Assessment of hand kinematics using inertial and magnetic sensors

If we are ever going to consistently recover hand function we need something like this to establish the baseline problems and then document exactly what stroke protocol creates recovery.

Assessment of hand kinematics using inertial and magnetic sensors

Journal of NeuroEngineering and Rehabilitation 2014, 11:70  doi:10.1186/1743-0003-11-70
Published: 21 April 2014

Abstract (provisional)

Background

Assessment of hand kinematics is important when evaluating hand functioning. Major drawbacks of current sensing glove systems are lack of rotational observability in particular directions, labour intensive calibration methods which are sensitive to wear and lack of an absolute hand orientation estimate.

Methods

We propose an ambulatory system using inertial sensors that can be placed on the hand, fingers and thumb. It allows a full 3D reconstruction of all finger and thumb joints as well as the absolute orientation of the hand. The system was experimentally evaluated for the static accuracy, dynamic range and repeatability.

Results

The RMS position norm difference of the fingertip compared to an optical system was 5?0.5 mm (mean ? standard deviation) for flexion-extension and 12.4?3.0 mm for combined flexion-extension abduction-adduction movements of the index finger. The difference between index and thumb tips during a pinching movement was 6.5?2.1 mm. The dynamic range of the sensing system and filter was adequate to reconstruct full 80 degrees movements of the index finger performed at 116 times per minute, which was limited by the range of the gyroscope. Finally, the reliability study showed a mean range difference over five subjects of 1.1?0.4 degrees for a flat hand test and 1.8?0.6 degrees for a plastic mold clenching test, which is smaller than other reported data gloves.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.