What Is Unilateral Hearing Loss?
Hearing loss that affects only one ear is known as unilateral hearing loss (UHL). This hearing loss can range in degree from mild to profound. Occasionally, unilateral hearing loss is referred to as minimal hearing loss, as the presence of one normal hearing ear allows for minimal effects on speech and language development; however, it should be noted that even when hearing loss is only in one ear, it can have significant impacts on a person’s day-to-day life.
Is Unilateral Hearing Loss the Same as Single-Sided Deafness?
Single-sided deafness (SSD) is when one ear is completely ineffective or there seems to be no usable hearing from that side. For example, a person with SSD may have normal hearing in one ear without any hearing in the other ear, while someone else with SSD may have some hearing in their ear with hearing loss, however, it is not enough sound to be considered helpful with understanding conversations.
Unilateral hearing loss means that there is some amount of hearing loss in one ear, but not necessarily a complete loss of hearing, like single-sided deafness. People with UHL could have a mild hearing loss in one ear, which is therefore, not considered deafness.
Who Is Affected by Unilateral Hearing Loss?
You can be born with unilateral hearing loss, or it can be progressive, meaning it develops over time. Unilateral hearing loss (UHL) that is acquired later in life can happen from certain illnesses, like viruses or autoimmune diseases, or can happen idiopathically which means, without a known cause. Congenital UHL or hearing loss in one ear that you are born with, can occur spontaneously, without having any risk factors at birth, or it can be caused by craniofacial differences, family history, or an associated syndrome.
What Are the Symptoms of Unilateral Hearing Loss?
Those who have unilateral hearing loss have reduced awareness of sound on the affected side. This may also be joined by unilateral tinnitus, or the perception of sound when there is not an external source. Research (Persson et al, 2001; Shaw and Vaillancourt, 1985) has shown that our brains rely on hearing from both ears to help us hear best in background noise and to localize where a sound is coming from. Acquired UHL has been associated with embarrassment, frustration, anxiety, insecurity, and social isolation due to sudden change in quality of life.
How Is Unilateral Hearing Loss Diagnosed?
Unilateral hearing loss is diagnosed by an audiologist with a comprehensive hearing evaluation. For children, a screening at birth, at the pediatrician’s office, or at school can detect a possible unilateral hearing loss, which should be confirmed with thorough testing by an audiologist.
Some signs of unilateral hearing loss in children can present as increased listening effort, poor behavior, and poor academic performance. If you notice these in your child, consider ruling out hearing loss as a contributing factor.
For adults, if unilateral hearing loss is sudden in nature, immediate appointments to their primary-care or an ear, nose, and throat physician is essential. The emergency room is another option, but many times the correct medical care and diagnosis are missed because most emergency rooms are unable to evaluate hearing.
How Is Unilateral Hearing Loss Managed and Treated?
The management and treatment of unilateral hearing loss depends on the degree of loss, as well as the degree of impact on daily life. If the unilateral loss is sudden in nature, the success of medical treatment depends on how quickly treatment is administered after onset of symptoms. Sudden hearing loss should always be immediately evaluated by an otolaryngologist, more commonly known as an ear, nose, and throat physician (ENT).
If the hearing loss is longstanding and if medical treatment is not an option, unilateral hearing loss can be treated with different technologies based the person’s needs and hearing loss qualifications. In conjunction with technology, good communication strategies should be used for people with UHL, as they may need an adjusted environment to succeed in speech understanding. Consider reducing background noise on the good side and enhancing speech on the good side.
The following options outline potential technologies for the treatment of unilateral hearing loss:
- Hearing Aid
- If appropriate, research supports the use of amplification on the affected ear. Hearing aid use has been shown to allow for improved access to conversation, balance of sound, and sound awareness.
- CROS Hearing Aid
- For those who have hearing loss that cannot be helped with a traditional hearing aid, a CROS system can be considered. A CROS (contralateral routing of sound) system looks like a hearing aid, but does not send any sound into the affected ear. Rather, it uses a microphone to pick up sound on the side of the person’s head with the hearing loss and sends it over into a device worn on the good ear. Though this cannot help to restore sound localization, this allows improved awareness of sound on the affected side.
- Bone-Anchored Implant
- A bone-anchored implant (BAI) can be considered for unilateral hearing loss, though the success of certain goals may depend on the degree and type of hearing loss in the affected ear. Hearing loss that is conductive or mixed in nature, meaning there is some abnormality in the ear canal or middle ear space, may have good success with a BAI for balance of sound. For single-sided deafness, a BAI would route the sound to the better hearing ear, acting similarly to a CROS device. As the BAI typically requires surgery, a non-surgical CROS device should be trialed first.
- Cochlear Implant
- For children who are born with severe to profound UHL, a cochlear implant can be considered; however, language and cognitive delays for young children are unlikely if they have one ear with normal hearing. For UHL that is acquired later in life, the success of cochlear implantation can depend on age, duration of hearing loss, and severity of hearing loss, so a full evaluation with an audiologist and otolaryngologist who specialize in cochlear implantation for individualized recommendations is encouraged.
- Remote Microphone
- A remote microphone, previously known as an FM system, can also be considered a treatment option for UHL. This device can be helpful when the speech of interest is at a distance or in the presence of background noise.
- No Treatment
- Finally, some choose not to treat the unilateral hearing loss at all. With one normal hearing ear, a person may perform well in daily activities and conversation and may be able to defer using technology until concerns arise.
Who Should I Call if I Suspect Unilateral Hearing Loss?
If you suspect unilateral hearing loss, consider consultation with an audiologist and otolaryngologist (ENT). If the unilateral hearing loss is sudden in nature and happens spontaneously throughout the day or upon waking up in the morning from sleep, immediate evaluation by an ENT is strongly recommended, as timing of treatment can affect recovery of hearing.
For longstanding unilateral hearing loss, consider consultation with an audiologist for baseline hearing evaluation and discussion of effects on communication and treatment options. If you or someone in your family suspect hearing loss, Find an Audiologist near you to set up an appointment.
Persson P, Harder H, Arlinger S, Magnuson B. (2001) Speech recognition in background noise: monaural versus binaural listening conditions in normal-hearing patients. Otol Neurotol 22(5):625-30.
Shaw EAG, Vaillancourt MM. (1985) Transformation of sound-pressure level from the free field to the eardrum presented in numerical form. J Acoustical Soc Amer 78:1120-1123.