The LMH Test For Monitoring Listening – Jane Madell and Joan Hewitt

Today’s blog discusses a new test for monitoring listening developed by Jane Madell and Joan Hewitt

We know that it is essential that children with hearing loss hear very well with their technology if they are going to be able to use listening to learn language and develop good literacy skills. That is the reason Dan Ling developed the 5 sound test (a, e, u, sh, s) which eventually became the 6 sound test with the addition of /m/.

The Ling test has been very useful as a way to monitor hearing of some of the sounds of speech. We have always known that the 6 sound test did not measure all the sounds of speech. It was truly meant to be only a screening test.

We recommend testing all phonemes in whatever language a child hears using something like the Medial Consonant Test as soon as the child able to perform the test. But when screening is called for, the LMH test will provide more information than the Lings.

In the time since the Ling  6 sound test was developed technology has improved sufficiently so that we have much more control of technology settings. In addition, children are receiving technology much earlier so they have access to sound at an earlier age. When the Ling developed the test we did not have cochlear implants and hearing aids were adjusted using only screwdrivers and had very limited options. With technology at the state it is now we have much more control over settings and we are obligated to monitor listening more carefully.

The Ling 6 sound test covers a range of consonant bands but there is not a lot of information in the 2^nd and 3^rd formant bands which are critical for consonant differentiation. (See figure 1) We are suggesting the addition of 4 more consonants to round out the test and to provide a better balanced test covering Low, Middle, and High frequencies (LMH).

Introducing the LMH Test (Ling, Madell, Hewitt or low, mid, and high frequency) Test

We are introducing the LMH test which is a screening test for low, mid and high frequencies. With the addition of 4 consonants the test is more balanced. Figure 2 shows the test with the 4 additional consonants added to the Ling 6.

With the addition of /n/, /h/, /z/ and /dj/ we can better expand the understanding of a child’s speech perception. There is more information in the 2^nd and 3^rd formant which can help us quickly screen for problem areas of perception.

How to Use the LMH Test

When testing infants or children new to technology we are looking for detection. We ask parents to report which phonemes a child hears at different distances.

As children get older, they are asked to repeat what they hear. Some children are more comfortable pointing to pictures, while others will repeat back. Once children can imitate, we expect them to repeat back.

Testing should be accomplished with the right technology, the left technology and with both together. If testing is accomplished only in the binaural condition, it will not be possible to know if one ear is not performing well. Without binaural testing, we will not know if the hearing in both ears together is causing distortion.

All children need more complex speech perception testing including use of the Medial Consonant Test to understand if they hear all consonants in their language. For very young children or children new to technology who struggle to repeat the medial consonant test using a VCV format, the consonant can be used in isolation. As they progress they need to use standard speech perception tests which are age appropriate.

Clinicians are responsible for teaching parents to develop the skills to do the testing on their own at home and reporting findings to the clinicians. As parents learn to provide reliable test findings, the clinicians’ job changes from repeating the same test to helping the child move on to more difficult tasks and helping parents expand what they are doing to include more consonants and test in different conditions.

In other words, once a child reliably detects the LMH at home for the parent, the clinician should be working on imitation. Once the child reliably imitates, the LMH at home, the clinician should be encouraging imitation of all phonemes.

How to Use the Results of the LMH Test

The goal of the LMH test and of all speech perception is to determine what a child is hearing and what they are missing. Speech perception and production need to be monitored regularly so that we know what the consistent errors are.

While testing with the LMH Test will give some information, testing all the consonants will provide much more information The information can then be used by the audiologist to adjust technology settings to provide better access to frequency bands not being perceived.

Figure 1: Formant /Frequency Bands of LING sounds

Figure 2 – The Ling, Madell, Hewitt (LMH) Test. (Additional phonemes are in red)