These technologies help the hearing impaired regain a new "voice"
On March 2, the World Health Organization released the "World Hearing Report."
The report shows that hearing loss affects more than 1.5 billion people worldwide, of which 430 million people have moderate or above hearing loss.
By 2050, one in four people is expected to have hearing problems, nearly 2.5 billion people will have some degree of hearing loss, and at least 700 million of them will need rehabilitation services.
March 3 is the National Ear Day, and the theme of this year’s Ear Day is "Everyone Enjoys Hearing Health".
Viral infections, congenital structural abnormalities, side effects caused by drugs, and decline in old age... hearing impairment or even deafness caused by these factors will cause people to fall into "silent pain."
Fu Yong, director of the Department of Otolaryngology, Children’s Hospital of Zhejiang University School of Medicine, said that for the prevention and treatment of hearing impairment, in addition to maintaining healthy ear habits in daily life, relevant screening, prevention, diagnosis and treatment techniques need to cover more ears. The blind spot of disease prevention and treatment.
In recent years, with the continuous upgrading of hearing aids and early screening technology, more and more hearing impaired people have been able to regain a new "sound".
Hearing loss can be compensated by surgery and technology
On March 2, the World Health Organization released the "World Hearing Report."
The report shows that hearing loss affects more than 1.5 billion people worldwide, of which 430 million people have moderate or above hearing loss.
By 2050, one in four people is expected to have hearing problems, nearly 2.5 billion people will have some degree of hearing loss, and at least 700 million of them will need rehabilitation services.
Nearly 80% of hearing-impaired people live in low- and middle-income countries, and most hearing-impaired people do not have access to intervention treatment.
Fu Yong explained that there are two ways of sound conduction, one is conduction through air, and the other is conduction through the skull. Under normal circumstances, air conduction is the main one.
Sound waves are transmitted to the tympanic membrane through the external auditory canal, causing the tympanic membrane to vibrate.
The vibration of the tympanic membrane will drive the vibration of the ossicular chain composed of three ossicles inside the tympanic membrane.
The ossicular chain then conducts the mechanical energy of the sound waves to the lymph fluid in the inner ear, causing the endolymph fluid in the cochlea to vibrate.
The vibration of the endolymph fluid will drive the vibration of the basement membrane on the cochlear and cochlear axis. The vibration of the basement membrane converts the mechanical energy of the sound wave vibration into electrical signals, which are transmitted to the auditory nerve through the nerves of the spiral ganglia, and finally to the auditory sense of the brain The cortex forms the sense of hearing.
This is the normal air conduction path of sound.
In addition to perforation of the tympanic membrane, the cause of hearing impairment caused by chronic otitis media is usually accompanied by the destruction and loss of the auditory ossicles.
For most patients with chronic otitis media with varying degrees of hearing impairment, artificial ossicular implant surgery can be performed.
Ossicular implant surgery is mainly for patients with chronic otitis media or other conductive hearing loss.
It is worth mentioning that in recent years, endoscopic minimally invasive surgery has gradually emerged. With its advantages of clear surgical field, small wound, short operation time, and quick postoperative recovery, it has unlocked new operating methods for artificial ossicular implant surgery. .
The cochlear implant surgery is mainly used for patients with severe or very severe sensorineural hearing loss.
In these patients, the function of the cochlear hair cells is impaired, which leads to errors in the sensory nerve conversion process. The cochlear implant does not rely on the remaining hair cells in the inner ear, and can directly obtain sound, which is encoded and converted into electrical signals to be transmitted to the spiral neuron cells. The transmission of level 4 neurons makes the cerebral cortex produce hearing.
"Nowadays, this kind of coding technology is still improving, hoping to produce more accurate and natural sound." Fu Yong introduced.
"In my country, cochlear implant technology has enabled tens of thousands of patients with bilateral severe and severe sensorineural hearing loss to regain hearing and restore communication skills." Yang Beibei, director of the Department of Otolaryngology, the Second Affiliated Hospital of Zhejiang University School of Medicine Said that the new technology of cochlear implant surgery enables children with congenital severe and severe deafness to avoid dumbness due to deafness, enabling them to go to school, education and even employment just like children with normal hearing.
"Patients with myopia can wear glasses or undergo eye surgery, but there is no specific medicine. The same is true for the ears, which are also sensory organs. Patients with hearing loss undergo medical treatment or surgery, and when the improvement is not obvious, they need to be fitted with hearing aids to compensate for hearing ." Yang Beibei introduced.
Nowadays, with the support of technologies such as intelligent noise reduction and wireless Bluetooth transmission, hearing aids have been greatly optimized in terms of wearing style and sound quality, in addition to being more compact and concealed.
Various methods to screen out patients with potential hearing impairment
To achieve "everyone enjoys hearing health", in addition to accurate diagnosis and treatment of known patients, screening of patients with potential hearing impairment is also essential.
According to statistics, about 60% of deaf patients are related to genetic factors, and there are also high gene mutations that cause deafness in the normal population.
Genetic testing of deafness is currently one of the most effective etiological analysis methods, which can provide guidance for the treatment, prevention and prognosis of deafness.
In 2002, the former Ministry of Health and the Chinese Disabled Including neonatal disabilities such as drug-induced deafness.
In September 2009, nine genetic test kits for genetic deafness developed by the Beijing National Engineering Research Center of Biochips and the Chinese People's Liberation Army General Hospital were approved for use.
By the end of 2018, more than 3.2 million newborns across the country had undergone genetic screening for hereditary deafness, and received deafness risk assessment and guidance.
In addition, for infants with congenital hearing loss, newborn hearing screening, children's hearing screening, and observation of children's hearing and speech development are also important means for early detection of their hearing loss.
Fu Yong introduced: “Congenital hearing loss accounts for about one-thousandth to three-thousandths of newborns in our country. Damage to the outer, middle, and inner ear structures and auditory nerves, as well as damage to the auditory center, can all lead to hearing loss. loss."
In 2004, the former Ministry of Health issued the "Technical Specifications for Hearing Screening of Newborns", which has been updated several times, which has accelerated the popularization of hearing screening for teenagers and children across the country.
According to reports, the currently used hearing screening instruments in China mainly rely on otoacoustic emission and automatic auditory brainstem response for hearing screening.
Otoacoustic emission is the inverse process of sound waves entering the inner ear. Sound energy originates from the cochlea, travels through the ossicles and tympanum, and enters the external auditory canal. It can be detected by a sensitive microphone. Its occurrence is related to the normal function of outer hair cells.
"Traditional newborn hearing screening can be carried out objectively, quickly and non-invasively within 72 hours after birth, in natural sleep or in a quiet state." Fu Yong said.
Research on new hearing compensation measures is ongoing
In June 2020, Liu Ruqian's team from the Broad Institute in the United States and researchers from Harvard Medical School used the latest single-base gene editing technology to successfully correct a genetic error that caused deafness in the mouse inner ear, allowing the mouse to recover part of it. hearing.
This first successful example of using genome editing technology to repair recessive disease-causing mutations has convinced researchers that, when the method is perfected, it may help improve the hearing of deaf patients.
In fact, the scientific community has been exploring treatments that are different from existing hearing compensation measures.
As early as 2003, the Deaf Molecular Diagnosis Center of the Chinese People's Liberation Army General Hospital took the lead in conducting a national molecular epidemiological survey of the deaf in China.
The results of their research and analysis showed that GJB2, SLC26A4 and mitochondrial genes are the most common pathogenic genes that cause hereditary deafness in my country. The total carrier rate in the normal population in China is 5% to 6%, which are respectively related to congenital deafness and late onset. The clinical onset of deafness and drug-induced deafness are closely related.
In addition, "Through researches such as inducing the development of stem cells into cochlear hair cells or spiral neuron cells, some synaptic connection nerves have been reconstructed in animal experiments, and the animals have restored part of their hearing, but they have not yet entered the stage of human experiments. "Fu Yong said.
He believes that there are still certain limitations and difficulties in carrying out relevant human experiments.
However, with the discovery of more deafness mechanisms and the improvement of treatment technology, humans will have more initiative in the competition with hearing impairment and deafness.
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Identify gene defects to reduce deafness caused by drugs
Many people believe that only the parents of hearing impaired can give birth to deaf children.
But clinical data show that 90% of deaf children have normal hearing from their parents.
However, 6 out of 100 people with normal hearing have deafness genetic defects.
If people with the same type of deafness genetic defects are married, their chances of having a deaf child will be much higher than that of ordinary people.
Studies have shown that genetic defects among all causes of deafness are the main reason for the birth of deaf children, accounting for nearly 60%.
Among a large number of patients with late-onset hearing loss, late-onset deafness, which is extremely sensitive to ear pressure, commonly known as slap deafness and drug deafness, cannot be detected in traditional newborn hearing screening.
However, in the later growth process of such patients, due to the external deaf environment or the use of aminoglycoside antibiotics such as gentamicin and kanamycin, the hearing will be irreparably damaged.
What's more frightening is that drug-induced deafness is inherited from the maternal line, which means that if a mother carries a drug-induced deafness gene mutation, her children will be deaf because of the use of such drugs.
Through genetic testing for hereditary deafness, it can be determined whether a person carries the defective gene.
Genetic testing for hereditary deafness after the baby is born can intervene in the best possible intervention, and it can also allow doctors to avoid contraindicated drugs and reduce the chance of deafness in the baby.