Question
I have a patient with a mild loss on his left side and a severe loss on his right side. The loss on his right side was sudden in nature and his otolaryngologist has said that it was due to a viral infection. The patient's word recognition score is excellent for his left ear, but only 40% for his right ear. The otolaryngologist told him that hearing aids will not help. My question is: Even if the word recognition is low, will a hearing aid help on the right ear? (I know a BICROS will work).
Answer
You didn't mention just how bad the right ear is, but I'll assume something in the 60-70 dB range. Since you said BICROS, not CROS, I'm assuming that the left ear also is aidable. So, we have five choices: aid the left ear only, aid the right ear only, a bilateral fitting, a BICROS fitting, or no hearing aids at all.
My choice would be a bilateral fitting, for a couple of reasons. First, the patient probably thinks that his left ear is normal. If you only aid the left ear, he will always wonder why you didn't aid the ear with the hearing loss. So would I. Assuming that the left ear has a 30-40 dB hearing loss, if only the right ear is aided, the patient would still be lacking audibility for soft speech; he probably has a very small dynamic range, and I doubt that you could achieve enough gain to make soft speech audible in the right ear. Which leads us to a bilateral fitting. While he probably won't experience all of the desired binaural benefits, we could expect improved localization, simply because you are now making many sounds audible in his right ear.
It's true, the decision would be easier if word recognition was better for the right ear. But, we do know that in general, patients will achieve a bilateral word recognition score equal to the best ear. In other words, you don't have to be concerned that right ear amplification will "pull down" overall speech understanding. Rather, the brain might be able to use loudness from the right ear, combined with speech clarity from the left ear to provide the patient with overall benefit, especially when people are talking to him from his right side (such as when he is driving a car). And also, you might find that aided, the word recognition score for the right ear is better than what you obtained with earphones.
I'd rate your chances of a successful bilateral fitting at 50/50 or better, which is worth a shot to me. It will depend somewhat on the resulting aided symmetry. I'd say that if you reduce the asymmetry, and make aided symmetry 15 dB or smaller, you'll probably be successful. If the aided asymmetry is too great, the patient will simply perceive all sounds in his good ear, and consider the hearing aid in the right ear a useless nuisance. But, you (and the patient) really need to know this before you totally eliminate this ear with a BICROS fitting (which may not work as well as you suggest).
H. Gustav Mueller, Ph.D. is Professor of Audiology at Vanderbilt University in Nashville, TN. He also is Senior Audiology Consultant, Siemens Hearing Instruments, and Contributing Editor of The Hearing Journal. Contact: GoVandy@GusMueller.net
