Finger Enslaving in the Dominant and Non-dominant Hand
Open Access
- Author:
- Wilhelm, Luke Andrew
- Graduate Program:
- Kinesiology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 31, 2013
- Committee Members:
- Vladimir M Zatsiorsky, Thesis Advisor/Co-Advisor
- Keywords:
- laterality
isometric
finger interaction
neural network - Abstract:
- Force enslaving, the production of force by non-instructed fingers when one finger is instructed to produce force, is a well-documented characteristic of finger interactions. Though the magnitude of this effect can vary based on age, gender, and neurological conditions, the effect is present in any multi-finger force production. However, the relation between enslaving and handedness has not been thoroughly explored. The dominant hand is known to be more dexterous and is given wider use in most tasks. Since enslaving effects are an indication of finger individuation, it is hypothesized that the non-dominant hand will have higher enslaving effects than the dominant hand. Twenty-two, male, right-handed subjects were tested with the Edinburgh Handedness Inventory, the Grooved Pegboard test, and the Jebsen-Taylor test to assess their levels of handedness. They also completed maximum voluntary contractions (MVC) with all fifteen single, double, triple, and quadruple finger combinations for both dominant and non-dominant hands. These MVC results were used to construct a neural network model of force production, which was used to obtain an interfinger connection matrix (IFC). From the IFC, overall enslaving indices for each hand were calculated, as well as individuation and stationarity indices for each individual finger. The dominant hand was found to be stronger than the non-dominant hand. In addition, the individuation patterns of the fingers followed the general patterns observed in previous studies of enslaving and finger individuation. However, enslaving indices were not found to be significantly different between the dominant and non-dominant hands. The enslaving indices also did not significantly correlate with any of the three assessments of handedness. To assess the reliability of the calculations of enslaving indices, 11 subjects were retested after two months. The values were compared with intraclass coefficients and standard error of the mean. Based on this analysis, the enslaving indices were deemed to be stable and reliable values. Consistent with other studies that have examined finger independence, it does not seem that lower enslaving is an underlying cause of the dominant hand’s superior dexterous skill.