Monday, December 14, 2009

The Importance of the Middle Ear

We go to Buffalo tomorrow for Nolan's repeat hearing test. Hopefully the most recent loss of hearing was due to the wax in his ears. Kids with hearing aids for a sensorineural loss rely on a healthy middle ear to maintain reasonable aided hearing levels. Nolan has a relatively mild loss, but middle ear problems can cause his hearing to drop into the severe range across all frequencies. This is the primary reason our ENT wants to get those adenoids and tonsils out.

With every hearing test, our audiologist runs a tympanogram. This measures the mobility of the eardrum and can give an indicator of middle ear health. A nice, healthy middle ear gives a "Type A" tympanogram, with a nice peak to indicate the eardrum is functioning properly. I actually only have one tympanogram with this configuration- this example is from Nolan's right ear during a relatively fluid-free period of time. This was also shortly after his second PE tube fell out of the right ear.

Nolan's right ear: possibly the only normal tymp. he's had.

The second type of Tympanogram is a "Type B," and is flat. This can mean fluid, or a perforation. When Nolan's right ear dropped to a hearing level of 80dB in December 2008, his tympanogram looked like this:

Type B tympanogram in a very fluid filled ear

You can't see a peak, and the line is very flat. With no PE tube in place, this was bad news. This is what earned Nolan his second set of Pressure Equalization (PE) tubes.

Not all "Type B" tympanograms are bad. Nolan's healthy left ear always displays a "Type B" tympanogram, because it has an intact PE tube. A child with a PE tube will display a flat tymp. with a large Ear Volume. The volume lets us know that the tube is in place and functioning as it should. The tympanogram is a good way of checking up on the status of his tubes:

Type B tympanogram with a patent PE tube.

There is also a "Type C" tympanogram, which is what Nolan's right ear is currently displaying. This means there is negative pressure in the middle ear space, causing the eardrum to retract. I don't have a picture of this tympanogram, because it was done as a quick check-up at our most recent ENT appointment. Type C tympanograms can be caused by congestion, and sometimes mean the middle ear space will soon fill with fluid.

Hopefully our hearing test tomorrow will show a return to our June 2009 hearing levels. If we see a decline in hearing ability, a tympanogram will be run again to verify a healthy middle ear.

I have my fingers crossed for good hearing levels and a nice "Type A" tympanogram!


Terena said...

Queen Teen still has her tonsils and adnoids. There was some debate about whether or not she needed them removed. Is there a reason you ENT wants your son's removed?

leah said...

Basically, chronic fluid and suspected sleep apnea. I'm really debating the whole thing- it is quite stressful. Nolan has had enough procedures that have required sedation (two sets of PE tubes, ablation of posterior urethral valves, MRI, CT scan, and upper endoscopy/24 hour pH probe placement- so that makes six sedations so far).

We're doing a sleep study before we make any decisions, but I really don't want to do it unless it is absolutely necessary. The chronic fluid wreaks havoc with his hearing, and they don't compensate for the fluctuating conductive issues (his hearing has dropped to a flat 80dB with fluid in the past).

melissa said...

Hope Nolan gets a nice healthy tymph tomorrow! I had a tymph done for my right ear on the 10th of this month, I never knew what it really was for but it was like A, the mountain shape!! Hope Buffalo goes well!