Adaptive Sensorimotor Control in Children with DCD

描述（由申请人提供）：本研究项目的长期目标是了解发育协调障碍（DCD）的潜在机制，并为儿童发育协调障碍的评估和干预提供科学依据。在小学，估计患有双相障碍的儿童占人口的6% （APA, 1994）。由于缺乏体育活动，这些儿童面临学习成绩差、社会情感困难和长期健康问题的风险。以前对DCD儿童的研究主要集中在知觉或任务缺陷上。这一建议检验了一种假设，即患有DCD的儿童在感知和行动之间的关系方面存在问题，更具体地说，是在适应这种关系以适应新环境和任务的能力方面存在问题（被称为适应性感觉运动控制）。在这个项目中，我们结合行为和计算方法来研究在稳定和变化的感觉运动环境中患有和没有DCD的7岁儿童的这种关系。实验采用四个实验范式（一个视觉运动绘画任务、两个体位任务、一个驱动视觉刺激和另一个驱动体感刺激的任务和一个听觉双侧敲击任务）。因此，我们通过多种运动任务（绘画，姿势，敲击），不同的模式（视觉，触觉，听觉）和不同的时间尺度（实时，短期适应或学习和发展时间）来检查儿童。包括这样的实验变化是为了解决这个人群的异质性问题，更具体地说，DCD的亚型可能是任务和/或模态依赖于识别的说法。本建议的具体目的是行为和计算：1)表征四个任务之间的感觉运动关系。我们假设患有DCO的儿童在所有任务中都有较少明确的感觉运动缺陷，通过测量空间和时间的准确性和可变性来确定。就个体而言，患有DCD的儿童在不同的任务中会表现出不同的感觉运动缺陷，这表明了该人群的异质性（和可能的亚型）。2)研究在四个任务中感觉运动关系的渐进式和阶梯式变化下新的内部模型的学习。我们假设患有DCD的儿童适应变化的能力较差，这是由时间过程、空间和时间精度以及变异性指标指标决定的。就个体而言，DCD患儿会表现出不同的影响，其突变和渐进的变化反映了不同的潜在机制。3)研究在四个任务中的感觉运动转换。我们假设，患有DCD的儿童在经历第二种新的感觉运动关系后，会表现出感觉运动关系之间的平均水平和/或需要更长的时间来稳定他们的感觉运动表现。4)描述两年后在四个任务中感觉运动关系和适应的发展变化。我们假设患有DCD的儿童将继续表现出广泛的和非适应性的感觉运动调谐，这是与特定目标#1 -3相关的实验指标所指示的。综上所述，来自这些特定目标的信息将为未来的干预研究以及对这种运动障碍的潜在机制的进一步调查奠定基础。

DESCRIPTION (provided by applicant): The long-term objective of this research program is to understand the underlying mechanisms of Developmental Coordination Disorder (DCD) and to provide a scientific basis for the evaluation, and interventions of children with this disorder. In elementary school, children with DCD are estimated to comprise up to 6 percent of the population (APA, 1994). These children are at risk for poor academic achievement, socio-emotional difficulties, and long-term health problems due to their lack of participation in physical activities. Previous work on children with DCD has focused primarily on perceptual or task deficits. This proposal examines the hypothesis that children with DCD have problems with the relationship between perception and action and more specifically with the ability to adapt this relationship to new environments and tasks (referred to as adaptive sensorimotor control). In this project, we combine behavioral and computational approaches to investigate this relationship in 7-year-old children with and without DCD in stable and changing sensorimotor environments. Four experimental paradigms are used (a visuomotor drawing task, two postural tasks, one with a driving visual stimulus and another with a driving somatosensory stimulus, and an auditory bilateral tapping task). Thus, we examine the children across multiple motor tasks (drawing, posture, tapping), varying modalities (visual, touch, auditory), and varying time-scales (real-time, short-term adaptation or learning and developmental-time). Such experimental variations are included to address the issue of heterogeneity in this population and more specifically the claim that there are subtypes of DCD that may be task and/or modality dependent for identification. The specific aims of this proposal are to behaviorally and computationally: 1) Characterize the sensorimotor relationships across four tasks. We hypothesize that children with DCO will have less well-defined sensorimotor deficits in all tasks as indexed by measures of spatial and temporal accuracy and variability. Individually, children with DCD will show differential sensorimotor deficits across tasks indicative of the heterogeneity (and possible subtypes) of this population. 2) Investigate the learning of novel internal models under gradual and step-like changes in sensorimotor relationships across four tasks. We hypothesize that children with DCD will be less able to adapt to changes as indexed by time-course, spatial and temporal accuracy and variability measures. Individually, children with DCD will demonstrate differential effects with the abrupt and gradual changes reflecting different underlying mechanisms. 3) Investigate sensorimotor switching across four tasks. We hypothesize that children with DCD will demonstrate an averaging between sensorimotor relationships and/or take longer to stabilize their sensorimotor performance after experiencing a second novel sensorimotor relationship. And 4) Characterize the developmental changes in sensorimotor relationships and adaptations across four tasks after two years. We hypothesize that children with DCD will continue to show broad and non-adaptive sensorimotor tuning as indexed by measures in experiments related to specific aims #1 -3. Taken together, the information from these specific aims will lay the groundwork for future intervention studies as well as further investigation into the underlying mechanisms of this movement disorder.