Methods - DPOAE

DPOAE data was collected for us by John Oghalai, M.D. at UCSF.  He used the same technique for collection as Kujawa et. al. [1].  Albino guinea pigs were anesthetized and prepared surgically for DPOAE recordings.  The primary tones chosen were 8.2 kHz and 10 kHz for f1 and f2 respectively.  These two tones generate a distortion product at 2f1 – f2, or 6.4 kHz.

Data was sent to us in the form of 80 continuous time signals recorded from the same test subject at varying f1 and f2 amplitude ratios.  The data consisted of 16 different combinations of varying f1 and f2 input levels, each with 5 time recordings.  Matlab was used to average each of the 16 signal subsets yielding one final time signal for each different f1 and f2 input level pair.  JTFA was conducted on the time-averaged data using a modified Bart-Hanning window; the magnitude of the bin representing 6.4 kHz was then plotted as a function of time.