This protocol was repeated while the subjects held their wrist comfortably in the following 6 static positions: flexed, extended, pronated, supinated, abducted, and adducted. Our study shows that incorporating intrinsic muscle EMG data and wrist motion can significantly improve the robustness of pattern recognition control for partial-hand applications.Classification accuracy for 19 motion classes (all finger motions and hand grasps) as a function of number of EMG channels. These muscles abduct the fingers away from the midline of the hand (spread the fingers).
To avoid fatigue, subjects were allowed 2–5 minutes of rest between trials, where a trial consisted of 15 hand or finger motions. Introduction: The muscles of the hand can be divided into extrinsic and intrinsic muscles. For amputees, we found no significant effect of wrist position training paradigm or muscle set on dynamic efficiency or completion time, in fact combining extrinsic and intrinsic muscle EMG increased selection times for successful trials.
This was repeated while the subject held their wrist in one of 7 randomly assigned static wrist positions.
His research interests include pattern recognition, biological signal processing, and myoelectric control of powered prostheses.Subjects were prompted to perform 2 functional hand-grasps (chuck and key grip), an open hand posture, and a rest posture.
It is worthwhile to note that the intrinsic muscles may be damaged or absent in some partial-hand amputees thus rendering them unsuitable as an EMG data source. The controlling muscles can be located in the hand itself (intrinsic hand muscles) or in the forearm (extrinsic hand muscles). White circles correspond to no occurrence and the deepest red circle corresponds to 7 occurrences.
Hargrove is a member of the Association of Professional Engineers and Geoscientists of New Brunswick.We tested two methods to mitigate the wrist position effect: (1) using both extrinsic and intrinsic muscle EMG data and (2) training with a hybrid static/dynamic wrist motion protocol. Thus an improvement in control was achieved without the need for the extensive multi-wrist position training. Subjects repeated this sequence of movements moving the wrist from (1) flexed to extended to flexed (2) extended to flexed to extended (3) supinated to pronated to supinated (4) pronated to supinated to pronated (5) abducted to adducted to abducted and (6) adducted to abducted to adducted. The contents do not necessarily represent the policies of the Department of Education or the official views of the National Institutes of Health, and you should not assume endorsement by the Federal Government.A virtual arm was used in these experiments since a physical partial-hand prosthesis was not available. (c) Classifier trained with both intrinsic and extrinsic muscle EMG. Arrows indicate channels that were consistently the most important intrinsic EMG channels.Effect of classifier training paradigm on online performance. Each combined movement was performed within 3s and repeated 10 times. The intrinsic muscles that control the thumb, unlike those of the fingers, are actually stronger than the extrinsic thumb muscles. Kuiken is currently Director of the Center for Bionic Medicine and of Amputee Services at the RIC, Chicago, IL, and Professor in the Departments of Physical Medicine and Rehabilitation, Biomedical Engineering, and Surgery, Northwestern University, Evanston, ILFour separate classifiers were trained with data collected from either (1) extrinsic EMG signals in a neutral wrist position, (2) extrinsic EMG signals with the hybrid wrist motion training protocol, (3) extrinsic and intrinsic EMG signals in a neutral wrist position, or (4) extrinsic and intrinsic EMG signals with the hybrid wrist motion training protocol. Subjects were asked to perform each hand posture while holding the wrist in a comfortable flexed position for 2s after which they were instructed to move the wrist to a comfortable extended position over a period of 2s while maintaining the grasp. The figure depicts how often an intrinsic EMG channel was one of the six channels that contributed the most to classification accuracy for all non-amputees. The muscles of the hand are the skeletal muscles responsible for the movement of the hand and fingers.The muscles of the hand can be subdivided into two groups: the extrinsic and intrinsic muscle groups. For both subject groups all 9 extrinsic channels were analyzed (left of the dashed line). Muscles originating in the forearm are the extrinsic muscles of the hand. We found that intrinsic muscles provide valuable EMG data that enables a pattern recognition system to better discriminate between up to 19 different hand grasp patterns and individual finger motions.