Speed of processing of the visual-orthographic and auditory-phonological systems in adult dyslexics: the contribution of "asynchrony" to word recognition deficits

This study investigated whether "asynchrony" in speed of processing (SOP) between the visual-orthographic and auditory-phonological modalities contributes to word recognition deficits among adult dyslexics. Male university students with a history of diagnosed dyslexia were compared to age-matched normal readers on a variety of experimental measures while event-related potentials and reaction time data were collected. Measures were designed to evaluate auditory and visual processing for non-linguistic (tones and shapes) and linguistic (phonemes and graphemes) low-level stimuli as well as higher-level orthographic and phonological processing (in a lexical decision task). Data indicated that adult dyslexic readers had significantly slower reaction times and longer P300 latencies than control readers in most of the experimental tasks and delayed P200 latencies for the lexical decision task. Moreover, adult dyslexics revealed a systematic SOP gap in P300 latency between the auditory/phonological and visual/orthographic processing measures. Our data support and extend previous work that found SOP asynchrony to be an underlying factor of childhood dyslexia. The present data suggests, however, that among adult dyslexics the between modalities asynchrony occurs at later processing stages than in children.     

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.     

A distributed, developmental model of word recognition and naming

A parallel distributed processing model of visual word recognition and pronunciation is described. The model consists of sets of orthographic and phonological units and an interlevel of hidden units. Weights on connections between units were modified during a training phase using the back-propagation learning algorithm. The model simulates many aspects of human performance, including (a) differences between words in terms of processing difficulty, (b) pronunciation of novel items, (c) differences between readers in terms of word recognition skill, (d) transitions from beginning to skilled reading, and (e) differences in performance on lexical decision and naming tasks. The model's behavior early in the learning phase corresponds to that of children acquiring word recognition skills. Training with a smaller number of hidden units produces output characteristic of many dyslexic readers. Naming is simulated without pronunciation rules, and lexical decisions are simulated without accessing word-level representations. The performance of the model is largely determined by three factors: the nature of the input, a significant fragment of written English; the learning rule, which encodes the implicit structure of the orthography in the weights on connections; and the architecture of the system, which influences the scope of what can be learned.     

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。     

Frequency effects with visual words and syllables in a dyslexic reader

The present study investigated the nature of the inhibitory syllable frequency effect, recently reported for normal readers, in a German-speaking dyslexic patient. The reading impairment was characterized as a severe deficit in naming single letters or words in the presence of spared lexical processing of visual word forms. Three visual lexical decision experiments were conducted with the dyslexic patient, an unimpaired control person matched to the patient and a control group: Experiment 1 manipulated the frequency of words and word-initial syllables and demonstrated systematic effects of both factors in normal readers and in the dyslexic patient. The syllable frequency effect was replicated in a second experiment with a more strictly controlled stimulus set. Experiment 3 confirmed the patient's deficit in activating phonological forms from written words by demonstrating that a pseudohomophone effect as observed in the unimpaired control participants was absent in the dyslexic patient.     

Distinctive phonological features differ in relevance for both spoken and written word recognition

This paper discusses four experiments on Dutch which show that distinctive phonological features differ in their relevance for word recognition. The relevance of a feature for word recognition depends on its phonological stability, that is, the extent to which that feature is generally realized in accordance with its lexical specification in the relevant word position. If one feature value is uninformative, all values of that feature are less relevant for word recognition, with the least informative feature being the least relevant. Features differ in their relevance both in spoken and written word recognition, though the differences are more pronounced in auditory lexical decision than in self-paced reading.     

Is dyslexia a visual perceptive disorder? New empirical data

Several studies have shown that a phonological deficit is the origin of developmental dyslexia, because dyslexics have important difficulties in mapping orthographic to phonological codes. However, visual criteria are still used for the diagnosis of dyslexia and to develop methods of intervention. This study attempts to determine whether there are visual problems in dyslexic children. To this aim, dyslexic children and children without reading difficulties, matched by chronological age, participated in two experiments. One study was based on the Reversal test and the other was a visual decision task in which participants had to decide whether two letters were the same or different. There were 40 pairs of letters, to measure reaction times and mistakes. The results showed that dyslexics had similar performance to controls in the detection of different visual stimuli. Developmental dyslexics do not appear to have visual perceptual problems, but a particular difficulty to retrieve the phonological code of graphemes.     

Morphological Structure Processing During Word Recognition and Its Relationship to Character Reading Among Third-Grade Chinese Children

In the present study, we explored the characteristics of morphological structure processing during word recognition among third grade Chinese children and its possible relationship with Chinese character reading. By using the modified priming lexical decision paradigm, a significant morphological structure priming effect was found in the subject analysis when reaction time difference was considered as dependent variable. In the regression analyses, the children’s implicit morphological structure processing demonstrated a significant effect on Chinese character reading, even though its effect became non-significant when morphological awareness was entered. We achieved this result after controlling for the children’s age, non-verbal intelligence, and phonological awareness. These findings indicate that third grade Chinese children are sensitive to morphological structure information in the processing of compound words. Moreover, such sensitivity is, to some extent, a good predictor of Chinese children’s word reading performance.     

The relationship between knowing a word and reading it aloud in children’s word reading development

This experiment examined the item-level relationship between 7-year-olds’ ability to read words aloud and their knowledge of the same words in the oral domain. Two types of knowledge were contrasted: familiarity with the phonological form of the word (lexical phonology), measured by auditory lexical decision, and semantic knowledge, measured by a definitions task. Overall, there was a robust relationship between word knowledge and reading aloud success. The association was stronger when words contained irregular spelling-sound correspondences. There was no evidence that a deeper or more semantic knowledge of words was more closely related to reading aloud success beyond the association between reading success and familiarity with the phonological form of the same words. This finding is not compatible with models that see semantics as contributing directly to the reading aloud process, at least during the relatively early stages of reading development. More critical was whether or not a word was considered a lexical item, as indexed by auditory lexical decision performance.     

Grammatical gender in spoken word recognition in German

The role of grammatical gender for auditory word recognition in German was investigated in three experiments and two sets of corpus analyses. In the corpus analyses, gender information reduced the lexical search space as well as the amount of input needed to uniquely identify a word. To test whether this holds for on-line processing, two auditory lexical decision experiments (Experiments 1 and 3) were conducted using valid, invalid, or noise-masked articles as primes. Clear gender-priming effects were obtained in both experiments. Experiment 2 used phoneme monitoring with words and with pseudowords deviating from base words in one or more phonological features. Contrary to the lexical decision latencies, phoneme-monitoring latencies showed no influence of gender but did show similarity mismatch effects. We argue that gender information is not utilized early during word recognition. Rather, the presence of a valid article increases the initial familiarity of a word, facilitating subsequent responses.     

Phonological similarity neighborhoods and children’s short-term memory: Typical development and dyslexia

In this article, we explore whether structural characteristics of the phonological lexicon affect serial recall in typically developing and dyslexic children. Recent work has emphasized the importance of long-term phonological representations in supporting short-term memory performance. This occurs via redintegration (reconstruction) processes, which show significant neighborhood density effects in adults. We assessed whether serial recall in children was affected by neighborhood density in word and nonword tasks. Furthermore, we compared dyslexic children with typically developing children of the same age or reading level. Dyslexic children are held to have impaired phonological representations of lexical items. These impaired representations may impair or prevent the use of long-term phonological representations to redintegrate short-term memory traces. We report significant rime neighborhood density effects for serial recall of both words and nonwords, for both dyslexic and typically developing children.     

Prosodic phonological representations early in visual word recognition

Two experiments examined the nature of the phonological representations used during visual word recognition. We tested whether a minimality constraint (R. Frost, 1998) limits the complexity of early representations to a simple string of phonemes. Alternatively, readers might activate elaborated representations that include prosodic syllable information before lexical access. In a modified lexical decision task (Experiment 1), words were preceded by parafoveal previews that were congruent with a target's initial syllable as well as previews that contained 1 letter more or less than the initial syllable. Lexical decision times were faster in the syllable congruent conditions than in the incongruent conditions. In Experiment 2, we recorded brain electrical potentials (electroencephalograms) during single word reading in a masked priming paradigm. The event-related potential waveform elicited in the syllable congruent condition was more positive 250-350 ms posttarget compared with the waveform elicited in the syllable incongruent condition. In combination, these experiments demonstrate that readers process prosodic syllable information early in visual word recognition in English. They offer further evidence that skilled readers routinely activate elaborated, speechlike phonological representations during silent reading.     

Orthography shapes the perception of speech: The consistency effect in auditory word recognition

Inconsistency in the spelling-to-sound mapping hurts visual word perception and reading aloud (i.e., the traditional consistency effect). In the present experiment, we found a consistency effect in auditory word perception: Words with phonological rimes that could be spelled in multiple ways produced longer auditory lexical decision latencies and more errors than did words with rimes that could be spelled only one way. This finding adds strong support to the claim that orthography affects the perception of spoken words. This effect was predicted by a model that assumes a coupling between orthography and phonology that is functional in both visual and auditory word perception.     

Phonological neighbors speed visual word processing: evidence from multiple tasks

The author investigated the role of phonological neighborhood on visual word recognition. Using a lexical decision task, the author showed in Experiment 1 that words with large phonological neighborhoods were processed more rapidly than those with smaller phonological neighborhoods. This facilitative effect was obtained even when the nonword fillers had the same number of phonological neighbors as the words. This finding indicates that phonological neighbors speed processing within the phonological system. In the next 2 experiments, this claim was further tested using the naming and semantic categorization tasks. In both experiments, the effect of phonological neighborhood was found to be facilitative. The results across all 3 experiments indicate that phonology is central to visual word recognition and that phonological neighborhood provides a reliable measure of phonological processing.     

Visual and name coding in dyslexic children

Summary Four experiments are reported which were designed to test for differences between dyslexic and non-dyslexic subjects at a number of visual information processing functions. It is argued that the older dyslexic child's reading problems cannot be ascribed to slowness of visual code production, to the limited capacity of the system, or to an extra rapid rate of decay. The results are compatible with the theory that, as a group, the dyslexic children tested show a slowness or inadequacy at a non-visual, name or linguistic coding level. It is suggested that this deficiency does not lie in the area of articulatory encoding but at an earlier stage where phonological or lexical codes are produced from visual stimuli.     

The relationship between reading ability and lateralized lexical decision

Although lexical decision remains one of the most extensively studied cognitive tasks, very little is known about its relationship to broader linguistic performance such as reading ability. In a correlational study, several aspects of lateralized lexical decision performance were related to vocabulary and reading comprehension measures, as assessed using the Nelson-Denny Reading Test. This lateralized lexical decision task has been previously shown to demonstrate (1) independent contributions from both hemispheres, as well as (2) interhemispheric interactions during word recognition. Lexical decision performance showed strong relationships with both reading measures. Specifically, vocabulary performance correlated significantly with left visual field (LVF) word accuracy and LVF non-word latency, both measures of right hemisphere performance. There were also significant, though somewhat weaker, correlations between reading comprehension and RVF non-word latency. Lexicality priming, a measure of interhemispheric communication during lexical decision, was also correlated with reading comprehension. These results suggest that hemispheric interaction during word recognition is common, and that lexical processing contribution from the right hemisphere, something commonly taken as minor and inconsequential, can lead to significant performance benefits and to individual differences in reading.     

发展性阅读障碍亚类型研究进展

发展性阅读障碍是一种特殊的学习障碍,伴有多种认知缺陷并且存在不同的亚类型。依据相关的阅读模型理论,阅读障碍可划分为语音型和表层型。从认知缺陷角度出发,语音加工缺陷是主要的缺陷表现,以此为特征形成一种主要的阅读障碍的亚类型,同时还有以正字法加工缺陷和快速命名缺陷为主的其他亚类型。而以基本感知觉缺陷为标准,主要有以视觉加工缺陷和以听觉加工缺陷为主的两种亚类型。在汉语条件下,依据同样的阅读模型理论,语音型阅读障碍亚类型比例明显低于拼音文字条件下的。汉语阅读障碍也具有分别以语音加工缺陷、快速命名缺陷和正字法加工缺陷为主要认知缺陷的亚类型。未来有必要从神经机制角度进一步明确不同亚类型的神经基础。     

Oral language deficits in dyslexic children: weaknesses in working memory and verbal planning

This paper focuses on the relationships among language processing (word- and sentence-level), working memory, and verbal/nonverbal linguistic output. The study examined oral language abilities in a group of 26 French-speaking dyslexic children, compared to two control groups (26 normally developing age-matched children and 26 normally developing younger children). The experimental procedure consisted of tasks involving auditory memory skills (digit span, unfamiliar word repetition, sentence repetition), word retrieval (with semantic, phonological and grammatical criteria), and sentence processing (with verbal and act-out production). The major findings reveal that (a) compared with their age-mates, the dyslexic children exhibited a significant deficit affecting all tasks; and (b) the dyslexic children and the younger controls performed similarly on several tasks. The results are consistent with the processing limitation hypothesis and suggest that the core deficit is the formulation of cognitive plans from auditory input to verbal output.     

视觉语言对听觉障碍人群阅读能力的影响及作用机制

听觉障碍人群由于听觉部分或完全受损, 视觉语言——唇读和手语就成为其阅读能力发展的主要途径。唇读有助于听觉障碍人群形成语音表征, 与词汇知识相互影响, 且可以促进字词阅读及阅读理解的水平; 口语或书面语的加工可以激活相应的手语表征, 手语影响着听觉障碍人群各个层次的阅读能力。未来研究应该关注语音意识、词汇知识等技能在视觉语言影响听觉障碍人群阅读能力过程中的作用机制, 并以视觉语言为中心, 发展出适合汉语听觉障碍人群阅读能力习得的理论模型。