Using Contingent Reinforcement to Augment Muscle Activation After Perinatal Brachial Plexus Injury: A Pilot Study

ABSTRACT

Aim: Examine the feasibility of increasing muscle activation with electromyographically (EMG)-triggered musical-video as reinforcement for children with perinatal brachial plexus injury (PBPI). Methods: Six children with PBPI (9.3 ± 6.3 months; 5 female, 1 male) and 13 typically developing (TD) controls (7.8 ± 3.5 months; 4 female, 9 males) participated. The left arm was affected in 5/6 children with PBPI. We recorded the integral (Vs) of biceps activation with surface EMG during two conditions per arm in one session: (1) 100 second (s) baseline without reinforcement and (2) 300 s reinforcement (musical-video triggered to play with biceps activation above threshold [V]). We examined the relation between the mean integral with reinforcement and hand preference. Results: Mean biceps activation significantly increased from baseline in the affected arm of the group with PBPI by the 2nd (p < .008) and 3rd (p < .0004) 100 s intervals of reinforcement. Six of 6 children with PBPI and 12/13 TD controls increased activation in at least one arm. A lower integral was linked with hand preference for the unaffected right side in the PBPI group. Conclusion: This study supports contingent reinforcement as a feasible method to increase muscle activation. Future work will examine training dose and intensity to increase arm function.

KEYWORDS:

• Brachial plexus injury
• contingent reinforcement
• electromyography
• infants
• muscle activation

Declaration of Interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This work was supported by a grant from the Academy of Physical Therapy of the American Physical Therapy Association under award number 1013 1RG02.

About the Authors

Susan V. Duff, EdD, PT, OT/L, CHT, is an Associate Professor at the Department of Physical Therapy in the Crean College of Health and Behavioral Science at Chapman University in Irvine, CA. Barbara Sargent, PhD, PT, PCS, is an Assistant Professor of Clinical Physical Therapy in the Division of Biokinesiology & Physical Therapy at the University of Southern California in Los Angeles, CA. Jason J. Kutch, PhD, is an Assistant Professor and Director of the Applied Mathematical Physiology Laboratory (AMPL) in the Division of Biokinesiology & Physical Therapy at the University of Southern California in Los Angeles, CA. Jamie Berggren, OTR/L, is an Occupational Therapist Level IV, Division of Pediatric Rehabilitative Medicine at Children's Hospital of Los Angeles in Los Angeles, CA. Benjamin E. Leiby, PhD, is an Associate Professor and Division Head of Biostatistics at Thomas Jefferson University in Philadelphia, PA. Linda Fetters, PT, PhD, FAPTA, is Professor and Sykes Family Chair in Pediatric Physical Therapy, Health and Development, Division of Biokinesiology & Physical Therapy and Department of Pediatrics, Keck School of Medicine, University of Southern California in Los Angeles, CA. She is the director of the Development of Infant Motor Performance Laboratory (DIMPL).