Developmental dyslexia: The role of the cerebellum

Nicolson, Roderick I.; Fawcett, Angela J.

doi:10.1002/(sici)1099-0909(199909)5:3<155::aid-dys143>3.0.co;2-4

Cited by 99 publications

(26 citation statements)

References 74 publications

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“…Frank and Levinson [7] were the first to report subjectively that dyslexic children showed neurological signs of cerebellar-vestibular deficiency (i.e., positive Romberg test, difficulty in tandem walking, articulatory speech disorders, hypotonia, and several dysmetric deficits). The cerebellar deficit hypothesis was confirmed by Nicolson and Fawcett [8] showing deficit in balance and motor coordination in a population of dyslexic children; their postural stability was affected by a secondary task, shifting attention away from the primary postural one. These authors suggested that dyslexics need to invest more attentional resources than non-dyslexics to control their balance when two tasks are performed simultaneously.…”

Section: Introductionmentioning

confidence: 82%

The Effect of a Stroop-like Task on Postural Control in Dyslexic Children

2013

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The influence of a secondary task on concurrent postural control was explored in twenty-one dyslexic children (mean age: 10.4±0.3 years). Data were compared with twenty age-matched non-dyslexic children. As a secondary task, a modified Stroop test was used, in which words were replaced with pictures of fruits. The postural control of children was recorded in standard Romberg condition as the children were asked to name the colour of fruits appearing consecutively on a computer screen. Two conditions were tested: a congruent condition, in which the fruit was drawn in its natural ripe colour, and a non-congruent colour condition (NC), in which the fruit was drawn in three abnormal colours. A fixating condition was used as baseline. We analyzed the surface, length and mean speed of the center of pressure and measured the number of correct responses in the Stroop-like tasks. Dyslexic children were seen to be significantly more unstable than non-dyslexic ones. For both groups of children, the secondary task significantly increased postural instability in comparison with the fixating condition. The number of correct responses in the modified Stroop task was significantly higher in the non-dyslexic than in the dyslexic group. The postural instability observed in dyslexic children is in line with the cerebellar hypothesis and supports the idea of a deficit in automatic performance in such children. Furthermore, in accordance with cross domain competition model, our findings show that attentional resources are used to a greater extent by the secondary task than in controlling body stability.

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Section: Introductionmentioning

confidence: 82%

The Effect of a Stroop-like Task on Postural Control in Dyslexic Children

2013

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“…Yet, along with these skills, cognitive learning mechanisms not specifically related to linguistic processing appear to mediate reading acquisition (Hulme, Goetz, Gooch, Adams, & Snowling, 2007; Windfuhr & Snowling, 2001). Specifically, non-linguistic mechanisms of associative learning may explain how reading is learned both implicitly and explicitly (Nicolson & Fawcett, 1999). Establishing the connections between written (grapheme) and spoken (phoneme) units is in fact the core learning activity of reading acquisition (Richardson & Lyytinen, 2014).…”

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confidence: 99%

Paired associate learning tasks and their contribution to reading skills

Mourgues

Tan

Hein

et al. 2016

Learning and Individual Differences

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Associative learning has been identified as one of several non-linguistic processes involved in reading acquisition. However, it has not been established whether it is an independent process that contributes to reading performance on its own or whether it is a process that is embedded in other linguistic skills (e.g., phonological awareness or phonological memory) and, therefore, contributing to reading performance indirectly. Research has shown that performance on tasks assessing associative learning, e.g., paired-associate learning (PAL) tasks, is lower in children with specific reading difficulties compared to typical readers. We explored the differential associations of two distinct verbal-visual PAL tasks (the Bala Bbala Graphogame, BBG, and a Foreign Language Learning Task, FLLT) with reading skills (word reading and pseudo-word decoding), controlling for phonological awareness, rapid naming, and letter and digit span in children at risk for reading disabilities and their typically developing peers. Our study sample consisted of 110 children living in rural Zambia, ranging in age from 7 to 18 years old (48.1% female). Multivariate analyses of covariance were used to explore the group differences in reading performance. Repeated-measures ANCOVA was used to examine children’s learning across the PAL tasks. The differential relationships between both PAL tasks and reading performance were explored via structural equation modeling. The main result was that the children at risk for reading difficulties had lower performance on both PAL tasks. The BBG was a significant predictor for both word reading and pseudo-word decoding, whereas the FLLT—only for word reading. Performance on the FLLT partially mediated the association between phonological awareness and word reading. These results illustrate the partial independence of associative learning from other reading-related skills; the specifics of this relationship vary based on the type of PAL task administered.

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“…One aetiological theory of dyslexia proposes that many of the behavioural symptoms stem from a common deficit in the development and functioning of the cerebellum. According to this theory, impairments of the cerebellum cause deficits in motor control such as posture and balance, and additional difficulties in achieving ‘automaticity’ of other learned skills, including those that impact directly upon literacy (e.g., grapheme to phoneme conversion and handwriting proficiency) (Nicolson & Fawcett, 1990, 1999). Supporting evidence for cerebellar abnormalities in dyslexia has been demonstrated in neuroimaging studies for measures of brain biochemistry (Rae et al., 1998), neural morphology (Rae et al., 2002) and functional activity related to motor learning (Nicolson et al., 1999).…”

mentioning

confidence: 99%

“…Several screening batteries for dyslexia, such as the Pre‐school Early Screening Test (PREST; Fawcett et al., 2001a) and the Dyslexia Screening Test – Junior (Fawcett & Nicolson, 2004) obtain measures of cerebellar function, including postural stability. The cerebellar deficit hypothesis predicts that balance in dyslexia is threatened by the failure to automate postural responses to perturbation, creating a continuous requirement for attentional resources to be drawn away from current activity toward the monitoring of posture (Nicolson & Fawcett, 1999). Balance in individuals with dyslexia is therefore predicted to depend upon a ‘conscious compensation’ process (Nicolson & Fawcett, 1999, p. 171) rather than on automatic control.…”

mentioning

confidence: 99%

“…The cerebellar deficit hypothesis predicts that balance in dyslexia is threatened by the failure to automate postural responses to perturbation, creating a continuous requirement for attentional resources to be drawn away from current activity toward the monitoring of posture (Nicolson & Fawcett, 1999). Balance in individuals with dyslexia is therefore predicted to depend upon a ‘conscious compensation’ process (Nicolson & Fawcett, 1999, p. 171) rather than on automatic control. Compensatory processes have been measured with dual‐paradigms in which a task secondary to the measure of balance is used to increase attentional load, thereby limiting the resources available for the preservation of balance (Nicolson & Fawcett, 1990).…”

mentioning

confidence: 99%

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