Tiny ear muscle device could help MND sufferers to communicate 06/05/2021, 12:06 am Earswitch is a Human-Computer Interface device that works by detecting intentional movement of your eardrum by one of the smallest muscles in your body, the tensor tympani (University of Bath/PA) A revolutionary device could allow people with neurological conditions to communicate again using a tiny hidden ear muscle. The Earswitch device is being developed by a GP and a team of researchers at the University of Bath and could offer fresh hope for people with conditions such as Motor Neurone Disease (MND). Earswitch enables people to control a keyboard by tensing the tensor tympani muscle in the ear.