Our Research Lab
Otoacoustics Emissions (OAEs)
DPOAEs are an essential clinical tool used to evaluate cochlear status and changes in cochlear function. For example, changes in cochlear function occur with age, administration of ototoxic drugs, and anoxia. These changes tend to first occur at high frequencies due to increased physiological vulnerability of the basal cochlea. However, most standard clinical DPOAE systems measure DPOAE amplitudes over a limited frequency range using discrete frequency steps. Alternatively, DPOAEs measured with frequency-swept-tones provide significantly more spectral detail, called DPOAE fine structure, which provides additional information. Swept-tone DPOAEs also provide the ability to simultaneously evaluate cochlear status of the f2/f1 overlap region as well as the region associated with 2f1-f2. The DPOAEs that come from these regions are called the generator and reflection components, respectively. The additional information provided by swept-tone DPOAEs is hypothesized to improve the sensitivity and specificity of detecting changes in the basal cochlea.
OAEToolBox (OTB) screenshot of setup.
Commercial OAE systems are limited because they use discrete frequency primaries. Here, we evaluate a new, efficient MATLAB-based tool called OAEToolBox (OTB) that uses frequency-swept tones to rapidly and reliably evoke and measure DPOAE fine structure up to 16 kHz. An additional advantage of the swept tone DPOAE paradigm is that it enables 2f1-f2 component separation. In this study, we compare and contrast swept-tone DPOAEs using OTB to DPOAEs collected with two commercial systems.
The goal of this collaborative project between USF and the City University of New York (CUNY) is to develop a user-friendly MATLAB-based software system (OAEToolBox or OTB) to measure distortion-product otoacoustic emissions (DPOAEs) using swept tone primary DPOAEs. In this project, we compared our new software-hardware system to two well-known commercial software-hardware systems: Intelligent Hearing System (IHS) SmartDPOAE and the Otodynamics (ILO) Echoport ILO V6. A second goal was to establish the most practical stimulus and recording parameters for use in clinical settings in anticipation of the future use of the swept-tone DPOAE method in clinic settings.
DPOAEs, within participant and across systems, showed good agreement in the locations
of amplitude spectrum peaks and nulls, especially in the range of 1000 to 4000 Hz.
However, the continuous swept-tone paradigm provided the following advantages; more
fine-structure detail across a wider range of frequencies (500 to 16000 Hz), lower
noise floors hence, better signal-to-noise ratios, and 2f1-f2 component separation.
These advantages were provided in a fraction of the test time required for each of
the clinical systems.