By: Dr. Matthew Seldine
Audiologists and hearing professionals expect to see symmetrical hearing levels in each ear, however, sometimes the ears are quite different from one another (asymmetrical). Single-sided deafness (SSD) is a hearing impairment where there is normal hearing in one ear and impaired hearing in the other ear. Fortunately, this is not a common occurrence but approximately 60,000 people in the United States are annually diagnosed with SSD. For people who have grown accustomed to knowing symmetrical hearing, the losing of hearing in one ear is anything but comforting. This leaves many patients searching for answers.
Single-sided deafness has many causes, among them physical damage to the ear, head trauma, an acoustic neuroma (a benign tumor beyond the inner ear), a viral or bacterial infection in the inner ear, or a circulatory system disorder. What results in many cases is the disorienting sensation of not being able to hear anything out of the affected ear and thus severely reduced audibility on that side of the body.
Humans are designed to have two ears and our brain is dependent on the sound input from both. The California Ear Institute states “that losing function out of one ear severely limits a person’s ability to localize sound (i.e. not knowing which direction a car horn is coming from) or hear in noise (being able to focus on your friend’s voice in a restaurant). Additionally, loss of hearing in one ear means the brain is required to work harder to make sense of auditory information in all environments thus complicating the listening process”.
Single-sided deafness can be a permanent diagnosis. In some cases, hearing can be restored. In other cases, audiological treatment and management may be utilized which includes wearing a hearing device; primarily the use of a CROS hearing device or a BAHA (bone anchored hearing aid). Medical management should be initiated as soon as possible, commonly within 24-48 hours of the occurrence (when considering individuals who were not born with SSD).
Every patient is unique and in each scenario a team effort is recommended to help the patient manage this condition. The good news is treatment for SSD is available and in many cases highly effective.