Item No. 8105085 12/2013 Page 1 of 3
Quick Guide - TEN(HL) test in AC440
The purpose of this document is to provide a Quick Guide for instructions on how to administer the TEN test
with the AC440 Audiometry module in the Equinox
2
, Affinity
2
and Callisto™. This Quick Guide is based on a
white paper that was written for Interacoustics by Brian C.J. Moore (2009)
What is the TEN test?
The TEN(HL) test was developed to provide clinicians with a quick and easy way to identify cochlear dead
regions. The test consists of measuring pure tone thresholds in a special masking noise, called the TEN
(Threshold Equalizing Noise).
What is a dead region?
A dead cochlear region is defined as a region of the cochlea where there are no functioning inner hair cells
and/or neurons. (Moore, 2001). When a pure-tone signal “falls” into a dead region, it can be heard by
neighboring hair cells, if the intensity of the signal is loud enough. This is because the pure tone produces
sufficient basilar-membrane vibrations in neighboring areas of the cochlea, where there are surviving IHCs and
neurons. This phenomenon is defined as “Off Frequency Listening”. Clinically, this will present as a threshold
on the traditional pure tone audiogram, but it may not be the real threshold. It is not possible to use traditional
pure tone audiometry to determine if there is a dead region present; the TEN test was developed for this very
purpose.
When to do the TEN test?
Characteristics that could indicate the presence of a dead region (from Moore, 2009):
Severe to profound hearing loss
Absolute threshold is at a specific (suspected) frequency is 70 dB HL or greater
Steeply sloping hearing loss
Complaints of distortion
Extremely poor speech discrimination
Criteria for diagnosing a dead region (Moore et al) :
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