BioSigRZ Software

BioSigRZ software is streamlined and optimized for ABR and DPOAE screening. The software provides a simplified interface for selecting stimuli and configuring how the response will be recorded and processed.

DPOAE

Two tones are typically presented at multiple frequencies to target specific areas of the subject's hearing range.

Out-of-the-Box Experiments

When the software is installed, out-of-box an experiment file for DPOAEs is stored at:

C:\TDT\BioSigRZ\Configs\DPOAE

The default values used in the pre-configured experiment are set to values suited to typical experiments. Your protocol or circumstance may differ from these values but these will work as an example or a starting point and can be modified to fit the needs of your lab.

To open the DPOAE experiment configuration:

1. Launch BioSigRZ

2. Click the menu File → Open Config. File

3. Browse to and open the following file:

   C:\TDT\BioSigRZ\Configs\DPOAE\Root_DPOAE.acf

   Two tones that are about 20% apart will be presented continuously. Distortion-product data will be collected every 20.971 milliseconds and averaged 512 times.

   DPOAEs will be measured at the following center frequencies(Fc): 4000 Hz, 8000 Hz, 16000 Hz, and 32000 Hz.

   The tone frequencies will be F1 and F2, are calculated using the center frequency where F1 is Fc * 0.909 and F2 is Fc * 1.09. This yields frequencies of primary 1, named Tone 1, and primary 2, named Tone 2, that are geometrically centered about Fc.

   The Level of the two primary tones will remain equal and will vary with each frequency from 80 dB SPL to 20 dB SPL in 10 dB decrements.

   This DPOAE test is designed to measure the level of the "cubic difference tone." which is at 2F1-F2.

The Stimulus Settings

The default stimulus settings represent a typical configuration and should be fine to begin, but you may eventually want to make adjustments.

The stimulus setting dialog boxes can be opened by clicking Setup → Stimulus.

The setting notes below provide information about each setting.

Setting	Notes
Enable Ch2	Enabled
CH1	DPOAE1.sig
CH2	DPOAE2.sig A complete list of signal parameters and variables from the .sig file are added to the BioSigRZ configuration file. During stimulus presentation, the variables change as a function of the SigGen Index (SGI), which is a set of variable conditions. The order of the presentation is called the stimulus schedule. You can access this schedule and choose to omit specific SGIs, if desired. See Modifying the Stimulus for more information on modifying the standard protocol.
Speaker Calibration	Leave blank for now All speakers have some variation in output across frequencies. When you use a speaker with a known frequency response, you can adjust the stimulus output for these known frequency characteristics. A USB drive with a speaker-specific calibration file is provided with your MF1 speaker. You will need to copy that file to the following directory: C:\TDT\BioSigRZ\TCF. After the file has been copied to this directory you will be able to select it from a list in the Stimulus Channel Setup. You can also make your own .tcf calibration file by following the instructions in BioSigRZ Manual The first time you run a DPOAE, we recommend skipping this step and any other calibration until after you have been able to successfully record a response. If the system has not yet been fully tested, small mistakes in calibration can become more difficult to diagnose. It is important to make sure everything else is working before calibrating.

The Acquisition Settings

The default acquisition settings should be fine to begin, but you may eventually want to make adjustments.

The acquisition settings dialog boxes can be opened by clicking Setup → Acquisition.

The setting notes below provide information about each setting.

Setting	Notes
Response Record File	All the data collected and displayed in the History plot during the DPOAE test are stored in a response record file (.arf). By default the file will be saved at: C:\TDT\BioSigRZ\ You can specify a name in the setup window or select the Prompt for File Name check box to be prompted for a name before each recording session. You will be prompted each time you click Begin.
Setup Inputs|Source	Audio A/D
Number of Averages	128 You need enough responses to get good signal quality and few enough to minimize the time to complete testing. For DPOAEs, the typical range is 64 - 128 averages.
Gain	1 The DPM1 microphone system connects directly to the RZ6 for acquisition. You must also set the Amp/Bypass switch on the RZ6 face to BYP (bypass).
Microphone Calibration	Choose the DPM1_600mV.tcf file that will match the history plot units to dB SPL. See Converting dBV to dB SPL for related information.

Auto Cursoring

The auto-cursor feature can place up to 10 cursors on each acquired trace as a mathematical function of a variable or at a specific frequency. BioSigRZ supports automatic feature finding to minimize the amount of manual cursor manipulation that has to be performed after data acquisition. Cursors are defined from the Setup menu, Auto Cursors command. Available choices include features such as peaks, valleys, zero-crossings, absolute positioning, and more. See the BioSigRZ Manual for more information on using Auto Cursor.

This experiment has auto-cursor pre-configured to mark F1, F2, and 2F1-F2 so they can be easily viewed and extracted later for analysis. After DPOAEs are acquired, you can add or edit cursors in the Edit Cursor window. This window is opened when you double click a trace (waveform) in the History or Worksheet plot.