August 5, 2011
Touch Sensitivity Improved With Vibrating Glove
Research has shown that sight, balance, and hearing in humans can be enhanced with the application of "white noise", or minute, random interference in the senses and this applies to the sense of touch as well.
A special glove has been developed by researchers at the Georgia Institute of Technology which is designed to improve the wearer's sense of touch by applying a small vibration to the side of the fingertip. This improves the tactile sensitivity and motor performance, according to their research results.Jun Ueda, assistant professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech explains, "This device may one day be used to assist individuals whose jobs require high-precision manual dexterity or those with medical conditions that reduce their sense of touch."
Researchers attached the device to the hands of 10 healthy adult volunteers who performed common sensory tasks including texture discrimination, two-point discrimination, single-point touch and grasp tests.
The experimental results showed that the volunteers performed statistically better on all of the tasks when mechanical vibration was applied.
"All of the experimental results showed that some mechanical vibration was better than none at all, but the level of vibration that statistically improved sensorimotor functions varied by test," noted Ueda.
The device uses an actuator to generate high-frequency vibration and is attached to the side of the fingertip so that the palm-side of the finger remains free and the individual wearing the glove can freely manipulate objects.
In one experiment, pieces of sandpaper with different grits were glued on one side of a plastic board. Researchers then randomly selected a test piece of sandpaper and attached it to the other side of the board -- which the subjects could not see.
Subjects touched the single piece of sandpaper and selected a matching piece from the nine samples on the other side of the board. At vibration levels of 50 and 100 percent of their thresholds, the subjects selected the correct piece of sandpaper 15 percent more often than when they were not exposed to any vibration.
For the grasping test, each subject pinched and held an object for three seconds with as small a force as possible without letting it slip. Statistically significant improvements in grasping were observed for cases of 50, 100 and 125 percent of threshold vibration.
All the sensing ability tests confirmed that the application of certain levels of mechanical vibration enhanced the tactile sensitivity of the fingertip. However, because the levels of vibration that created statistically significant results varied, the researchers are currently conducting experiments to determine the optimal amplitude and frequency characteristics of vibration and the influence of long-term exposure to vibrations.
The researchers are also working on optimizing the design of the glove and testing the effect of attaching actuators to both sides of the fingertip or the fingernail.
"The future of this research may lead to the development of a novel orthopedic device that can help people with peripheral nerve damage resume their daily activities or improve the abilities of individuals with jobs that require skills in manipulation or texture discrimination," said Ueda.
Details of the device and preliminary test results were presented in May at the 2011 IEEE International Conference on Robotics and Automation in Shanghai.
Image Caption: Georgia Tech researchers have developed a glove with a vibrating fingertip that improves tactile sensitivity and motor performance. The device uses an actuator made of a stack of lead zirconate titanate layers to generate high-frequency vibration to the side of the fingertip. Credit: Georgia Tech/Gary Meek
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