The development of reading impairment: a cognitive neuroscience model

This review discusses recent cognitive neuroscience investigations into the biological bases of developmental dyslexia, a common disorder impacting approximately 5 to 17 percent of the population. Our aim is to summarize central findings from several lines of evidence that converge on pivotal aspects of the brain bases of developmental dyslexia. We highlight ways in which the approaches and methodologies of developmental cognitive neuroscience that are addressed in this special issue-including neuroimaging, human genetics, refinement of cognitive and biological phenotypes, neural plasticity and computational model-can be employed in uncovering the biological bases of this disorder. Taking a developmental perspective on the biological bases of dyslexia, we propose a simple cascading model for the developmental progression of this disorder, in which individual differences in brain areas associated with phonological processing might influence the specialization of visual areas involved in the rapid processing of written words. We also discuss recent efforts to understand the impact of successful reading interventions in terms of changes within cortical circuits associated with reading ability.     

Applications for tracking reading behavior on the Macintosh

Two applications for the Macintosh that permit students to read the sentences in a text in any order also provide a record of reading behavior from which processing time and reading strategies can be determined. The applications differ: READIT! presents the sentences one at a time, whereas SELECT THE TEXT presents the entire passage with a mask, which resembles the moving window technique. Unique to these applications is that students may return to sentences to reread them any number of times and in any order. Because these applications allow students to reexamine parts of the text, the reading that they enable is more similar to normal reading than has been the case with previous methodologies for tracking student reading behavior. The applications are described, and a summary of the major results of the work in which we have used the applications is provided.     

Perceptual span,visual span,and visual attention span: Three potential ways to quantify limits on visual processing during reading

Many lines of evidence have revealed limitations of the human visual system, most notably that only a portion of available information is processed in a single glance. A degree of conceptual confusion has emerged, however, regarding the underlying concepts or mechanisms explaining limited visual processing in reading; perceptual span, visual span, or visual attention span. While the original definitions of these three concepts are clear and well-differentiated, they are routinely used inconsistently in the literature. The primary goal of the present review is to re-specify these three concepts in terms of what they correspond to and how they are determined. Further, we investigate whether these three spans refer to vision-related measurements and/or are based on general cognitive abilities. This review should lead to a better understanding of the involvement of visual functions in reading performance.     

Modelling relations between sensory processing, speech perception, orthographic and phonological ability, and literacy achievement

The general magnocellular theory postulates that dyslexia is the consequence of a multimodal deficit in the processing of transient and dynamic stimuli. In the auditory modality, this deficit has been hypothesized to interfere with accurate speech perception, and subsequently disrupt the development of phonological and later reading and spelling skills. In the visual modality, an analogous problem might interfere with literacy development by affecting orthographic skills. In this prospective longitudinal study, we tested dynamic auditory and visual processing, speech-in-noise perception, phonological ability and orthographic ability in 62 five-year-old preschool children. Predictive relations towards first grade reading and spelling measures were explored and the validity of the global magnocellular model was evaluated using causal path analysis. In particular, we demonstrated that dynamic auditory processing was related to speech perception, which itself was related to phonological awareness. Similarly, dynamic visual processing was related to orthographic ability. Subsequently, phonological awareness, orthographic ability and verbal short-term memory were unique predictors of reading and spelling development.     

Reading acquisition enhances an early visual process of contour integration

The acquisition of reading has an extensive impact on the developing brain and leads to enhanced abilities in phonological processing and visual letter perception. Could this expertise also extend to early visual abilities outside the reading domain? Here we studied the performance of illiterate, ex‐illiterate and literate adults closely matched in age, socioeconomic and cultural characteristics, on a contour integration task known to depend on early visual processing. Stimuli consisted of a closed egg‐shaped contour made of disconnected Gabor patches, within a background of randomly oriented Gabor stimuli. Subjects had to decide whether the egg was pointing left or right. Difficulty was varied by jittering the orientation of the Gabor patches forming the contour. Contour integration performance was lower in illiterates than in both ex‐illiterate and literate controls. We argue that this difference in contour perception must reflect a genuine difference in visual function. According to this view, the intensive perceptual training that accompanies reading acquisition also improves early visual abilities, suggesting that the impact of literacy on the visual system is more widespread than originally proposed.     

视觉复杂性和字间距调节汉语发展性阅读障碍儿童的视觉拥挤效应:来自眼动的证据

采用眼动追踪技术,通过笔画数多少构成高低不同的视觉复杂性,操纵文本的字间距,来考察视觉复杂性和字间距对汉语发展性阅读障碍儿童的视觉拥挤效应的影响。结果发现,阅读障碍儿童阅读低视觉复杂性文本时,随着字间距的不断增加,字间距增加到一定程度时（+6 pt）阅读时间最长、总注视次数最多,随后在本实验字间距最大条件下（+12 pt）阅读时间变短、总注视次数变少,正常儿童不存在这种现象。结果表明,文本阅读中,字间距和视觉复杂性对阅读障碍儿童的视觉拥挤效应起到调节作用,低视觉复杂性文本可以降低阅读障碍儿童的视觉拥挤效应,阅读障碍儿童的视觉拥挤效应强度和字间距大小的数量关系呈非线性。     

Gender-specific contribution of a visual cognition network to reading abilities

Based on the assumption that boys are more likely to tackle reading based on the visual modality, we assessed reading skills, visual short-term memory (VSTM), visual long-term memory for details (VLTM-D), and general non-verbal cognitive ability in primary school children. Reading was within the normal range in both accuracy and understanding. There was no reading performance gap in favour of girls, on the contrary, in this sample boys read better. An entire array of visual, non-verbal processes was associated directly or indirectly with reading in boys, whereas this pattern was not observed for the girls.     

Visual scanning and reading ability in normal and dyslexic children

Very few studies have investigated the development of visual search of aligned stimuli in relation to normal reading acquisition and in developmental dyslexia. In this study we used a new computerised experimental task which requires a visuo-motor response (RT) to a target appearing unpredictably in one out of seven different spatial positions on a horizontally aligned array of 18 geometrical figures. The aims of the study were to investigate: 1) the visual scanning development in normal children from pre-school to school age; 2) whether visual scanning performance in kindergarten children could predict reading acquisition; 3) the visual scanning abilities in a group of developmental dyslexic children. The main results were: 1) a significant decrement of RTs with age and a progressive increase of the left-to-right gradient with reading experience; 2) visual scanning abilities in kindergarten proved to be a good predictor of reading acquisition; 3) dyslexics were slow scanners and did not present the left-to-right strategy typical of normal readers. The results support the hypothesis of a relationship between visual scanning and reading abilities.     

Does silent reading speed in normal adult readers depend on early visual processes? evidence from event-related brain potentials

Little is known about the relationship of reading speed and early visual processes in normal readers. Here we examined the association of the early P1, N170 and late N1 component in visual event-related potentials (ERPs) with silent reading speed and a number of additional cognitive skills in a sample of 52 adult German readers utilizing a Lexical Decision Task (LDT) and a Face Decision Task (FDT). Amplitudes of the N170 component in the LDT but, interestingly, also in the FDT correlated with behavioral tests measuring silent reading speed. We suggest that reading speed performance can be at least partially accounted for by the extraction of essential structural information from visual stimuli, consisting of a domain-general and a domain-specific expertise-based portion.     

Visual spatial skill: a consequence of learning to read?

Does learning to read influence one’s visual skill? In Study 1, kindergartners from Hong Kong, Korea, Israel, and Spain were tested on word reading and a task of visual spatial skill. Chinese and Korean kindergartners significantly outperformed Israeli and Spanish readers on the visual task. Moreover, in all cultures except Korea, good readers scored significantly higher on the visual task than did less good readers. In Study 2, we followed 215 Hong Kong Chinese kindergartners across 1 year, with word reading and visual skills tested twice. In this study, word reading at Time 1 by itself predicted 13% of unique variance in visual skill at Time 2. Together, these results underscore the potential importance of the process of learning to read for shaping one’s visual spatial skill development.     

Venturing into the visual voice: combining photos and interviews in phenomenological inquiry around marginalisation and chronic illness

In this article, we present a reflection on the research process of combining photographs with phenomenologically oriented interviews. Two studies in the field of chronic illness with marginalised individuals (lesbian, gay, bisexual and trans* people living with MS; men diagnosed with breast cancer) are employed to illustrate a range of conceptual, methodological and pragmatic issues. Both studies draw upon an integrative theoretical framework within a critical health psychology epistemological paradigm informed by phenomenological psychology and visual methodologies. The data collected for both studies have been analysed through interpretative phenomenological analysis (IPA). We offer some thoughts regarding certain challenges and opportunities of synergising verbal and visual data and illustrate our arguments through a series of examples from the two studies, which are critically discussed. We argue that qualitative research in psychology benefits from an enhanced multimethodological approach employing existential phenomenological psychology and visual methodologies, especially when exploring chronic illness in marginalised communities, and we outline benefits for the wider community of qualitative researchers in psychology.     

The reading ability of good and poor temporal processors among a group of college students

In this study, we examined whether good auditory and good visual temporal processors were better than their poor counterparts on certain reading measures. Various visual and auditory temporal tasks were administered to 105 undergraduates. They read some phonologically regular pseudowords and irregular words that were presented sequentially in the same ("word" condition) and in different ("line" condition) locations. Results indicated that auditory temporal acuity was more relevant to reading, whereas visual temporal acuity was more relevant to spelling. Good auditory temporal processors did not have the advantage in processing pseudowords, even though pseudoword reading correlated significantly with auditory temporal processing. These results suggested that some higher cognitive or phonological processes mediated the relationship between auditory temporal processing and pseudoword reading. Good visual temporal processors did not have the advantage in processing irregular words. They also did not process the line condition more accurately than the word condition. The discrepancy might be attributed to the use of normal adults and the unnatural reading situation that did not fully capture the function of the visual temporal processes. The distributions of auditory and visual temporal processing abilities were co-occurring to some degree, but they maintained considerable independence. There was also a lack of a relationship between the type and severity of reading deficits and the type and number of temporal deficits.     

When meaning matters,look but don’t touch: The effects of posture on reading

Much of the reading that we do occurs near our hands. Previous research has revealed that spatial processing is enhanced near the hands, potentially benefiting several processes involved in reading; however, it is unknown whether semantic processing—another critical aspect of reading—is affected near the hands. While holding their hands either near to or far from a visual display, our subjects performed two tasks that drew on semantic processing: evaluation of the sensibleness of sentences, and the Stroop color-word interference task. We found evidence for impoverished semantic processing near the hands in both tasks. These results suggest a trade-off between spatial processing and semantic processing for the visual space around the hands. Readers are encouraged to be aware of this trade-off when choosing how to read a text, since both kinds of processing can be beneficial for reading.     

Temporal processing ability in above average and average readers

In the present study, we compared the rapid visual and auditory temporal processing ability of above average and average readers. One hundred five undergraduates participated in various visual and auditory temporal tasks. The above average readers exhibited lower auditory and visual temporal resolution thresholds than did the average readers, but only the differences in the auditory tasks were statistically significant, especially when nonverbal IQ was controlled for. Furthermore, both the correlation and stepwise multiple regression analyses revealed a relationship between the auditory measures and the wide range achievement test (WRAT) reading measure and a relationship between the auditory measures and a low spatial frequency visual measure and the WRAT spelling measure. Discriminant analysis showed that together both the visual and auditory measures correctly classified 75% of the subjects into above average and average reading groups, respectively. The results suggest that differences in temporal processing ability in relation to differences in reading proficiency are not confined to the comparison between poor and normal readers.     

Eye movements and attention in reading,scene perception,and visual search

Eye movements are now widely used to investigate cognitive processes during reading, scene perception, and visual search. In this article, research on the following topics is reviewed with respect to reading: (a) the perceptual span (or span of effective vision), (b) preview benefit, (c) eye movement control, and (d) models of eye movements. Related issues with respect to eye movements during scene perception and visual search are also reviewed. It is argued that research on eye movements during reading has been somewhat advanced over research on eye movements in scene perception and visual search and that some of the paradigms developed to study reading should be more widely adopted in the study of scene perception and visual search. Research dealing with “real-world” tasks and research utilizing the visual-world paradigm are also briefly discussed.     

Cross-task strategic effects

When easy and difficult items are mixed together, their reading aloud latencies become more homogeneous relative to their presentation in unmixed ("pure") conditions (Lupker, Brown, & Colombo, 1997). We report two experiments designed to investigate the nature of the mechanism that underlies this list composition, or blocking, effect. In Experiment 1, we replicated Lupker et al.'s (1997) blocking effect in the reading aloud task and extended these findings to the visual lexical decision task. In Experiment 2, we found that blocking effects generalized across tasks: The characteristics of stimuli in a visual lexical decision task influenced reading aloud latencies, and vice versa, when visual lexical decision and reading aloud trials were presented alternately in the same experiment. We discuss implications of these results within time-criterion (Lupker et al., 1997) and strength-of-processing (Kello & Plaut, 2000, 2003) theories of strategic processing in reading.     

Parafoveal Magnification: Visual Acuity Does Not Modulate the Perceptual Span in Reading

ABSTRACT— Models of eye guidance in reading rely on the concept of the perceptual span—the amount of information perceived during a single eye fixation, which is considered to be a consequence of visual and attentional constraints. To directly investigate attentional mechanisms underlying the perceptual span, we implemented a new reading paradigm—parafoveal magnification (PM)—that compensates for how visual acuity drops off as a function of retinal eccentricity. On each fixation and in real time, parafoveal text is magnified to equalize its perceptual impact with that of concurrent foveal text. Experiment 1 demonstrated that PM does not increase the amount of text that is processed, supporting an attentional-based account of eye movements in reading. Experiment 2 explored a contentious issue that differentiates competing models of eye movement control and showed that, even when parafoveal information is enlarged, visual attention in reading is allocated in a serial fashion from word to word.     

Reading with a filtered fovea: The influence of visual quality at the point of fixation during reading

Reading relies critically on processing text in foveal vision during brief fixational pauses, and high-quality visual input from foveal text is fundamental to theories of reading. However, the quality of visual input from foveal text that is actually functional for reading and the effects of this input on reading performance are unclear. To investigate these issues, a moving, gaze-contingent foveal filtering technique was developed to display areas of text within foveal vision that provided only coarse, medium, or fine scale visual input during each fixational pause during reading. Normal reading times were unaffected when foveal text up to three characters wide at the point of fixation provided any one visual input (coarse, medium, or fine). Wider areas of coarse visual input lengthened reading times, but reading still occurred, and normal reading times were completely unaffected when only medium or fine visual input extended across the entire fovea. Further analyses revealed that each visual input had no effect on the number of fixations made when normal text was read, that adjusting fixation durations helped preserve reading efficiency for different visual inputs, and that each visual input had virtually no effect on normal saccades. These findings indicate that, despite the resolving power of foveal vision and the emphasis placed on high-quality foveal visual input by theories of reading, normal reading functions with similar success using a range of restricted visual inputs from foveal text, even at the point of fixation. Some implications of these findings for theories of reading are discussed.     

The role of visual and auditory temporal processing in reading irregular and nonsense words.

In the present study, the role of rapid visual and auditory temporal processing in reading irregular and nonsense words was investigated with a group of normal readers. One hundred and five undergraduates participated in various visual and auditory temporal-processing tasks. Readers who primarily adopted the phonological route in reading (nonsense-word readers) showed a trend for better auditory temporal resolution but readers who primarily adopted sight word skills (irregular-word readers) did not exhibit better visual temporal resolution. Both the correlation and stepwise multiple-regression analyses, however, revealed a relationship between visual temporal processing and irregular-word reading as well as a relationship between auditory temporal processing and nonsense-word reading. The results support the involvement of visual and auditory processing in reading irregular and nonsense words respectively, and were discussed with respect to recent findings that only dyslexics with phonological impairment will display temporal deficits. Further, the temporal measures were not effective discriminants for the reading groups, suggesting a lack of association between reading ability and the choice of reading strategy.