A sensorimotor representation impairment in dyslexic adults: A specific profile of comorbidy

Postural and Proprioceptive Deficits Clinically Assessed in Children with Reading Disabilities: A Case-Control Study

Several studies have reported motor deficiencies in children with dyslexia, in line with the cerebellar deficit theory. In the present study, we explored whether tests used by physiotherapists during clinical evaluation were able to report motor deficits in a group of fifty-six dyslexic children (mean age 10.9 ± 0.2 years old) compared to a group of thirty-eight non-dyslexic children (mean age 11.2 ± 0.4 years old). The occurrence of instability on an unstable support; spinal instability in the sagittal, frontal and horizontal plane; head-eye discoordination; and poor eye stability were clinically assessed in the two groups of children. All such measures were found to be significantly more frequent in dyslexic than in non-dyslexic children (p < 0.001, p < 0.05, p < 0.001 and p < 0.001, respectively, for occurrence of instability on an unstable support, spinal instability, head-eye discoordination and poor eye stability). These results, firstly, confirmed the poor motor control of dyslexic children, suggesting deficient cerebellar integration. Secondly, for the first time, we reported that simple tests that can be done by pediatricians and/or during a clinical routine evaluation could be useful to discriminate children with reading difficulties. The tests used in this study could be a reference for a first exploration of motor deficiencies in children with dyslexia that can be easily assessed by clinicians and/or physiotherapists.

Phoneme Representation and Articulatory Impairment: Insights from Adults with Comorbid Motor Coordination Disorder and Dyslexia

Phonemic processing skills are impaired both in children and adults with dyslexia. Since phoneme representation development is based on articulatory gestures, it is likely that these gestures influence oral reading-related skills as assessed through phonemic awareness tasks. In our study, fifty-two young dyslexic adults, with and without motor impairment, and fifty-nine skilled readers performed reading, phonemic awareness, and articulatory tasks. The two dyslexic groups exhibited slower articulatory rates than skilled readers and the comorbid dyslexic group presenting with an additional difficulty in respiratory control (reduced speech proportion and increased pause duration). Two versions of the phoneme awareness task (PAT) with pseudoword strings were administered: a classical version under time pressure and a delayed version in which access to phonemic representations and articulatory programs was facilitated. The two groups with dyslexia were outperformed by the control group in both versions. Although the two groups with dyslexia performed equally well on the classical PAT, the comorbid group performed significantly less efficiently on the delayed PAT, suggesting an additional contribution of articulatory impairment in the task for this group. Overall, our results suggest that impaired phoneme representations in dyslexia may be explained, at least partially, by articulatory deficits affecting access to them.

Visual Occlusion Effects On Bipedal Stance Control In Chinese-Speaking Children With Dyslexia

Visual processing of complex character configurations is especially challenging for Chinese-speaking children with dyslexia (CSCD). The purpose of this study was to compare the effects of visual occlusion on postural control between dyslexic and non-dyslexic Chinese-speaking children by examining their visual-perceptual capacity and movement coordination with scale measures. Sixteen dyslexic children (10 males and, 6 females, 9.46 ± 1.26 yrs) and sixteen non-dyslexic children (10 males and 6 females, 9.91 ± 1.18 yrs) were recruited from the campus in Taiwan. Motor and visual perceptual performance were assessed with the Movement Assessment Battery for Children, 2nd Edition (MABC-2) and the Test of Visual-Perceptual Skills, 4th Edition (TVPS-4). Root mean square (RMS) and sample entropy (SampEn) of center of pressure (COP) were characterized during a bilateral upright stance with eyes open (EO) and eyes closed (EC). The results showed significant group differences in six of the seven TVPS-4 subscales (P < .001-.017) and one category of the MABC-2 (P = .006). In the EO condition, the children with dyslexia showed a greater RMS of COP specifically in the anterior-posterior (AP) direction than did the non-dyslexic children (P = .029). However, SampEn of COP in the two directions were not group dependent (P > .05). In the EC condition, RMS and SampEn of COP did not vary with group (P > .05). RMS of COP in the AP direction was negatively correlated with the sub-score of visual figure-ground in the TVPS-4 (r = - .381, P = .031). In summary, postural control of Chinese-speaking children with dyslexia is more affected with eyes open than with eyes closed, and the effect is related to visual disturbance of the foreground and background.