TEN is a kind of masking noise that was created in such a way that the threshold for detecting a tone in the presence of this noise is the same for frequencies 250 – 10,000 Hz for normally hearing individuals. In an individual with hearing loss, when a pure tone falls in a cochlear dead region, the tone will only be detected when it provides enough basillar membrane vibration to be detected by a region in the cochlea with surviving inner hair cells and neural connections. TEN is used to mask these surviving regions, similar to masking during pure tone audiometry, so dead regions, or regions that will not respond, can be identified.

In individuals with sensorineural hearing loss, inner hair cells (IHC) within the cochlea are damaged. At times, this damage can be so extensive that IHCs in certain cochlear regions, along with their corresponding auditory neurons, may not function at all. These regions are often called cochlear dead regions. If a tone that should be detected in these regions is loud enough, however, it can be detected by surrounding regions. In this case, a response would be elicited during pure tone audiometry. Since thresholds in these regions can still be clinically obtained, it is difficult to determine if a dead region is present. In terms of clinical application, cochlear dead regions have a big impact on hearing aid benefit. If a cochlear dead region is present, traditional amplification may not provide benefit in that region. Patient’s may even report that amplified signals sound distorted.

TEN test was developed to provide clinicians with a quick and easy way to identify dead regions in the cochlea utilizing a special masking noise. 

Pure tone signals can be heard in adjoining hair cells if the signal is loud enough; as a result of this, it is not possible to use Pure Tone Audiometry to identify dead regions in the cochlea. Rehabilitation of the hearing loss, as well as provision of more accurate information for hearing aid fittings, are just some of the reasons that TEN testing should be performed. 

The TEN test is easily accessible in the Measure software. A clinician would present a pure tone sound through Channel 1 and a continuous masking noise through Channel 2. The intensity levels should be set in accordance with the following rules: 

For frequencies where hearing loss is up to 60dBHL the TEN level should be set to 70dB 

For frequencies where hearing loss is 70dB or more the TEN level should be set to 85dBHL. 

If the TEN sound is too loud or the maximum TEN level is reached of 90dBHL then the level should be set to the audiometric threshold of the frequency. 

In individuals with normal hearing, the threshold of the pure tone will be the same as the presentation level of the TEN noise. For those with hearing loss, but without a dead region at that frequency, the threshold of the pure tone in the presence of TEN noise will be slightly above that of the presentation level of the TEN. In individuals with cochlear dead regions, the threshold of the pure tone in the presence of TEN will be 10 dB or more above the presentation level of TEN.