How much trouble is a unilateral hearing loss? How much does it interfere with listening, learning and literacy? Well, it varies from person to person but we cannot assume that it is not a problem. Some parents feel that unilateral hearing loss is a problem and others feel that if a child has one good ear he or she will be fine. Maybe he will, but maybe he will struggle. Research clearly indicates that unilateral hearing loss is educationally significant. Bess et al (1998), Bess et al (1986) English and Church (1999) demonstrated that 1/3 of children with unilateral hearing loss had to repeat a grade by 3rd grade. Other studies have demonstrated similar effects. While a unilateral hearing loss may not be the same kind of emergency that a bilateral hearing loss is, auditory brain development is just as critical for these children.
Why do we need two ears?
We know the following about two ears – they enable us to localize sound, and improve the ability to hear when there is competing noise. How important is this? Pretty important, especially if you are a little kid and trying to learn in classrooms – which we know are noisy. Adults who lose hearing in one ear report feeling off balance and report having significant problems hearing in many situations.
Does it matter which ear?
We need two ears, and for adults, there may not be a significant difference if a hearing loss develops in the right or left ear, but for a child things are different. Brain research has demonstrated that language is a left brain activity and the majority of fibers from the right ear go to the left side of the brain so, if a child is going to have a hearing loss in one hear, it would be better if it were the left one. (If only we could control this.)
How do we know how much of a problem a unilateral hearing loss is?
As in all other aspects of audiology, we should be making decisions based on data. So prior to making a decision about whether or not to try a hearing aid on the ear with the hearing loss we need to assess speech perception in a bunch of different situations.
My suggestions for testing the functional effects of a unilateral hearing are as follows:
• Have the child seated facing forward with loudspeakers at 45o
• Present speech from the loudspeaker on the side of the poor ear
• Present noise (4 talker babble) from the loudspeaker on the side of the good ear
(This is the most difficult listening condition.)
• Test speech perception in the following conditions using tests at the child’s vocabulary level and recorded if possible (Madell, 2008).
o 50 dB HL (normal conversation)
o 35 dBHL (soft conversation)
o 50 dBHL +5 SNR (Normal conversation in competing noise)
Interpreting the test information
If a child demonstrates difficulty hearing soft speech or speech in noise, technology can easily be justified. A hearing aid should be ordered for a trial for the poorer hearing ear. If testing indicates that the child is doing well for soft speech and in noise a decision about technology can be delayed. Even if a child does well, the strain of listening all day with a unilateral hearing loss, will have a negative effect on the ability to attend for a long school day and an FM system should be recommended.
Kids with unilateral hearing loss should receive a speech-language evaluation to assess speech, language and listening skills to determine if skills are at grade level and to justify therapy if necessary. A psycho-educational evaluation should be scheduled to assess learning skills and to determine if any additional learning issues require assistance.
As with any hearing loss, kids should be monitored on a regular basis. Hearing can change, and auditory development can change. By regularly monitoring auditory function we can make a determination about auditory management.
1. BESS, FRED H.; DODD-MURPHY, JEANNE; and PARKER, ROBERT A. 1998. “Children with Minimal Sensorineural Hearing Loss: Prevalence, Educational Performance, and Functional Status.” Ear and Hearing 19 (5):339–354.
2. BESS, FRED; KLEE, THOMAS; and CULBERTSON, JAN L. 1986. “Identification, Assessment, and Management of Children with Unilateral Sensorineural Hearing Loss.” Seminars in Hearing 7 (1):43–50.
3. ENGLISH, KRISTINA, and CHURCH, GERALD. 1999. “Unilateral Hearing Loss in Children: An Update for the 1990s.” Language, Speech, and Hearing Services in Schools 30 (1):26–31.
4. Madell, J.R. (2008), Speech Perception, in Madell, J.R. and Flexer, C,; Pediatric Audiology: Diagnosis, Technology and Management, Thieme, NY