Aspects of hearing loss
Hearing loss causes problems understanding in noisy and unpredictable listening environments. This is because the elevated threshold makes soft sounds inaudible. Also, temporal information and frequency information are often less useable.
Some people also have problems with recruitment, i.e. abnormal loudness growth. This can cause changes in loudness that is perfectly tolerated by persons with no hearing impairment to sound very dramatic to those with hearing loss.
These aspects of hearing loss are important because they affect how easy it is to organize, select, and follow a target talker in a competing background.
| Hearing loss dimension |
Description |
Consequence |
| Elevated hearing threshold |
Soft sounds not heard. |
Subtle speech or spatial cues not audible. |
| Recruitment |
Loud sounds appear as loud or even louder than without hearing loss. |
Changes in level in the environment will appear more dramatic to the listener and may be more uncomfortable. |
| Using detailed temporal information |
Hearing loss and aging also leads to less precise temporal coding in the auditory system. |
Interaural temporal cues are known to be important for localizing sounds in the left/right dimension. |
| Using detailed frequency information |
Peaks and valleys in a frequency spectrum cannot be analysed detailed. Especially narrow valleys are detected less reliably. |
Localizing sounds in the up/down and front/back dimensions becomes more challenging, as detailed spectral information at high frequencies is used for localization in these dimensions. |
Listening in complex environments can be challenging
Organizing the listening environment is challenging with hearing loss because the listener has reduced access to speech and spatial cues as well as a decline in sensitivity and frequency resolution. It requires undue time and effort to build a sufficiently detailed mental map of the environment.
Using selective attention is harder when the resolution of the mental map is poor. Particularly in noisy environments, when conversation is lively and more people are talking at the same time.
Reduced target enhancement
Following a conversation in a noisy environment can be challenging for a normal hearing listener. For hearing impaired listeners a similar amount of effort is typically required in a less noisy environment. This means the listener is not able to focus attention as efficiently as required in order to suppress information from unwanted sound sources.
As a result, the enhancement of a target sound, normally done by the brain, is less effective, because information about the target sound is mixed with information from disturbing sounds. This makes it difficult for the brain to identify which sound sources to enhance and which to suppress, making listening tiring and energy consuming.
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