Please lets test speech perception. I am hearing from so many speech-language pathologists, listening and spoken language specialists, teachers of the deaf and parents that their audiologists are not doing speech perception testing. WHY?
What is the reason we use technology? The one and only reason is to improve understanding of speech. Technology makes sound louder, not always clear. By carefully evaluating speech perception in a variety of test conditions, we can determine what phonemes are not clear and can make some adjusting of technology settings to improve speech perception.
Only by testing speech perception can we tell what a person with hearing loss is hearing and what they might be missing.
Let’s remember, real ear (probe mic verification) is not perfect. First, it only measures what is reaching the eardrum, not what is reaching the brain. Second, it is an average. Many people will do well at the real ear targets but not everyone. We have an obligation as clinicians to be sure that our patients hear as well as they can.
Here are some examples of cases in which patients met real ear targets but speech perception testing indicated they were not hearing well.
Right hearing aid
Left hearing aid
Binaural hearing aids
CNC 50 dBHL
This patient has a symmetrical hearing loss but speech perception is not symmetrical. In this case we can see that this patient has fair speech perception with the right hearing aid but poor speech perception with the left hearing aid. In addition, the poor speech perception with the left hearing aid is pulling down the binaural speech perception scores.
Once I have these test results I can plan. In this case, once I was sure that the left hearing aid was working well, no distortion, and providing sufficient gain through the frequency range, I would as the patient to remove the left hearing aid for 2-3 hours a day to build listening skills in that ear, hopefully with the help of a listening and spoken language specialist. We know that in this child will have difficulty hearing in a classroom because he is not hearing normal conversation well in a classroom or in a work setting. Retesting after 2-3 months of listening training will provide information about what is needed further.
Another important tool is to evaluate perception errors, not just a total score. When I score speech perception tests, I record the mistakes. This allows me to look at a phoneme frequency allocation table and determine which frequencies the person is missing.
For example if I say the word /miss/ and the person says /mit/ I know they did not hear /s/. By looking at a frequency allocation table I know that /s/ has energy at 5000-6000 Hz. In this case, I would try and increase the energy in the technology in the area of 5000-6000 Hz and retest to see if the person can now hear it.
If I person substitutes /b/ for /p/, (/bay/ for /pay/) they may have too many low frequencies. If a person has a /sh/ for /s/ substitution (ship for sip) I think he may not ave enough energy in the higher frequencies since he is not hearing /s/.
By testing in different test conditions we can figure out what to expect. For example, this child hears well at a normal conversational level but has poor speech perception for soft speech and in competing noise.
50 dBHL +5SNR
We can make a good case for a remote microphone system in this case. This child does not hear well at soft speech levels or in competing noise. If she cannot hear soft speech she will not be able to overhear conversation, which will significantly reduce language exposure. She will not hear the other children in the classroom, and will not hear he teacher at a distance.
Since every classroom is noisy we know that, without a remote microphone system, this child (or adult) will have difficulty in many situations. These test results will also justify use of a remote microphone system at home.
Looking at test results
There really no excuse for not doing speech perception testing. If we do not test we really have no way of knowing what a person with hearing loss is hearing and, more importantly, what they are missing.
We have an obligation to know what our patients are missing so we can fix it. And if we do the work, we can actually fix it a lot of the time. Often there is a correction we can make in technology settings or we can suggest therapy to help improve perception. If we don’t test, we don’t even know something is wrong.
PLEASE TEST SPEECH PERCEPTION!!!
*featured image courtesy ENT Institute