Patrick L Marcus and Andrew J Fuglevand 2009 J. Neural Eng. 6 066008 doi:10.1088/1741-2560/6/6/066008
Patrick L Marcus1,3 and Andrew J Fuglevand1,2,3,4
Show affiliationsSpinal cord injury is often accompanied by impaired tactile and proprioceptive sensations. Normally, somatosensensory information derived from such sensations is important in the formation of voluntary motor commands. Therefore, as a preliminary step toward the development of an electrotactile feedback system to restore somatosensation, psychophysical methods were used to characterize perceptual attributes associated with electrical stimulation of the skin on the back of the neck in human subjects. These data were compared to mechanical stimulation of the skin on the back of neck and on the distal pad of the index finger. Spatial acuity of the neck, evaluated using two-point thresholds, was not significantly different for electrical (37 ± 14 mm) or mechanical stimulation (39 ± 10 mm). The exponent (β) of the best fitting power function relating perceived intensity to applied stimulus strength was used to characterize perceptual sensitivity to mechanical and electrical stimuli. For electrical stimuli, both current amplitude-modulated and frequency-modulated trains of pulses were tested. Perceptual sensitivity was significantly greater for current amplitude modulation (β = 1.14 ± 0.37) compared to frequency modulation (β = 0.57 ± 0.24) and mechanical stimulation (0.51 ± 0.12). Finally, based on the data gathered here, we derive a transfer function that could be used in the future to convert mechanical stimuli detected with artificial sensors placed on the fingers into electrotactile signals that evoke perceptions similar to those arising from normal mechanical stimulation of the skin.
87.19.R- Mechanical and electrical properties of tissues and organs
87.19.lt Sensory systems: visual, auditory, tactile, taste, and olfaction
Issue 6 (December 2009)
Received 22 June 2009, accepted for publication 28 October 2009
Published 17 November 2009
Patrick L Marcus and Andrew J Fuglevand 2009 J. Neural Eng. 6 066008
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