Single sided deafness (SSD), sometimes referred to as unilateral hearing loss, is a condition in which an individual experiences unaidable hearing loss in one ear but can hear normally out of the other ear. An unaidable hearing loss is defined as hearing loss that is so poor that traditional amplification is no longer helpful. While the majority of patients with a hearing impairment suffer from bilateral (two-sided) hearing loss, SSD is diagnosed in approximately 60,000 people in the United States each year.
Patients with SSD find understanding speech in the presence of background noise especially problematic and have great difficulty localizing sound (recognizing the location or origin of a sound source). Sound localization depends on subtle hearing cues from two ears; removing one from the equation confuses the brain. Other symptoms might include anxiety, stress, social isolation, dizziness, difficulty paying attention and speaking loudly.
Causes of Single Sided Deafness (SSD)
SSD can be caused by a variety of factors.
- Acoustic neuroma
- A benign, slow growing tumor that can push against the auditory nerve and affect the ability to hear properly in one ear.
- Sudden hearing loss
- A viral infection that causes inflammation in the cochlea, resulting in damage to either the hearing hair cells or stria vascularis and, a rapid onset of hearing loss.
- Other factors may be due to Meniere’s disease, head trauma, genetic disorders, labyrinthitis, etc.
Treatments for Single Sided Deafness (SSD)
With medical clearance, the options that exist for helping patients manage their unilateral hearing include:
- Contralateral routing of signal (CROS) system
- A CROS is a microphone that is placed on the side with no hearing or unuseable hearing, while a traditional hearing device is placed on the patient’s “good” or normal ear.
- The CROS picks up sound and then transmits them over to the patient’s “good” or normal ear, essentially re-routing the signal to the ear with better hearing.
- This pairing is called a biCROS for patients with some degree of hearing loss in the “good” ear.
- Bone-anchored hearing system
- This is a surgically implanted titanium abutment with a removeable sound processor, which uses direct bone conduction to transmit sounds to the good ear.
- This particular device is helpful for patients with outer and middle ear issues because traditional amplification is not as effective.