A quantitative taxonomy of human hand grasps.
Francesca Stival, Stefano Michieletto, Matteo Cognolato and 3 others
PMID 30770759WHAT IT FOUND
Hand grasps grouped by finger position and muscle use into five categories: flat, distal, cylindrical, spherical, ring.
The common power versus precision split was not well supported in these 40 intact subjects.
Key findings
01The quantitative taxonomy divided hand grasps into five categories: flat, distal, cylindrical, spherical and ring.
02Muscular and kinematic taxonomies agreed closely, with an edit distance of 33 between the two supertrees.
03The traditional power, intermediate and precision subdivision was not well supported; those grasps were usually split across the five categories.
STILL TO COME
How it was doneWhat they foundWhat it means for OTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The dataset included 40 intact subjects, and the paper notes that muscle activation patterns can differ strongly between intact and transradial amputees. The division into five categories is described by the authors as arbitrary, made to help comparison with previous taxonomies. The movements were not randomized. The analysis was limited to the considered data and time-domain features. The trees used unweighted edges, so part of the information in the dendrograms was lost. Subjects were instructed not to lift objects or exert unnatural grip force. Edit distance boundaries depend on the number of nodes.
Declared interests
Funding was provided by Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Hasler Stiftung and the Department of Information Engineering. No author conflict-of-interest declaration is included in the supplied text.
The easy way to misread this
Do not read the five-category taxonomy as evidence that a hand rehabilitation programme works or that the power-versus-precision split should be replaced in clinical classification. The study classified movements in 40 intact subjects, and the authors state that the division into categories is arbitrary.