What Is Neuroplasticity?
Neuroplasticity refers to the brains remarkable ability to respond and change by re-organising it’s structure, function and connections. This includes changes that occur as a result of maturation, learning, sensory stimulation, sensory deprivation, injury, and disease.
Neuroplasticity & Hearing Loss…
When an individual begins to lose their hearing, their brain also starts to change because of this loss. It is important for Audiologists to understand this, because it can actually help with the fitting of hearing aids or cochlear implants. For example, one study found that in infants with hearing loss, their cortical auditory evoked potential was outside the normal limits of a child that age. After being fitted with hearing aids, this response fell within the normal limits. Measuring this neuroplastic change can also identify what type of intervention is needed.
The same study showed another case of a child born prematurely resulting in a diagnosis of Auditory Neuropathy Spectrum Disorder. They found that their cortical auditory evoked potential was significantly outside the normal limits, and hearing aids did not do anything to bring it down. Within several months of having a cochlear implant fitted, it fell within the normal limits. Therefore, by looking at the way hearing loss alters the brain, audiologists can see which type of intervention would be more suitable for each individual.
Another interesting way in which the brain changes due to hearing loss is called cross-modal neuroplasticity. When auditory cortical areas of the brain are deprived of normal input due to a hearing loss, areas of the brain which normally process sound are “repurposed” by other intact areas. Visual and somatosensory areas of the brain repurpose auditory anatomy for their own processing. For example, visual stimulation in the normal hearing individuals expectedly localizes in occipital (visual) cortical regions. However, visual stimulation in people with a hearing loss localizes in occipital (visual) cortical regions as well as temporal (auditory) cortical regions. This is known as cross-modal reorganisation.
In addition to this, individuals with untreated hearing loss show recruitment of the frontal cortex during these tasks. The recruitment of this area could indicate an increased effort or cognitive load. These previous studies did show that through intervention with hearing aids, this cross-modal reorganisation can be reversed AND they can help make significant improvements in an individual’s cognitive performance.
If you have found this interesting, you can read about the studies discussed above by clicking here.