Some people who have average hearing capabilities, still tend to have difficulties with understanding speech noises. It may be labeled under the phrases auditory processing disorder, or hidden hearing loss. Even with significant efforts in research, there is still little information explaining this hearing experience.
Predictions and Test Subjects’ Results
The theory of hidden hearing loss predicts that if adults who experience normal hearing standards but struggle with hearing noise, may indicate that the primary ear-to-brain connections have deteriorated. This theory was tested on 194 adults who have average hearing capabilities, or audiograms.
First, a common measurement of hidden hearing loss - known as ABR Wave I - was conducted, in addition to surveys about each participant’s past exposures to noise and hearing. They also analyzed subjects on the QuickSIN (a Quick Speech in Noise test) to measure the ability, or inability, to comprehend speech with background noise. They concluded that there was no evidence that Wave I measurements were dissimilar between test subjects who reported a significant noise exposure and those who did not. They also did not find data supporting any parallels between speech-in-noise and Wave I amplitudes.
Another hypothesis, which asked why listeners have difficulty hearing noise, was tested for those with poor high-frequency hearing. This theory argued that damage in hair cells beyond the bounds measured by a standard audiogram weakens speech comprehension under difficult listening environments. There are indications that very high-frequency speech cues contribute important repetitions to speech in loud atmospheres. The test subjects indicated that listeners exposed to noise had marginally poorer high-frequency hearing thresholds, and there was no link to speech-in-noise efficiency.
The test subjects had sought out help from an audiology clinic, so they were more likely to suffer from one or both of the theories. But the conclusions agree with many other extensive reviews of hearing-in-noise abilities that recommend dismissing external factors.
This conclusion suggests that hidden hearing loss and high-frequency hearing loss do not jeopardize hearing-in-noise capabilities in a general population.
Which factors control hearing-in-noise difficulties?
The central nervous system for auditory encoding and general cognitive abilities may be a factor that controls hearing-in-noise difficulties. Take for instance listeners who have better hearing-in-noise capabilities. They have stronger abilities to convert important speech characteristics such as harmonics, pitch, and timing. Exercises to improve hearing also increases the elements of auditory encoding. Cognitive abilities, like attention and working memory, are associated with hearing. These cognitive abilities process sound for us to understand.
A functioning auditory periphery is needed to hear. Basic elements in the neural development of sound, in addition to cognitive abilities, most likely control speech-in-noise awareness. With that said, these should be important considerations during clinical assessments and rehabilitation procedures.
If you, or a loved one, have difficulty hearing noise or understanding speech, please contact us at Pure Sound Hearing Aids for a free hearing test and consultation.