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Abstract:
Amyotrophic lateral sclerosis (ALS) is neurodegenerative disease that leads to complete muscle paralysis. Brain- Computer Interfaces (BCIs) can be used for basic communication by ALS patients in early and advanced stages of the disease, but not yet by patients in the completely locked-in (CLI) state. This is arguably a result of the focus in BCI research on sensorimotor processes, which are affected by the disease already at an early stage. We have argued that to communicate with late-stage ALS patients it is essential to develop BCIs based on high-level cognitive processes that are less likely to be impaired. Here, we report successful communication by a late-stage (but not yet locked-in) ALS patient by means of self-regulation of theta-power in the precuneus, a brain region that is linked to self-referential thought. The male patient participated in 30 neurofeedback sessions over the course of one year, based on high-density EEG recordings. In each session, he received visual and auditory feedback on his current state of theta-power (2?5 Hz) in the precuneus. He used this signal to answer yes/no questions online, to which he had provided the correct answers in advance. The patient achieved an online decoding accuracy, averaged across all 30 sessions, of 70.5%, with a significant positive trend across sessions. Our study thus shows that it is feasible to use self-regulation of theta-power in the precuneus for communication in late-stage ALS.
