Can a Faulty Microwave Deprogram Hearing Aids?

Question

Answer

Thank you for the question. I consulted with Jim Anderson, one of the engineers here at GN Resound, and we do not think a microwave could cause any damage to a hearing aid, unless of course it was placed inside the microwave while the oven was running.

Here is the reasoning behind this statement. The federal requirements for microwaves are as follows (taken from www.fda.gov/cdrh/consumer/microwave.html)

"A Federal standard limits the amount of microwaves that can leak from an oven throughout its lifetime to 5 milliwatts (mW) of microwave radiation per square centimeter at approximately 2 inches from the oven surface. This limit is far below the level known to harm people. Microwave energy also decreases dramatically as you move away from the source of radiation. A measurement made 20 inches from an oven would be approximately one one-hundredth of value measured at 2 inches."

We do know a lot about how mobile phone radiation can interact with hearing aids as people use mobile phones while wearing hearing aids on a regular basis. Additionally, mobile phone radiation is in the same frequency range as microwave radiation. So, it would be a fair comparison to use mobile phone radiation to help answer the question.

Mobile phones are used close to the hearing aid and have output powers of a few watts maximum. Let's assume 1 watt for sake of argument. If we assume the power from the mobile phone radiates evenly through a sphere, (not so since the antenna is very close to the head and not a point source, but still OK to assume for sake of approximate comparison), we can find the radius of that sphere where the power density is the same as that microwave oven example above (5 milliwatts (mW) of microwave radiation per square centimeter).

The surface area (As) in cm2 would be 1 Watt/ 5mW/ cm2 = 200 cm2.
The radius of a sphere is: r = {(As)/(4*pi)}1/2 .
Therefore r = {(200/(4*pi)}1/2 = 4cm. or approximately 1.6 inches.

Therefore, if you hold the phone at 1.6 inches from your head, you get about the same exposure as the oven at 2 inches.

This means that if there were a problem, the mobile phone would cause at least as much a problem as the microwave oven. We have not experienced any such deprogramming due to mobile phone use and so would not expect any issues around microwaves.

If your hearing aids have lost their programming, you should take them into your hearing professional so that the problem can be further diagnosed and resolved.

Laurel Christensen, Ph.D., is Vice President, Research Audiology for GN Resound Group (www.gnresound.com)