Longevity of a Brain–Computer Interface for Amyotrophic Lateral Sclerosis

The durability of communication with the use of brain–computer interfaces in persons with progressive neurodegenerative disease has not been extensively examined. We report on 7 years of independent at-home use of an implanted brain–computer interface for communication by a person with advanced amyotrophic lateral sclerosis (ALS), the inception of which was reported in 2016. The frequency of at-home use increased over time to compensate for gradual loss of control of an eye-gaze–tracking device, followed by a progressive decrease in use starting 6 years after implantation. At-home use ended when control of the brain–computer interface became unreliable. No signs of technical malfunction were found. Instead, the amplitude of neural signals declined, and computed tomographic imaging revealed progressive atrophy, which suggested that ALS-related neurodegeneration ultimately rendered the brain–computer interface ineffective after years of successful use, although alternative explanations are plausible. (Funded by the National Institute on Deafness and Other Communication Disorders and others; ClinicalTrials.gov number, NCT02224469 .) In a person with amyotrophic lateral sclerosis, an implanted brain–computer interface for assisted communication was effective for more than 7 years. ALS-related neurodegeneration ultimately rendered the device ineffective.