title: A brain-computer interface based on self-regulation of gamma-oscillations in the superior parietal cortex.
abstract: OBJECTIVE
  Brain-computer interface (BCI) systems are often based on motor- and/or sensory processes that are known to be impaired in late stages of amyotrophic lateral sclerosis (ALS). We propose a novel BCI designed for patients in late stages of ALS that only requires high-level cognitive processes to transmit information from the user to the BCI.
  
  
  METHODS
  We trained subjects via EEG-based neurofeedback to self-regulate the amplitude of gamma-oscillations in the superior parietal cortex (SPC). We argue that parietal gamma-oscillations are likely to be associated with high-level attentional processes, thereby providing a communication channel that does not rely on the integrity of sensory- and/or motor-pathways impaired in late stages of ALS.
  
  
  RESULTS
  Healthy subjects quickly learned to self-regulate gamma-power in the SPC by alternating between states of focused attention and relaxed wakefulness, resulting in an average decoding accuracy of 70.2%. One locked-in ALS patient (ALS-FRS-R score of zero) achieved an average decoding accuracy significantly above chance-level though insufficient for communication (55.8%).
  
  
  CONCLUSIONS
  Self-regulation of gamma-power in the SPC is a feasible paradigm for brain-computer interfacing and may be preserved in late stages of ALS. This provides a novel approach to testing whether completely locked-in ALS patients retain the capacity for goal-directed thinking.
authors.affiliation: Department Empirical Inference, Max Planck Institute for Intelligent Systems, Spemannstrasse 38, D-72076 Tübingen, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Grosse-Wentrup
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schölkopf
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology* / Q000534:rehabilitation; D001683:Biological Clocks / Q000502:physiology*; D062207:Brain-Computer Interfaces; D003143:Communication Devices for People with Disabilities; D004562:Electrocardiography / Q000379:methods*; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013647:Task Performance and Analysis