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Step-by-step instructions for measuring masked thresholds in the TEN(ER3) The TEN(ER3) test for diagnosis of dead regions in the cochlea 1. Brian C. J. Moore, Brian R. Glasberg and Michael A. Stone This CD is intended for use in diagnosing regions in the cochlea where there are no functioning inner hair cells and/or neurones; these are called dead regions. The test is suitable for use with two-channel audiometers that employ Etymõtic Research ER-3A earphones. The test involves measuring the threshold for detecting a sinusoidal test tone presented in a special background noise called “threshold-equalising noise” – TEN(ER3). The noise is spectrally shaped so that the masked threshold, specified in dB HL, is approximately the same for all frequencies in the range 500 Hz to 4000 Hz, for people with normal hearing and for people with hearing loss without dead regions. The masked threshold is approximately equal to the nominal level of the noise specified in dB HL/ERB N, where ERBN stands for the equivalent rectangular bandwidth of the auditory filter. For example, a level per ERBN of 60 dB HL leads to a masked threshold of about 60 dB HL. Absolute thresholds in dB HL can be determined either using the audiometer or using the test tones on the CD. A reasonably high-quality CD player is required for this. The level per ERB N of the noise to be used depends on the severity of the hearing loss of the person being tested. If possible, the level per ERBN should be about 10 dB higher than the audiometric threshold in dB HL in the frequency region of interest. Levels up to 90 dB HL/ERB N can easily be obtained with most audiometers, but levels above 85 dB may be judged as unpleasantly loud by some hearing-impaired people. Both absolute thresholds and masked thresholds can be measured using standard audiometric methods. However a 2-dB final step size is recommended for measuring masked thresholds in the TEN(ER3). 2. 3. 4. 5. 6. 7. 8. Feed the left output from the CD player to the left (or A) line-level input on the audiometer, and the right output from the CD player to the right (or B) input. Select the left (A) input for channel 1 on the audiometer, and the right (or B) input for channel 2 on the audiometer. Play track 1, set the audiometer so that both line inputs are played continuously (press the interrupt buttons), and adjust both VU meters to read 0 dB. Turn off the two inputs (press the interrupt buttons). Mix the two channels, and direct the mixed channels to the desired ear (left or right). Set the desired noise level using the channel 1 control. The level in dB HL/ ERBN corresponds to the dial reading on the audiometer. Measure the masked threshold for each ear at each frequency, using tracks 2-8 of the CD, while playing the noise continuously (press the interrupt button for channel 1). The test-tone level is controlled via channel 2. The level in dB HL corresponds to the dial reading on the audiometer. Use a 2-dB final step size. Repeat steps 4-6 for the other ear, if desired. A dead region for a particular frequency is indicated by a masked threshold that is at least 10 dB above the absolute threshold and 10 dB above the TEN(ER3) level per ERBN. If a dead region is detected at one or more frequencies, it is recommended that the absolute threshold be re-measured for those frequencies, using the test tones on the CD, and a 2-dB step size, to check that the masked threshold is 10 dB or more above the absolute threshold. 2012, Brian C. J. Moore, Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB. The TEN(ER3) test for diagnosis of dead regions in the cochlea The TEN(ER3) test for diagnosis of dead regions in the cochlea Brian C. J. Moore, Brian R. Glasberg and Michael A. Stone Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK http://hearing.psychol.cam.ac.uk/ Track 1: Calibration tone on both channels: Use to set VU meters to 0 dB Duration: 5 minutes Track 2: 500-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 3: 750-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 4: 1000-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 5: 1500-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 6: 2000-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 7: 3000-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Track 8: 4000-Hz test tone on right channel, TEN(ER3) on left channel Duration: 9.5 minutes Brian C. J. Moore, Brian R. Glasberg and Michael A. Stone