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

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.

研究目的：探讨以肌电图（electromyography, EMG）触发的音视频作为强化手段，提升围产期臂丛神经损伤（perinatal brachial plexus injury, PBPI）儿童肌肉激活水平的可行性。
研究方法：本研究共纳入6名PBPI患儿（年龄9.3±6.3月龄；女性5名，男性1名）及13名典型发育（typically developing, TD）对照儿童（年龄7.8±3.5月龄；女性4名，男性9名）。6名PBPI患儿中5名左侧上肢受累。受试者单次实验中，每侧上肢分别在两种条件下采集表面肌电记录的二头肌激活积分（单位：Vs）：(1) 100秒无强化基线期；(2) 300秒强化期（当二头肌激活幅度超过阈值[V]时触发音视频播放）。本研究分析了强化阶段平均激活积分与利手性之间的关联。
研究结果：PBPI组患儿患侧上肢的平均二头肌激活水平，在强化阶段第2个100秒区间（p<0.008）及第3个100秒区间（p<0.0004）较基线期显著提升。6名PBPI患儿及13名TD对照儿童中的12名，至少在一侧上肢出现激活水平提升。PBPI组中，更低的激活积分与非受累右侧上肢的利手性相关。
研究结论：本研究证实依随式强化是提升肌肉激活水平的可行手段。未来研究将探讨提升上肢功能所需的训练剂量与强度。