Intermittent stimulation delays adaptation to electrocutaneous sensory feedback.
Electrotactile displays deliver information to the user by means of electrocutaneous stimulation. If such displays are used in prostheses, the functionality depends on long term stability of this information channel. The perceived sensation, however, decays within 15 min due to central adaptation if the stimulation is applied continuously and at constant strength. In this study, the effects of stimulus amplitude and intermittent stimulation on adaptation were investigated in ten healthy subjects. The perceived sensation was recorded during 15 min of constant stimulation using a visual analog scale (VAS). The sensation level with time thus measured were parameterized by the initial sensation level, the time constant of decay and the end sensation level after fitting of an exponential function through the VAS data. The time constant increased significantly when applying a high stimulation level (at 80% of the range between sensation and pain thresholds) if compared with lower levels of stimulation (20% and 50%) during continuous stimulation. Intermittent stimulation at this high stimulation level significantly increased end sensation level.
Buma
Dorindo G
DG
Biomedical Signals and Systems Group, Institute for Biomedical Technology BMTI/Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, 7500 AE Enschede, The Netherlands.
Buitenweg
Jan R
JR
Veltink
Peter H
PH
D000222:Adaptation, Physiological / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods*; D005246:Feedback / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D017288:Pain Threshold / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012677:Sensation / Q000502:physiology*; D012879:Skin Physiological Phenomena; D013997:Time Factors