Masters Applied Projects

Project 28

Dexterous Finger Force Control

Student: Patience Yaa Yeboah

Mentors: Dr. Marco Santello – SBHSE
Dr. Sydney Schaefer – SBHSE
Dr. Claire Honeycutt – SBHSE

YouTube Link: View the video link below before joining the zoom meeting

Zoom link: https://asu.zoom.us/j/89453266111

Time: 10am – 2pm

Abstract

Dexterous finger control is the basis of dexterous manipulation. It has been reported that, when humans try to generate forces with only one finger (‘instructed’ or ‘master’ finger), the non- instructed finger(s) also tend to generate force. This phenomenon is called ‘finger force enslaving’. It has also been shown that finger force enslaving is greater for adjacent than non-adjacent fingers. Peripheral and central constraints contribute to the enslaving phenomenon. Some of the peripheral constraints include connective tissue between tendons transmitting muscle force to multiple fingers. The central constraints may include overlap of the cortical representations of finger muscles and multiple cortical neurons being activated by movement of a single finger. Despite these constraints finger individuation could be achieved in healthy populations. The goal of this project is to evaluate the efficacy of a novel training protocol to reduce finger force enslaving and therefore improve independent finger force control. In this study, we focused on the middle finger because it is characterized by the largest force enslaving. Twelve participants were instructed to accurately generate middle finger forces while minimizing forces at the non- instructed fingers in a 2 day training session. The first day consisted of a pre,learn and post sessions and the second day was a retention session. Finger force enslaving was measured at baseline (before training) and at the end of the experiment and a day after the training. The baseline for enslaving for all the subjects during the pre-session was 24.04% which decreased to 21.25% during the post-session and 23.26% during the retention session. Subjects were then grouped into responding and non-responding groups where the values from the pre and post sessions were compared. That of the post and retention values were also compared using p-test analysis. The values obtained for the pre-post comparison were 0.0228 for non-responders and 0.1517 for the responders. The values obtained from the post-retention comparison were 0.9120 for non- responders and 0.6180 for responders. From these results, we cannot conclude that our training protocol was effective or not.