Impaired recognition of traffic signs in adults with dyslexia

Using representational similarity analysis to reveal category and process specificity in visual object recognition

Cross-condition comparisons on neurodevelopmental conditions are central in neurodiversity research. In the realm of visual perception, the performance of participants with different category-specific disorders such as developmental prosopagnosia (problems with faces) and dyslexia (problems with words) have contributed to understanding of perceptual processes involved in word and face recognition. Alterations in face and word recognition are present in several neurodiverse populations, and improved knowledge about their relationship may increase our understanding of this variability of impairment. The present study investigates organizing principles of visual object processing and their implications for developmental disorders of recognition. Some accounts suggest that distinct mechanisms are responsible for recognizing objects of different categories, while others propose that categories share or even compete for cortical resources. We took an individual differences approach to estimate the relationship between abilities in recognition. Neurotypical participants (N = 97 after outlier exclusion) performed a match-to-sample task with faces, houses, and pseudowords. Either individual features or feature configurations were manipulated. To estimate the separability of visual recognition mechanisms, we used representational similarity analysis (RSA) where correlational matrices for accuracy were compared to predicted data patterns. Recognition abilities separated into face recognition on one hand and house/pseudoword recognition on the other, indicating that face recognition may rely on relatively selective mechanisms in neurotypicals. We also found evidence for a general visual object recognition mechanism, while some combinations of category (faces, houses, words) and processing type (featural, configural) likely rely on additional mechanisms. Developmental conditions may therefore reflect combinations of impaired and intact aspects of specific and general visual object recognition mechanisms, where featural and configural processes for one object category separate from the featural or configural processing of another. More generally, RSA is a promising approach for advancing understanding of neurodiversity, including shared aspects and distinctions between neurodevelopmental conditions of visual recognition.

The Role of Visual Factors in Dyslexia

What are the causes of dyslexia? Decades of research reflect a determined search for a single cause where a common assumption is that dyslexia is a consequence of problems with converting phonological information into lexical codes. But reading is a highly complex activity requiring many well-functioning mechanisms, and several different visual problems have been documented in dyslexic readers. We critically review evidence from various sources for the role of visual factors in dyslexia, from magnocellular dysfunction through accounts based on abnormal eye movements and attentional processing, to recent proposals that problems with high-level vision contribute to dyslexia. We believe that the role of visual problems in dyslexia has been underestimated in the literature, to the detriment of the understanding and treatment of the disorder. We propose that rather than focusing on a single core cause, the role of visual factors in dyslexia fits well with risk and resilience models that assume that several variables interact throughout prenatal and postnatal development to either promote or hinder efficient reading.

Featural and configural processing of faces and houses in matched dyslexic and typical readers

While dyslexia is typically described as a phonological deficit, recent evidence suggests that ventral stream regions, important for visual categorization and object recognition, are hypoactive in dyslexic readers who might accordingly show visual recognition deficits. By manipulating featural and configural information of faces and houses, we investigated whether dyslexic readers are disadvantaged at recognizing certain object classes or using particular visual processing mechanisms. Dyslexic readers found it harder to recognize objects (houses), suggesting that visual problems in dyslexia are not completely domain-specific. Face recognition accuracy was equivalent in the two groups. Lower recognition accuracy for houses was also related to reading difficulties even when accuracy for faces was kept constant, which could indicate a specific relationship between visual word processing and visual processing of non-face objects. Representational similarity analyses (RSA) revealed that featural and configural processes were clearly separable in typical readers, which was not the case for dyslexic readers who appear to rely on a single process. This was not restricted to particular visual categories, occurring for both faces and houses. We speculate that reading deficits in some dyslexic readers reflect their reliance on a single process for object recognition.

Words as Visual Objects: Neural and Behavioral Evidence for High-Level Visual Impairments in Dyslexia

Developmental dyslexia is defined by reading impairments that are disproportionate to intelligence, motivation, and the educational opportunities considered necessary for reading. Its cause has traditionally been considered to be a phonological deficit, where people have difficulties with differentiating the sounds of spoken language. However, reading is a multidimensional skill and relies on various cognitive abilities. These may include high-level vision—the processes that support visual recognition despite innumerable image variations, such as in viewpoint, position, or size. According to our high-level visual dysfunction hypothesis, reading problems of some people with dyslexia can be a salient manifestation of a more general deficit of high-level vision. This paper provides a perspective on how such non-phonological impairments could, in some cases, cause dyslexia. To argue in favor of this hypothesis, we will discuss work on functional neuroimaging, structural imaging, electrophysiology, and behavior that provides evidence for a link between high-level visual impairment and dyslexia.

Better read it to me: Benefits of audio versions of variable message signs in drivers with dyslexia

Adults with dyslexia may find difficulties in reading the messages on variable message signs (VMS) while driving. These signs are an essential part of the traffic communication systems, aimed at informing road users of special circumstances, such as congestion, traffic diversion, or unexpected events. A driving simulation experiment was conducted to test if complementary audio versions of the VMS would be helpful for drivers with dyslexia. Twenty adults with dyslexia and 20 matched controls participated. They were asked to classify the messages displayed on VMS posted along a simulated route, which was completed twice: one with text VMS (visual condition), and another one with text VMS plus complementary audio messages (audio + visual condition). The results showed that in the ordinary, visual condition, the participants with dyslexia needed to be closer to the VMS than controls to correctly classify the message, but, crucially, these group differences vanished when the driver received an audio version of the message (audio + visual condition). Moreover, the availability of audio versions had positive effects for all participants, as shown by higher accuracy in the message classification task, as well as better driving performance. Therefore, technologies aimed at providing audio versions of VMS can help drivers with dyslexia. A mobile application, READit VMS, which is able to provide real-time complementary audio versions of VMS, is presented as an example.

Accident ahead? Difficulties of drivers with and without reading impairment recognising words and pictograms in variable message signs

A timely and accurate acquisition of the information provided by variable message signs (VMS) can be crucial while driving. In the current study, we assess the difficulties of adults with dyslexia acquiring the information shown in VMS and provide evidence to discuss the controversial use of pictograms as potential countermeasures. Twenty-two adults with dyslexia and 22 matched controls completed a simulated driving session. The legibility of 12 VMS was assessed, including six text messages (e.g. "ACCIDENT") and six single pictograms (e.g. the icon for "accident ahead"). On average, participants with dyslexia started reading text messages when they were closer to the VMS. In addition, while approaching text VMS, they dedicated more gazes and manifested worse control of speed. Regarding pictogram VMS, we observed no differences in response distance, accuracy, response duration, or number of gazes. To sum up, the evidence provided reveals that adults with dyslexia, despite potential compensation effects, may still find difficulties reading text messages in VMS (shorter legibility distances, longer reading times, and increased cognitive effort), whereas we found no such differences in the recognition of pictograms (only some difficulties keeping a steady speed). Research on inclusive measures to improve reading in low-skilled or dyslexic drivers must be encouraged.

People with dyslexia and heart, chest, skin, digestive, musculoskeletal, vision, learning, speech and mental disorders were more dissatisfied with neighbourhoods: Scottish Household Survey, 2007-2008

Rarely do we know the perception toward neighbourhoods in people specifically with health conditions. Therefore, the aim of the present study was to understand the perception toward neighbourhoods among adults with a series of the existing health conditions in a country-wide and population-based setting. Data were retrieved from and analysed in Scottish Household Survey, 2007-2008. Information on demographics, self-reported health conditions and perception toward neighbourhoods and the surrounding facilities was obtained by household interview. Analysis including chi-square test, t test and logistic regression modelling were performed. Of 19,150 Scottish adults (aged 16-80) included in the study cohort, 1079 (7.7 %) people were dissatisfied with their living areas; particularly for those who experienced harassment (15.4 %), did not recycle or with dyslexia, chest, digestive, mental and musculoskeletal problems. Twenty to forty per cent reported common neighbourhood problems including noise, rubbish, disputes, graffiti, harassment and drug misuse. People with heart or digestive problems were more dissatisfied with the existing parks and open space. People with arthritis, chest or hearing problems were more dissatisfied with the waste management condition. People with dyslexia were more dissatisfied with the existing public transportation. People with heart problems were more dissatisfied with the current street cleaning condition. People with hearing, vision, speech, learning problems or dyslexia were also more dissatisfied with sports and recreational facilities. People with heart, chest, skin, digestive, musculoskeletal, vision, learning, speech and mental disorders and dyslexia were more dissatisfied with their current neighbourhood environments. Upgrading neighbourhood planning to tackle social environment injustice and put pleasant life experience as priorty would be suggested. Graphical abstract interrelations of individual health and neighbourhood health.

Learning to drive in young adults with language impairment

Language impairment (LI) is a common developmental disorder which affects many aspects of young people's functional skills and engagement with society. Little is known of early driving behaviour in those with this disability. This longitudinal study examines early driving experience in a sample of young adults with LI, compared with a sample of typically developing age-matched peers (AMPs). At age 24 years, significantly fewer participants with LI had acquired a driving licence. A crucial hurdle for those with LI appeared to be the Theory part of the (UK) test. Logistic regression analysis indicated that language ability and a measure of independence at age 17 contributed to the prediction of licence possession at age 24. There was no evidence of differences in traffic violations or accident rates between those with and without LI. There is little evidence that young people with LI are at greater risk on the roads than peers without LI, but some individuals with LI might benefit from support in the course of preparation for driving and in the driving test.

Implicit sequence learning in dyslexia: a within-sequence comparison of first- and higher-order information

The present study examines implicit sequence learning in adult dyslexics with a focus on comparing sequence transitions with different statistical complexities. Learning of a 12-item deterministic sequence was assessed in 12 dyslexic and 12 non-dyslexic university students. Both groups showed equivalent standard reaction time increments when the sequence was unexpectedly changed, suggesting that learning of the sequence took place. However, a novel analysis comparing transitions of differing complexity within the learning blocks indicated that dyslexic participants were impaired only for higher-order but not first-order sequence learning. No difference was found in the explicit awareness contribution between the two groups and this was found not to correlate with reaction time performance. This result suggests that statistical complexity of the sequence may account for intact and impaired learning performance in dyslexia.