Types of hearing loss - sensorineural, conductive and mixed

Hearing loss affects people of all ages. Statistics Canada reports one in five Canadians experience some degree of hearing loss that can arise from a number of different causes. 

Hearing loss impacts the quality of life for you and your loved ones. Hearing loss can be linked to fatigue, social isolation and depression. The good news is, help is available.  

What type of hearing loss do you have?

Hearing loss of any kind can affect one or both ears and range from mild to profound in severity. Hearing loss is commonly categorized into three main types based on the location where it occurs:

• Sensorineural hearing loss occurs in the inner ear or the auditory nervous system, which delivers sound to the brain.
• Conductive hearing loss occurs in the outer or middle ear.
• Mixed hearing loss, as the name suggests, is a combination of sensorineural and conductive hearing loss and occurs in the inner and middle and/or outer ear.

The type of hearing loss you have will determine the type of treatment that will work best for you.

Sensorineural hearing loss

Sensorineural hearing loss is a result of damage to the inner ear, primarily the cochlea, and/or the auditory nervous system. Tiny hair cells in the cochlea that detect sound waves are easily damaged. It is the most common type of hearing loss and is permanent but treatable.

Causes

Sensorineural hearing loss is most often related to aging and/or exposure to loud noise, either from a sudden loud sound or long-term exposure to a noisy environment. This is known as noise-induced hearing loss.

Other causes of sensorineural hearing loss include:

• Genetic factors
• Head injuries
• Certain medications
• Meniere’s disease
• Viral or bacterial infections of the inner ear 

Symptoms

Those suffering with sensorineural hearing loss typically experience a reduced ability to hear a range of sounds and often reduced clarity of speech.

Both how loudly (volume) and how clearly (clarity) you perceive sound are affected. Common signs that you may be experiencing sensorineural hearing loss include if you:

• Frequently ask others to repeat themselves
• Turn up the television or radio volume
• Misunderstand conversation
• Report that friends and family mumble
• Strain to hear others in conversation 
• Experience tinnitus (ringing or buzzing) in the ears

Treatment

Age-related and/or noise-induced hearing loss is permanent but can be effectively treated using hearing aids. Hearing loss caused by viral or bacterial infections can sometimes be reversed with the timely use of medication. 

If hearing aids are not able to overcome damage in the inner ear or auditory nervous system to help you hear well, cochlear implants may be an option.

While age-related hearing loss cannot be avoided, prevention of noise-induced hearing loss should always be taken seriously whether we are five or 95 years old. It is always recommended to use good quality ear plugs or earmuffs when in loud noise to prevent noise-induced hearing loss and protect your hearing health.

Conductive hearing loss

Conductive hearing loss refers to hearing loss in the outer ear and/or middle ear and includes the ear canal, ear drum, and the middle ear bones. Conductive hearing loss may be temporary or permanent, depending on the cause. 

Causes

Conductive hearing loss occurs when the pathway for sound to travel from the outer ear and middle ear to the inner ear is blocked. It can also occur from conditions that cause the ear drum or middle ear bones to not properly function. It can cause full or partial hearing loss. 

Common causes of conductive hearing loss are:

• Excess earwax
• Fluid build-up from outer or middle ear infection
• Ruptured or perforated ear drum
• Different types of hearing disorders, such as stiffening or narrowing of the inner ear (atresia or stenosis)
• Abnormal bone growth
• Abnormal growth or tumor
• Eustachian tube dysfunction (this tube connects the middle ear to the back of the nose and throat)

Symptoms

Similar to the symptoms of sensorineural hearing loss, conductive hearing loss will cause a reduced ability to hear sound, but not clarity. Often, a sensation of fullness or "plugged" ears is experienced along with tinnitus. If an infection is present, pain or drainage may also accompany the hearing loss.

Treatment

Many causes of conductive hearing loss are treatable to the extent that hearing loss can either be significantly reduced or reversed all together. Treatment can include removal of excess earwax, prescription of antibiotics for infection, or surgery by an ear, nose and throat doctor (ENT). For any residual hearing loss that cannot be reversed, the use of a hearing aid is often effective. Bone-anchored hearing systems also may be a good option.

Mixed hearing loss

Mixed hearing loss refers to the presence of both sensorineural and conductive hearing loss. It occurs in the inner ear and/or auditory nervous system and the outer and/or middle ear.

Causes

Mixed hearing loss is caused by a combination of conditions leading to sensorineural and conductive hearing loss. For example, a person with age-related sensorineural hearing loss with earwax blockage, or a person with noise-induced sensorineural hearing loss with an ear infection.

Symptoms

As with sensorineural and conductive hearing loss, symptoms include a reduced ability to hear sounds, particularly with reduced clarity in understanding speech. Other symptoms can include tinnitus, a sensation of fullness in the ears, pain and/or fluid discharge.

Treatment

Treating mixed hearing loss often starts with determining how to address the conductive component of the hearing loss, which can include antibiotics, removal of excess earwax, or surgery. Once the conductive component of hearing loss has been treated, hearing aids are most commonly prescribed to treat residual conductive hearing loss or permanent sensorineural hearing loss.

A hearing test can help determine what type of hearing loss you have.

How to get help

There are several factors that can contribute to hearing loss in the outer, middle, and inner ears or auditory nervous system. Some of the causes or conditions can be reversed, but most often hearing loss is permanent and can be treated with prescribed hearing aids or other options. In children, untreated hearing loss can lead to communication disorders. 

If you are experiencing any symptoms indicative of hearing loss, visit a local hearing clinic near you. A hearing healthcare professional will give you a hearing test and discuss the best treatment options for you.