OBJECTIVE

1. Effects of Remote Vibrotactile Noise on Fingertip Tactile Sensation in Healthy Adults Kishor Lakshminarayanan, M.S., John G. Webster, Ph.D., Na Jin Seo, Ph.D. • OBJECTIVE • To determine if remote vibrotactile noise could enhance fingertip tactile sensation in healthy adults. • APPROACH • Stochastic resonance is a phenomenon in which addition of a vibrotactile noise improves detection of weak sensory signals. • Studies have shown subthresholdvibrotactile noise applied on the finger pad improve fingertip tactile sensation in the hand. • However, a vibrotactile noise-generating device placed directly on the fingertip interferes with object manipulation and dexterous hand movement. • The primary goal of this study was to determine if subthresholdvibrotactile noise applied away from the fingertip enhances fingertip tactile sensation. • The secondary goal is to determine a good hand location to apply the noise and the subthreshold level that would give the desired output.

2. Effects of Remote Vibrotactile Noise on Fingertip Tactile Sensation in Healthy Adults Kishor Lakshminarayanan, M.S., John G. Webster, Ph.D., Na Jin Seo, Ph.D. • METHODS • Subjects: 12 healthy individuals • Procedure: • A vibrating C-3 Tactor (Engineering Acoustics, Inc. Casselberry, Florida) was used to apply vibrotactile noise at 4 remote hand locations. • The noise was applied at three different intensities namely 60%, 80%, and 120% of the sensory threshold at each of these locations. • Another Tactor was used to measure fingertip tactile sensation at the index finger and thumb for each of these conditions. • Fingertip tactile sensation was also measured without remote vibrotactile noise. • Statistical analysis: • Fingertip tactile sensation of the index finger and thumb was compared with vs. without vibrotactile noise using a repeated measures ANOVA. • Additionally, the effect of noise intensity and remote location on the fingertip tactile sensation was compared in the same ANOVA.

3. Effects of Remote Vibrotactile Noise on Fingertip Tactile Sensation in Healthy Adults Kishor Lakshminarayanan, M.S., John G. Webster, Ph.D., Na Jin Seo, Ph.D. Without Vibrotactile Noise With 60% Vibrotactile Noise With 80% Vibrotactile Noise With 120% Vibrotactile Noise • RESULTS • Fingertip tactile sensation significantly improved with the 60% vibrotactile noise, but did not change with the 80% vibrotactile noise, and significantly worsened with the 120% vibrotactile noise, for all remote locations and both fingers • CONCLUSIONS • Remote vibrotactile noise improved finger tactile sensation. • Remote vibrotactile noise at 60% of the sensory threshold improved finger sensation the most. The 120% suprathresholdvibrotactile noise worsened fingertip tactile sensation. This may be due to the excessive noise added to the central nervous system interfering with sensation for fingertips. This was observed across all remote hand locations. • The study demonstrates a potential for an assistive device worn away from the fingertips that improves fingertip tactile sensation and dexterity for applications ranging from human performance enhancement to sensorimotor rehabilitation. * Fingertip Tactile Sensation (V)