Assistive tech may let locked-in users communicate via "ear-clicks"
Although there are systems that allow physically challenged users to communicate by twitching facial muscles, for some people even those muscle movements are impossible. A new setup offers a possible alternative, however, by going into the ear.
Known as "Earswitch," the technology is being developed at Britain's University of Bath, by a team led by Dr. Nick Gompertz. It's designed first and foremost for users who are "locked-in," meaning they're paralyzed and unable to speak.
At the heart of the experimental system is a computer-connected silicone earpiece containing a tiny camera and light, which is temporarily inserted into the patient's ear canal. The camera then monitors the middle ear's tensor tympani muscle – it's one of the smallest muscles in the body, and could thus conceivably still be tensed by people who have lost control over most other muscles.
Such people may include stroke victims, or those with late-stage Motor Neurone Disease.
The user views a virtual keyboard – displayed on a computer screen – on which the rows of keys are sequentially highlighted. When the row containing the desired letter is highlighted, the user selects it by tensing their tensor tympani muscle. The earpiece camera detects that movement, and triggers the computer to select that line of keys.
Next, the individual keys within that line are highlighted sequentially. Again, the user selects the desired key by tensing their ear muscle when that key is highlighted. In this way, they can gradually "type" out messages. In order to speed the process up, a predictive text system displays complete words that the user may be trying to type, which they can also select.
Gompertz and colleagues are now commercializing the Earswitch technology via a spinoff company, possibly even for use by non-paralyzed users who wish to perform everyday tasks hands-free. They are also conducting an online survey – open to members of the public both with and without neurological conditions – to determine what percentage of the population is able to voluntarily move their tensor tympani muscle.