Manipulation of objects with and without the use of the index finger: implications for digital amputations

Abstract

Study design: Clinical Measurement.

Purpose: To evaluate changes in temporal and amplitude movement accuracy with tasks requiring fine motor manipulation with and without the use of the index finger (WIF).

Participants: Twenty right-handed participants (10 males, 10 females, aged 24-47 years) were recruited.

Methods: Three objects, ranging in weight and size, that required the use of 2 or 3 fingers were selected for this study. Motor performance was quantified during manipulation of a pen, cork, and wine glass using a computerized visual guided tracking task. The miniBird (Ascension Technology, Burlington, VT, USA) miniature motion tracking sensor was attached to each object to measure and record the 3D linear and angular motion.

Results: Task performance and temporal accuracy of the pen task in the normal condition was more accurate (P=.033). During the WIF condition there was significantly more motion performing the wine task (P<.001).

Conclusions: The protocol directly measures the ability of the hand to coordinate movement in response to a visual tracking target. Both temporal accuracy and amplitude consistency can be objectively evaluated. The current study evaluates the ability of the hand to manipulate 3 objects used in fine motor manipulation, using motion analysis and visual tracking.

Level of evidence: 3b.