gms | German Medical Science

14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

17.06. - 21.06.2019, Berlin

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Clustering of muscle activation pattern between thenar and extrinsic hand muscles during various grasp tasks

Meeting Abstract

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  • presenting/speaker Shota Date - Hiroshima University, Hiroshima, Japan
  • Hiroshi Kurumadani - Hiroshima University, Hiroshima, Japan
  • Toru Sunagawa - Hiroshima University, Hiroshima, Japan

International Federation of Societies for Surgery of the Hand. International Federation of Societies for Hand Therapy. 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT). Berlin, 17.-21.06.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. DocIFSHT19-1229

doi: 10.3205/19ifssh1522, urn:nbn:de:0183-19ifssh15226

Published: February 6, 2020

© 2020 Date et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

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Objective: Improvement of the thumb opposition after opponensplasty may not always be enough, which could be occurred due to a neural control problem. To further improve thumb opposition after surgery, it may be necessary to focus on a typical activation pattern between thenar muscle and extrinsic hand muscle based on a neural base of grasping. However, it remains unclear whether thenar muscles have a typical muscle activation pattern with extrinsic hand muscles. This study aimed to examine a common muscle activation pattern between thenar and extrinsic hand muscles during grasp tasks.

Materials and Methods: Seven healthy subjects performed two types of reach-to-grasp tasks: power- and precision-grasp. During the tasks, we recorded muscle activities of the thenar (APB, FPB) and extrinsic hand muscles (EPL, ED, ECR, ECU, FCR, FCU, FDS and PL) by using surface EMG. Then, we detected the muscle activation pattern from acquired muscle activities by using principal component analysis and reconstructed each muscle activation pattern. Further, to examine similar muscle activities to the thenar muscles, we classified the muscle activation patterns by hierarchical clustering.

Results: Muscle activation patterns of thenar muscles were different for the types of grasp. The pattern during power-grasp increased and peaked at 80% end of the task. On the other hand, the pattern during precision-grasp increased but peaked at the end of the task. Further, extrinsic hand muscles of the same cluster as thenar muscles were also different for the types of grasp. EPL and wrist/finger flexor muscles (FCR, FCU, FDS and PL) activated with thenar muscles during power grasp, while wrist extensor (ECR, ECU) and wrist flexor muscles activated with thenar muscles during precision grasp.

Conclusions: Depending on the types of grasp, the pattern and classified muscles as the same of thenar muscles were different. If the flexor extrinsic hand muscle is selected as the donor for opponensplasty, it might be better to practice with power grasp after surgery.