Distortion product otoacoustic emission response characteristics in older adults.

Abstract

The primary purpose of this study was to determine the distortion product otoacoustic emission (DPOAE) and noise response characteristics in a large sample of older adults. Another purpose was to evaluate how specific absolute DPOAE levels or DPOAE/Noise ratios differentiated hearing status in these individuals. A cross-sectional design was utilized for this study. As a part of the Epidemiology of Hearing Loss Study (EHLS), DPOAEs were measured in 937 of the 3,429 participants aged 48 to 92 yr. The DPOAE and noise response characteristics were evaluated at 1,000, 2,000, 4,000, and 8,000 Hz. Absolute DPOAE level and DPOAE/Noise ratios were measured in the participants. The DPOAE data were compared with individual pure-tone frequencies (1,000, 2,000, 4,000, and 8,000 Hz) in the participants to investigate how DPOAE responses differentiated ears with normal hearing from impaired ears. Sensitivity, specificity, positive and negative predictive values, and accuracies were calculated for various absolute DPOAE levels and DPOAE/Noise ratios. Due to the considerable overlap between DPOAE responses and the noise levels at 1,000 Hz, this frequency was not used for any analyses. Sensitivity and specificity were calculated for various DPOAE responses. Sensitivity and specificity varied by frequency for absolute DPOAE levels and DPOAE/Noise ratios. Receiver operator characteristic (ROC) analyses were used to determine which DPOAE responses differentiated normal hearing from hearing loss. The ROC analyses demonstrated that -6 dB SPL at 2,000 Hz, -14 dB SPL at 4,000 Hz, and -22 dB SPL at 8,000 Hz and a +9 dB DPOAE/Noise ratio at each of these frequencies yielded the highest discrimination. Sensitivity and specificity varied by DPOAE response characteristics and frequency. The decision as to which DPOAE response criterion used should be based on careful consideration of objectives and the possible consequences of misdiagnosis. The results of this study support the use of DPOAEs as a clinical measure for older adults.