonemic verbal fluency (VF) tests, and the Trail Making test version B. To investigate the association between cognitive performance and HL, we used linear regression models adjusted for sociodemographic and clinical variables. RESULTS: Of the total of participants, 7.6% had HL. After adjustment for sociodemographic and health confounding variables, only VF was associated with HL; a 10 dB increase in the PTA in the better ear was associated with worse performance in the phonemic VF test (ß = -0.115 [95% CI, -0.203 to -0.027], p = 0.01). We found a significant interaction between HL and age in the VF domain ( p = 0.01). HL was related to poor VF performance among older adults only. CONCLUSION: In a community-dwelling sample of most middle-aged adults, objectively measured HL was associated with lower VF. These results should be evaluated with caution, given the likelihood of residual confounding and the fact that only VF showed an association with HL.

Effects of hearing protector devices on speech intelligibility: the importance of individualized assessment.

Objectives. This study aimed to compare speech intelligibility in noise with and without hearing protection devices (HPDs). Methods. Fifty-one workers were distributed into three groups: noise-induced hearing loss group (NIHLG), normally hearing noise-exposed group (NG) and normally hearing non-exposed to noise group (CG). A free field system was used to emit monosyllables (65, 70 and 75 dB) and pink noise in different signal-to-noise ratios (SNRs) (0, -5, -10 and -15). Results. In situations with HPDs, all groups showed a decrease in the percentage of correct responses with an increase in noise level. The HPD had little effect on speech intelligibility in the NIHLG and NG. Considering the effect caused by the HPD on speech intelligibility, it was observed that the group with the greatest loss was the CG for SNRs of -5, -10 and -15. Conclusion. Although speech intelligibility is influenced by the hearing threshold, the noise level and SNR are crucial for good speech intelligibility, either with or without an HPD. It is highlighted that the NG had worse results when compared with the CG, which may indicate changes in the auditory pathway resulting from continuous noise exposure, even in the absence of changes in the audiometric thresholds.