title: Impacts of selected stimulation patterns on the perception threshold in electrocutaneous stimulation.
abstract: BACKGROUND
  Consistency is one of the most important concerns to convey stable artificially induced sensory feedback. However, the constancy of perceived sensations cannot be guaranteed, as the artificially evoked sensation is a function of the interaction of stimulation parameters. The hypothesis of this study is that the selected stimulation parameters in multi-electrode cutaneous stimulation have significant impacts on the perception threshold.
  
  
  METHODS
  The investigated parameters included the stimulated location, the number of active electrodes, the number of pulses, and the interleaved time between a pair of electrodes. Biphasic, rectangular pulses were applied via five surface electrodes placed on the forearm of 12 healthy subjects.
  
  
  RESULTS
  Our main findings were: 1) the perception thresholds at the five stimulated locations were significantly different (p < 0.0001), 2) dual-channel simultaneous stimulation lowered the perception thresholds and led to smaller variance in perception thresholds compared to single-channel stimulation, 3) the perception threshold was inversely related to the number of pulses, and 4) the perception threshold increased with increasing interleaved time when the interleaved time between two electrodes was below 500 μs.
  
  
  CONCLUSIONS
  To maintain a consistent perception threshold, our findings indicate that dual-channel simultaneous stimulation with at least five pulses should be used, and that the interleaved time between two electrodes should be longer than 500 μs. We believe that these findings have implications for design of reliable sensory feedback codes.
authors.affiliation: Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers vej 7 D, Aalborg Øst, Denmark. bogeng@hst.aau.dk
authors.forename: Bo
authors.initials: B
authors.lastname: Geng
authors.forename: Ken
authors.initials: K
authors.lastname: Yoshida
authors.forename: Winnie
authors.initials: W
authors.lastname: Jensen
mesh_terms: D000328:Adult; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D010465:Perception / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology*; D012727:Sex Characteristics; D012879:Skin Physiological Phenomena; D012984:Software; D055815:Young Adult