Expert: Harriet B Jacobster, Au.D. - 6/20/2008

Question
My 23 month old son has passed a hearing test. Specific results included: Otoscopy was remarkably bilateral. Tympanometry reveled type A typanograms therefore indicative of normal middle ear function. And visual reinforced audiometry in sound field indicated normal hearing sensitivity. The reason I tried to give you the specifics of the hearing test he passed is because my question is- is there anymore testing that should be done. Is there more to hearing than just the sound? Is there such thing as him hearing sounds, but not necessarily with enough clarity to decipher words? Also, is it possible the he can hear only sometimes and not others. He has no history of ear infections. He has no words and does not follow commands. We are starting speech therapy. I welcome any thoughts. Thank you for your help.

Answer
Hi Vicky,
When we test infants and toddlers, the main goal is to determine whether the child has sufficient hearing to develop speech and language.  If there are no concerns, then the standard testing consists of typanometry and soundfield audiometry in toddlers.  The biggest problem with soundfield audiometry is that the child could still have hearing loss in one ear ("unilateral") yet have a "normal" result. However, even with one normal ear, the child should develop language and speech normally.  At 23 months, your son should be saying about a dozen words, and be able to follow simple commands.  There are many reasons for language delay other than a hearing loss.  I would recommend that you start speech therapy and, if he doesn't show significant improvement in a few months, that the next audiometric testing that should be conducted would be Otoacoustic Emissions and Auditory Brainstem Responses.  There are very simple tests, they require no participation from your son and they will give more specific information on how his ears and the auditory nerves are functioning.  There are instances where sounds are heard but words are still unclear.  Unfortunately, with one exception, it is difficult to test for these with children younger than 7 years old, such as the case with auditory processing deficits where the brain "jumbles" the auditory signal.  However, there is one condition, known as Auditory Neuropathy (aka Auditory Dys-synchrony), that can be diagnosed with the above mentioned tests.  With children, if there is any type of hearing loss, the earlier it is treated, the better the outcome.
Hope this helps.
Harriet B. Jacobster, AuD
Board Certified in Audiology