Have you ever heard about eardrum scaffolds or wondered how the brain reacts to different sounds? Get the latest scoop on hearing loss news in this latest Audicus blog!
This month has brought in new science developments that have given us a better look into how sound changes the brain as well as current methods for reconstructive ear surgery. New hearing loss updates include:
Sound Perception and Changes in the Brain
New research from the University at Buffalo and Johns Hopkins University School of Medicine has found that the cells responsible for transmitting sound signals to the brain look and behave differently when exposed to different sound levels.
Mice (and humans) are able to hear because certain chemicals called neurotransmitters are produced by the auditory nerve cells and sent to the brain after a sound stimulus. There is a limit to the amount of neurotransmitters auditory nerve cells can make, so exposure to loud, repetitive noises could force these nerve cells to use up a big proportion of their neurotransmitters. This makes it hard for a person to hear after extended periods of time in loud settings.
Cells that adapt to noise, however, can control their neurotransmitter levels. Scientists exposed mice to particular noises over a period of a week and found that auditory cells can actually send out smaller amounts of neurotransmitters so that they will have enough to last them during these extended noise sessions.
The structures also changed in a way that suggested these cells were increasing their reservoir of neurotransmitters. Mice that were switched from high to low sound settings eventually developed cells with similar behaviors and structures to cells that had never been exposed to loud noise in the first place. Learning the mechanism behind these cell adaptations can help scientists to develop new medicines that counteract human hearing loss during extensive exposure to loud noises.
Hearing Loss and Ear Drum Replacement
Researchers from the University of Pisa have created artificial scaffolds that can replace human eardrums. These scaffolds are modeled after the collagen structures found in the eardrum.
The eardrum lies between the external ear and the middle ear and can heal itself after minor damage that may or may not result in temporary hearing loss. However, extensive damage may warrant myringoplasty, a special type of surgery performed on the ear drum.
In this revolutionary eardrum scaffolding procedure, however, cell tissues are grown around a specialized polymer and then implanted in the ear. This new form of treatment can result in better recovery rates for individuals that have suffered ear drum damage due to bacterial infection.
High Frequency Hearing and Echoes
The University of Southampton has found the link between people that use echoes to detect objects and the ability to hear high frequencies. Scientists tested the ability of participants to use echolocation by asking them whether a certain object was to their left or to their right. These researchers used a virtual auditory space tool that removed non- echo sounds from the patients’ environment that would otherwise hint at where the object was hidden.
Individuals that displayed echolocation capabilities had exceptional sensitivity to high frequencies in both ears. Participants that had good hearing in only one ear were less successful at detecting objects. This amazing ability is similar to the methods that bats and dolphins use to pinpoint food and other objects.