Hearing Test and Audiogram

Yesterday, Nolan had a hearing test at Buffalo Children's. His hearing has been hit-or-miss, and his speech has shown some regression. Nothing serious, mind you, but I still don't like the disappearance of our friends /s/, /j/, /ch/, and /z/,

I don't have his official audiogram in the mail right now, but his unaided test scores are fairly consistent with the October results. His left ear has dropped by about 20 dB at 2,000 Hz, in typical Nolan fashion.

For those who are unfamiliar with audiograms, Nolan cannot hear the sounds above the lines without his hearing aids. Basically, he can't hear any speech sounds at normal conversational volumes. If you shout at him or talk directly into his ear, he can hear enough to make out what you are saying. This is a moderately severe to severe hearing loss.

The reason for his "slushy" speech is more likely due to his aided hearing levels. Obtaining a pure-tone aided audiogram is a tricky business, because digital hearing aids suppress pure-tones as "background noise," which can make the audiogram a bit tricky to interpret. A child may show hearing thresholds of 30 dB across the board, for instance, but really be able to pick up voices at 20 dB.

With that said, Nolan's aided audiogram is terrible. The suppression effect should affect all frequencies equally, and Nolan's results are showing a significant drop-off in the high frequencies. His higher frequencies are not set appropriately for his hearing loss. His aided results are:

Hearing with both ears, Nolan can't really detect f, th, or s with his hearing aids. Z and V are also above the 35 dB line, which explains why he's having difficulty with those sounds. The audiologist noted he couldn't detect her voice until it was at 30 dB with his hearing aids on - essentially, Nolan has a mild-moderate hearing loss even with his hearing aids on.

I did ask about his bone conduction results and whether the BAHA could be an option for him (to eliminate some fluctuation and to give him better hearing). The audiologist stated that the sensorineural component of his hearing loss is too severe for a BAHA, so he is not a candidate for that technology.

His hearing loss isn't severe enough for a cochlear implant, so he doesn't qualify for that technology, either.

Since Buffalo Children's does not have a hearing aid program, they can't adjust Nolan's hearing aids. Since Nolan's current audiologist does not believe in aided testing, she won't adjust Nolan's hearing aids.

Buffalo Children's was very surprised that our current audiologist does not do real-ear measurements, as this may be part of the problem. The DSL program that sets hearing aid amplification levels is based on a set of averages, but is not specific to an individual child's ear canal size and hearing loss type. With a mixed loss, Nolan likely needs more amplification than a child with a purely sensorineural loss.

And then there is the problem of  recruitment and a narrow dynamic range. Recruitment is a problem for people with severe losses. All of the outer hair cells are damaged, so only the inner hair cells remain to transmit sound in the cochlea. There is no gradual increase in the perception of volume - a sound goes from being inaudible to being WAY TOO LOUD very quickly. This makes setting hearing aids particularly difficult, as the level of amplification needed to make a sound audible is very close to the level which causes pain.

So the hearing aid program must be compressed to fit into this narrow range of hearing - the range between audibility and pain. We may not be able to increase his amplification by much, because it would cause him discomfort with sounds that are too loud.

Rock, meet hard place.

Other than the slushy speech sounds, however, Nolan is doing well - so we'll just repeat ourselves more often, use the FM more consistently, and monitor his hearing to see if (when) he qualifies for different hearing technology.

Cutting and Pasting

We had several interesting lectures today, including lectures on the development of speech sounds, literacy and the deaf child, and how to create experience books. In support group, we wrote letters to our hearing children, telling them how much we love them- the letters will be read to the siblings in the sibling program on the last day of the clinic. After this session, we all went to the larger conference room and created two experience books.

The first was made by stacking four sheets of paper and then folding it over, so there was a "lift the tab" type book. The pages are stacked vertically (the blue and orange book in the picture), and you place all the text on the exposed tabs. The pictures are placed under the tab, so you lift it to reveal the picture after you've read the text. This reinforces the "listening before looking" method, and also demonstrates that text has meaning, since only the text is visible on the outside of the book. This type of book is very useful for discussing sequenced activities (you could talk about the steps in getting dressed, for example). One parent has made one of these with different items that need to be accomplished in the day, and the book has a reward chart on the back. When all the items are checked off, the child earns a reward (such as a sticker). Nolan's is blank, because we didn't really have time to finish the books. When we get home, I think I will make a book about proper conduct in the car (we don't scream or throw sippy cups at Mommy's head, for example).

The smaller book was made from paper lunch bags. Three were stacked, with the middle sack facing the opposite direction as the top and bottom sacks. The book was folded in half and secured, and this creates a book with a page/pouch style. You can place items in the pouch that relate to the text on the page. This one is very clever, and I can't wait to finish this one. I might do ours with a hiking theme. On the page, we will talk about walking through the woods. In the pouch, I will place things like leaves, pictures of rocks, birds, etc. that we would see in the woods. On the next page, I could place a creek and put items like frogs, fish, tadpoles, and swimming trunks in the pouch. I'll post images when we finish our books (probably not until we get home, unfortunately)!

John Tracy also had a book fair today (always bad for my wallet, since I love books). They also had adorable hats on sale for $1 each, with the John Tracy logo. For $1, I couldn't pass them up- I bought four of them.

Unfortunately, our SLT had to cancel our appointment today due to an emergency (I hope everything is OK)! We didn't get to talk about Nolan's audiogram, but we'll take that as it comes. I'm not sure whether or not I believe the new audiogram. We've had a few bone conduction tests at BHSC that show a rising sensorineural loss based on bone conduction, and his ABR at birth showed a rising loss with absent OAE in the low frequencies and present OAE in the high frequencies (consistent with a rising sensorineural hearing loss). I've drawn a very crude example of the difference between the JTC results and our audiology clinic's results:



As you can see, these are pretty conflicting results. I suppose, in the end, it doesn't really matter if he has these odd bone conduction scores if his air conduction is about the same and his aided testing is fine. He does have an air-bone gap, but I'm not keen on putting Nolan through exploratory surgery since he'd have to wear hearing aids no matter what (even if they could find and fix a conductive problem with his ossicles, he still has the sensorineural loss). And if his air conduction hearing aids work well for him, I couldn't see putting him through the implant surgery for a BAHA (bone anchored hearing aid). Plus, I don't even know if BAHA could handle the high frequency sensorineural loss that JTC is showing. There are a lot of unknowns, and it is difficult to integrate such different information into what we know about Nolan's loss.

All we do know is:

1. If JTC's results are correct, then Nolan has been misdiagnosed for three years. Since his CT scan is normal, he has type A tymps when his tubes are out, and he currently has no fluid and he does have patent PE tubes, there is no discernable cause for the "conductive" loss. He also lacks all OAE, and has since birth in this region. The only way to see if his ossicles are affected (since the CT scan was completely normal) is to do exploratory surgery, which has risks of its own. Especially since Nolan has central apnea.

2. If JTC's results are not correct, then we have to wonder why we are getting such variable responses from Nolan. At BHSC, it seems like he has lost some sensorineural hearing, or has a mixed loss. He has also had more than one bone conduction test at BHSC (by more than one audiologist), and these results have been consistent with a rising slope.

His results at BHSC are more consistent with his ABR/OAE testing at birth than the JTC results, but his testing seemed pretty reliable (his attention was well focused) at JTC. On the other hand, he was really well focused at BHSC when we got the rising slope bone conduction scores.

We have two completely different results, with very different interpretations... and no way to tell which is the "correct" answer. Push come to shove, we'll just leave his hearing aids where they are and ignore the conductive component, because he is developing speech and language with no problem with his current hearing aids. There's no way I'd put the little guy through more surgery for no real gain. On the other hand, if we could find the cause of the conductive component (if truly there), it might explain the cause of Nolan's hearing loss (if he had a congenitally fixed stapes or something of that nature that wouldn't show up on a CT scan). And if a BAHA would be significantly better than an air conduction hearing aid for him, it would be worth exploring.

When you have a kid whose hearing loss profile changes every time you step into the booth, you go through the grief process over and over again- including the denial/anxiety portion. If only these tests weren't so subjective!

Of Baseball and Car Fires

Nolan's earmolds are Dodger Blue

It's never a good sign to have your car start spewing out smoke as you're waiting in a thick line of traffic, attempting to enter the stadium. On the other hand, it allows for great language lessons: Car Fire, Overheating, Clutch, Nasty-Burning-Smell, and OMG-Are-We-Ever-Going-To-Park were discussed heavily.

Fortunately, we were able to find a parking spot soon after getting through the parking booths. Unfortunately, the car was still smoking and we were quite far from our "pavillion" (though we didn't know this at the time). Dennis popped the hood and we all agreed that we saw smoke. I'm pretty sure there were car parts in there, too- I know as much about cars as I do about the inner workings of the space shuttle. All I know was that smoke was coming off the stuff under the hood, and that is generally not good.

We decided to let the car sit there and cool down a little, so we headed up to the stands. The other two families were already there, and we ate some free Dodger Dogs, popcorn, and peanuts while watching the game. We stayed just until after the "Take Me Out to the Ballgame" song. Matt was extremely tired and we were a wee bit concerned about the car spontaneously igniting on the way home. Luckily, it seemed to drive well (despite the horrid burning smell) and we arrived safely home.


Today, we have our support team meetings, then a lecture on experience books and a Scholastic Book Fair. My bookcases at home may never forgive me- I have a ridiculous love for books, so I am sure a few will come home with us. We have a lecture on speech assessments, then a lecture on literacy and the hard of hearing or deaf child. I also have an appointment with Miss C., Nolan's SLT. She has completed his language and articulation tests, so I am interested to see his scores (I understand he did very well, so that is always exciting news)!

I do have to say, I love John Tracy. While we got completely different information about Nolan's hearing loss yesterday, we are not left high and dry. We are going to discuss the discrepancies with Nolan's SLT, we have other parents to talk to, and his audiologist is going to try to get him in for more booth testing so we can get a better handle on the situation. We'd also like to get an aided audiogram, but like at home, his changing hearing loss characteristics usually means that we spend too much time in the booth trying to get his unaided levels to ever get around to aided levels. We're trying for a third audiology session (he has a second session on the 28th of July). If we can get consistent information here, we'll have to take it to our audiologist and ENT at home, to discuss the situation. Adapting to such radically different information about your child's "condition" can be difficult. If true, it is exciting if it can be "fixed," though Nolan's sensorineural component can never be fixed. I'm not so thrilled about the possibility of going from air-conduction aids to a BAHA system (an implanted system for permanent conductive losses). We'll have to see what the repeated testing shows, and we have learn about all of the options, pros, and cons before making any decisions.

I'm off to brew some coffee before Nolan wakes up- it is going to be a busy day today!

Dennis left for Oxnard at 5:30am today, taking a very tired Matt and Smokey the Car with him. I'm not sure when he'll be back- probably on Friday afternoon to pick Nolan and me up.

Audiological Angst

With a child who is hard-of-hearing, understanding what he can hear unaided vs. aided is often quite confusing. There are many times that Nolan shows a response to something (with his aids off) and we wonder if this whole thing has been a great big mistake. That he has normal hearing after all, and the tests have been one big giant error. Other times, he acts totally deaf, not turning to people calling his name or to other sounds that he "should" hear. Then we worry that he has lost more hearing, and this can cause a great deal of stress.

The one thing that gives us reassurance is consistent booth test results. After all, if the booth tests are consistent, then we can be fairly sure of the testing methodology. While we've had some fluctuation in the high frequencies with Nolan's hearing, his low frequencies have been fairly stable. His bone conduction scores have also always been stable, with his scores going from 50dB in the lows to 30dB in the highs. This is consistent with his ABR at birth, and with his OAE results at birth (absent OAE in the lows, but present in the highs).

That was true until today. Nolan's audiological testing threw me for a complete loop today. His bone conduction scores were the exact opposite of what they've been in the past. Nolan tested at 5dB at 250Hz, 25dB at 500Hz, and 25dB at 1000Hz.

Big difference from 50dB, yah?

And so now, it looks like this all might have been one giant, colossal mistake. Could Nolan's loss have been conductive since birth? He had no fluid or ear infections at birth, and his CT scan shows a normal ossicular chain. So really, it doesn't make any sense (especially in conjunction with the missing DPOAE in the lows, which were present in the highs). Sure, he's had some fluid and infections since he turned about 1 year old, but his first tests were prior to all the infection hullabaloo.

The amount of anxiety this produces is insane. For instance, the type of device that Nolan is using might be inappropriate if his loss is primarily conductive. A BAHA would be a more appropriate hearing aid for him (if this is true). Or, possibly, the conductive component could be corrected if the source could be found. With a 60dB conductive loss (his air conduction thresholds are fairly similar to his test in May), something is drastically wrong with his middle ear system. This kind of loss isn't caused by tubes- especially since he's had it since birth. The CT scan showed a completely normal middle ear, so there isn't anything really wrong with the bones there.

Which is why I have a hard time believing the latest test results. With a normal middle ear (no fluid, normal ossicular chain, PE tubes), a child shouldn't have a 40-60dB conductive loss. Nolan also doesn't have a craniofacial syndrome, which rules out other strange anatomical things going on. Then there are the bone conduction tests obtained at home, which are all consistent and show a 50dB rising to 30dB loss (which is consistent with his air conduction booth test in May 2008).

Anyhow, Nolan is not hearing at a normal level. His air conduction thresholds are still moderately severe across the board for the left ear, and are at a moderate level for the right ear. Bone conduction does show a sensorineural loss for the 2-4KHz range, so he doesn't have an air-bone gap at the higher frequencies. For the first time in his life, he shows a sloping sensorineural loss.

Our audiology clinic at home shows a moderately severe to moderate loss, with a possible slight conductive component across several frequencies. John Tracy is showing a moderately severe conductive loss in the low frequencies, with a moderate sensorineural loss in the high frequencies. Now the question is: which one is right? Has Nolan been misdiagnosed all along? Or are we getting "false" bone conduction readings?

We may ask for a referral to House Ear Institute to sort this all out. If only there were an objective way to get bone conduction scores!