Measurement of Spatial Stability in Precision Grip

Area of Science:

• Biomechanics
• Neuroscience
• Human-Computer Interaction

Background:

• Grasping involves complex sensorimotor control.
• Understanding finger force direction is crucial for analyzing grip stability.
• Current methods for evaluating fine motor control during grasping are limited.

Purpose of the Study:

• To indirectly evaluate finger force direction during object manipulation.
• To analyze the relationship between force direction, center of pressure (COP) trajectory, and grasping physiology.
• To assess sensorimotor deficits and compensatory strategies using COP trajectory analysis.

Main Methods:

• Utilized a thin, flexible, high-resolution pressure sensor sheet to measure fingertip pressure distribution.
• Recorded center of pressure (COP) trajectory, force amplitude, and temporal regulation during object manipulation tasks.
• Analyzed COP trajectory length as an indicator of grasping control.

Main Results:

• Increased COP trajectory length correlated with sensorimotor deficits in stroke patients.
• Decreased COP trajectory length indicated a compensatory strategy to prevent object slippage in the elderly.
• Dual-task interference also led to a decrease in COP trajectory length.

Conclusions:

• Finger COP trajectory analysis provides a sensitive measure of grasping control.
• This method can differentiate between pathological and compensatory grasping strategies.
• The findings contribute to understanding the physiology and pathophysiology of grasping and sensorimotor control.