Dpoae System with Advanced Noise Cancellation Techniques

A dual Distortion Product Otacoustic Emission (DPOAE) and Auditory Brainstem Response (ABR)automated newborn hearing screener will be developed. This application focuses on new noisecancellation techniques for DPOAE acquisition in order to increase the reliability and testing bandwidthbelow 1500 Hz. Currently available systems provide limited noise rejection capabilities whichsubstantially increase testing time by increasing the number of sweeps necessary. These noise reductiontechniques utilize a primary microphone and two additional microphones to acquire internal and externalnoise reference signals. These techniques include: Adaptive Noise Cancellation (ANC), SpectralEnhancement Averaging (SEA) and Adaptive Wiener Filtering (AWF). Each of these methods will betested with a full complement of noise sources and each will be compared to standard averaging (5A)with artifact rejection. One set of single sweep data will be collected from 12 newborns in order tocompare directly the various processing schemes. Phase I testing will focus on 5 frequencies, 0.5, 1,1.5, 4 and 8 kHz. The performance of the processing strategies will be evaluated using ANOVAtechniques using as dependent variables the signal-to-noise ratio (SNR) and number of sweeps requiredto reach an SNR level.