[visionlist] bite bar and bone conduction

[Christian Kaernbach]

Dear List,

This is a question on an auditory issue (sound transmission) posted to 
the visionlist because people on visionlist will have quite some 
experience with bite bars. Hopefully some of them will at the same time 
have experience with auditory experiments....

We plan to do experiments involving bite bars (in order to guarantee a 
certain position of the head) and sound transmission via bone 
conduction. We could use normal bone conduction transducers strapped to 
the mastoid but it might be compelling to apply the sound via the bite 
bar. Has anybody experience with sound application through bite bars?

I have found in the internet that potential users of BAHA (bone anchored 
hearing aids) are encouraged to test the effect of bone conduction sound 
via bite bars. Stefan Stenveldt did experiments on the evaluation of 
BAHA via bite bars, and it seems to work quite well. Their only problem 
was that the maximum measuring time was rather short: Some participants 
didn't work through the entire three-minute (!) session. The did not use 
bite bars with dental impressions. Hopefully dental impressions will 
make things more comfortable, spreading the bite pressure more evenly.

It could be that bite bar sound transmission will be variable depending 
on bite pressure. Hopefully bite bars with dental impressions will 
ensure a good contact so that sound transmission should not depend too 
much on bite pressure. A five-dB variability would be acceptable. ... 
And what about the sound transmission to the table? Can it be ignored? 
Would mounting the bite bar to the table make it more difficult to apply 
sounds via the bite bar? Any ideas about the construction that could 
favor sound transmission and/or the coupling to the transducer?

And I am happy about all (maybe off-list) informations for newbies: Can 
we do the dental impressions ourselves, or will we have to involve a 
dentist? Can we conceive the mounting of the bite bars as we please or 
is there anything we should watch out for? How to keep the dental 
impressions in good hygienic condition? Or better hand it over to the 
participant to care for between sessions? ...

Thanks in advance,
Christian

-- 
Prof. Dr. Christian Kaernbach
Allgemeine Psychologie
Institut für Psychologie
Christian-Albrechts-Universität zu Kiel
Olshausenstr. 62
D-24098 Kiel
Germany
www.kaernbach.de