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Earswitch: Control from within the ear

  • Name
    Dorothy Hardy
    COG-MHEAR Research Programme Manager

Nick Gompertz started to work on his Earswitch after watching someone with ALS (motor neuron disease) lose his ability to use his speechwriter equipment. He was also inspired by Jonathan Bryan, who wrote ‘Eye can write’ by focusing on individual letters on a Perspex screen, with an assistant writing down each letter. A switch controlled by muscles in the ear could give make this type of communication easier.

Nick explained that he knew that there was a muscle in his ear that he could control, so he looked inside his ear and saw that he could voluntarily move his ear drum. The muscle that he was using is the tensor tympani. When this muscle is contracted it pulls on the eardrum. You know you are using it when you hear a muffled roar as you yawn. Nick realised that the ear has a lot of potential as an input device. He invented a switch that could be placed into the ear canal (like an in-ear headphone) to detect each time the ear drum moves. Inventing this Earswitch has provided a way of controlling several devices at once, for example an eye tracking device and a robotic, prosthetic arm.

The main driver for development of the Earswitch is assistive technology, but there are many other potential applications, from gaming and control of a phone to measurement of biometric signals from within the ear. Nick has picked up nanometer levels of movement of the ear drum in response to sound. He also explained that there is a pressure change in the ear 5 milliseconds before the eyes move. He showed us a trace of heartbeat measured from within the ear, and accurate enough to show slight irregularities.

So how could this device help with using hearing aids? It could be quite a natural progression: as the tensor tympani is probably a muscle that we use when straining to hear something. This switch might help a listener to indicate which speaker they would like to hear in a group setting and to switch between voices, with noise cancellation removing unwanted sound. This could make hearing with multi-modal hearing aids feel and look more natural in difficult listening environments. There would not be a need to press buttons or point microphones at target speakers. The control could be within the ear.

Nick pointed out that a microphone in the ear is not affected by wind or rustling hair. There are many potential applications for the Earswitch, and associated technology such as the possibility of hearing aids that include biometric sensors. Look out for more from this exciting development in assistive technology with a wide range of applications.

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