I had suddenly become deaf in one ear. The first thing to pass through the mind of a neurologist who has suddenly become deaf is the possibility of a nasty tumour at the cerebellopontine angle. Close on the heels of this unwanted thought, however, was the much more reassuring realisation that this was almost certainly a recurrence of an ongoing problem with build-up of wax that I had just let go too long.
There was one quick way to make sure. Many neurological tests—such as those assessing power or tone—are essentially impossible to perform on oneself. Eliciting your own reflexes is just about possible, but only if you are ambidextrous with a tendon hammer and supple enough to kneel on a chair while reaching round to tap your Achilles tendon. Simple tests of hearing, however, are easily performed. So when I arrived home, I took a tuning fork out of my bag and performed Rinne's and Weber's tests.
Both are quite simple. Sound is normally conducted to the inner ear more easily through air than bone. In Rinne's test you strike the tuning fork and hold it against the outcrop of bone immediately behind the ear until you can't hear it anymore. Then you put the tuning fork in the air about an inch from the earlobe, at which point, under normal circumstances, the tone can be heard again. I heard nothing, suggesting that there was indeed something (wax was the usual suspect) blocking the free passage of sound waves from the outer to the inner ear.
Then I did Weber's test. For this you strike the tuning fork and put it down on the middle of the forehead. In patients with nerve deafness on one side, the sound is heard better on the normal side. So far, so sensible. But in patients—and indeed in neurologists—with wax blocking their ears, the sound is heard better in the blocked side. If you have a tuning fork you can demonstrate this simply by blocking one ear with your finger.
Why should this be? There should be no difference between the intensity of the sound waves reaching each cochlea via the bones of the skull. The good ear, in addition, should be getting additional sound via air conduction. So surely the sound should be louder in the normal ear?
I have yet to find anybody—ear, nose, and throat surgeon or neurologist—who can give a convincing answer to my question. If anyone can enlighten me, I would be delighted.
Footnotes
We welcome articles up to 600 words on topics such as A memorable patient, A paper that changed my practice, My most unfortunate mistake, or any other piece conveying instruction, pathos, or humour. If possible the article should be supplied on a disk. Permission is needed from the patient or a relative if an identifiable patient is referred to. We also welcome contributions for “Endpieces,” consisting of quotations of up to 80 words (but most are considerably shorter) from any source, ancient or modern, which have appealed to the reader.