Article

User feedback about grasping force and hand aperture is very
important in object handling with myoelectric forearm prostheses but is lacking
in current prostheses. Vibrotactile feedback increases the performance of healthy
subjects in virtual grasping tasks, but no extensive validation on potential
users has been performed. OBJECTIVES: Investigate the performance of upper-limb
loss subjects in grasping tasks with vibrotactile stimulation, providing hand
aperture, and grasping force feedback. METHODS: A
total of 10 subjects with upper-limb loss performed virtual grasping tasks while
perceiving vibrotactile feedback. Hand aperture feedback was provided through an
array of coin motors and grasping force feedback through a single miniature
stimulator or an array of coin motors. Objects with varying sizes and weights had
to be grasped by a virtual hand. RESULTS: Percentages correctly applied hand
apertures and correct grasping force levels were all higher for the vibrotactile
feedback condition compared to the no-feedback condition. With visual feedback,
the results were always better compared to the vibrotactile feedback condition.
Task durations were comparable for all feedback conditions. CONCLUSION:
Vibrotactile grasping force and hand aperture feedback improves grasping
performance of subjects with upper-limb loss. However, it should be investigated
whether this is of additional value in daily-life tasks. CLINICAL RELEVANCE:
This study is a first step toward the implementation of sensory vibrotactile feedback
for users of myoelectric forearm prostheses. Grasping force feedback is crucial
for optimal object handling, and hand aperture feedback is essential for
reduction of required visual attention. Grasping performance with feedback is
evaluated for the potential users.
CI - (c) The International Society for Prosthetics and Orthotics 2014.

Langue : ANGLAIS