Nadia Northway

Bio: Nadia Northway is an academic researcher from Glasgow Caledonian University. The author has contributed to research in topics: Reading (process) & Noise. The author has an hindex of 4, co-authored 8 publications receiving 87 citations.

Coloured filters improve exclusion of perceptual noise in visually symptomatic dyslexics

Abstract: Previous studies of visually symptomatic dyslexics have found that their contrast thresholds for pattern discrimination are the same as non-dyslexics. However, when noise is added to the stimuli, contrast thresholds rise markedly in dyslexics compared with non-dyslexics. This result could be due to impaired noise exclusion in dyslexics. Some dyslexics report a reduction in discomfort experienced while reading and show increased reading speed when using coloured lenses. We hypothesised that coloured lenses work by aiding noise exclusion. Thus the coloured lenses should help performance best under conditions of high visual noise. We measured contrast thresholds for discriminating symbols in the absence and presence of visual noise. The results showed that visually symptomatic dyslexics, who otherwise had elevated contrast thresholds for discriminating symbols in visual noise, had thresholds similar to non-dyslexics when wearing coloured filters. These findings provide evidence that in visually symptomatic dyslexics coloured filters can improve noise exclusion to normal levels.

Why do words jump? An exploration of visually symptomatic readers

Abstract: Aim: To provide an insight into the current issues in assessing visually symptomatic readers and the role of the orthoptist in the management of these patients. Methods: A literature-based review was undertaken to investigate the assessment of patients presenting with visual symptoms associated with reading. Areas related to binocular vision and visual stress, visual discomfort and illusions are covered. The importance of differentiating between the correction of visual discomfort and the correction of dyslexia is also highlighted. Results: Visual symptoms associated with reading are common, particularly in struggling readers, and the incidence of binocular vision anomalies in these patients is high. An evidence base spanning more than 40 years has demonstrated that binocular vision anomalies are common in those who complain of symptoms when reading and that correction of these anomalies is associated with improvement in reading function. The production of visual distortions and discomfort and links with reading have been noted in the literature. The use of colour has also been advocated to reduce visual discomfort associated with reading, and theories of pattern glare, noise exclusion and hyperexcitability are still being pursued to try to improve our understanding of how colour affects visual processing and can reduce symptoms of headache and visual discomfort. In addition binocular vision anomalies and distortion of text known as visual stress can coexist, and differential diagnosis is required when trying to improve visual comfort when reading, thus providing a role for the orthoptist in such cases. Conclusions: Orthoptists can play a vital role in the assessment of visually symptomatic readers and should modify their assessment, as well as considering a range of treatments when assessing visually symptomatic readers. They should, however, be clear that treating visual symptoms is not treatment for dyslexia per se but that alleviation of visual symptoms associated with reading can be beneficial to those with reading discomfort and can help those with dyslexia and those without known reading difficulties.

International clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder

Abstract: Aim: These international clinical practice recommendations (CPR) for developmental coordination disorder (DCD), initiated by the European Academy of Childhood Disability (EACD), aim to address key questions on the definition, diagnosis, assessment, intervention, and psychosocial aspects of DCD relevant for clinical practice. Method: Key questions in five areas were considered through literature reviews and formal expert consensus. For recommendations based on evidence, literature searches on ‘mechanisms’, ‘assessment’, and ‘intervention’ were updated since the last recommendations in 2012. New searches were conducted for ‘psychosocial issues’ and ‘adolescents/adults’. Evidence was rated according to the Oxford Centre for Evidence-Based Medicine (level of evidence [LOE] 1–4) and transferred into recommendations. For recommendations based on formal consensus, two meetings of an international, multidisciplinary expert panel were conducted with a further five Delphi rounds to develop good clinical practice (GCP) recommendations. Results: Thirty-five recommendations were made. Eight were based on the evidence from literature reviews (three on ‘assessment’, five on ‘intervention’). Twenty-two were updated from the 2012 recommendations. New recommendations relate to diagnosis and assessment (two GCPs) and psychosocial issues (three GCPs). Additionally, one new recommendation (LOE) reflects active video games as adjuncts to more traditional activity-oriented and participation-oriented interventions, and two new recommendations (one GCP, one LOE) were made for adolescents and adults with DCD. Interpretation: The CPR–DCD is a comprehensive overview of DCD and current understanding based on research evidence and expert consensus. It reflects the state of the art for clinicians and scientists of varied disciplines. The international CPR–DCD may serve as a basis for national guidelines. What this paper adds: Updated international clinical practice guidelines on developmental coordination disorder (DCD). Refined and extended recommendations on clinical assessment and intervention for DCD. A critical synopsis of current research on mechanisms of DCD. A critical synopsis of psychosocial issues in DCD, with implications for clinical practice. The first international recommendations to consider adolescents and adults with DCD.

Cognitive and neuroimaging findings in developmental coordination disorder: new insights from a systematic review of recent research

Abstract: Aim To better understand the neural and performance factors that may underlie developmental coordination disorder (DCD), and implications for a multi-component account. Method A systematic review of the experimental literature published between June 2011 and September 2016 was conducted using a modified PICOS (population, intervention, comparison, outcomes, and study type) framework. A total of 106 studies were included. Results Behavioural data from 91 studies showed a broad cluster of deficits in the anticipatory control of movement, basic processes of motor learning, and cognitive control. Importantly, however, performance issues in DCD were often shown to be moderated by task type and difficulty. As well, we saw new evidence of compensatory processes and strategies in several studies. Neuroimaging data (15 studies, including electroencephalography) showed reduced cortical thickness in the right medial orbitofrontal cortex and altered brain activation patterns across functional networks involving prefrontal, parietal, and cerebellar regions in children with DCD than those in comparison groups. Data from diffusion-weighted magnetic resonance imaging suggested reduced white matter organization involving sensorimotor structures and altered structural connectivity across the whole brain network. Interpretation Taken together, results support the hypothesis that children with DCD show differences in brain structure and function compared with typically developing children. Behaviourally, these differences may affect anticipatory planning and reduce automatization of movement skill, prompting greater reliance on slower feedback-based control and compensatory strategies. Implications for future research, theory development, and clinical practice are discussed.

The Relationship between Dyslexia and Meares-Irlen Syndrome.

Abstract: Meares-Irlen Syndrome (MIS) is characterised by symptoms of visual stress and visual perceptual distortions that are alleviated by using individually prescribed coloured filters. Coloured overlays (sheets of transparent plastic that are placed upon the page) are used to screen for the condition. MIS is diagnosed on the basis of either the sustained voluntary use of an overlay or an immediate improvement (typically of more than 5%) on the Wilkins Rate of Reading Test (WRRT). Various studies are reviewed suggesting a prevalence of 20–34% using these criteria. Stricter criteria give a lower prevalence: for example, 5% of the population read more than 25% faster with an overlay. It has been alleged that MIS is more common in dyslexia, but this has not been systematically investigated. We compared a group of 32 dyslexic with 32 control children aged 7–12 years, matched for age, gender and socio-economic background. Participants were tested with Intuitive Overlays, and those demonstrating a preference had their rate of reading tested using the WRRT with and without their preferred overlay. Both groups read faster with the overlay, and more so in the dyslexic group. ANOVA revealed no significant effect of group, but a significant improvement in WRRT with overlay (p=0.009) and a significant interaction between group and overlay (p=0.031). We found a similar prevalence of MIS in the general population to that in previous studies and a prevalence in the dyslexic group that was a little higher (odds ratio for >5% criterion: 2.6, 95% confidence limit 0.9–7.3). The difference in prevalence in the two groups did not reach statistical significance. We conclude that MIS is prevalent in the general population and possibly a little more common in dyslexia. Children with dyslexia seem to benefit more from coloured overlays than non-dyslexic children. MIS and dyslexia are separate entities and are detected and treated in different ways. If a child has both problems then they are likely to be markedly disadvantaged and they should receive prompt treatments appropriate to the two conditions. It is recommended that education professionals as well as eye-care professionals are alert to the symptoms of MIS and that children are screened for this condition, as well as for other visual anomalies.