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Roderick I Nicolson

Publications and source records attributed to Roderick I Nicolson.

10 recordsLinked to original sources
PubMed2006

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.

Adolescent↗
PubMed2005

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.

Cerebellum↗
PubMed2004

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.

Adult↗
PubMed2003

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.

Auditory Perception↗
PubMed2003

Evaluation of an exercise-based treatment for children with reading difficulties.

An evaluation is reported of an exercise-based approach to remediation of dyslexia-related disorders. Pupils in three years of a Warwickshire junior school were screened for risk of literacy difficulty using the Dyslexia Screening Test (DST). The 35 children scoring 0.4 or over on the DST were divided randomly into two groups matched for age and DST score. One quarter of the participants had an existing diagnosis of dyslexia, dyspraxia or ADHD. Both groups received the same treatment at school but the intervention group used the DDAT exercise programme daily at home. Performance on the DST and specialist cerebellar/vestibular and eye movement tests were assessed initially and after six months. Cerebellar/vestibular signs were substantially alleviated following the exercise treatment whereas there were no significant changes for the control group. Even after allowing for the passage of time, there were significant improvements for the intervention group in postural stability, dexterity, phonological skill, and (one-tailed) for naming fluency and semantic fluency. Reading fluency showed a highly significant improvement for the intervention group, and nonsense passage reading was also improved significantly. Significantly greater improvements for the intervention group than the control group occurred for dexterity, reading, verbal fluency and semantic fluency. Substantial and significant improvements (compared with those in the previous year) also occurred for the exercise group on national standardized tests of reading, writing and comprehension. It is concluded that, in addition to its direct effects on balance, dexterity and eye movement control, the benefits of the DDAT exercise treatment transferred significantly to cognitive skills underlying literacy, to the reading process, and to standardized national literacy attainment tests.

Apraxias↗
PubMed2002

Eyeblink conditioning indicates cerebellar abnormality in dyslexia.

There is increasing evidence that cerebellar deficit may be a causal factor in dyslexia. The cerebellum is considered to be the major structure involved in classical conditioning of the eyeblink response. In a direct test of cerebellar function in learning, 13 dyslexic participants (mean age 19.5 years) and 13 control participants matched for age and IQ undertook an eyeblink conditioning experiment in which for 60 acquisition trials an 800-ms auditory tone (conditioned stimulus, CS) was presented. On 70% of the trials an 80-ms corneal airpuff (unconditioned stimulus, US) was presented 720 ms after the tone onset. The cerebellar deficit hypothesis, uniquely of the causal hypotheses for dyslexia, predicts that the dyslexic participants would show abnormal performance in the incidence and/or timing of the conditioned response (CR) of an eyeblink in response to the tone (and before the US). Three of the dyslexic group showed no conditioning at all. Furthermore, the dyslexic group showed significantly worse "tuning" of the CR timing, together with significantly reduced habituation of the orienting response (OR) to the CS. Individual analyses indicated that 85% of the dyslexic group showed either no conditioning or abnormally poor CR tuning and/or abnormally low OR habituation. It is concluded that the findings provide further converging evidence of cerebellar abnormality in dyslexia and for the first time demonstrate that there are fundamental abnormalities in the way that dyslexic people learn. Equally important, the eye blink conditioning paradigm provides a method of investigating further both homogeneity and heterogeneity in the learning deficits underlying dyslexia and other developmental disorders.

Adolescent↗
PubMed2002

Evidence for a neuroanatomical difference within the olivo-cerebellar pathway of adults with dyslexia.

Recent behavioural evidence has indicated that cerebellar impairment may be strongly associated with dyslexia. Previous neuroanatomical research has shown the presence of anomalies within the cerebral cortex of brains of dyslexic people. This paper reports equivalent analyses on the cerebella of the same brain specimens. Cross sectional areas and cell packing densities of Purkinje cells in the cerebellar cortex, and cells in the inferior olivary and dentate nuclei of four dyslexic and four control brains were measured using the dissector method. A significant difference in mean cell area in medial posterior cerebellar cortex was identified, with the dyslexic cells having larger mean area. Furthermore, analysis of cell size distributions not only confirmed the significant differences in the posterior lobe, with an increased proportion of large neurons and fewer small neurons for the dyslexics, but also revealed significant differences in the anterior lobe, again with a pattern of more large and fewer small cells. Similar distributional differences were seen in the inferior olive. No differences were found in the flocculonodular lobe or the dentate nucleus. While caution is necessary in generalising from the results given the small number of specimens, together with the age difference, the neuroanatomical data established here provides further converging evidence of cerebellar abnormality in dyslexia.

Adolescent↗
PubMedDate not supplied

The dyslexia ecosystem.

It is all too easy, in everyday interactions in dyslexia, to see the interactions in a semi-adversarial fashion--parents competing to get more support for children, researchers competing to get more support for their theories, schools trying to get more money for their programmes. Such a set of analyses may be described as 'zero-sum'. If one party gains, the other one loses. If, by contrast, one views the dyslexia community as a complex, inter-dependent 'ecosystem', a much more positive view emerges. It becomes clear that there are solutions for the system as a whole that are in a sense optimal for the system as a whole, solutions that are 'win-win', that is, all parties gain and none lose. In this article I develop this concept of the 'dyslexia ecosystem', and outline targets that would lead to progress for the ecosystem as a whole.

Cooperative Behavior↗
PubMedDate not supplied

Children with dyslexia are slow to articulate a single speech gesture.

In addition to their well-established problems in phonological processing, children with dyslexia show reduced speed of articulation. Two groups of children with dyslexia, mean ages 13 and 16 years, participated together with two groups of normally achieving children matched for age and IQ, with 33 participants in total. Participants were asked to articulate repeatedly, as fast as they could, either a single articulatory gesture /p/ /t/ or /k/ or the sequence 'putuku'. The waveforms generated were analysed in two ways; the time per gesture excluding inter-articulatory pauses (articulatory duration); and the mean time including the pauses (gesture duration). No age effects were found, but dyslexic groups were significantly slower on all tests. Deficits were greater in relative magnitude for gesture duration than articulatory duration. The results suggest that children with dyslexia have significant problems in articulation, not only in gesture planning, but also in the speeded production of single articulatory gestures.

Adolescent↗