The Brain and Hearing Loss

When we think of the word ‘restructuring’, we don’t normally link it to the brain, but recent studies show that is precisely what occurs when we start to experience hearing loss.  This new information is enlightening us as to the connection between hearing loss and dementia and Alzheimer’s disease, which could have long term effects on hearing loss screening and intervention.

The study looks into neuroplasticity – the way in which the brain restructures itself by forming new neural connections throughout our lives – and how it causes the brain to adapt after hearing loss, which in effect is the brains ability to change at any age. The mainstream belief was the brain was unable to change past childhood development, however, this has been proven to not be the case. In hearing loss cases, the part of the brain that is designated to hearing can be restructured to serve other functions.

Throughout the study, adults and children with varying degrees of hearing loss had up to 128 sensors attached to their heads to measure their brain activity in response to different sound stimuli. By doing this, the scientists were able to map the way in which the brains of people with hearing loss respond in comparison to those with normal hearing.

The studies showed that when hearing loss occurs, areas of the brain that were dedicated to hearing get restructured to process vision or touch. This phenomenon is known as cross-modal cortical reorganization, and it is indicative of the brains ability to compensate for the loss of other senses by rewiring itself. This can be seen as a positive outcome in certain cases like people have lost their sight, and their brain compensates by expanding the sense of smell or hearing; however the reorganization for hearing loss can have a seriously detrimental effect on cognition.

Even mild hearing loss can lead to cognitive decline, and early intervention in the event of any level of hearing loss is vital to maintaining strong cognitive function. French studies that were conducted indicate that cochlear implants in elderly patients enabled their cognitive skills to improve as their speech comprehension improved.

When one suffers from hearing loss, the compensatory adaptation system impacts the brain’s ability to process sound, which reduces the ability to comprehend speech. Even if hearing loss is mild, the hearing parts of the brain start deteriorating due to the parts of the brain used for higher level cognition compensating for the weaker parts. The compensation for the loss of hearing leaves those areas unable to do their primary function, thus the higher-level decision-making parts of the brain are being used to simply hear sounds. This compensation may explain the correlation between age-related hearing loss and dementia.

Due to this correlation, even the early stages of hearing loss need to be treated seriously and quickly, as the brain starts to restructure as soon as the deterioration begins. The solution could be as simple as early hearing loss screening, as early intervention is imperative in preventing long term cognitive issues later on.

Hearing loss is one of the most common conditions experienced by older adults, with one in three adults between the ages of 65 and 74 experience some degree of hearing loss, and nearly 50 percent of people over 75. Yet, less than 1 in 4 people who need hearing aids get them, and the average time for someone to find treatment is 7 years. A great degree of cognitive decline can occur in that time, so seeking treatment as soon as the hearing decline is experienced is imperative to maintaining cognitive health.