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Hearing aid hears theft detectors?

HearWHAC hearwhac at netins.net
Sat Jul 5 21:57:17 EST 1997

Jim Lellman wrote:
> Apparently more stores are using those little labels and the detectors
> at the doorway.  My son wears a hearing aid with a bone vibrator.
> He can "hear" the detectors at the doorway when he walks by them.

Jim's comments have generated an interesting discussion thread. My
comment is not directly related to "theft detectors," but there are some
devices available that automatically turn lights on and off with "motion
detectors." You will occasionally find one of these in use in a rest
room that is not frequently used. When you enter the room, your motion
causes the lights to come on. After you leave and there is no motion for
a certain period of time, the lights go out - energy saving device.

These devices generate a sound at a high frequency that cannot be heard
by the human ear. One of our hearing aid patients was a school teacher
and they installed this feature in her class room. The high frequency,
in this case, 25,000 Hz, caused her hearing aid to "jam." This posed a
very difficult problem for her, and for us - should we ask the hearing
aid manufacturer to change the hearing aid - or should the school system
ask the device manufacturer to change the frequency. They eventually had
to do the latter and the frequency was changed one octave to 50,000 Hz,
enough to eliminate the hearing aid "jamming" problem. I share this
experience because some of you may run into a similar situation.

Paul Woodard ;-)

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