Preterm children usually suffer from mild hand motor performance, however, the problem are rarely detected in time. Identifying the pathology causing deficits in sensorimotor control of a hand helps the occupational therapist to determine appropriate clinical decision-making for intervention. Well-motor performance requires complete sensorimotor control. Understanding hand sensorimotor control mechanism and its neural control can help clinicians find the reason behind hand motor deficits. The analysis of motion adaptation of the precision pinch behavior in the perturbing environment has been regarded as a clinically meaningful tool for evaluating sensorimotor control of a hand, especially for the complex anatomical structure of bone and tendon. The motor adaptation analysis for the precision grip behavior can provide the temporal and spatial parameters of dynamic grip force adjustment. Therefore, the exploration of motor adjustment can provide in-depth understanding of the neural mechanisms that lead to impairment of motor function and skill acquisition of a child, which can assist clinical occupational therapist in identifying the cause and severity of impairment of children's hand skills and provide appropriate strategies and types of treatment. The recent research on children's motor adaptation focuses on the discussion of the efficiency of motor adaptation in unfamiliar or disturbing task situations. Thus, the first purpose of this research is to develop an easy-to-detect apparatus to detect the adjustment efficiency of a responsive grip behavior of children in a disturbing pinch-lifting task and to construct the reliability of its evaluation. The second purpose of the research is to understand the correlation between the efficiency of children's reactive pinch performance adjustment and the results of traditional evaluation of fine motor development scale and sensorimotor control assessments. The third purpose of the research is to analyze the difference in motor adjustment of a precision pinch performance at different ages of preschool children. The fourth purpose is to compare the efficiency of motor adaptation in preterm and term children. In addition, preterm birth is often accompanied by white matter abnormalities and affects future hand motor performance. Investigating white matter imaging markers for predicting motor adaptation can help early detection of problems. Therefore, the fifth objective was to explore whether specific white matter imaging markers can predict the efficiency of reactive motor adaptation.

Inclusion Criteria:

1. Must be able to do reach-to-grasp performance
2. Intact comprehension ability

Exclusion Criteria:

1. Diagnosis of cerebral palsy and other genetic or congenital damage
2. Bone and nerve damage in the upper limbs in the past year
3. Un-correctable problems of vision or hearing impairment

healthy adults: 20-39 years old term children: 24-60 months preterm children: 24-48 months