A study revealed that single-sided deafness (SSD) is closely related to issues concerning brain plasticity, specifically the alignment of brain hemispheres.
It was then determined that hearing optimization may and should be an option for patients, as the participants suffering from SSD had different neurological responses to hearing stimuli through their working ear depending on where the sound was coming from.
Studying hearing loss
The background of the research was based on studies that showed how the human brain is able to undergo plastic change. Deafened animals display the ability to reorganize their sensory abilities in order to deal with their impediment. This is also true for the functions associated with the auditory cortex, where the researchers proved that humans also display similar cross-sensory brain plasticity.
A number of 13 adults suffering from SSD and 13 control participants were reviewed during the study by researchers from the University of California.
The tests involved registering the response within the auditory cortices ipsilateral and contralateral to different sound frequencies; researchers played light sounds on both ears of the participants and took note of which one was disabled due to SSD, ipsilateral referring to a same-sided hemispherical response and contralateral to an opposite side response.
The study also involved the illustration through computer imaging of the areas where the brain had the greatest activity when the 0.5 kHz to 4 kHz sound was played.
The results displayed a significant difference when the sounds were played next to the disabled ear, as the brain showed a higher level of neurological activity in the contralateral hemisphere when compared to ipsilateral stimuli. For control patients, the brain activity appeared to be the same whether the sound was played on the right or left ear.
It was determined that, even if the brain is able to adapt to using just one ear, this behavior may lead to more severe hearing deficits as the other parts of the brain keep processing information by using both brain hemispheres.
More research is to take place, but the study led researchers to believe that there may be a solution through brain stimulation. Even if it’s not able to completely restore the hearing process on the disabled ear, it may be able to prevent further damages to the auditory cortex in both hemispheres.
Source: The Laryngoscope