Brugia Malayi - Clark Science Center - Smith College

Measuring Otoacoustic Emissions Using HearID and Acoustic
Processing Hardware
Erika Miguel
This summer, I conducted engineering research in Susan Voss’ laboratory for five weeks. I focused on three main projects:
power reflectance measurements; utilizing a MOTU audio mixer to make DPOAE measurements (via MATLAB programs); and
programming TDT Real-Time Processors to generate tones and record them.
I have been taking power reflectance measurements with my lab partner, Defne Abur, since Fall 2011. This summer has
been a continuation of this work. The goal of this research is to analyze the intrasubject and intersubject variability in power
reflectance measurements in three different locations of the ear over an approximately ten week time period. The procedure for
new subjects involves an ear examination with Susan Voss for approval to participate in the study. Once approved, we administer
a one-time only hearing test of the subject. Then, for every visit over the ten-week time period, we measure the difference in
pressure between the middle and outer ear through a tympanometer test and proceed with three power reflectance measurements,
in different locations, in both ears.
There were multiple stages to this MOTU Audio Mixer for DPOAE Measurements project. First, I had to understand how
the MOTU worked at its most basic level, as a music recording audio mixer. I spent the first two weeks of my research learning
how to control the mixer through its pre-installed programs, how to navigate its interface without computer control, and how to
produce sound from the mixer through speakers that were hooked up to the console and from the computer itself. Then, I had to
understand ARLas, a MATLAB-based audio software that can perform various otoacoustic experiments. Prior to making actual
measurements, I had to work through bugs and glitches in the program, which often meant being in contact with the program
creator himself. After working through those technical difficulties, I have since been taking and analyzing distortion product
otoacoustic emission (DPOAE) measurements on my own ears. This involves placing a probe into my ear canal and listening to
two tones. In the fall, I will continue to analyze the ARLas program code and understand how it works from a computer scientist’s
perspective and will specifically look at how it saves data and how to plot and retrieve it.
There, too, were multiple stages to my Programming TDT Real-Time Processors project. I spent the three weeks of my
research diagnosing a computer hardware issue that involved making a TDT PO5 card to work on Susan’s desktop system so
that the computer can communicate with the processors. After fixing the computer, I had to understand how the TDT RP2.1
(Real-Time Processor) worked; I did this by reading the product descriptions on the manufacturer’s website. Then, I had to learn
a new programming language, RPvdsEx, so that I could control the processors from the computer. RPvdsEx works by making
circuit designs connected in a diagram-like fashion, which is not common to regular computer languages. From there, I needed to
understand how RPvdsEx worked in conjunction with ActiveX so that I could program the RP2 in MATLAB.
I have since figured out how to generate tones on the RP2 and graph them in MATLAB. I will continue this research in the
fall. (Supported by the National Science Foundation)
Advisor: Susan Voss
2012
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