title: The design and testing of a novel mechanomyogram-driven switch controlled by small eyebrow movements.
abstract: BACKGROUND
  Individuals with severe physical disabilities and minimal motor behaviour may be unable to use conventional mechanical switches for access. These persons may benefit from access technologies that harness the volitional activity of muscles. In this study, we describe the design and demonstrate the performance of a binary switch controlled by mechanomyogram (MMG) signals recorded from the frontalis muscle during eyebrow movements.
  
  
  METHODS
  Muscle contractions, detected in real-time with a continuous wavelet transform algorithm, were used to control a binary switch for computer access. The automatic selection of scale-specific thresholds reduced the effect of artefact, such as eye blinks and head movement, on the performance of the switch. Switch performance was estimated by cued response-tests performed by eleven participants (one with severe physical disabilities).
  
  
  RESULTS
  The average sensitivity and specificity of the switch was 99.7 +/- 0.4% and 99.9 +/- 0.1%, respectively. The algorithm performance was robust against typical participant movement.
  
  
  CONCLUSIONS
  The results suggest that the frontalis muscle is a suitable site for controlling the MMG-driven switch. The high accuracies combined with the minimal requisite effort and training show that MMG is a promising binary control signal. Further investigation of the potential benefits of MMG-control for the target population is warranted.
authors.affiliation: Bloorview Research Institute, Bloorview Kids Rehab, Toronto, Ontario, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Alves
authors.forename: Tom
authors.initials: T
authors.lastname: Chau
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001331:Automation; D001767:Blinking / Q000502:physiology; D003463:Cues; D004867:Equipment Design; D005138:Eyebrows / Q000502:physiology*; D005152:Facial Muscles / Q000502:physiology*; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction; D009213:Myography / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted; D013119:Spinal Cord Injuries / Q000503:physiopathology; D013647:Task Performance and Analysis; D013997:Time Factors; D014584:User-Computer Interface