Date Presented 03/26/20
Infants who sustain brachial plexus injury are at risk for neuromuscular and sensibility deficits contributing to prehensile dysfunction. OTs practicing in early intervention often have limited resources available to improve muscle activation. Yet our experimental program offers a solution, since infant-initiated muscle activation or arm movement will trigger a toy to move, reinforcing them to move again. If done repeatedly, this program could contribute to their recovery.
Primary Author and Speaker: Susan Duff
Contributing Authors: Milan Stevanovic, Jamie Berggren, Barbara Sargent, Andrew Kimbel, Cyril Rakovski, Ehsan Yaghmaei, Peter Pidcoe, Benjamin Leiby, Mitchel Seruya, Eric Wade
PURPOSE: Our ongoing study objectives are to (1) test the feasibility of a parent-lead in-home 2-week intervention for infants with Perinatal Brachia Plexus Injury (PBPI); and (2) determine the effect size for the primary outcome measures in preparation for a future definitive randomized controlled trail (RCT).
DESIGN: Feasibility RCT.
METHODS: This study is comparing two in-home interventions in 3 to 12-month-old infants with upper trunk PBPI; (1) experimental (n=12); and (2) dose-equivalent active control (n=12). For the experimental intervention, infants trigger a musical toy to move and play via biceps contraction above a preset individual threshold (Volts) based on surface electromyography (SEMG). For the control intervention, toys are available to play with, yet, there is no reinforcement for biceps activation. The 10-minute interventions occur twice daily for 10 days, within 2-weeks. The outcome measures are assessed before the intervention, immediately after the intervention, one-month post-intervention and three-months post-intervention. The outcome measures are: (1) Parent feasibility questionnaire and interview; (2) the integral of biceps muscle activation over 5 minutes gathered with SEMG (Volts x seconds); (3) the arm use ratio (affected/unaffected arm) after 8-hour daytime sensor wear of wrist-based APDM inertial sensors (Portland, OR); and (4) the laterality index based on the Almli Test of Handedness. We hypothesize that both interventions will be feasible, and the outcome measures will provide preliminary support for our experimental intervention. This preliminary data is from two age-matched infants (11 months of age) with PBPI, from the first two data points only: one from the experimental group (left arm affected) and the other from the control group (right arm affected).
RESULTS: Both interventions were conducted successfully within 5 days based on pre-set criteria. Both the experimental and control intervention were reported to be feasible by the parent groups. Post-intervention, the infant in the experimental group displayed 10% greater overall muscle activation (Vs) in the affected arm and greater arm use ratio (0.60/1.0) over an 8-hour daylong period, than the control (0.50/1.0). The infant in the experimental intervention revealed a laterality index for reach of +1 at each time-point thus did not change from pre- to post-intervention suggesting a mild preference to use the right unaffected arm vs. left affected arm to reach. The infant control increased the laterality index from -2.12 to -2.83 suggesting a moderate preference to use the left unaffected arm more than affected arm from pre- to post-intervention.
CONCLUSION: While the preliminary results are promising, since data collection is incomplete it is not clear whether the experimental intervention will promote greater muscle activation and arm activity than the control intervention. At this point recruitment and data collection remain in process.
References
Duff, S.V., Sargent, B., Kutch, J.J., Berggren, J., Leiby, B. E., Fetters, L. (2017). Using contingent reinforcement to increase muscle activation after Perinatal Brachial Plexus Injury. Physical and Occupational Therapy in Pediatrics, 37(5), 555-65.
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Duff, S.V., DeMatteo, C. (2015). Clinical assessment of the infant and young child following perinatal brachial plexus injury. Journal of Hand Therapy. 28(2), 126-33.
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