The use of masks reduces communication tools for people with hearing problems; however, their correct use protects against infection by COVID-19 and other diseases that are transmitted through small droplets produced when infected people cough, sneeze or talk, which is why they have become indispensable during the pandemic, said Antonio Soda Merhy, an academic at the Faculty of Medicine (FM) of the UNAM.
During the health emergency, patients have had to cope with the situation as they can: taking distance, requesting that the interlocutor speak louder, or speaking slowly. That is why it is important for the population to be patient and help facilitate communication, suggested Soda Merhy.
The fact is that the mask "deforms" the voice and lowers the decibels to those who listen to us; moreover, it prevents us from seeing the mouth and facial expression, essential for someone with hearing impairment to be able to read lips or better understand his interlocutor. Its use becomes a disadvantage at work, school, and in relationships with other human beings, he warned.
The specialist recalled that in medical terms, hearing impairment is described as hypoacusis and has different degrees. Someone with normal hearing perceives from 0 to 20 decibels; with this condition, from 20 to 40; medium, from 40 to 60; severe, from 60 to 80; and profound, more than 80.
The causes of hypoacusis, explained by the otolaryngologist, can be congenital or acquired. In the first group are children who are born with poor hearing, and in the second group are people who lose the ability to hear due to various diseases. "Here the important thing is that someone who is born with hearing acquires language; those who are not, become deaf-mute patients."
According to the World Health Organization in the world, there are approximately 70 million with this condition; more than 80 percent live in developing nations. "In our country, more than 10 million inhabitants could present some degree of hearing impairment," said the university professor.
In this regard, the specialist explained that the anatomy of the ear is divided into external, middle, and internal: the external ear is made up of the pinna and the auditory canal that ends in the eardrum; in the middle ear there are three ossicles (hammer, anvil, and stirrup); and the internal ear is made up of the cochlea or snail and the labyrinth (different nerves).
The hearing takes place when the sound wave enters the eardrum, which moves the ossicles and the stapes to the liquid of the inner ear; up to this point, the stimulus is mechanical. When mobilizing the liquid, the snail works as an energy transducer that converts the stimuli into bioelectrical waves, which through the auditory nerve are sent to the cerebral cortex where they are processed to obtain the auditory sensation. Accordingly, hearing losses are conductive when the problem is in the outer or middle ear and sensorineural at the inner ear level.
"When there are problems in the external and middle ear, and the sound wave does not reach the inner ear, it is called conductive hearing loss, because the conduction of sound is interfered either by a cerumen plug (wax that is produced in the external auditory canal), or lack of development of the same; in the middle ear, by perforation of the tympanic membrane, presence of mucus or pus and caries or fixation of the ossicles. And if the problem is at the level of the inner ear, it is a sensorineural hypoacusis".
In the first case, there are several treatments: enlarging the canal, replacing the tympanic membrane or placing a graft to correct it if it is perforated, or placing a prosthesis in place of the ossicles. In the second type, when a person is born without hearing, or when hearing is progressively lost due to aging, hearing aids or hearing aids can help. However, if it is severe or profound, they are no longer useful.
One of the most significant advances in otology and medicine in this area is the "revolution" of cochlear implants because a damaged neuroepithelium is replaced by an electrical device. In this way, the destiny of a person can change from being deaf-mute to developing normal language without having to go to special schools, study, work and pay taxes; that is the cost-benefit relation, Soda Merhy emphasized.
The university expert commented that for the mouthpiece not to be an obstacle in communication, mouthpieces can be designed with a window of transparent material at the level of the mouth so that lips can be read; in fact, they are already used in Spain in the deaf-mute community. "They are tools that are being created to try to replace a hearing loss that is accentuated with the mask, and to try not to make it so."
He emphasized that patients with hearing failure who did not frequently use the hearing aid in quiet places, now use it more. The expert recommended avoiding places with noisy environments.