Hearing loss is a common problem that can affect anyone, regardless of age or gender. More than 13% of people aged 12 and older (approximately 30 million people) experience some form of hearing loss, with varying degrees of severity. Hearing loss can be temporary or permanent depending on the severity and type of damage sustained, and treatments vary accordingly.
In cases of temporary hearing loss, medical treatment is often the best solution. However, for more severe forms of hearing loss, hearing aids or other medical interventions may be necessary.
What is conductive hearing loss?
There are three main forms of hearing loss and four degrees of severity. These three forms are conductive hearing loss, sensorineural hearing loss (SNHL), and mixed hearing loss:
Conductive hearing loss: Conductive hearing loss refers to a situation where an obstruction in the outer or middle ear prevents sounds from reaching the inner ear and impairs hearing. Damage related to conductive hearing loss is also referred to as temporary or transient, and it is more easily corrected.
Sensorineural hearing loss: Sensorineural hearing loss, or SNHL, corresponds to impaired hearing due to damage to the inner ear, the cochlea and its hair cells, or the auditory pathways and nerves. In people with SNHL, the damage is generally more permanent than in conductive hearing loss.
Mixed hearing loss: Mixed hearing loss occurs when there is damage to both the inner ear, as in SNHL, and damage to the outer or middle ear. As with SNHL, the damage can be more permanent than with conductive hearing loss alone.
People with conductive hearing loss have more difficulty hearing faint sounds, which seem unclear to them, regardless of their pitch.
The severity of hearing loss
In addition to diagnosing the type of hearing loss, it is essential to assess its severity. There are four degrees of hearing loss: mild, moderate, severe, and profound.
These degrees range from the easiest forms to treat to definitive loss. It is estimated that approximately 2% of the US adult population over 45 experiences a more severe form of hearing loss.
What causes conductive hearing loss?
Conductive hearing loss is a common disorder whose causes are easy to diagnose. An assessment by your primary care physician or an ENT specialist will help evaluate the extent of the damage and its probable origin.
Common forms of hearing loss
A malformation of the ear or its structure
Otosclerosis, a genetic anomaly affecting an ossicle of the middle ear that prevents sound from being transmitted to the inner ear
Chronic infections: these can be hereditary or environmental in origin
Tumors located in or near the ear and ear canal
Colds and allergies, which can cause swelling and trap fluid in the ear
Accumulated or impacted earwax in the ear canal. Earwax is the most common cause of obstruction.
Head trauma
Common symptoms of conductive hearing loss
Among the most frequent symptoms of conductive hearing loss are ear pain and discomfort, as well as vertigo and dizziness, muffled sounds, a bad odor emanating from the ear, and a feeling of pressure in the ear, or a combination of these signs. These symptoms usually appear when fluid accumulates in the ear canal without being able to drain, creating an obstruction that blocks sound and impairs hearing.
What treatments are available?
Several treatments exist for conductive hearing loss. Depending on the severity of the hearing loss, simple solutions may suffice, such as antibiotics or other medical procedures. In more complex cases, a hearing aid may be necessary.
How hearing aids work
A hearing aid is an electronic device worn behind or inside the ear that amplifies sound so that the person can hear it at a normal volume. Hearing aids differ in their design, specific functions, and the type of technology used to amplify sound, whether analog or digital.
Composed of three essential elements, a hearing aid captures sound, amplifies it, and diffuses it into the ear to make it a stronger signal, easier for the brain to process.
The three components of a hearing aid are a microphone, an amplifier, and a speaker, which amplify the sound for the wearer. The way a hearing aid works is as follows: the microphone converts sound into electrical signals. The amplifier increases the power of these signals, which are then diffused by the speaker into the ear.
As the device captures sound, it amplifies it and transmits it through the ear canal, where hearing is difficult. Hearing loss that requires the use of a hearing aid is due to damage to the small sensory hair cells of the ear. A hearing aid amplifies sounds to support the remaining hair cells, by accentuating the sound vibrations that pass through the ear canal. This amplified sound makes everyday noises and speech more understandable, allowing the person to carry out their daily activities.
What are the best hearing aids for conductive hearing loss?
Depending on the severity of the hearing impairment, several hearing aid options are possible. A thorough examination by your doctor or an ENT specialist — an otolaryngologist or an audiologist — will identify the impairment, its cause, and the most suitable type of hearing aid.
There are several hearing aid options, some of which also take aesthetic criteria into account for the wearer.
Types of hearing aids
Hearing aids are designed to address specific impairments and come in several types. Some are designed to be placed externally and rest behind the ear, others to be housed inside the ear, while others are implanted in the ear canal or cochlea: these are called cochlear implants.
Behind-the-ear hearing aids
Made of rigid plastic, they rest behind the ear and conform to the shape of the auricle: behind-the-ear hearing aids are the most classic hearing devices. The only drawback of a traditional behind-the-ear hearing aid is that the custom earmold can give an unpleasant feeling of a blocked ear. These devices are used for mild to moderate hearing loss and are the most common solution for less severe hearing loss.
A variant of the behind-the-ear hearing aid is called a mini-BTE or open-fit BTE. The casing is placed behind the ear, but instead of a custom earmold on the auricle as with classic devices, the mini-BTE or open-fit BTE uses a thin, narrow tube that fits into the ear and leaves the ear canal open. The mini-BTE is appreciated for its discreet design and the comfort it offers compared to a traditional behind-the-ear hearing aid.
In-the-ear hearing aids
For more significant hearing loss, moderate to severe, an internal hearing aid is ideal. Made of rigid plastic, the in-the-ear hearing aid fits entirely within the ear. Some in-the-ear models have a telecoil, a small magnetic coil that helps the user receive sound without going through the microphone.
This design helps the user hear certain sounds, such as telephone conversations. People with common hearing loss, especially those who use a hearing aid, know that a phone call is difficult to hear because it produces different frequencies from those of a face-to-face conversation.
Another advantage of telecoils is that some public places are equipped with specific sound systems called "induction loops." An induction loop is often found in public places like schools or libraries, as they improve the listening ability of people equipped with in-the-ear aids. Young children do not wear this type of hearing aid, as the plastic casing must be replaced regularly as their ear grows.
In-the-canal hearing aids
There are two types of in-the-canal, or ITC, hearing aids. Both are designed to be placed in the ear canal, are sized according to the wearer's canal, and are for mild to moderate hearing loss. The basic model is the in-the-canal (ITC) hearing aid, shaped precisely according to the user's ear canal. The other type of in-the-canal hearing aid is the CIC, for completely-in-canal devices. This is a device inserted into the ear canal and virtually invisible to the naked eye. Due to their size, these in-ear devices are excellent aesthetically, but they are difficult to remove, do not allow for options like a telecoil, and are more delicate to maintain.
The general design of hearing aids
Hearing aids are designed in two formats. The first is the analog device, the second is the digital hearing aid. The main difference between the two is that with analog, the sound is reproduced as it was transmitted: the volume and modulation remain as natural as originally.
With a digital hearing aid, the first difference is that the sound is not converted into electrical waves as on an analog device: it is transformed into digital values before being amplified. Another difference with a digital device: the sound is modulated by the device, so loud noises can be attenuated and faint sounds reinforced as needed.
Analog hearing aids
The first category is the analog hearing aid, which converts sound into electrical waves on a continuous spectrum. This means that the sound is not modulated, but received as a continuous sound wave, and then simply made louder. This can be annoying or uncomfortable, depending on whether the sound is too faint or too loud, and the amplification cannot be increased.
The patient's audiologist programs analog hearing aids to account for different sound levels the person may encounter, such as the noise of a crowded restaurant compared to the quiet of a library. The volume adjusts to the user's listening environment with the press of a button. Analog devices are generally less expensive and easier to adapt to each person's particular needs.
Digital hearing aids
Digital hearing aids work much like a computer. The device is programmed to translate sound into binary code and to apply the necessary modulation or amplification to the sound wave before it continues its journey into the ear canal. These devices can be programmed according to precise criteria and frequencies, on a case-by-case basis, making digital models much more flexible than analog versions.
Additional functions of hearing aids
Options vary from one hearing aid to another, but generally, the ability to program the type of sound amplification needed comes from
Telecoil: The telecoil setting allows for the elimination of ambient sounds, such as the din of a crowded room, to isolate the sound one wishes to focus on. This feature is very useful for phone calls, in cinemas, and wherever unwanted noise needs to be reduced.
Direct audio input: This feature allows an external microphone to transmit sound directly from a device such as a television, headphone jack, or computer.
Directional microphone: This feature directs the microphone in a specific direction to amplify only sounds coming from that direction. This setting allows the user to better control unnecessary or ambient noise and to focus on the desired sound, such as speech, in the chosen direction.
Feedback suppression: Anyone who has brought their cell phone close to another during a call knows the sound of feedback. This whistling comes from the interference between the microphones of the two phones. For the person wearing a hearing aid, this feedback can be painful: having a feature that reduces the feedback effect is therefore particularly valuable.
