Cognitive-Motor Training Improves Reading-Related Executive Functions: A Randomized Clinical Trial Study in Dyslexia.

Children with developmental dyslexia (DD) often struggle with executive function difficulties which can continue into adulthood if not addressed. This double-blinded randomized clinical trial study evaluated the short-term effects of the Verbal Working Memory-Balance (VWM-B) program on reading-related executive functions, reading skills, and reading comprehension in Persian children with DD. The active control group [12 children with DD with a mean age of 9 years (SD = 0.90)] received training using the single-task VWM program, while the experiment group [15 children with DD with a mean age of 8 years (SD = 0.74)] received training with the dual-task VWM-B program. Both groups received fifteen training sessions, and assessments were conducted before and after the intervention. The groups were homogenized for possible confounders of age, gender, IQ level, and attention level. The study employed separate mixed ANOVA analyses to estimate the impact of training programs on various measured functions. Significant improvements were observed in the outcome measures of backward digit span, text comprehension, verbal fluency, Stroop color-word test and interference, and the reading subtests. Additionally, significant correlations were found between reading skills and backward digit span, text comprehension, verbal fluency, and Stroop variables. In conclusion, the dual-task VWM-B program was found to be more effective than the single-task VWM program in improving selective attention, cognitive inhibition, verbal working memory capacity, information processing speed, naming ability, and lexical access speed. These enhanced executive functions were associated with improved reading skills in children with DD.

Verbal Working Memory-Balance program training alters the left fusiform gyrus resting-state functional connectivity: A randomized clinical trial study on children with dyslexia.

Sufficient activation of the left fusiform gyrus is important in reading ability acquisition due to its role in reading and naming, working memory (WM), and balance tasks. Recently, a newly-designed training program, Verbal Working Memory-Balance (VWM-B), has been evaluated on children with dyslexia, and its positive effects were shown on reading ability, WM capacity, and postural control. In the present study, we aimed to estimate the functional connectivity alterations of the left fusiform gyrus following training by the VWM-B. Before and after 15 sessions of training, the fMRI and other tools data were collected on a sample of children with dyslexia, who were allocated into two control and experiment groups. Data analyses showed the increased functional connectivity of the left fusiform gyrus between the left anterior temporal fusiform cortex, left and right Crus II regions of the cerebellum, and the left middle frontal gyrus. Moreover, VWM-B training significantly improved the reading and naming ability, WM capacity, and postural control of participants in the experiment group in comparison to the control. The current study findings emphasize the critical role of the left fusiform gyrus in reading ability. Moreover, it provides evidence to support the existence of cerebellar deficits in dyslexia.

Evaluating a new verbal working memory-balance program: a double-blind, randomized controlled trial study on Iranian children with dyslexia.

BACKGROUND: It is important to improve verbal Working Memory (WM) in reading disability, as it is a key factor in learning. There are commercial verbal WM training programs, which have some short-term effects only on the verbal WM capacity, not reading. However, because of some weaknesses in current verbal WM training programs, researchers suggested designing and developing newly structured programs that particularly target educational functions such as reading skills. In the current double-blind randomized clinical trial study, we designed a new Verbal Working Memory-Balance (VWM-B) program which was carried out using a portable robotic device. The short-term effects of the VWM-B program, on verbal WM capacity, reading skills, and postural control were investigated in Iranian children with developmental dyslexia. RESULTS: The effectiveness of the VWM-B program was compared with the VWM-program as a traditional verbal WM training. In comparison with VWM-program, the participants who received training by the VWM-B program showed superior performance on verbal WM capacity, reading skills, and postural control after a short-term intervention. CONCLUSIONS: We proposed that the automatized postural control resulting from VWM-B training had a positive impact on improving verbal WM capacity and reading ability. Based on the critical role of the cerebellum in automatizing skills, our findings support the cerebellar deficit theory in dyslexia. TRIAL REGISTRATION: This trial was (retrospectively) registered on 8 February 2018 with the Iranian Registry of Clinical Trials (IRCT20171219037953N1).

Development of Dyslexia: The Delayed Neural Commitment Framework.

It is now evident that explanations of many developmental disorders need to include a network perspective. In earlier work, we proposed that developmental dyslexia (DD) is well-characterized in terms of impaired procedural learning within the language networks, with the cerebellum being the key structure involved. Here, we deepen the analysis to include the child's developmental process of constructing these networks. The "Delayed Neural Commitment (DNC)" framework proposes that, in addition to slower skill acquisition, dyslexic children take longer to build (and to rebuild) the neural networks that underpin the acquisition of reading. The framework provides an important link backwards in time to the development of executive function networks and the earlier development of networks for language and speech. It is consistent with many theories of dyslexia while providing fruitful suggestions for further research at the genetic, brain, cognitive and behavioral levels of explanation. It also has significant implications for assessment and teaching.

Dyslexia and Substance Use in a University Undergraduate Population.

BACKGROUND: A number of cognitive deficits are associated with dyslexia. However, only a limited amount of research has been performed exploring a putative link between dyslexia and substance use. As substance use is thought to involve a cognitive component, it is possible that the pattern of substance use would be different for dyslexic participants, when compared to nondyslexic controls. During the current study, a guiding hypothesis was that people with dyslexia would demonstrate less substance use than nondyslexic controls. Theories of memory activation, automaticity, and attentional bias in substance use suggest that cognitive components of substance use are important in the development and maintenance of continued substance use and it is thought that, at least some of these components, would be impaired in a dyslexic population. OBJECTIVES: If the cognitive deficits displayed by dyslexics somehow impair the development of cognitive components of substance use, substance use for dyslexic participants may be less pronounced. This paper therefore examines this hypothesis by comparing substance use within dyslexic and nondyslexic participants, from an undergraduate population. METHODS: This was an exploratory questionnaire-based study. Dyslexic participants (n = 35) were compared to control participants (n = 62) on a series of questions designed to measure their substance use history. RESULTS: The results provided preliminary evidence of a difference between dyslexic and nondyslexic substance use. Dyslexics reported a substance use history that was significantly lower than nondyslexic controls. CONCLUSIONS/IMPORTANCE: These results are interpreted in terms of cognitive deficits within dyslexia and with reference to the cognitive model of substance use.

Consensus paper: Language and the cerebellum: an ongoing enigma.

In less than three decades, the concept "cerebellar neurocognition" has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the "linguistic cerebellum" in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper.

The proposed changes for DSM-5 for SLD and ADHD: international perspectives--Australia, Germany, Greece, India, Israel, Italy, Spain, Taiwan, United Kingdom, and United States.

This article presents an international perspective of the proposed changes to the DSM-5 for learning disabilities (LD) and attention-deficit/hyperactivity disorders (ADHD) across ten countries: Australia, Germany, Greece, India, Israel, Italy, Spain, Taiwan, the United Kingdom, and the United States. We provide perspectives of the present situation for youth with LD and youth with ADHD and describe the legislation, prevalence rates, and educational systems that serve students with disabilities in the respective countries. We also present a discussion of the expected impact of the proposed changes for the diagnosis of LD and ADHD in each country.

Striking the right balance: motor difficulties in children and adults with dyslexia.

Balance difficulties are an enduring feature of dyslexia research, however results have been inconsistent. We propose that between-study heterogeneity may be attributable to variability in balance tasks, balance measurement, participant age, and inclusion of comorbid disorders such as ADHD. This study attempted to clarify these issues, employing quantitative, continuous measures of balance and blindfolded balance, and using both adult and child participants without comorbid ADHD. Eighty-seven individuals participated: dyslexic adults (n = 17), matched adult controls (n = 30), dyslexic children (n = 16) and matched child controls (n = 24). The study found significant balance deficits for the child dyslexic group in the eyes-open task and a result approaching significance in the blindfolded task. By contrast, the adult dyslexic group showed significant deficits in the blindfolded task only. This result is interpreted in terms of lack of sensitivity of the non-blindfolded balance task for adults, owing to ceiling effects. This highlights the need for the use of age-appropriate tests, and may explain some of the heterogeneity in the literature. It is concluded that there is a significant incidence of balance difficulties in children and adults with dyslexia, even for those without comorbid attention deficit.

Cerebellar volume and cerebellar metabolic characteristics in adults with dyslexia.

Developmental dyslexia is associated with problems in a range of linguistic and non-linguistic skills. Some of those problems have been attributed to dysfunction of the cerebellum and its associated neural systems. Two studies of cerebellar structure were undertaken by our group. In Study 1, white and grey matter volumes in the cerebellum were investigated in 10 dyslexic and 11 control adult male, right-handed participants using whole-brain volumetric MRI (3D-T1-weighted data sets with a spatial resolution of 0.8 x 0.8 x 0.8 mm(3)). The key finding was that the dyslexic group had a larger volume of white matter in both cerebellar hemispheres, differences that remained significant even when adjusting for total cerebellar volume. In Study 2, with the same participants, long-echo-time proton spectroscopy was used to investigate the ratios of the metabolites choline (Cho), N-acetylaspartate (NAA), and creatine (Cr) in the cerebellar hemispheres and vermis. Two significant differences were found: The dyslexic group had a lower ratio of NAA/Cho in the right cerebellar hemisphere together with a higher ratio of Cho/Cr in the left cerebellar hemisphere. Although it is difficult to interpret the volumetric and spectroscopic results unambiguously, taken together they suggest two possible interpretations: excessive connectivity or abnormal myelination.

Procedural learning difficulties: reuniting the developmental disorders?

During the past 30 years, research into developmental disorders has fragmented, emphasizing differences rather than commonalities. We propose that reunification might be achieved by using a "neural-systems" approach. Deficits in dyslexia are attributed to an intact declarative learning system combined with an impaired procedural learning system--a network that includes prefrontal language systems and basal ganglia, parietal and cerebellar structures. A typology is provided for other prevalent learning disabilities; this framework focuses on different learning skills in the understanding of learning disabilities and emphasizes the diagnostic significance of "secondary" symptoms. This approach highlights the need for development of "neurocognitive" tests to probe the function of components of each neural system and improve strategies for explanation, diagnosis and support of developmental disorders.

Dyslexia, learning, and pedagogical neuroscience.

The explosion in neuroscientific knowledge has profound implications for education, and we advocate the establishment of the new discipline of 'pedagogical neuroscience' designed to combine psychological, medical, and educational perspectives. We propose that specific learning disabilities provide the crucible in which the discipline may be forged, illustrating the scope by consideration of developmental dyslexia. Current approaches have failed to establish consensus on fundamental issues such as theoretical causes, diagnostic methods, and treatment strategies. We argue that these difficulties arise from diagnosis via behavioural or cognitive symptoms, even though they may arise from diverse causes. Rather than an inconvenience, variability of secondary symptoms within and across learning disabilities can inform both diagnosis and treatment. We illustrate how brain-based theories lead to radical restructuring of diagnostic methods and propose that there is an urgent need to develop genetic and brain-based diagnostic methods designed to lead to individually-appropriate remediation and treatment methods.

Prisms throw light on developmental disorders.

Prism adaptation, in which the participant adapts to prismatic glasses that deflect vision laterally, is a specific test of cerebellar function. Fourteen dyslexic children (mean age 13.5 years); 14 children with developmental coordination disorder (DCD): 6 of whom had comorbid dyslexia; and 12 control children matched for age and IQ underwent prism adaptation (assessed by clay throwing accuracy to a 16.7 degrees visual displacement). All 8 DCD children, 5 of the 6 children with comorbid DCD and dyslexia and 10 of the 14 dyslexic children showed an impaired rate of adaptation, thereby providing strong evidence of impaired cerebellar function in DCD and developmental dyslexia. Taken together with other emerging evidence of overlap between developmental disorders, these findings highlight the importance of complementing research on the individual disorders with research on the commonalities between the disorders.

Balancing and pointing tasks in dyslexic and control adults.

Developmental dyslexia may affect as much as 15% of the population, but the aetiology of the disorder is still being debated. The cerebellar theory of dyslexia proposes that cerebellar dysfunction could lead to the myriad of symptoms seen in dyslexic individuals, both in literacy and non-literacy domains. The cerebellum is crucial to the fluent performance of motor skills. Previous studies have found that dyslexic children are worse than control children on certain motor and balancing tasks. Here the performance of 28 dyslexic compared to 26 control adults on rapid pointing and balancing measures, tasks which are thought to reflect cerebellar function, was investigated. There were no significant differences between the dyslexic and control participants on the balancing tasks or when the speed and accuracy of pointing were analysed separately. However, when the speed and accuracy of pointing were combined, the dyslexic participants showed poorer performance than the controls (p = 0.045). Furthermore, there were significant relationships between performance on the pointing task and literacy skills, and regression analysis showed that the error and speed of pointing contributed significantly to the variance in literacy skill. The implications for the role of the cerebellum and processing speed in dyslexia are discussed.

Impaired balancing ability in dyslexic children.

Children with developmental dyslexia struggle to learn to read and spell despite adequate intelligence and educational opportunity. Several lines of research are attempting to establish the neurobiological basis of dyslexia, and low-level sensory and motor deficits have been found in dyslexic populations; furthermore, behavioural and imaging data point to cerebellar dysfunction in dyslexia. To investigate this, normal readers (n=19) and children with developmental dyslexia (n=16) were asked to perform various cognitive, literacy, and balancing tasks. Children balanced on the left or right foot, with eyes open or closed, for a period of 10 s during which their movements were recorded with a motion-tracking system. Dyslexic children were less stable than the control children in both eyes-open conditions (left foot P=0.02, right foot P=0.012). While there were no group differences during the eyes-closed conditions, the dyslexic children dropped a foot to correct balance significantly more often than control children (P<0.05). Incidence analysis showed that 50% of the dyslexic group fell into the 'impaired' category on the eyes-open balancing tasks; when the mean balancing scores and the foot drops were considered, only three of our dyslexic children showed no evidence of balancing difficulties. There were strong correlations between reading and spelling scores and the mean eyes-open balancing score (r=0.52 and 0.44, respectively). Thus, while not all children with developmental dyslexia show impaired balancing skills, low-level motor dysfunction may be associated with impaired literacy development. This could be due to several factors, including the involvement of the cerebellum, the magnocellular system, or more general developmental immaturity.

Dyslexic students have more everyday cognitive lapses.

There is a dearth of information about the everyday performance difficulties of adult dyslexic people. This study investigates the empirical support for anecdotal reports of increased vulnerability to distraction in dyslexia, using the self-report Cognitive Failures Questionnaire (CFQ). Two groups of university students, a dyslexic group and a non-dyslexic control group, were asked to complete the CFQ. The dyslexic group reported a higher frequency of everyday lapses in cognition, scoring significantly higher on a number of CFQ items. Representative problems include distractibility, over-focusing (so that relevant peripheral information is missed), and word-finding difficulties. A similar measure administered to close friends of dyslexic people, the CFQ-for-others, yielded results consistent with those of the CFQ, with major findings being that their friends considered them to be more disorganised, more distractible, and more absent-minded than normal. The results indicate clearly the continuing effects of dyslexia on cognition in adulthood and demonstrate that dyslexic impairments are not limited to "artificial" laboratory tasks or even literacy tasks but, instead, pervade everyday life.

The International Adult Literacy Survey in Britain: impact on policy and practice.

There is increasing concern for the skills of the workforce in the UK and elsewhere, but despite this concern until recently there has been little information available which objectively measures basic skills in adults. In this paper, evidence derived from the prose scale of the International Adult Literacy Survey (IALS, 1996) is outlined, with emphasis on the performance of adults at the lowest levels, 1 and 2 in the United Kingdom. A new analysis based on the 183 adults who self-reported learning disabilities demonstrates that over 50% of this group perform at level 1 on the prose scale. Over 60% report that these disabilities persist into adult life, although this number falls to 50% in the youngest age group, reflecting changes in recognition of learning disabilities within the education system. The paper concludes with a case study of the redefinition of basic skill levels in Britain based on the IALS levels. The impact of the IALS findings on policy and practice, and in particular through the recommendations of the Moser report, are discussed.

Dyslexia and music: measuring musical timing skills.

Over the last few decades, a growing amount of research has suggested that dyslexics have particular difficulties with skills involving accurate or rapid timing, including musical timing skills. It has been hypothesised that music training may be able to remediate such timing difficulties, and have a positive effect on fundamental perceptual skills that are important in the development of language and literacy skills (Overy, 2000). In order to explore this hypothesis further, the nature and extent of dyslexics' musical difficulties need to be examined in more detail. In the present study, a collection of musical aptitude tests (MATs) were designed specifically for dyslexic children, in order to distinguish between a variety of musical skills and sub-skills. 15 dyslexic children (age 7-11, mean age 9.0) and 11 control children (age 7-10, mean age 8.9) were tested on the MATs, and their scores were compared. Results showed that the dyslexic group scored higher than the control group on 3 tests of pitch skills (possibly attributable to slightly greater musical experience), but lower than the control group on 7 out of 9 tests of timing skills. Particular difficulties were noted on one of the tests involving rapid temporal processing, in which a subgroup of 5 of the dyslexic children (33%) (mean age 8.4) was found to account for all the significant error. Also, an interesting correlation was found between spelling ability and the skill of tapping out the rhythm of a song, which both involve the skill of syllable segmentation. These results support suggestions that timing is a difficulty area for dyslexic children, and suggest that rhythm skills and rapid skills may need particular attention in any form of musical training with dyslexics.