Hearing impairment … the strongest factor in dementia


Riyadh: Dr. Abeer Mubarak

The medical community continues to recall the importance of medical treatment for hearing impairment and deafness in children and adults, and give it a greater importance than those with this health problem value.

Dementia factors

In the August 8 issue of the Lancet medical journal, The 2020 Lancet Commission on Dementia Prevention, Intervention, And Care stated that among the group of risk factors Modifiable Risk Factors Because of the high risk of developing dementia, which is twelve factors, “hearing impairment” occupied the highest percentage in the depth of the health impact to cause the risk of dementia and poor memory.

The report explained that the following set of key elements: low level of education, high blood pressure, poor hearing, smoking, obesity, depression, physical inactivity, diabetes, lack of social contact, air pollution, head injuries in accidents, and alcohol use are, in fact, ethnic. Ten risk factors, each of which is “adjustable” for developing dementia, and that targeting all attention, medical education about it for the general public, and remedial work to mitigate its health effects, results in reducing the risk of dementia and delaying it by more than 40 percent.

When the researchers assessed the contribution of each of these twelve risk factors to dementia, expressed in terms of the Population Attributable Fraction, the hearing loss had the greatest effect.

Hearing and memory impairment, and the

term PAF means “the rate of occurrence of a health problem (for example, dementia) among people, due to the presence of a specific risk factor (hearing impairment, for example).” This means that the “depth” of the memory repercussions of hearing impairment are the most damaging and causing dementia compared to the likelihood that any of the other factors will cause dementia.

“The evidence that hearing loss is one of the most important risk factors for dementia is very strong,” said Professor Jill Livingston of University College London and chair of the report’s team. New studies show that correcting hearing loss using a stethoscope negates any future increased risk of hearing loss on memory.

“Hearing loss is a common problem, and it carries a high relative risk of developing dementia, so it contributes to a great extent in cases of dementia,” he added. This is an aspect that we can reduce relatively easily by encouraging the use of hearing aids. It should be more accessible, more comfortable, and more acceptable, and this could make a big difference in reducing dementia cases in the future. ”

They explained that relationship by saying that hearing impairment may lead to a continuous and progressive decline in cognitive perception (Cognitive Decline) as a result of a low level of cognitive stimulation (Cognitive Stimulation). The researchers presented a group of studies that followed for long periods, some of them more than 25 years, the relationship of hearing impairment and dementia. They said: “The long follow-up periods in these studies indicate that the use of hearing aids (Hearing Aid) to treat hearing loss is a preventive way to reduce the risk of dementia.”

Cognitive decline,

say researchers from the “Mayo Clinic”: “Hearing loss may significantly affect quality of life, and older adults with hearing loss may express feelings of depression.” Because hearing loss causes difficulty communicating, some people may feel isolated, and hearing loss may be associated with impairment and cognitive impairment (cognitive impact). The link between hearing loss, cognitive impairment, depression and isolation is still being studied extensively. Preliminary research indicates that treating hearing loss can have a positive effect on cognitive performance, especially on memory.

“Hearing loss may also contribute to symptoms of dementia,” says Dr. Colin Driscoll, a head and neck surgeon at the Mayo Clinic, saying, “We have always thought of hearing loss as just one of those things that happen as we age, but hearing loss can begin.” By forming a series of health problems, including making dementia symptoms worse. And he continues, saying: “If you suffer from hearing loss, you are now devoting more and more of your cognitive ability to trying to understand what is being said, and the mind then works for additional time in order to sort the words and understand the sentences, that is, it makes an extra effort that should have been done automatically in normal cases. .

So if I were to exhaust a whole range of my energy to apply to this simple task of listening and understanding speech, I would not have time to do my other activities.

Hearing loss does not cause Alzheimer’s disease or dementia due to structural disturbances in the structure of the brain (Structural Dementia), but rather dementia caused by a change in your cognitive ability. “There is evidence that improving hearing will improve cognitive perception, and we know that improving hearing reduces the risk of social isolation and depression,” he says. A simple hearing test, followed by appropriate treatment interventions, can improve your quality of life and your health.

Degrees of hearing

and the medical community classifies the extent of a person’s hearing impairment into four grades: mild, moderate, severe, or very severe. This is done according to the results of the audiogram chart when conducting the hearing tests. And in it, the level of hearing is measured in relation to the sounds of tones, speech sounds, in one or both ears.

According to medical sources, the use of “hearing aids” can help most people who suffer from mild to moderate “sensorineural” hearing loss in both ears.

As for the more severe levels of hearing loss, medical stethoscopes are not sufficient. The reason for this is that the impairment of sensorineural hearing in such extreme degrees causes distortion and amplification of sounds when using hearing aids, which makes the sound really louder but less clear. Even high-quality hearing aids can make the sound distorted if the inner ear has been severely damaged. At that time, a cochlear implant is useful.

The “cochlear implant” is an electronic device that is implanted by surgery to bypass the damaged inner part of the ear to stimulate the hearing nerve directly. A cochlear implant differs from medical stethoscopes that only amplify the sound, as a cochlear implant converts sound waves into electrical impulses that are transmitted through the nerves to the brain without the need for the inner ear to work, in a manner consistent with normal hearing.

In cases of very severe hearing loss in one ear without the other, a “bone conduction transplant” can be performed, which provides for the transmission of sound through the bone, from the damaged ear to the inner ear that operates on the other side of the head.

Various mechanisms of hearing loss

Understanding how sounds are heard helps to understand how hearing loss occurs. The ear consists of three parts; They are: the outer ear, the middle ear, and the inner ear.

The sound waves enter the outer ear to cause vibrations in the eardrum. Then the eardrum and 3 small bones inside the middle ear amplify these vibrations as they enter the inner ear. These vibrations then pass through a fluid inside the cochlear tubes associated with the neurons, and then the sound vibrations are translated into electrical signals that are transmitted to the brain by the neural pathway.

There are three main types of hearing loss: These are: “conductive hearing impairment”, “sensorineural hearing impairment”, and “mixed hearing impairment” for the first and second types.

Hearing impairment occurs as a result of damage to either the inner ear or the nerve pathway for hearing, which leads to the failure of electrical signals to be transmitted efficiently from the inner ear to the brain. As in cases of aging, genetics, birth defects, exposure to loud sounds for a long time, or sudden loud sounds, or taking some medications (such as the antibiotic gentamicin and others, Viagra, some chemotherapy drugs, high doses of aspirin and painkillers. Other, or anti-malarial drugs or diuretics), or because of some diseases that are accompanied by a high temperature.

And “conductive hearing impairment” may occur as a result of a defect in the outer or middle ear. That is, either: Hearing caused by a blockage in the outer ear canal, or as a result of an infection in the outer or middle ear, or an abnormal growth of bone or tumors. As well as when the eardrum is ruptured as a result of exposure to sudden loud sounds, sudden changes in pressure, perforation of the eardrum in any external body, and microbial infection.

Hearing test … from the sound of breathing to the roar of the plane

The ear doctors at Mayo Clinic report that the signs and symptoms of hearing loss include:

Disappeared speech and other sounds.

Difficulty understanding words, especially with background noise or crowds.

Difficulty hearing consonants.

> Repeated requests to speak more slowly, clearly, and loudly than others.

> The need to raise the volume of the television or radio.

> Withdrawing from conversations.

Avoid being in certain social settings.

In addition to the clinical examination of the ear and its visible parts, there are several types of “hearing tests” to evaluate both: the ability of hearing (hearing test) and the causes of weakness in it (Weber and Rennes test), if any.

Sounds consist of two main components: the intensity of the loudness of the sound, and the pitch of the velocity of vibration of sound waves. Therefore, the hearing test evaluates the sensitivity and accuracy of a person’s hearing capabilities in each ear according to the change in the intensity and pitch of the sounds.

The level of hearing impairment is measured in “decibels”, and the number given by the hearing test represents the lowest level of sound that a person can hear. According to measuring the intensity of the sound, the sound of normal breathing is 10 decibels, the whisper of speech is about 20 decibels, the sound of the refrigerator is 30 decibels, the normal normal conversation close up is about 60 dB, the dishwasher is 75 dB, the motorcycle is 90 dB, and the drill bit is about 110 dB. , The ambulance siren is about 120 decibels, the fireworks are about 140 decibels, the jet engine is about 180 db.

And a normal person can hear low levels of sound up to the level of 20 decibels. When the sound weakens to the point where the sound can only be heard between 25 and 39 decibels, there is slight impairment of hearing, and the person suffers from understanding the speech of the person speaking to him in loud places. Moderate hearing impairment is when the ability to hear sound is between 40 and 69 decibels, and the person suffers from difficulty understanding speech except by using a headphone device. And when a person can not hear the sound except between 70 and 89 dB, he has severe hearing impairment, and then he needs a cochlear implant in order to be able to understand speech. If there is a very severe weakness, that is, the volume must be higher than 90 decibels, then the person must either rely on lip reading to understand the speech of the person talking to him or use sign language with him or his cochlear implant.


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