Why do we put technology on kids with hearing loss? One reason and only one reason: to be sure they are hearing well enough to learn speech and language. There is an enormous amount of data demonstrating that the amount of auditory exposure a child receives will determine how much language they develop. Parents can talk talk talk, but if the child is not hearing absolutely every phoneme it will effect brain development. So how do we know that a child is receiving sufficient brain development?
Validation AND Verification
The standard of care to be sure that children are hearing well includes BOTH verification using real ear measures, and validation using behavioral measures. If we don’t do both we do not know what a child is hearing. If the audiologist does not do both, your child can be missing out.
Will real-ear testing tell us what a child hears with technology?
Real ear testing is a critical first step when fitting hearing aids. It is the beginning of determining how to set equipment. But it is important to remember that real ear tells us how much sound is reaching the tympanic membrane – not what is reaching the brain. We need to verify what a child is hearing with technology and real ear will not tell us. Real ear is a starting place, but without validation we will not know what the child is hearing. Unless we can ensure that a child is hearing with her technology we cannot expect children to learn using audition. So how do we find out what the child is hearing?
Behavioral testing is the gold standard. It is the only way we can measure the entire auditory system and know what the child is responding to. Many audiologists will validate a child’s performance using speech perception testing, and I believe that speech perception testing is a critical part of validation, but speech perception testing does not provide all the information we need.
Aided thresholds – yes we can !!
Aided thresholds are really critical. We do them routinely for children with cochlear implants. Why are audiologists so resistant to using them for children with hearing aids? As we develop more technology, like real ear and ABR, we seem to think that they substitute for behavioral testing. They do not, they should be in addition to what we already do. Aided testing can help us fine tune a child’s hearing aid settings. I routinely test aided thresholds after the hearing aids are set using real ear verification. I often find that the child is not hearing enough high frequencies. I know, that if the child is not receiving enough high frequency information, she will not hear /s/, /sh/, /f/, and all the other high frequency sounds. That means she will miss hearing plurals, possives, and some non-salient morphemes. Does this matter? Will it effect language? Literacy? Absolutely. So I am not comfortable sending a child out unless I know for sure she is hearing what she needs to hear. The goal? Aided thresholds at 20 dB from 500 – 4000 Hz.
Testing speech perception
Speech perception testing is an essential part of validating hearing aid performance. For very young children, we may only be able to obtain thresholds to the Ling Sounds but that will provide critical information. If presented in the way speech falls in general conversation, we will get good information about what a child is hearing and what they are missing. Don’t try and make the /s/ as loud as the /u/. Vowels carry most of the energy of speech, but consonants, the meaning. But /s/ is much softer when presenting we should keep that in mind. For example, if a child does not hear the /s/ I know, he is not hearing enough at 4000 Hz and I need to boost 4000 Hz in the settings.
Once a child can point to pictures or repeat words, we can do extensive speech perception testing with each ear separately and both ears together. Why do we need to do it this way? If testing is only performed with both ears we will not know if one ear is not performing well or what we need to do: improve settings, do therapy with the poor performing ear alone, or change technology. If you don’t test you don’t know.
Testing at normal conversational levels in quiet (50 dB HL) monaurally and binaurally, at a soft conversational levels (35 dB HL) at least binaurally, and at 50 dB HL with competing noise will provide a lot of information. But the best information will be provided if speech perception testing is accomplished using phoneme scoring. Whole word scoring provides good information but it does not tell you what, specifically, a child is not hearing. Phoneme scoring gives the audiologist, speech-language pathologist, listening and spoken language specialist and parents the opportunity to determine what a child is not hearing. That tells us all what we have to do to first, fix technology settings, and, once we know technology is providing information at normal levels throughout the speech frequencies, to plan remediation.
So what needs to be tested with technology to know if a child is hearing well enough?
50 dB HL
35 dB HL
50 dB HL + 5 SNR