The investigator's study objectives are to (1) test the feasibility of a parent-lead in-home 2-week intervention for infants with BPBP; and (2) determine the effect size for the primary outcome measure(s) in preparation for a future definitive randomized controlled trial (RCT). In this feasibility RCT, the investigators will compare two in-home interventions in 3 to 12-month-old infants with upper trunk BPBP; n=12 per group: (1) experimental; and (2) dose-equivalent active control. For the experimental intervention, infants will trigger a musical toy to move and play via biceps contraction above a preset individual threshold. For the control intervention, toys will be available to play with, yet, there will be no reinforcement for biceps activation.
