Coordination of reach-to-grasp in physical and haptic-free virtual environments.
Mariusz P Furmanek, Luis F Schettino, Mathew Yarossi and 3 others
PMID 31248426WHAT IT FOUND
Thirteen healthy adults reached and grasped objects in a virtual environment without haptic feedback.
They moved slower and opened their hands wider than in the physical world. However, the coordination between reaching and grasping remained intact.
Key findings
01Participants moved slower in the virtual environment, taking an average of 1063.3 ms compared to 999.7 ms in the physical environment.
02The timing relationship between the arm's peak velocity and the hand's peak aperture was preserved across both environments.
03Participants opened their hands proportionally wider for smaller virtual objects, suggesting increased uncertainty.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The study involved only thirteen healthy young adults, so results may not apply to patients with neurological or orthopedic conditions. The physical environment was tested in a dark room with glow-in-the-dark objects to match visual conditions, which is an artificial setup. The virtual environment lacked haptic feedback, which the authors note may have turned grasping into an aperture matching task under visual guidance. The collision detection algorithm used in the virtual environment had a set error margin, which may have influenced how participants perceived object contact.
Declared interests
The study was supported by the National Institutes of Health, the National Institute on Disability, Independent Living, and Rehabilitation Research, and the National Science Foundation.
The easy way to misread this
Do not assume that kinematic differences observed in this healthy cohort will replicate in clinical populations. The study used young, neurologically intact adults in a controlled setting, so applying these specific timing and aperture values to patients with motor impairments is not supported by this data.