de Freitas Paulo B, Pedão Sabrina T, Barela Jose A
Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil.
Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil.
Res Dev Disabil. 2014 Oct;35(10):2352-8. doi: 10.1016/j.ridd.2014.06.002. Epub 2014 Jun 22.
Developmental Dyslexia negatively affects children's reading and writing ability and, in most cases, performance in sensorimotor tasks. These deficits have been associated with structural and functional alterations in the cerebellum and the posterior parietal cortex (PPC). Both neural structures are active during visually guided force control and in the coordination of load force (LF) and grip force (GF) during manipulation tasks. Surprisingly, both phenomena have not been investigated in dyslexic children. Therefore, the aim of this study was to compare dyslexic and non-dyslexic children regarding their visuomotor processing ability and GF-LF coordination during a static manipulation task. Thirteen dyslexic (8-14 YO) and 13 age- and sex-matched non-dyslexic (control) children participated in the study. They were asked to grasp a fixed instrumented handle using the tip of all digits and pull the handle upward exerting isometric force to match a ramp-and-hold force profile displayed in a computer monitor. Task performance (i.e., visuomotor coordination) was assessed by RMSE calculated in both ramp and hold phases. GF-LF coordination was assessed by the ratio between GF and LF (GF/LF) calculated at both phases and the maximum value of a cross-correlation function (rmax) and its respective time lag calculated at ramp phase. The results revealed that the RMSE at both phases was larger in dyslexic than in control children. However, we found that GF/LF, rmax, and time lags were similar between groups. Those findings indicate that dyslexic children have a mild deficit in visuomotor processing but preserved GF-LF coordination. Altogether, these findings suggested that dyslexic children could present mild structural and functional alterations in specific PPC or cerebellum areas that are directly related to visuomotor processing.
发育性阅读障碍会对儿童的读写能力产生负面影响，在大多数情况下，还会影响其在感觉运动任务中的表现。这些缺陷与小脑和顶叶后皮质（PPC）的结构和功能改变有关。在视觉引导的力控制过程以及操作任务中负载力（LF）和握力（GF）的协调过程中，这两个神经结构都会活跃起来。令人惊讶的是，这两种现象尚未在阅读障碍儿童中进行研究。因此，本研究的目的是比较阅读障碍儿童和非阅读障碍儿童在静态操作任务中的视觉运动处理能力和GF-LF协调能力。13名阅读障碍儿童（8-14岁）和13名年龄及性别匹配的非阅读障碍（对照）儿童参与了该研究。他们被要求用所有手指的指尖抓住一个固定的装有传感器的手柄，并向上拉动手柄，施加等长力，以匹配计算机显示器上显示的斜坡-保持力曲线。任务表现（即视觉运动协调能力）通过在斜坡和保持阶段计算的均方根误差（RMSE）来评估。GF-LF协调能力通过两个阶段计算的GF与LF的比率（GF/LF）、互相关函数的最大值（rmax）及其在斜坡阶段计算的相应时间滞后进行评估。结果显示，阅读障碍儿童在两个阶段的RMSE均大于对照儿童。然而，我们发现两组之间的GF/LF、rmax和时间滞后相似。这些发现表明，阅读障碍儿童在视觉运动处理方面存在轻度缺陷，但GF-LF协调能力保持完好。总之，这些发现表明，阅读障碍儿童在与视觉运动处理直接相关的特定PPC或小脑区域可能存在轻度的结构和功能改变。
