To do Calorics or not to do??

[GEM]

I had a patient recently referred for Caloric testing. The patient had a unilateral dead ear (left ear) and normal hearing in the right ear. Middle ear analysis demonstrated tympanic membrane compliance values of 1.3ml right ear and 3.0ml in the left ear. Would calorics be appropriate due to tympanometry being outside the normal range or should the calorics be replaced with the headshake test and head thrust?

[Guy]

The long awaited revision to the BSA caloric test recommended procedure is likely to include the following in its list of possible contraindications: "Hypermobile or atrophic tympanic membrane - care should be taken for severe hyper-mobility and a second medical opinion obtained."

I think I would try to find out the reason for the hypermobility (which I wouldn't regard as severe) - including any relevant history of trauma or perforation and would perform otoscopy very carefully. If all appeared well then I would inform the referring clinician and defer to their decision. If the test was to be performed I would take even greater care than normal to ensure that the water stimulus, if water was used, was introduced gradually (unfortunately not all stimulators allow control of this) and that the nozzle did not occlude the external canal.

I am currently analysing the tympanometric data of several hundred patients (mep, compliance and canal volume) together with TM temperature with respect to their caloric results to see whether there is any significant association. That should provide the answer to the query that is often raised about this.

[GEM]

The referring clinician has re-referred for calorics stating this is not a contraindication (no middle ear pathology is present) and will not cause any affect to the results (and therefore assuming can be compared to normative data). However, the irrigator used is water and the initial start of flow cannot be graduated -just on or off. The clinician wishes to determine if there is a CP in the "dead ear" and are far as seen there is no obvious cause for the hypermobility. Would you go ahead in this case?

[Cochlear]

As Guy mentioned, it is very important how the TM looks like; what's the otoscopic finding ?
If it is ok, than go agead, you can't harm the patient.

Any history data about unilateral kophosis ?

Because the 3,0ml compliance is at the "dead" ear it is dificult to explain, but it could be because of osseous disarticulation and it wouldn't influence calloric examination. It's the most common cause if you have normal otoscopic finding.

If it is just important to examine if there is any vestibular activity at that side you can perform Toroc's test: just put the 2ml of cold watter (10C) in that ear and wait to see if there is any response from that side.

[Guy]

I agree with Cochlear that an ice water test would answer the question of whether there is any response on the side of the hearing "dead ear". However I certainly wouldn't do that without first doing a conventional caloric because if that ear has normal or reasonable vestibular sensitivity the patient is likely to show you his breakfast. In my opinion ice water calorics should be reserved for cases in which conventional calorics show no or almost no response.

Since your water system is poorly designed, with no user control of flow introduction, (I'm being intentionally rude to manufacturers in the hope that one of them will take the hint and make a decent system) then start it with the water directed onto the pinna and then transfer into the canal, taking care to avoid canal occlusion.

[Cochlear]

when you have hypermobile TM the flow of water can't harm the TM
also I doubt that you can harm the inner ear,
but of course you can direct the flow of water to the chanal wall.

[Guy]

I think I will have to disagree!
There have been a number of cases of ruptured TM caused by syringing, some of them ending up as compensation cases.
I think the suspicion is that a paper-thin TM might be in danger even with the more limited flows and pressures involved in a caloric stimulus.

[Cochlear]

Excuse me for my bad english, but what I wanted to say is:
if the otoscopic finding is ok, that means there are no thin TM, nor weak points, there are not retracion pockets or athelectatic TM . . .
and you just have the hyper mobile TM according to the tympanometry, that means because of hypermobiliby that TM is more elastic and even less vulnerable to rupture.