Generality
Hearing loss consists in the partial or total impairment of hearing, which can be classified as mild, moderate, severe or profound hearing loss.
To prevent hearing loss, a series of measures can be taken, but in some cases the process is impossible to reverse.
Diagnosis
The first diagnostic approach consists in gathering information on the medical history of the patient and his family, also investigating the behaviors that may have caused hearing loss (exposure to noise, use of ototoxic drugs, etc.). The doctor will ask the patient to report any symptoms associated with hearing loss (such as ear pain, tinnitus or dizziness), the approximate date in which it was first experienced and if it worsened over time.
The doctor then examines the ears and performs some simple tests to evaluate:
- The degree and characteristics of hearing loss (one or both ears);
- The cause of hearing loss (as far as possible);
- The most appropriate treatment options.
Otoscopic examination
During otoscopy an instrument is used, called an otoscope, which directs a light into the ear allowing examination of the tympanic membrane and the external auditory canal, in search of alterations such as:
- Obstruction caused by earwax, fluid or foreign body;
- Infection at the ear canal;
- Infection inside the middle ear (protruding red tympanic membrane);
- Fluid behind the eardrum (otitis media with effusion);
- Abnormalities of the ear canal or tympanic membrane (perforation, tympanosclerosis, presence of amber-colored fluid or blood, unusual lesions or growths);
- Collection of skin in the middle ear (cholesteatoma).
Referral to a specialist
After an initial evaluation, the doctor can refer the patient to an otorhinolaryngology specialist and a hearing care professional so that specific tests can be carried out that define the patient's ability to hear.
Bone and air conduction tests (tuning fork test) are used to place a first discrimination between conductive auditory disorders and nerve deficits (a tuning fork is a Y-shaped metal object that produces severe tonal sound waves when struck) . If you put a finger in your ears and speak slowly, you can still hear the voice, as the bones of the skull lead the sound to the cochlea, bypassing the middle ear. In a bone conduction test, the doctor places a tuning fork against the skull, placing it on the mastoid portion of the temporal bone (bony prominence behind the auricle); this test, called the Weber test, allows us to highlight sensorineural hearing loss. The test is complementary to the Rinne test, an audiometric-type exam that allows rapid assessment of a conductive disorder: the specialist touches the tuning fork to make it vibrate and positions it at about 2 cm from the ear ( air conduction test ); if the subject hears the sound with the tuning fork resting on the mastoid portion of the temporal bone, but not while it is held close to the auricle, the problem is located at the level of the external or middle ear. If, on the other hand, the subject does not respond to both stimuli, the problem must be attributed to receptors or auditory pathways.
Both tests represent rapid and easy to perform screening tests, but they do not replace tonal audiometry, which allows us to define the extent of hearing loss and to determine the underlying causes of the disorder. This procedure represents the most common hearing test: the subject hears a sound of varying frequency and intensity generated at irregular intervals; in the meantime, his answer is recorded on paper, the audiogram, which is compared with reference parameters. The audiogram is a standardized instrument that allows to record the subject's auditory threshold, through conduction by air and bone.
Neonatal screening program
Performing a hearing screening immediately after birth means identifying early hearing loss, although it is not easy to detect hearing loss in young children. An examination that is commonly used in these circumstances is the Acoustic Emissions Test (OAE). This test involves the insertion of a tiny probe in the outer ear. If possible, the test will be performed while the baby sleeps: the probe emits small sounds and controls to measure the corresponding response of the ear. If there is no reaction to the otoacoustic emission, it does not necessarily mean that the child has hearing problems, but further tests will be needed to investigate the causes.
Treatments
Hearing loss can have a significant impact on quality of life, affecting the ability to communicate and social skills. If the hearing is compromised, several treatment options are available, which depend on the underlying cause and the severity of the hearing loss.
- Conductive hearing loss There are many effective treatments for conductive problems . A help can be given by the simple increase in stimulation intensity, you can surgically repair the tympanic membrane or intervene on auditory ossicles, if damaged, artificially replacing them. Even in the case of a wax plug, hearing loss is reversible and the doctor can simply remove the obstruction.
- Sensorineural hearing loss . In cases where there is neurosensory damage, the hearing loss is permanent, but some options can still improve the ability to hear and communicate. These include: hearing aids, cochlear implants, language training and educational and social support.
Hearing aids
If hearing loss is caused by damage to the inner ear, a hearing aid can improve hearing ability by amplifying the perceived sound.
A hearing aid is an electronic device that consists of:
- a microphone (detects sound);
- an amplifier (makes the sound louder);
- a speaker (sends the sound into the ear so you can hear it);
- a battery (supplies power to the electronic components);
- volume control (increases or decreases the sound volume).
Modern hearing aids are very small and discreet and can be worn inside the ear. These devices are able to distinguish background noise (such as traffic) from noise in the foreground (like a conversation). However, hearing aids are not suitable for all patients and are not always able to restore normal hearing. For example, they may not be effective for patients with profound hearing impairment. A hearing care professional can discuss the potential benefits of a hearing aid with the patient and recommend the most suitable device. Hearing aids, in fact, are available in a series of models, which differ in size and application methods to the ear. Some are small enough to fit inside the ear canal, a feature that makes them almost invisible, while others adapt partially to the conduit. In general, the smaller hearing aid is also more expensive, less powerful and with a shorter battery life.
The main hearing aids are:
- Behind-the-ear hearing aids: apply behind the ear. The sound is conveyed into the ear canal by a fitting that reaches the inside of the ear. These aids are usually used for patients with moderate, severe or very severe hearing loss. Some types of behind-the-ear hearing aids are equipped with two microphones that allow you to hear nearby sounds or concentrate on sounds that come from a specific direction. This feature can be particularly useful in noisy environments.
- In-ear hearing aids : they are inserted into the ear canal and a shell protrudes to lightly fill the outer ear opening. They are indicated for moderate to severe hearing losses.
- Hearing aids placed in the canal: they are inserted into the auditory canal and are barely visible. This hearing aid can improve mild to moderate hearing loss.
- Hearing aids fully placed in the canal: they are shaped to fit inside the ear canal and can improve mild to moderate hearing loss. However, they are not recommended in cases of severe hearing loss.
- Bone conduction hearing aids: are recommended for people with conductive hearing loss or for those who cannot wear a conventional type of hearing aid. This device is surgically positioned at the level of the mastoid bone. The bone conduction hearing aid vibrates in response to sounds that reach a microphone and transmits the stimulus to the cochlea, which converts the sound.
Cochlear implants
If you have severe hearing loss in one or both ears, a cochlear implant may be an option. Unlike a hearing aid, which amplifies the sound and directs it into the ear canal, a cochlear implant (also known as a "bionic ear") artificially compensates for the damaged or non-functional parts of the inner ear, sending language directly to the cochlear nerve environmental noises.
Cochlear implants are composed of an external component (microphone receiver and audio processor) and internal parts surgically inserted under the skin of the mastoid process, including a receiving coil, an electronic chip and an array of electrodes that reaches the cochlear nerve and it stimulates. When the external processor of the device receives a sound picked up by the microphone, it analyzes it and converts it into signals that are transmitted to the internal receiver, decoded by the microchip and sent in the form of electrical impulses to the intraclocalization electrodes stimulating the fibers of the state-acoustic nerve (or vestibulocochlear what to say). This means that cochlear implants are only suitable for people with normal hearing pathways. The increase in the number of contacts and variations in the implant site make it possible to perceive the different sensations. A cochlear implant is sometimes indicated for adults or children who have profound sensorineural hearing loss in both ears and who cannot benefit from traditional hearing aids. However, some approximate sound stimuli are not perceived, and the individual must learn to recognize the meaning of certain sounds.
Prevention
Prevent hearing loss
The ears are fragile structures that can be damaged in many ways, and it is not always possible to prevent such damage. For example, hearing loss due to otitis media can be prevented through early diagnosis and appropriate therapeutic interventions.
It is estimated that half of all cases of hearing loss can be avoided with primary prevention. Some of these simple prophylactic strategies include:
- Immunize children against childhood diseases, including measles, meningitis, rubella and mumps;
- Immunize adolescent girls and women of reproductive age against rubella before pregnancy;
- Screening and possible treatment of syphilis and other infections in pregnant women;
- Improve prenatal and perinatal care, including promoting safe birth;
- Avoid the use of ototoxic drugs, unless prescribed and monitored by a qualified doctor;
- Monitor the condition of children with high risk factors (for example those with a family history of deafness, those born with low birth weight, neonatal asphyxia, jaundice or meningitis);
- Reduce exposure (both professional and recreational) to loud noises, using personal protective equipment.
Other preventive measures reduce the risk of hearing loss induced by exposure to loud noises and avoid a worsening of age-related hearing reduction.
The risk of suffering damage due to acoustic trauma depends on the intensity and duration of exposure to noise. Let's see some tips to minimize this risk:
- Protect your ears at work . If you work in a noisy environment, such as a pub, a disco or a construction site, it is advisable to use hearing protection, such as headphones or ear plugs. Specially designed headphones are able to protect the ears, allowing you to tolerate the loudest sounds and to perceive them at an acceptable level. A continuous exposure to noise equal to or greater than 85 dB can, over time, cause hearing loss.
- Avoid risks associated with recreational activities . Some recreational activities, such as snowmobiling, hunting and listening to music at too high a volume and for long periods of time, can damage your hearing. Wearing ear protectors or taking breaks from loud noises protects your ears.
Lowering the volume while listening to music can help you avoid hearing loss. This is especially important if small children are present at home, as their ears are more sensitive. If it is not possible to have a comfortable conversation with someone who is positioned two meters away, try to reduce the volume. Finally, you should not hear muffled or ringing in your ears after listening to music.
