Nobusako Satoshi, Hashizoe Kenya, Nakai Akio
Neurorehabilitation Research Center, Kio University, Nara, Japan.
Graduate School of Health Science, Kio University, Nara, Japan.
Front Hum Neurosci. 2025 Jul 24;19:1620941. doi: 10.3389/fnhum.2025.1620941. eCollection 2025.
Bimanual coordination, particularly the ability to perform independent and simultaneous asymmetric movements with both hands, is essential for many daily activities and develops throughout childhood. However, its developmental trajectory remains unclear. This study investigated age-related changes in bimanual coordination using the bimanual circles-lines coupling (BC) task and explored its relationship with fine motor skills in children aged 5 to 13 years.
A total of 150 typically developing children completed the BC task under unimanual (UM) and bimanual (BM) conditions. The bimanual coupling effect (BCE), reflecting interference between concurrent motor programs, was calculated as the difference in ovalization index (OI) between the two conditions. Fine motor abilities were assessed using the manual dexterity component of the Movement Assessment Battery for Children-2nd Edition (M-ABC2), yielding scores for preferred hand, non-preferred hand, bimanual, and handwriting skills.
Across age groups, OI was significantly higher in the BM than in the UM condition, indicating the presence of BCE. Both UM-OI and BM-OI significantly decreased with age, while BCE showed a weak but significant negative correlation with age. These findings suggest a gradual developmental improvement in the ability to perform independent bimanual movements. Partial correlation analyses, controlling for age, revealed significant associations between BCE/BM-OI and bimanual motor skills, suggesting that the ability to overcome intermanual interference is closely linked to age-appropriate bimanual coordination.
Given that asymmetric bimanual control involves not only the fronto-parietal network but also executive functions in the prefrontal cortex and interhemispheric motor communication, the present behavioral findings may reflect multifaceted neural maturation during childhood-specifically, the development of the fronto-parietal network, prefrontal cortex, and transcallosal motor pathways. The BC task, which requires only minimal equipment and administration time, may serve as a valid, cost-effective, and developmentally sensitive tool for quantifying bimanual coordination abilities in children. Its practical applicability highlights its potential as an assessment measure for motor development in both research and clinical contexts. This study contributes to a better understanding of how independent bimanual control emerges during childhood and may inform future approaches to evaluating fine motor function in pediatric neuromotor disorders.
双手协调，尤其是双手同时进行独立且不对称运动的能力，对许多日常活动至关重要，且在整个童年时期不断发展。然而，其发展轨迹仍不明确。本研究使用双手圆圈-线条耦合（BC）任务调查了双手协调与年龄相关的变化，并探讨了其与5至13岁儿童精细运动技能的关系。
共有150名发育正常的儿童在单手（UM）和双手（BM）条件下完成了BC任务。双手耦合效应（BCE）反映了同时进行的运动程序之间的干扰，计算为两种条件下椭圆化指数（OI）的差异。使用儿童运动评估量表第二版（M-ABC2）的手动灵巧性部分评估精细运动能力，得出优势手、非优势手、双手和书写技能的得分。
在各年龄组中，BM条件下的OI显著高于UM条件，表明存在BCE。UM-OI和BM-OI均随年龄显著降低，而BCE与年龄呈弱但显著的负相关。这些发现表明，进行独立双手运动的能力在逐渐发展改善。控制年龄的偏相关分析显示，BCE/BM-OI与双手运动技能之间存在显著关联，表明克服双手间干扰的能力与适合年龄的双手协调密切相关。
鉴于不对称双手控制不仅涉及额顶叶网络，还涉及前额叶皮质的执行功能和半球间运动交流，目前的行为学发现可能反映了儿童期多方面的神经成熟——具体而言，是额顶叶网络、前额叶皮质和胼胝体运动通路的发育。BC任务仅需极少的设备和施测时间，可能是一种有效、经济且对发育敏感的工具，用于量化儿童的双手协调能力。其实际适用性突出了其作为研究和临床环境中运动发育评估指标的潜力。本研究有助于更好地理解儿童期独立双手控制是如何出现的，并可能为未来评估小儿神经运动障碍中精细运动功能的方法提供参考。
