Central auditory dysfunction associated with exposure to a mixture of solvents.

OBJECTIVE

The aim of the present research was to investigate central auditory functioning in normal-hearing, solvent-exposed subjects compared to normal-hearing subjects without solvent exposure, with a comprehensive test battery of behavioural central auditory functioning procedures.

STUDY SAMPLE

Forty-six normal-hearing, solvent-exposed subjects and 46 normal-hearing, control subjects were selected to participate in the study.

DESIGN

All subjects must present with normal hearing thresholds and absence of history of variables related to the onset of auditory dysfunction. Subjects were evaluated with a test battery comprising pure-tone audiometry (PTA), dichotic digits (DD), pitch pattern sequence (PPS), filtered speech (FS), random gap detection (RGD), masking level difference (MLD), and hearing-in-noise (HINT) tests.

RESULTS

Analyses of covariance (ANCOVA) were performed to compare the mean values of the dependent variables (results for DD, PPS, FS, RGD, MLD, and HINT) between solvent-exposed and control subjects. Age and average hearing thresholds (500-8000 Hz) were included in the analyses as covariates. Significant differences for DD, PPS, FS, and RGD results were found between groups.

CONCLUSION

This study provides further evidence of the central auditory dysfunction associated with solvent exposure.