Evaluating the origins of the preferred hand and manual performance asymmetries in unimanual and bimanual tasks across the lifespan

喜欢用一只手完成大多数单手的任务是一个耐人寻味的人类特征。手偏好的一个值得注意的方面是，某些任务往往比其他任务产生更强的偏好和对首选手的更多选择。同样，优先手优势的大小在很大程度上取决于所考察的任务(McManus，van Horn&Bryden，2016)。一种经常被引用的解释是，执行特定任务所需的技能程度可能会驱动手的选择，从而允许优先手变得更熟练地完成那些高技能的任务(Steenhuis&Bryden，1989)。在对我们的工作(46、6、31)的回顾中，我们认为“熟练的行为”可能不能充分解释利手行为。关于肢体选择和操作能力，仍需确定每个肢体/大脑半球系统的专业性。这项拟议的研究将阐明在单手和双手任务中，每个肢体/大脑半球系统在肢体选择和操作能力方面的专业性。重点将放在理解非首选肢体和左撇子个体的操作能力上，这两个方面在过去的研究中都被忽视了。重要的是，这项工作还将检查不同年龄段的肢体选择和操作能力的变化，从儿童到老年人。因此，长期目标是建立一个运动偏侧化成熟的寿命模型，以更好地解释单手和双手任务中无数相互矛盾的发现。短期目标是检查：a)在单手和双手任务中的肢体选择(研究主题D1)；b)在单手和双手任务中每只手的相对能力(研究主题D2)；以及c)在单手和双手任务中侧向偏好和表现的成熟(研究主题D3)。为了进一步梳理出每个肢体/大脑半球系统的专业性，我们将探索在单手和双手任务中的横向偏好和表现：d)左撇子(研究主题D4)；e)运动规划/执行受损的个人(例如自闭症谱系障碍，ADHD)(研究主题D5)。虽然过去已经对运动功能的利手和偏侧化进行了研究，但在我们对每个肢体/大脑半球系统在肢体选择和操作能力方面的专门化方面的理解上存在很大差距。不幸的是，许多研究只包括年轻人或惯用右手的人，因此没有捕捉到横向偏好、选择和操作能力的完整图景。这项拟议的研究将填补当前理论中的几个空白，向研究人员提供有关惯用手的衡量标准，并将其应用于教育、工业和培训的各个方面。

The preference to perform most unimanual tasks with one hand is an intriguing human characteristic. One notable aspect of hand preference is that certain tasks tend to produce stronger preferences and greater selection of the preferred hand than other tasks. Likewise, the magnitude of the preferred-hand advantage depends heavily on the task examined (McManus, van Horn & Bryden, 2016). One often cited explanation is that the degree of skill required to perform a particular task may drive hand selection, which then allows the preferred hand to become more adept at those highly skilled tasks (Steenhuis & Bryden, 1989). In reviews of our work(46, 6, 31) we have argued that "skilled behaviour" may not adequately explain handedness. Work remains to determine the nature of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities. The proposed research will elucidate the nature of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities in both unimanual and bimanual tasks. An emphasis will be placed on understanding the performance abilities of the non-preferred limb and left-handed individuals, both of which have been overlooked in past research. Importantly this work will also examine changes in limb selection and performance abilities across different age groups, from children to seniors. The long-term objective is thus to create a lifespan model of the maturation of motor lateralization that better explains the myriad of contradictory findings in unimanual and bimanual tasks. Short-term objectives will be to examine: a) limb selection in both unimanual and bimanual tasks (Research Theme D1); b) the relative abilities of each hand in unimanual and bimanual tasks (Research Theme D2); and c) maturation in lateral preference and performance in both unimanual and bimanual tasks (Research Theme D3). To further tease apart the nature of what each limb/hemisphere system is specialized for we will explore lateral preference and performance in both unimanual and bimanual tasks in; d) left handers (Research Theme D4); e) individuals with impaired motor planning/execution (e.g. autism spectrum disorder, ADHD) (Research Theme D5). While handedness and lateralization of motor function have been studied in the past, there are large gaps in our understanding of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities. Unfortunately, many studies include only young adults or only right-handed individuals, thus not capturing the complete picture of lateral preference, selection, and performance abilities. The proposed research will fill several gaps in current theories, inform researchers regarding the metrics of handedness, and be applied to aspects of education, industry, and training.