EMG-Based Hand-Wrist Control: Study B Mirrored

Early Phase 1CompletedNCT04692571

Liberating Technologies, Inc.20 enrolled

Overview

Study assessing four-channel prosthesis controller, that compares contralateral (mirrored) EMG-force training to ipsilateral EMG-target training with both limb-absent and able-bodied subjects

System identification models relating forearm electromyogram (EMG) signals to phantom wrist radial-ulnar deviation force, pronation-supination moment and/or hand open-close force (EMG-force) are hampered by lack of supervised force/moment output signals in limb-absent subjects. In able-bodied and unilateral transradial limb-absent subjects, we studied three alternative supervised output sources in one degree of freedom (DoF) and 2-DoF target tracking tasks: (1) bilateral tracking with force feedback from the contralateral side (non-dominant for able-bodied/ sound for limb-absent subjects) with the contralateral force as the output, (2) bilateral tracking with force feedback from the contralateral side with the target as the output, and (3) dominant/limb-absent side unilateral target tracking without feedback and the target used as the output.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Amputation Amputation; Traumatic, Hand Amputation, Congenital Prosthesis User

Interventions

PSICON Measurement ApparatusDEVICE

Test apparatus acquires 16 sEMG channels, measure four DoFs of force/moment at the hand-wrist \[hand open-close (Opn-Cls); wrist extension-flexion (Ext-Flx), radial-ulnar deviation (Rad-Uln) and pronation-supination (Pro-Sup)\]. sEMG system used 16 custom encased bipolar electrodes. A commercial LTI EMG amplifier (BE328) conditioned each EMG signal before A/D conversion on a PC. A thermoplastic hand cuff secured the wrist to a six-axis load cell (AMTI, model MC3A-100) for force/moment measurement. A separate hand-grasp one-axis load cell (Omega Engineering Inc., model LCR-150) was Velcro-secured between the fingers and the thumb, to measure power grip forces. The PC acquired and stored the sEMG and load cell data, and commanded a triangular screen target. The subject controlled a second triangular cursor. Left-right movement of the cursor was controlled by wrist Ext-Flx, up-down movement by Rad-Uln deviation, cursor rotation by Pro-Sup and cursor size by hand Opn-Cls forces.

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Limb-absent subjects: unilateral trans-radial limb absence or amputation * Be capable of completing the requested contractions on the affected dominant side Exclusion Criteria: * Past injuries to the upper limbs that would limit their ability to complete the requested contractions * Scars that would impede the use of surface electrodes

Locations (2)

Liberating Technologies, Inc

Holliston, Massachusetts, United States

Worcester Polytechnic Institute

Worcester, Massachusetts, United States

Outcomes

Primary Outcomes

EMG-Force Models

Electromyogram waveform measurements (signal amplitude, frequency) will be related to force measurements (magnitude and moment) as related to the target tracking tasks. These signal-force data will be use to generate the models. The specific outcome for each subject will be the RMS error measured in the tracking tasks as the difference between the generated control signal from the user versus the prompted target signal, as measured by an EMG array.

Time frame: 1 day visit

Data from ClinicalTrials.gov

This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.