Process dissociation of sight vocabulary and phonetic decoding in reading: a new perspective on surface and phonological dyslexias

Recent research on developmental dyslexia has suggested a phonological core deficit hypothesis (e.g., Manis, Seidenberg, Doi, McBride-Chang, & Peterson, 1996; Stanovich, Siegel, & Gottardo, 1997) whereby pure cases of developmental phonological dyslexia (dysfunctional phonetic decoding processing but normal sight vocabulary processing) can exist, but pure cases of developmental surface dyslexia (dysfunctional sight vocabulary processing but normal phonetic decoding processing) should not. By applying Jacoby's (1991) and Lindsay and Jacoby's (1994) process dissociation procedure to the reading of regular and exception words, we present a method that serves to estimate readers' reliance on sight vocabulary and phonetic decoding during real word recognition. These reliance estimates are then used in Castles and Coltheart's (1993) regression-based approach to identify normal readers and developmental dyslexics. This new method: (1) allows one to explore normal reading acquisition and both the delay and deviance accounts of developmental dyslexia, (2) provides an alternative to matching dyslexics to both chronological-age and reading-age control groups, and (3) uses only real words. We present evidence that pure cases of developmental surface dyslexia can be obtained with both Castles and Coltheart's measure as well as our own, and that developmental surface dyslexia is not simply a delayed reading deficit. The theoretical importance and utility of estimates of reliance on sight vocabulary and phonetic decoding is discussed.     

Reading in callosal agenesis

It has been suggested that deficits in explicit phonological processing are causal in developmental dyslexia. Deficits in such skills have been reported in developmental phonological dyslexia, though not in developmental surface dyslexia. The reading performance of two children with callosal agenesis, who have been previously shown to have impairments on rhyming tasks, are reported. Neither child is dyslexic in the traditional sense, since word reading levels are appropriate for age. However, both children have impaired development of the phonological reading route despite normal lexical skills. The pattern of their reading is therefore comparable to developmental phonological dyslexia. Problems in explicit phonological processing may be causal in the failure to establish an efficient phonological reading route but this is insufficient to create difficulty with word recognition itself. The corpus callosum may be essential for the normal development of a phonological reading route.     

发展性阅读障碍儿童的新词习得及其改善

本研究通过比较重复学习新词时个体眼动模式的变化, 探讨发展性阅读障碍儿童的新词习得及改善途径。实验1以发展性阅读障碍、生理年龄和阅读能力匹配儿童为被试, 采用重复学习新词的范式, 探讨发展性阅读障碍儿童的新词习得。结果发现, 与匹配组相比, 发展性阅读障碍儿童在新词的首次注视时间和凝视时间上需要更多的语境才出现显著下降, 且在总注视时间上表现出更缓慢的下降。表明发展性阅读障碍儿童的新词习得慢于正常儿童。实验2以词间空格和正常无空格两种文本呈现方式, 仍采用重复学习新词范式, 探讨词间空格是否能促进发展性阅读障碍儿童的新词习得。结果发现, 在词间空格条件下, 发展性阅读障碍儿童的新词习得可达到正常儿童的水平。表明作为视觉词切分线索的词间空格, 可促进发展性阅读障碍儿童的新词习得。本研究结果为发展性阅读障碍儿童新词习得提供了一条新的途径。     

It's about time: revisiting temporal processing deficits in dyslexia

Temporal processing in French children with dyslexia was evaluated in three tasks: a word identification task requiring implicit temporal processing, and two explicit temporal bisection tasks, one in the auditory and one in the visual modality. Normally developing children matched on chronological age and reading level served as a control group. Children with dyslexia exhibited robust deficits in temporal tasks whether they were explicit or implicit and whether they involved the auditory or the visual modality. First, they presented larger perceptual variability when performing temporal tasks, whereas they showed no such difficulties when performing the same task on a non‐temporal dimension (intensity). This dissociation suggests that their difficulties were specific to temporal processing and could not be attributed to lapses of attention, reduced alertness, faulty anchoring, or overall noisy processing. In the framework of cognitive models of time perception, these data point to a dysfunction of the ‘internal clock’ of dyslexic children. These results are broadly compatible with the recent temporal sampling theory of dyslexia.     

The processing of lexical stress during visual word recognition: typicality effects and orthographic correlates

Many studies that have examined reading at the single-word level have been restricted to the processing of monosyllabic stimuli, and, as a result, lexical stress has not been widely investigated. In the experiments reported here, we used disyllabic words and nonwords to investigate the processing of lexical stress during visual word recognition. In Experiments 1 and 2, we found an effect of stress typicality in naming and lexical decision. Typically stressed words (trochaic nouns and iambic verbs) elicited fewer errors than atypically stressed words (iambic nouns and trochaic verbs). In Experiment 3, we carried out an analysis of 340 word endings and found clear orthographic correlates of both grammatical category and lexical stress in word endings. In Experiment 4, we demonstrated that readers are sensitive to these cues in their processing of nonwords during two tasks: sentence construction and stress assignment. We discuss the implications of these findings with regard to psycholinguistic models of single-word reading.     

The processing of lexical stress during visual word recognition: Typicality effects and orthographic correlates

Many studies that have examined reading at the single-word level have been restricted to the processing of monosyllabic stimuli, and, as a result, lexical stress has not been widely investigated. In the experiments reported here, we used disyllabic words and nonwords to investigate the processing of lexical stress during visual word recognition. In Experiments 1 and 2, we found an effect of stress typicality in naming and lexical decision. Typically stressed words (trochaic nouns and iambic verbs) elicited fewer errors than atypically stressed words (iambic nouns and trochaic verbs). In Experiment 3, we carried out an analysis of 340 word endings and found clear orthographic correlates of both grammatical category and lexical stress in word endings. In Experiment 4, we demonstrated that readers are sensitive to these cues in their processing of nonwords during two tasks: sentence construction and stress assignment. We discuss the implications of these findings with regard to psycholinguistic models of single-word reading.     

汉语阅读障碍的语音加工及正字法加工缺陷的实验研究

本研究对汉语阅读障碍的加工缺陷进行探讨,期望有助于揭示语言加工的普遍性与特殊性,以及阅读障碍的成因,并可为后期的干预提供帮助。研究采用改编的言语认知测验对阅读水平匹配组与阅读障碍组和生理年龄匹配组进行比较后发现,阅读障碍组在语音意识和正字法加工任务上的成绩均明显差于生理年龄控制组和阅读水平匹配组;阅读障碍组在快速命名和语音记忆任务上的成绩不如生理年龄匹配组,仅达到阅读水平匹配组水平。因此,汉语发展性阅读障碍儿童存在语音意识和正字法加工缺陷,这两种缺陷可能是阅读障碍儿童面临的最主要的两大缺陷;阅读障碍儿童在快速命名和语音记忆上的不足可能是发展迟滞所致。同时,大多数的汉语阅读障碍儿童存在不止一种的认知缺陷。阅读障碍儿童在语音意识和正字法加工上存在缺陷的比例最高。     

Difficulties in auditory organization as a cause of reading backwardness? An auditory neuroscience perspective

Over 30 years ago, it was suggested that difficulties in the ‘auditory organization’ of word forms in the mental lexicon might cause reading difficulties. It was proposed that children used parameters such as rhyme and alliteration to organize word forms in the mental lexicon by acoustic similarity, and that such organization was impaired in developmental dyslexia. This literature was based on an ‘oddity’ measure of children's sensitivity to rhyme (e.g. wood, book, good) and alliteration (e.g. sun, sock, rag). The ‘oddity’ task revealed that children with dyslexia were significantly poorer at identifying the ‘odd word out’ than younger children without reading difficulties. Here we apply a novel modelling approach drawn from auditory neuroscience to study the possible sensory basis of the auditory organization of rhyming and non‐rhyming words by children. We utilize a novel Spectral‐Amplitude Modulation Phase Hierarchy (S‐AMPH) approach to analysing the spectro‐temporal structure of rhyming and non‐rhyming words, aiming to illuminate the potential acoustic cues used by children as a basis for phonological organization. The S‐AMPH model assumes that speech encoding depends on neuronal oscillatory entrainment to the amplitude modulation (AM) hierarchy in speech. Our results suggest that phonological similarity between rhyming words in the oddity task depends crucially on slow (delta band) modulations in the speech envelope. Contrary to linguistic assumptions, therefore, auditory organization by children may not depend on phonemic information for this task. Linguistically, it is assumed that ‘book’ does not rhyme with ‘wood’ and ‘good’ because the final phoneme differs. However, our auditory analysis suggests that the acoustic cues to this phonological dissimilarity depend primarily on the slower amplitude modulations in the speech envelope, thought to carry prosodic information. Therefore, the oddity task may help in detecting reading difficulties because phonological similarity judgements about rhyme reflect sensitivity to slow amplitude modulation patterns. Slower amplitude modulations are known to be detected less efficiently by children with dyslexia.     

发展性阅读障碍与小脑异常：小脑的功能和两者的因果关系

发展性阅读障碍(下文简称为"阅读障碍")不仅会影响个人的终身发展,还会对社会造成沉重的经济负担,深入探讨相关的神经机制,对实现阅读障碍的早期预测和干预十分重要。以往关于阅读障碍神经机制的模型多集中于大脑,近些年的研究发现,阅读障碍也与小脑异常有关,但到目前为止我们仍不清楚两者的关系。通过总结最新的研究进展,我们发现小脑在阅读障碍中可能发挥着多种功能,且小脑异常与阅读障碍可能互为因果。在此基础之上,我们提出了"阅读中小脑与大脑的功能映射假说",旨在从一个全新的角度揭示小脑与阅读的关系,以及两者与大脑的关系。相关内容对全面揭示阅读障碍的神经机制,以及小脑在高级认知加工中的作用,具有重要的启示意义。     

Delayed development of phonological constancy in toddlers at family risk for dyslexia

Phonological constancy refers to infants’ ability to disregard variations in the phonetic realisation of speech sounds that do not indicate lexical contrast, e.g., when listening to accented speech. In typically-developing infants, this ability develops between 15- and 19-months of age, coinciding with the consolidation of infants’ native phonological competence and vocabulary growth. Here we investigated the developmental time course of phonological constancy in infants at family risk for developmental dyslexia, using a longitudinal design. Developmental dyslexia is a disorder affecting the acquisition of reading and spelling skills, and it also affects early auditory processing, speech perception, and lexical acquisition. Infants at-risk and not at-risk for dyslexia, based on a family history of dyslexia, participated when they were 15-, 19-, and 26-months of age. Phonological constancy was indexed by comparing at-risk and not at-risk infants’ ability to recognise familiar words in two preferential looking tasks: (1) a task using words presented in their native accent, and (2) a task using words presented in a non-native accent. We expected a delay in phonological constancy for the at-risk infants. As predicted, in the non-native accent task, not at-risk infants recognised familiar words by 19 months, but at-risk infants did not. The control infants thus exhibited phonological constancy. By 26 months, at-risk toddlers did show successful word recognition in the native accent task. However, for the non-native accent task at 26 months, neither at-risk nor control infants showed familiar word recognition. These findings are discussed in terms of the impact of family risk for dyslexia on toddlers’ consolidation of early phonological and lexical skills.     

Subcortical aphasia with deep dyslexia: A case study of a Japanese patient

The reading performance of a Japanese Broca-type aphasic patient on a single-word reading test was investigated. The result indicated that the subject fits the symptom complex of deep dyslexia in more than one aspect. Unique characteristics of this subject included (1) the isolated subcortical site of the lesion, which apparently produced deep dyslexia, and (2) double dissociations between kanji and kana processing and between oral reading and reading comprehension. The performance of this subject was compared with that of another Japanese deep dyslexic subject in S. Sasanuma (1980, In M. Coltheart, K. Patterson, & J. C. Marshall (Eds.), Deep dyslexia, London: Routledge & Kegan Paul). A theoretical implication was attempted based on a dual coding process scheme by S. Sasanuma and O. Fujimura (1978, Cortex, 7, 1-18).     

Specifying theories of developmental dyslexia: a diffusion model analysis of word recognition

The nature of word recognition difficulties in developmental dyslexia is still a topic of controversy. We investigated the contribution of phonological processing deficits and uncertainty to the word recognition difficulties of dyslexic children by mathematical diffusion modeling of visual and auditory lexical decision data. The first study showed that poor visual lexical decision performance of reading disabled children was mainly due to a delay in the evaluation of word characteristics, suggesting impaired phonological processing. The adoption of elevated certainty criteria by the disabled readers suggests that uncertainty contributed to the visual word recognition impairments as well. The second study replicated the outcomes for visual lexical decision with formally diagnosed dyslexic children. In addition, during auditory lexical decision, dyslexics presented with reduced accuracy, which also resulted from delayed evaluation of word characteristics. Since orthographic influences are diminished during auditory lexical decision, this strengthens the phonological processing deficit account. Dyslexic children did not adopt heightened certainty criteria during auditory lexical decision, indicating that uncertainty solely impairs reading and not listening.     

No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding

Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams in the left and the right visual field (LVF, RVF) to 20 undergraduate students with dyslexia and 20 matched controls. The trigrams were presented at different locations (from –2.5° to?+?2.5°) in both visual half fields. Participants were asked to identify the letters, and accuracy rates were compared. In line with the predictions of the SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model of visual word recognition, a typical U-shaped pattern was found at all retinal locations. Accuracy also decreased the further away the stimulus was from the fixation location, with a steeper decrease in the LVF than in the RVF. Contrary to the hypothesis, the students with dyslexia showed the same pattern of results as did the control participants, also in the LVF, apart from a slightly lower accuracy rate, particularly for the central letter. The latter is in line with the possibility of enhanced crowding in dyslexia. In addition, in the dyslexia group but not in the control group the degree of crowding correlated significantly with the students’ word reading scores. These findings suggest that lateral inhibition between letters is associated with word reading performance in students with dyslexia.     

发展性阅读障碍儿童阅读中的眼跳定位缺陷：基于新词学习的实验证据

通过与生理年龄匹配儿童比较新词重复学习中眼跳定位模式变化的异同, 探讨发展性阅读障碍儿童在新词学习中的眼跳定位是否存在缺陷。以发展性阅读障碍儿童和生理年龄匹配儿童为被试, 采用重复学习新词范式, 结果发现：(1)与生理年龄匹配组相比, 发展性阅读障碍儿童跳入新词的眼跳距离较短、首次注视落点位置更靠近词首; (2)生理年龄匹配组儿童利用学习次数调节新词眼跳定位模式的能力高于发展性阅读障碍儿童, 即随着新词学习次数的增加, 生理年龄匹配组儿童跳入和跳出新词的眼跳距离随之增长, 首次注视落点位置更靠近词中心; 相比之下, 发展性阅读障碍儿童仅在跳出新词的眼跳距离上有所增长, 但增加幅度也显著小于生理年龄匹配组。结果表明, 发展性阅读障碍儿童在新词学习中的眼跳定位, 及利用学习次数对眼跳定位的调节上均表现出一定缺陷。     

Evidence‐based interventions for reading and language difficulties: Creating a virtuous circle

Background. Children may experience two very different forms of reading problem: decoding difficulties (dyslexia) and reading comprehension difficulties. Decoding difficulties appear to be caused by problems with phonological (speech sound) processing. Reading comprehension difficulties in contrast appear to be caused by problems with ‘higher level’ language difficulties including problems with semantics (including deficient knowledge of word meanings) and grammar (knowledge of morphology and syntax). Aims. We review evidence concerning the nature, causes of, and treatments for children's reading difficulties. We argue that any well‐founded educational intervention must be based on a sound theory of the causes of a particular form of learning difficulty, which in turn must be based on an understanding of how a given skill is learned by typically developing children. Such theoretically motivated interventions should in turn be evaluated in randomized controlled trials (RCTs) to establish whether they are effective, and for whom. Results. There is now considerable evidence showing that phonologically based interventions are effective in ameliorating children's word level decoding difficulties, and a smaller evidence base showing that reading and oral language (OL) comprehension difficulties can be ameliorated by suitable interventions to boost vocabulary and broader OL skills. Conclusions. The process of developing theories about the origins of children's educational difficulties and evaluating theoretically motivated treatments in RCTs, produces a ‘virtuous circle’ whereby theory informs practice, and the evaluation of effective interventions in turn feeds back to inform and refine theories about the nature and causes of children's reading and language difficulties.     

Deep dyslexia is right-hemisphere reading

Two views exist concerning the proper interpretation of the form of acquired dyslexia known as deep dyslexia: (a) that it represents reading by a multiply damaged left hemisphere reading system; (b) that it represents reading which relies extensively on right-hemisphere orthographic and semantic processing. Price, Howard, Patterson, Warburton, Friston, and Frackowiak (1998) have recently reported a brain-imaging study whose results, they claim, "preclude an explanation of deep dyslexia in terms of purely right-hemisphere word processing." Their claim conflicts with the conclusions of previous published work, which strongly supports the RH hypothesis, work which they do not mention. Furthermore, I argue that their own results also favor the RH hypothesis (even though they claim otherwise); indeed, their results permit the formulation of a much more detailed version of the RH hypothesis than has hitherto been possible. Hence I conclude that the right-hemisphere interpretation of deep dyslexic reading remains the preferred explanation of deep dyslexia.     

汉语老年读者的多词单元加工：来自眼动研究的证据

选取由两个双字词组成的多词组合（单词组合、模糊词组合、双词组合）,比较老年人和青年人对多词单元的加工情况。结果发现,相比于其他两类组合,所有被试在单词组合上的注视时间更短,第一遍注视次数更少,成分词上的注视时间更短,跳读率更高,表现出多词单元的加工优势,而且这一加工优势不存在显著的年龄差异。结果表明,汉语老年读者同样将多词单元作为整体进行加工。     

Word recognition and comprehension skills in hyperlexic children

Five hyperlexic boys (4-5 to 10-1 years), who had been diagnosed with infantile autism or pervasive developmental delay in early childhood, were evaluated. Measures of intelligence, single-word recognition and comprehension, and picture naming were administered to determine the precocity or deficiency of reading recognition and comprehension, the underlying mechanisms of oral reading, and possible parallels with the acquired dyslexia subtypes. The results indicated that hyperlexia may be operationalized as unexpected reading precocity as compared to IQ; however, reading comprehension was not unexpectedly deficient. The phonological route to reading appeared to be preferred to the lexical route, and the overall pattern of performance most closely paralleled that of the surface dyslexic subtype.     

Parafoveal processing in reading

The present review summarizes research investigating how words are identified parafoveally (and foveally) in reading. Parafoveal and foveal processing are compared when no other concurrent task is required (e.g., in single-word recognition tasks) and when both are required simultaneously (e.g., during reading). We first review methodologies used to study parafoveal processing (e.g., corpus analyses and experimental manipulations, including gaze-contingent display change experiments such as the boundary, moving window, moving mask, and fast priming paradigms). We then turn to a discussion of the levels of representation at which words are processed (e.g., orthographic, phonological, morphological, lexical, syntactic, and semantic). Next, we review relevant research regarding parafoveal processing, summarizing the extent to which words are processed at each of those levels of representation. We then review some of the most controversial aspects of parafoveal processing, as they relate to reading: (1) word skipping, (2) parafoveal-on-foveal effects, and (3) n + 1 and n + 2 preview benefit effects. Finally, we summarize two of the most advanced models of eye movements during reading and how they address foveal and parafoveal processing.     

藏语阅读中中央凹词频效应及对副中央凹预视效应的影响

在不同语言文字系统中, 对于眼动控制的本质及其发生机制, 尤其是阅读过程中注意资源的分配是序列分布还是平行分布的问题, 目前仍然存在着争论和分歧。藏语是拼音文字, 但它同时又具有汉语的特点, 独具语言特色。因此, 通过对藏语阅读过程中中央凹词频对副中央凹预视效应影响这一问题的探讨, 可以在一种已有研究未曾涉及的文字系统中进一步推动上述争议的解决。本研究采用眼动记录法, 设计了两个实验。实验1操纵了中央凹词频(高频、低频), 考察藏语阅读中中央凹词的词频效应及词频延迟效应, 结果发现, 藏语阅读中存在词频效应及词频延迟效应。实验2同时操纵中央凹词频和副中央凹预视词类型, 借助边界范式, 考察藏语阅读中副中央凹预视效应及中央凹词频对副中央凹预视效应的影响, 结果发现, 藏语阅读中存在副中央凹预视效应, 且与低频中央凹词相比, 高频中央凹词对副中央凹预视效应的促进作用更大。两个实验结果表明:(1)藏语阅读中存在显著的词频效应, 且表现在词汇加工的整个过程; (2)藏语阅读中存在显著的词频延迟效应, 并贯穿于词汇加工的整个过程; (3)藏语阅读中存在显著的副中央凹预视效应, 读者能通过副中央凹预视提取到语音和字形信息。藏语阅读中中央凹词频影响副中央凹预视效应的大小, 且词频只在词汇加工的早期对形的预视信息的提取产生影响, 即在形似预视条件下高频词的预视效应更大; (4)本研究发现的词频延迟效应及副中央凹预视效应, 支持了E-Z读者模型中有关副中央凹序列加工的观点。