title: Visuomotor processing and hand force coordination in dyslexic children during a visually guided manipulation task.
abstract: 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.
authors: Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil. Electronic address: deFreitasPB@gmail.com.
authors: Paulo B
authors: PB
authors: de Freitas
authors: Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil.
authors: Sabrina T
authors: ST
authors: Pedão
authors: Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil; Department of Physical Education, Institute of Biosciences, São Paulo State University, Rio Claro, SP, Brazil.
authors: Jose A
authors: JA
authors: Barela
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D004410:Dyslexia / Q000503:physiopathology*; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D014796:Visual Perception
keywords: Control; Coupling; Dyslexia; Feedback; Grip; Load; Reading problem