Input-output functions of the nonlinear-distortion component of distortion-product otoacoustic emissions in normal and hearing-impaired human ears

• Published in: The Journal of the Acoustical Society of America Vol. 141; no. 5; pp. 3203 - 3219
• Main Authors: Zelle, Dennis, Lorenz, Lisa, Thiericke, John P., Gummer, Anthony W., Dalhoff, Ernst
• Format: Journal Article
• Language: English
• Published: United States Acoustical Society of America 01.05.2017
• Subjects: Acoustic Stimulation; Acoustics; Adolescent; Adult; Aged; Audiometry, Pure-Tone; Auditory Perception; Case-Control Studies; Cochlea - physiopathology; Female; Hearing Loss, Sensorineural - diagnosis; Hearing Loss, Sensorineural - physiopathology; Hearing Loss, Sensorineural - psychology; Humans; Male; Middle Aged; Nonlinear Dynamics; Otoacoustic Emissions, Spontaneous; Persons With Hearing Impairments - psychology; Psychoacoustics; Psychological and Physiological Acoustics; Signal Processing, Computer-Assisted; Time Factors; Young Adult
• ISSN: 0001-4966; 1520-8524; 1520-8524
• DOI: 10.1121/1.4982923

Distortion-product otoacoustic emissions (DPOAEs) arise in the cochlea in response to two tones with frequencies f1 and f2 and mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Wave interference between these components limits the accuracy of DPOAEs when evaluating the function of the cochlea with conventional continuous stimulus tones. Here, DPOAE components are separated in the time domain from DPOAE signals elicited with short stimulus pulses. The extracted nonlinear-distortion components are used to derive estimated distortion-product thresholds (EDPTs) from semi-logarithmic input-output (I/O) functions for 20 normal-hearing and 21 hearing-impaired subjects. I/O functions were measured with frequency-specific stimulus levels at eight frequencies f2 = 1,…, 8 kHz (f2/f1 = 1.2). For comparison, DPOAEs were also elicited with continuous primary tones. Both acquisition paradigms yielded EDPTs, which significantly correlated with behavioral thresholds (p < 0.001) and enabled derivation of estimated hearing thresholds (EHTs) from EDPTs using a linear regression relationship. DPOAE-component separation in the time domain significantly reduced the standard deviation of EHTs compared to that derived from continuous DPOAEs (p < 0.01). In conclusion, using frequency-specific stimulus levels and DPOAE-component separation increases the reliability of DPOAE I/O functions for assessing cochlear function and estimating behavioral thresholds.