Dependence of distortion-product otoacoustic emissions on primary levels in normal and impaired ears. I. Effects of decreasing L2 below L1

• DOI: 10.1121/1.411959
• Publication Date: 2005-10-14T19:39:58Z
• Authors: M. L. Whitehead; M. J. McCoy; B. L. Lonsbury-Ma...; G. K. Martin
• Keywords: Otoacoustic emission; Stimulus (psychology)

The 2f1−f2 distortion-product otoacoustic emission (DPOAE) is evoked by two primary tones of frequencies f1<f2, and levels L1 L2. Previous reports indicate that decreasing L2 below L1=L2 can; (1) increase DPOAE amplitude in normal ears, (2) the degree to which amplitudes are reduced cochlear trauma. Although both these factors could be advantageous for clinical applications DPOAEs, neither has been explored detail. In present study, DPOAE-amplitude frequency functions were collected from impaired ears rabbits humans, with L1=L2, L2<L1, at each three values L1. rabbits, controlled tonal or noise overexposures used produce permanent reductions amplitudes. Comparison pre- postexposure demonstrated frequency-specific DPOAEs enhanced obtained various combinations 16 provide preliminary normative data stimulus-level condition. L1−L2 produced maximum was systematically dependent on Thus most frequencies, substantially mean when L1≥75 dB SPL, but increased L1=65 SPL. However, SPL small, being less than 3.5 frequencies. More importantly, decreased considerably without reducing relative L1=L2. Inspection subjects mild moderate sensorineural hearing losses indicated that, regions impairment, can enhance reduction corresponding amplitudes, It concluded potential performance applications.