How To Ensure Your Child Hears the “S” Sound
Written By: Dr. Jane Madell, CCC-A/SLP, LSLS Cert. AVT
It may seem obvious, but it is important to remember that the problem with hearing loss is that it makes it difficult to hear many things. But fortunately, with the technology available today, we are able to provide auditory access to allow children to hear all phonemes. The most important reasons for fitting technology is to permit access to speech information. One of the most important sounds for kids to hear is “s”. Why? Well, “s” provides critical grammatical information, such as pluralization (e.g., boot, boots), present vs. past (e.g., she put it on, she puts it on), 3rd person present (e.g., she eats), possessive pronouns, (e.g., hers, his, theirs), contractions (e.g., it’s). This grammatical information is very important for language learning and for literacy.
Where is the Energy for “s”?
The phoneme “s” has energy at 5000-6000 Hz. How are we going to be sure kids hear it? Don’t assume. When selecting hearing aids, it is important to choose technology that will provide access to high frequencies. After fitting hearing aids, we again should not assume, but should test to be certain that the child is hearing high frequencies.
Testing to be Sure the Child Hears “s”
Real ear testing will not tell us if a child is hearing high frequency sounds. It tells us what is reaching the tympanic membrane but not what is reaching the auditory cortex. To know what is reaching the auditory cortex, we need to test. Threshold testing and speech perception testing will provide that information. Threshold testing using noise band thresholds will provide information about what the child hears in each frequency band. We need to test 6000 Hz and 8000 Hz to be sure that the child is hearing “s” at sufficiently soft levels in the critical high frequencies. Standard speech perception tests will be more useful if we record phoneme errors, not just whether the word is correct. By looking at specific phoneme errors we can find out what phonemes a child is hearing correctly and which present a problem for a child.
Therapists and parents use the Ling sounds (ah, ee, oo, sh, s and m) to see what a child is hearing, and this can be especially useful for young children and to monitor that technology is providing the necessary benefit in school. This is a great screening test but needs to be carefully used. It is important to remember that sounds should be presented in the way the phoneme would fall in general conversation. The phoneme “s” is not as loud as the other phonemes. Vowels provide 90 percent of the energy of speech but only 10 percent of the intelligibility. Consonants provide only 10 percent of the energy of speech but 90 percent of the intelligibility. The vowels (ah, ee, oo, and consonant m) will be louder than “sh” and “s”. “S” can be 30 decibels (dB) softer than the vowels. Audiologists need to be careful not to peak all the phonemes on the VU meter since this would make all sounds equally loud and would not be a good indicator of how phonemes actually sound in conversation. Therapists and teachers also need to present the sounds as they would fall in general conversation. We need to present sounds at a level at which the sound would fall in normal conversation. In other words, “s” will be softer. In testing for detection, this can be difficult to control. If testing for discrimination, we can present with a carrier phrase (“John, say /ah/;” “John say /s/”) and let the phoneme fall where it may.
The Medial Consonant Test
The Medial Consonant Test is a way to check that a child is hearing different phonemes. The phonemes are presented in random order and embedded in a vowel (aba, ava, afa, etc.). We then record if the child heard the consonant correctly. We can use the information about which consonants are misperceived to help modify technology settings.
The Western Ontario Plurals Test
Once a child can repeat words point to pictures, the Western Ontario Plurals Test is a good way to assess high frequency perception. The test presents words in singular and plural format (e.g., boot, boots) and the testing provides information about whether the child can hear high frequencies.
What do we do if a Child Cannot Hear High Frequencies?
While it is true that many current hearing aids do not have bandwidth that extends to the high frequencies, we still need to test to demonstrate what the child hears and does not hear. The test information will be useful in planning remediation. First, we need to see if there is other technology that can provide high frequency information. It may require simply changing hearing aid settings or trying different hearing aids. If that does not work, it may be time to consider cochlear implants. Remote Microphone Systems may provide more auditory access because of the close microphone, but it may not provide as much access as is needed in everyday listening. Auditory-based therapy will be useful in helping children improve auditory skills. But, the primary responsibility falls on the audiologists. Audiologists need to be sure that technology is set to good auditory access, and we use threshold and speech perception information to do that.
The important thing is to test to be sure that the child is hearing what he or she needs to hear and moving forward to fix it if sounds are not being heard.