Muffled hearing loss in one ear? Cros hearing aids can help.

Have you ever been in a noisy room and were unable to hear your spouse or colleagues because they weren’t positioned on the side of your good ear? Or perhaps you’re completely unaware of your environment while on a phone call? If this sounds familiar, then you may have one-sided hearing loss or one-sided deafness (SSD).

Although some cases have easy fixes, sometimes it can be much more serious and may require medications, surgery, or hearing aids. You should always contact your nearest audiologist or hearing specialist if you ever experience any type of hearing loss.

In this article, you’re going to learn everything there is to know about one-sided hearing loss and how CROS/BiCROS hearing aids may help you.

What is hearing loss in one ear?

Hearing loss doesn’t necessarily happen equally in both ears. One-sided hearing loss (unilateral hearing loss) is a condition where one ear has hearing loss, but the other ear can hear normally. This condition is common in both children and adults.


Our bodies were designed to have two ears for a reason – both ears constantly communicate with each other as they absorb sounds from the environment. This is known as binaural hearing. Thus, hearing loss in one ear provides unique challenges such as difficulty in:


  • Detecting the origin of a sound (sound localization)
  • Hearing and understanding speech
  • Hearing clearly & loudly (sound may be muffled)
  • Tuning out background sounds

Hearing loss of this type can range from mild to profound; if the loss is severe enough, it may indicate that the person is deaf from one ear. This is known as single-sided deafness (SSD).

Causes of hearing loss in one ear

There are a number of potential causes for hearing loss on one side or SSD, including but not limited to:



An ear infection or illness is a common cause of muffled hearing or hearing loss in one ear. Most ear infections or illnesses cause fluid to build up in the middle ear, thus blocking the sound from entering the inner ear. Often, ear infections are mild and can clear on its own, but others can lead to impaired hearing if left untreated.


Ear blockage:

Believe it or not, a common culprit of muffled hearing in one ear is due to excessive earwax (cerumen). Although earwax acts as a lubricant and prevents dirt and debris from entering the ear canal, sometimes severe buildup can lead to muffled hearing.   



Referring to gradual age-related hearing loss, Presbycusis is a common type of sensorineural hearing loss of high-pitched sound caused by natural ageing. It occurs gradually and over time can result in the inability to clearly hear sounds at progressively lower frequencies. Those diagnosed with Presbycusis often notice that the speaker is loud enough but not clear – as if the speaker is mumbling. 


Exposure to loud noise:

Have you ever spent the evening at your favourite rock concert enjoying loud music with your friends and then walked out with a ringing in your ear? Extremely loud bursts of sound, especially those of firearms, explosions, or live concerts can temporarily or permanently damage your ears. The inner mechanism of your ear is extremely delicate and loud sounds can tear a hole in the eardrum or damage the delicate bones in the middle ear.


Exposure to certain drugs:

Medication can react differently to different bodies. Especially those that are ototoxic, which may contribute to hearing loss in one ear or both. These medicines may damage the sensitive nerve cells in the inner ear, leading to temporary or permanent hearing loss. Check with your doctor if you take any of the following:

  • Antibiotics
  • Loop diuretics
  • Chemotherapy drugs
  • Pain relievers such as ibuprofen

Other symptoms of medicine-induced hearing loss include vertigo, tinnitus, and fullness in the ear.


Traumatic brain injury or head trauma:

Hearing loss is extremely common following a sudden, intense injury to the heard or brain. Car accidents being the number one cause, a traumatic head injury can damage the tympanic membrane, middle ear and nerve cells in the cochlea resulting in hearing loss, tinnitus, dizziness, or loss of balance.

Sometimes a cause may not be identified or is due to a combination of these factors. 

Hearing loss in one ear can develop quickly, so you should always act fast if you or a loved one experiences sudden hearing loss. The quicker you seek treatment, the better are your chances of full recovery.

Single-sided hearing loss treatment

The good news is that there are several options for treating a one-sided hearing loss. As soon as you start to experience any symptoms of hearing loss in your ears, you should contact a physician as soon as possible. Depending on the cause, treatment may include:

  • Antibiotics (for ear infections)
  • Removing the impacted ear wax (or foreign object stuck in-ear)
  • Surgery (ex. to repair a perforated eardrum)
  • Hearing aids

In the case of hearing aids, you may be recommended a CROS, BiCROS, or bone-anchored hearing system. It is important to get this treated quickly, as there are many consequences of not using a hearing aid.

CROS hearing aid verses BiCROS

Contralateral routing of sound (CROS) system is designed for individuals who have near-total hearing loss in one ear, but normal hearing in the other. It’s a very simple solution in where the individual wears a transmitter device on their bad ear and a receiver on their good ear. Simply put, the transmitter detects sound occurring on the deaf ear and routes it to the good ear where the amplifier processes the sound and delivers it via the receiver.

The sound that is transmitted to the good ear is not amplified as the person has a relatively normal hearing on the receiver side.


While wearing the CROS hearing aid, if someone speaks to you while positioned next to your bad ear, their voice will be picked up by the transmitter and will be heard on the receiver side just as if they were sitting next to you.

With an exactly same set-up, Bilateral Contralateral routing of sound (BiCROS) system is designed for people whose functional ear has moderate-to-severe hearing loss. Thus, the only difference is that the receiver on the better ear is provided with amplification via a typical hearing aid to help overcome the hearing loss on that better side.


EARly offers a wide range of CROS and BiCROS hearing aids which are easy to use, stylish and discreet, and powerful.

Bone-anchored hearing systems

Bone-anchored hearing systems or BAHA is an alternative to CROS & BiCROS hearing aids which requires surgical implantation. Utilizing a process known as bone conduction, these devices send sound vibrations directly to the inner ear through the skull bone. This can be helpful when middle ear or ear canal problems prevent sound waves and signals from reaching the inner ear. In those cases, standard hearing aids are ineffective.

For more information

If you are interested in learning more about whether you are a good candidate for CROS or BiCROS hearing aids, call us at 044-48136878 or write to us at

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