Look and click
Sometimes it doesn't last longer than a blink of an eye - as a result of an accident or a stroke, speech, motor skills and facial expressions fail. Patients with skull/brain injuries can often understand speech and formulate spoken utterances mentally, but are no longer able to express themselves verbally express. Together with the Waldeck specialist hospital, scientists at the branch of the Fraunhofer Institute for Graphic Data Processing IGD in Rostock are developing devices that make it easier for the severely disabled to communicate independently with their environment. Patients can control a computer and enter text using alternative input methods such as muscle contractions, eye movements or blinking.
"We use both bioelectrical and optical methods to register the movement of the eyes," explains Dr.-Ing. Heide-Rose Vatterrott from the IGD. With the bioelectric method, changes in the horizontal and vertical viewing directions are recorded using two electrodes. The optical method is different: Here, an infrared camera captures the center of the pupil and the corneal reflection and uses this to calculate the precise viewing direction. "From this information, the system can distinguish between the patient's voluntary eye movements and accidental ones and adapt to personal characteristics," says Dr. Fatherrott further. Not mouse or keyboard input, but the patient's gaze controls the computer input.
With this method, the patient can use standard applications via a specially designed on-screen keyboard. To support rehabilitation, the scientists at the IGD also developed various applications such as an exercise system for naming pictures and a mathematical training system.