Memory disorders|If the important cells of the inner ear are destroyed, the brain’s receptor for sounds is broken
The summary is made by artificial intelligence and checked by a human.
Hearing loss can impair brain health and increase the risk of memory disorders.
A hard of hearing person loses contact with other people and becomes socially isolated.
Hearing loss is a common long-term disease of people over 70 years old.
A cochlear implant can reduce the risk, but requires surgery and rehabilitation.
Memory disorders one of the risks has been overlooked. It’s hearing loss that can do a surprising amount of damage to brain health. That’s what the professor says Aarno Dietz from the University of Eastern Finland.
The first explanation for why hearing loss can be related to memory disease is kind of understandable. A hearing-impaired person loses contact with other people, and therefore brain stimuli are reduced.
Professor Aarno Dietz
“The first symptom of a person’s hearing loss is difficulty understanding speech, especially in background noise,” says Dietz.
“For example, he is no longer able to participate in a conversation with several people. Thus, even in the early stages of hearing problems, a person can become socially isolated.”
Usually hearing loss is caused by the fact that the sensory cells in the inner ear, or the so-called hair cells, degenerate with age. In medicine, we talk about sensory-type or sensorineural hearing loss.
It often starts already in middle age, but usually progresses slowly, so a person may adapt to the problem. Hearing loss is one of the most common long-term diseases of people over 70 years old.
“Unfortunately, it is often considered an inevitable part of aging and not something that can be rehabilitated to maintain social participation, increase activity and possibly even reduce the risk of memory disorders,” says Dietz.
Hearing loss middle age is also a significant risk factor for dementia, the medical journal Lancet’s expert commission estimated in the summer in his report.
As the population ages, hearing loss can be expected to become more common in Finland as well. Effective treatment for hearing loss is included in the recent Käypä treatment recommendation for memory disorders.
The connection between hearing loss and memory disorders has been observed in many epidemiological studies, where the connections between the issues are clarified with extensive data. It is therefore a connection, i.e. a correlation, not a direct cause and effect relationship.
However, there is also evidence that long-lasting absence of auditory stimuli causes permanent structural changes in the brain and its functions.
In hearing loss, the gray matter of the brain even decreases in the temporal lobe, frontal lobe and hippocampus. The functions of the cerebral cortex are also reorganized.
in Kuopio a study funded by the Academy of Finland is about to start, the purpose of which is to find out the effects of effective hearing rehabilitation on brain health.
In addition to brain imaging, the research investigates, among other things, with the help of electroencephalograms, how the regular use of hearing aids affects the brain’s auditory pathways.
According to Dietz, in a recent US study, the use of a hearing aid reduced the risk of memory disorders, at least in those subjects who had other risk factors for memory disorders.
Mild and moderate hearing loss can be corrected first with a traditional hearing aid that amplifies the sound acoustically.
In sensorineural hearing loss, the hair cells of the inner ear partially do not work. Therefore, acoustic amplification of sounds can cause sound distortion, which hinders hearing.
Therefore, in more severe hearing loss, simply amplifying the sounds is not always enough.
“If the amplifier, i.e. the inner ear, is partially or completely broken, installing a preamplifier, i.e. a hearing aid, does not necessarily help,” Dietz compares.
“Correcting hearing with a hearing aid is not the same as correcting a refractive error with glasses. The brain has to learn a new way of listening with hearing aids, and it can take a few months. Occasional use of hearing aids is usually not beneficial.”
Dietz also speaks in favor of cochlear implants, if the patient no longer gets enough benefit from the hearing aid. The implant must be installed in the inner ear during surgery.
Cochlear implants differ from sound-amplifying hearing aids in that the sound is converted into an electrical signal.
The device has an electrode chain that is inserted into the inner ear. The acoustic sound is converted to digital and the electrode irritates the inner ear electrically. The brain learns to recognize it as sound.
“With the help of implants, the risk of memory disorders can very well be reduced. Every time we have installed a cochlear implant on a person, I wonder how miraculously it works,” says Dietz.
A cochlear implant requires not only surgery but also the patient’s active rehabilitation and learning to hear in a new way. However, the brain is molded, Dietz reminds.
In Finland, about 2,700 people have a cochlear implant. The device with surgeries and rehabilitation costs more than 15,000 euros. In Dietz’s opinion, the price and effectiveness of the cost is comparable to artificial joint surgeries of the lower limbs.