Electrodes implanted between the skull and the brain have enabled a locked-in ALS patient to type a message using thought alone, researchers reported here.
It's not that the words the patient thinks appear on a screen; it's far more complicated than that. Instead, a computer program translates the 59-year-old woman's thoughts about lifting her hand into mouse clicks that help her select letters on a computer screen to type a message.
It's a slow-going effort, at two letters per minute -- compared with eye-tracking technology, which researchers estimate can produce 10 to 20 letters per minute -- but author Nick Ramsey, MD, of University Medical Center Utrecht in the Netherlands, says it can be useful for those who have little eye movement and gets around challenges of eye-tracking technology, such as not being able to communicate when outdoors given changes in lighting.
"Now she can enjoy her backyard," Ramsey told MedPage Today. "She can't do that with the eye tracker because of the lighting. Just clouds passing could change the lighting. If you can't communicate outside, everyone is nervous because in a split second something can go wrong -- a problem with the ventilator, some saliva build-up. Little things we don't think about as able people."
While he acknowledged the slow rate of word formation, Ramsey said the technology lays the framework for alternative means of being able to help these patients.
"This is the first implant of its kind worldwide, and the first one that works for a patient at home," Ramsey said. "The future is not in increasing its speed, but putting more electrodes in there to start to decode not just movements, but [imagined] gestures" -- such as teaching patients sign language to speed up communication.
Mariska J. Vansteensel, Ph.D., Elmar G.M. Pels, M.Sc., Martin G. Bleichner, Ph.D., Mariana P. Branco, M.Sc., Timothy Denison, Ph.D., Zachary V. Freudenburg, Ph.D., Peter Gosselaar, M.D., Sacha Leinders, M.Sc., Thomas H. Ottens, M.D., Max A. Van Den Boom, M.Sc., Peter C. Van Rijen, M.D., Erik J. Aarnoutse, Ph.D., and Nick F. Ramsey, Ph.D. Fully implanted brain–computer interface in a locked-in patient with ALS. NEJM November 12, 2016DOI: 10.1056/NEJMoa1608085
Options for people with severe paralysis who have lost the ability to communicate orally are limited. We describe a method for communication in a patient with late-stage amyotrophic lateral sclerosis (ALS), involving a fully implanted brain–computer interface that consists of subdural electrodes placed over the motor cortex and a transmitter placed subcutaneously in the left side of the thorax. By attempting to move the hand on the side opposite the implanted electrodes, the patient accurately and independently controlled a computer typing program 28 weeks after electrode placement, at the equivalent of two letters per minute. The brain–computer interface offered autonomous communication that supplemented and at times supplanted the patient’s eye-tracking device. (Funded by the Government of the Netherlands and the European Union; ClinicalTrials.gov number, NCT02224469.)