Until the last 15 or 20 years there has been a significant change in the way unilateral hearing loss has been viewed. Until recently audiologists and ENT’s assumed that a unilateral hearing loss (UHL) did not cause any language or learning problems.
We now know that unilateral hearing loss causes significant problems. Cheryl Deconde Johnson has demonstrated the socio-emotional aspects of unilateral hearing loss. They have difficult in peer-to-peer interaction. We know now that this is the result of language and listening difficulties that are the result of unilateral hearing loss. Dawna Lewis, PhD and others have demonstrated that children with UHL have difficult locating the speaker in a group and have difficult hearing in noise compared to their typical hearing peers.
Technology and unilateral hearing loss
For children with mild hearing losses in the poorer hearing ear, hearing aids can work well. If the hearing loss is severe they may receive insufficient benefit from hearing aids and the perception may cause some distortion.
CROS hearing aids have been used for many years and they improved performance in some situations, especially when the signal was on the side of the poorer ear. Remote microphones were also recommended to assist in hearing in the classroom. Like all others, children with unilateral hearing loss often rejected remote microphones as they got older.
In recent years, cochlear implants have been used in cases of unilateral hearing loss. They have been well received and improved word recognition. As will other children with hearing loss results will be best if the child is implanted by one to two years.
Bone conduction hearing aids are another possibility and have worked well for some children.
As with all hearing loss, children need to be tested with technology to know for sure that they are hearing well enough.
Testing children with unilateral hearing loss
Some families will feel that children with unilateral hearing loss do not need assistance. Testing a child with unilateral hearing loss can show the family what the child is missing.
When I test, I test with speech information presented on the side of the bad ear and noise on the side of the good ear. That way any listening difficulties will be clear.
Language outcomes of children with unilateral hearing loss
Research by Christine Yoshinaga-Itano, PhD, has demonstrated that language delays of children with UHL develop by 2-3 years of age demonstrating delays in vocabulary and comprehension of abstract language. As a result, all children with UHL should be evaluated at age 2 and then annually after.
As language becomes more complex, more problems are likely to develop. By testing over time problems will be identified as they develop.
Judith Lieu, MD has shown that children with UHL have language delays that first manifest in early childhood but last through adolescence. She also demonstrated that children with UHL are ten times more likely to fail a grade, confirming the earlier research by Bess and Tharpe. Lieu also showed that children with UHL demonstrated a reorganization of certain brain areas so that auditory weaknesses could be supported by other regions involved in processes like vision, language and motor function.
Fatigue and hearing loss
Research from the Vanderbilt group has demonstrated that children with hearing loss have significant problems with fatigue. It was originally thought that fatigue would not be a problem for children with UHL. Recent research has should that this is not correct.
Fatigue is a problem for ALL children with HL, not just for children with bilateral HL.
UHL is not a minor problem. Families need to understand that UHL needs to be taken seriously. For this to happen, audiologists, pediatricians, otolaryngologists, speech-language pathologists and teachers need to consider UHL a disability like all others.
Children with UHL need to be recognized as needing assistance and need to be offered all the services they will need.
*featured image courtesy www via flckr