What is mixed hearing loss?

Mixed hearing loss is a combination of sensorineural and conductive hearing loss. Conductive hearing is due to injury to the ear canal, tympanic membrane, or middle ear that prevents sound conduction to the inner ear. Sensorineural hearing loss occurs as a result of damage to the inner ear or auditory nerve. Mixed hearing loss is a rare condition that affects the external or middle ear and the inner ear or auditory pathway to the brain.

What are the symptoms of mixed hearing loss?

Mixed hearing loss might be associated with more severe hearing loss compared to conductive or sensorineural hearing loss alone. Patients complain of trouble hearing soft sounds. They often need to increase the volume of the TV. Patients face difficulties understanding speech, especially when there is background noise or when they try to converse with several individuals simultaneously. Mixed hearing loss may also present with tinnitus, an irritating ringing sound in the ears. Other common symptoms include ear pain and fullness due to the outer and middle ear impairment.

What causes mixed hearing loss?

Mixed hearing loss can result from a combination of factors that leads to sensorineural and conductive hearing loss. The most common causes are age-related hearing loss, noise exposure, temporal bone trauma, chronic ear infections, and genetic diseases.

Ear infections mainly damage the outer and middle ear, which causes conductive hearing loss. However, sometimes infections can affect the inner ear, leading to mixed hearing loss.

Severe head injury with or without the temporal bone or skull fracture can impair sound conduction and neural transduction, causing mixed hearing loss.

Age-related hearing loss or presbycusis is the most common cause of sensorineural hearing loss. It causes gradual and irreversible hearing loss among the elderly population.

Noise exposure is another risk factor that injures the specialized hearing cells in the inner ear. It is mainly associated with sensorineural hearing loss. People working in loud factories or construction are exposed to occupational noise. Recreational noise exposure, such as loud concerts or frequent use of headphones at high volumes, increases the risk of hearing loss.

How is mixed hearing loss diagnosed?

Diagnosing mixed hearing loss can sometimes be challenging as it includes both sensorineural and conductive hearing loss characteristics. Various audiological evaluations are required to make the diagnosis. Audiometry evaluates hearing and identifies the type and degree of hearing loss. Tympanometry detects the middle ear function, while the otoacoustic emissions assess the activity of hearing cells in the inner ear. Speech audiometry tests how well the patient understands speech.

What is the management for mixed hearing loss?

The audiologist considers various factors, such as the primary cause and degree of hearing impairment, when developing the treatment plan for mixed hearing loss.

Hearing aids improve hearing and speech understanding by amplifying external sounds. There are various hearing device types and styles to meet patients' individual needs.

In the case of chronic middle ear diseases, surgical interventions might be needed to restore the normal anatomical structure of the middle ear and enhance hearing.

Cochlear implants are helpful with severe hearing loss that cannot be corrected by hearing aids. These are surgically inserted devices that directly send signals to the auditory nerve in case of specialized hearing cell damage.