发展性阅读障碍的ERP研究

发展性阅读障碍,ERP,语音缺陷假说,Oddball范式。行为实验已经发现,语音能力的缺损是拼音文字发展性阅读障碍的核心。然而近年来行为研究和神经生理学的研究也发现,发展性阅读障碍与基本知觉障碍有关。事件相关电位（event-related potentials ,简称ERP）作为一种独特的电生理学研究手段,从一个更为直观的角度验证了行为实验的结果,推动了发展性阅读障碍的进展。语言认知水平ERP研究表明,发展性阅读障碍者在存在语音加工和信息整合的缺陷。感知觉加工层次的ERP研究结果则不尽一致,有的研究发现,阅读障碍存在着基本的听觉加工缺陷;有的研究则发现发展性阅读障碍存在言语声音加工的缺陷,而对非言语声音的加工与正常读者没有显著差别;有的研究支持大细胞通路受损假说,发现阅读障碍在低对比度和低空间频率上存在视觉加工的缺陷,有的研究结果则没有发现发展性阅读障碍者与正常读者在不同对比度和空间频率上的差异。     

发展性阅读障碍的听觉时间加工缺陷

发展性阅读障碍是指个体在智力正常并且不缺乏学校教育的情况下, 仍无法获得与年龄相匹配的阅读技能的一种学习障碍, 其缺陷的本质一直是研究者争论的焦点。大量研究显示, 阅读障碍者常表现出听觉时间加工损伤。在行为层面, 阅读障碍者难以辨别快速、连续呈现刺激的顺序以及刺激本身的动态时间特征。在神经层面, 阅读障碍者诱发的失匹配负波更弱且具有异常的神经同步加工。这些损伤同时存在于对言语和非言语刺激的加工中, 表明听觉时间加工缺陷非言语加工所特有。未来的研究还需阐明以下几个问题：1)阅读障碍的听觉时间加工缺陷发生在哪些时间窗口, 随年龄增长如何变化; 2)阅读障碍听觉时间加工缺陷在神经层面的时间进程是怎样的; 3)听觉时间加工缺陷是否为阅读障碍的核心缺陷。     

动作视频游戏对发展性阅读障碍者阅读技能的影响及其内在机制

发展性阅读障碍是一种在获得阅读技能方面的特殊困难, 这种障碍会严重影响个体的发展, 如何帮助发展性阅读障碍者改善其阅读技能是近年来研究的焦点。传统的干预方法主要针对发展性阅读障碍者的语音缺陷, 这类方法存在一些问题, 如费时费力、给阅读障碍者带来阅读压力等。近年来, 大部分研究表明通过趣味性的动作视频游戏训练可以显著地提高发展性阅读障碍者的阅读技能, 但是其背后的机制尚不明确。基于大细胞通路缺陷理论框架, 从视觉空间注意、注意跨通道转换、视觉运动加工等方面来梳理动作视频游戏与阅读之间的关系, 揭示了动作视频游戏训练对阅读效率影响的可能内在机制。未来的研究可以在大细胞通路缺陷理论的框架下, 深入分析动作视频游戏改善阅读的神经机制, 并尝试开发更适合发展性阅读障碍者的干预程序。     

发展性阅读障碍的理论及眼动研究

关于发展性阅读障碍,国外研究者,基于认知和生物因素,先后提出了语音缺陷论、小脑缺陷论、一般性大细胞功能障碍论等对发展性阅读障碍进行解释,并考察了患者的眼动特征,提出了有效的诊治方法。目前,汉语发展性阅读障碍研究主要局限在语音和正字法领域,也涉及局部脑区的功能缺陷,但还未从多角度测查其成因,如眼动。这里,在理论梳理的基础上,系统探讨了发展性阅读障碍者的眼动特征,如注视时间、注视次数、眼跳、回视等,及视觉加工的眼动机制     

发展性阅读障碍的神经生物学研究进展

发展性阅读障碍的研究起源于英语国家。因英语是一种深正字法语言 ,而且许多调查表明深正字法语种国家阅读障碍的发生率高于浅正字法语种国家 ,许多认知实验也证明阅读障碍者存在语音缺陷 ,因此开始时心理学家们倾向于用语音缺损 (phonologicaldeficit)理论来解释发展性阅读障碍的发生 ;但另一方面 ,部分研究者坚持认为阅读障碍的发生有其神经生物学原因 ,大量的相关研究表明阅读障碍个体表现出一定的神经系统结构和功能的异常 ,人们推测在脑异常与包括语音加工缺陷在内的阅读障碍间存在某种因果联系。最近E .Paulesu等 (2 0 0 1)的一个跨…     

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。     

听觉、时间加工能力与发展性阅读障碍

近年来阅读障碍者的知觉加工越来越受到重视 ,本文介绍了近期国外关于阅读障碍者的听觉加工能力、时间加工能力的最新研究进展。快速听觉加工能力的缺失在阅读障碍者身上普遍存在 ,并被认为是阅读障碍产生的主要原因 ;有研究者提出“时间控制障碍”假说 ,认为阅读障碍源自一种普遍性的时间知觉障碍 ,不具有通道特异性。除此之外 ,还发现阅读障碍者对声音频率、响度等非时间特征也出现了觉察困难。通过这些研究我们可以看到 ,听觉加工能力、快速时间加工能力与阅读能力之间可能有着密切的关系 ,但这几种能力如何具体作用于阅读发展 ,它们之间如何相互作用、相互影响仍需进一步探讨。     

阅读障碍与注意缺陷多动障碍儿童的语言加工和反应抑制

阅读障碍与注意缺陷多动障碍(ADHD)高度共病,以往研究结果显示两种障碍在语言加工、执行功能等领域的缺陷既相似又不同。本研究采用语音意识测验、快速命名测验、语素意识测验和停止信号任务,以及阅读广度测验,分别考察四组被试（阅读障碍组、ADHD组、双重障碍组、正常控制组）的基础语言加工、反应抑制和言语工作记忆能力,结果发现：阅读障碍组和双重障碍组在语言加工任务上的成绩均显著差于ADHD组和正常组;ADHD组和双重障碍组在停止信号任务上的成绩显著差于阅读障碍组和正常组;所有障碍组在阅读广度测验上的成绩显著差于正常组。表明阅读障碍的特异性缺陷体现在语言加工过程上,而注意缺陷多动障碍的特异性缺陷体现在反应抑制上。这对于今后单一障碍的研究及临床诊断和干预具有重要的参考价值。     

脑干诱发电位在言语感知研究中的应用

脑干诱发电位是一种考察听觉脑干加工声音信号时神经活动的非侵入性技术, 近年来被广泛用于探索言语感知的神经基础。相关研究主要集中在考察成年人和正常发展儿童语音编码时脑干的活动特征及发展模式, 探讨发展性阅读障碍及其他语言损伤的语音编码缺陷及其神经表现等方面。在已有研究的基础上进一步探索初级语音编码和高级言语加工之间的相互作用机制, 考察阅读障碍的底层神经基础将成为未来该技术在言语感知研究中应用的重点。     

中文阅读障碍儿童的时间加工缺陷:来自知觉学习干预研究的证据

前人研究指出,阅读障碍群体具有听觉通道内的时间加工缺陷,但截止目前为止,该缺陷的非模态性、跨语言一般性、干预前景及具体机制尚不明确。本文通过综述三项在中文阅读障碍儿童中开展的听觉、视觉时间加工知觉训练,以及它们对阅读成绩的迁移效应,对时间加工技能与阅读障碍的关系,及其影响阅读发展的认知机制进行了探讨和分析,并在此基础上,提出了未来的研究构想,以充实该领域的理论建构。     

Instability of Double-Deficit Subtypes Among At-Risk First Grade Readers

The double-deficit hypothesis provides a framework for identifying students at-risk for persistent reading difficulties. I examined the temporal stability of four double-deficit subtypes (no-deficit, naming-speed deficit, phonological deficit, and double-deficit) in 197 low-performing, first-grade readers. Concurrent analyses in fall and spring revealed that students with poor phonemic awareness and naming speed were the lowest readers in the sample; however, having a double-deficit in fall was not a good predictor of subsequent progress, most likely because subtypes were not stable over the first half of grade 1. Only about half the sample retained the same subtype from fall to spring.     

Perception of speech and nonspeech stimuli by children with and without reading disability and attention deficit hyperactivity disorder

The auditory temporal deficit hypothesis predicts that children with reading disability (RD) will exhibit deficits in the perception of speech and nonspeech acoustic stimuli in discrimination and temporal ordering tasks when the interstimulus interval (ISI) is short. Initial studies testing this hypothesis did not account for the potential presence of attention deficit hyperactivity disorder (ADHD). Temporal order judgment and discrimination tasks were administered to children with (1) RD/no-ADHD (n=38), (2) ADHD (n=29), (3) RD and ADHD (RD/ADHD; n=32), and (4) no impairment (NI; n=43). Contrary to predictions, children with RD showed no specific sensitivity to ISI and performed worse relative to children without RD on speech but not nonspeech tasks. Relationships between perceptual tasks and phonological processing measures were stronger and more consistent for speech than nonspeech stimuli. These results were independent of the presence of ADHD and suggest that children with RD have a deficit in phoneme perception that correlates with reading and phonological processing ability. (c) 2002 Elsevier Science (USA).     

Visual rapid naming and phonological abilities: different subtypes in dyslexic children

One implication of the double-deficit hypothesis for dyslexia is that there should be subtypes of dyslexic readers that exhibit rapid naming deficits with or without concomitant phonological processing problems. In the current study, we investigated the validity of this hypothesis for Portuguese orthography, which is more consistent than English orthography, by exploring different cognitive profiles in a sample of dyslexic children. In particular, we were interested in identifying readers characterized by a pure rapid automatized naming deficit. We also examined whether rapid naming and phonological awareness independently account for individual differences in reading performance. We characterized the performance of dyslexic readers and a control group of normal readers matched for age on reading, visual rapid naming and phonological processing tasks. Our results suggest that there is a subgroup of dyslexic readers with intact phonological processing capacity (in terms of both accuracy and speed measures) but poor rapid naming skills. We also provide evidence for an independent association between rapid naming and reading competence in the dyslexic sample, when the effect of phonological skills was controlled. Altogether, the results are more consistent with the view that rapid naming problems in dyslexia represent a second core deficit rather than an exclusive phonological explanation for the rapid naming deficits. Furthermore, additional non-phonological processes, which subserve rapid naming performance, contribute independently to reading development.     

The relationship between auditory temporal processing,phonemic awareness,and reading disability

Recent research suggests an auditory temporal deficit as a possible contributing factor to poor phonemic awareness skills. This study investigated the relationship between auditory temporal processing of nonspeech sounds and phonological awareness ability in children with a reading disability, aged 8-12 years, using Tallal's tone-order judgement task. Normal performance on the tone-order task was established for 36 normal readers. Forty-two children with developmental reading disability were then subdivided by their performance on the tone-order task. Average and poor tone-order subgroups were then compared on their ability to process speech sounds and visual symbols, and on phonological awareness and reading. The presence of a tone-order deficit did not relate to performance on the order processing of speech sounds, to poorer phonological awareness or to more severe reading difficulties. In particular, there was no evidence of a group by interstimulus interval interaction, as previously described in the literature, and thus little support for a general auditory temporal processing difficulty as an underlying problem in poor readers. In this study, deficient order judgement on a nonverbal auditory temporal order task (tone task) did not underlie phonological awareness or reading difficulties.     

Auditory temporal processing deficits in children with periventricular brain injury

The present study investigated whether auditory temporal processing deficits are related to the presence and/or the severity of periventricular brain injury and the reading difficulties experienced by extremely low birthweight (ELBW: birthweight <1000 g) children. Results indicate that ELBW children with mild or severe brain lesions obtained significantly lower scores on a test requiring auditory temporal order judgments than ELBW children without periventricular brain injury or children who were full-term. Structural equation modeling indicated that a model in which auditory temporal processing deficits predicted speech sound discrimination and phonological processing ability provided a better fit for the data than did a second model, which hypothesized that auditory temporal processing deficits are associated with poor reading abilities through a working memory deficit. These findings suggest that an impairment in auditory temporal processing may contribute to the reading difficulties experienced by ELBW children.     

The evidence for a temporal processing deficit linked to dyslexia: A review

The existence of a phonemic deficit that is predictive of, and probably causal to, many cases of reading difficulty is well established. Tallal (1984) has suggested that this phonemic deficit is in fact a symptom of an underlying auditory temporal processing deficit. Our purpose in this paper is to evaluate the plausibility of this hypothesis. The various components that might constitute sequential (or temporal) processing are described. Our review of the literature reveals considerable evidence for a deficit in dyslexics in stimulus individuation tasks (e.g., gap detection) and temporal order judgments in both the auditory and visual modalities. The possibility that a general temporal processing deficit is associated with dyslexia, as suggested by Tallal (1984), is explored, and possible etiologies for such a deficit are discussed. The possibility of a causal link between temporal processing deficits and some reading disabilities is demonstrated, and converging evidence from morphological studies is reviewed. It is concluded that a temporal processing deficit does appear to be present in many developmental dyslexics, and strategies are suggested for further research aimed at evaluating the hypothesis that this deficit may be the root cause of a number of cases of dyslexia itself.     

What is the deficit in phonological processing deficits: auditory sensitivity, masking, or category formation?

Although children with language impairments, including those associated with reading, usually demonstrate deficits in phonological processing, there is minimal agreement as to the source of those deficits. This study examined two problems hypothesized to be possible sources: either poor auditory sensitivity to speech-relevant acoustic properties, mainly formant transitions, or enhanced masking of those properties. Adults and 8-year-olds with and without phonological processing deficits (PPD) participated. Children with PPD demonstrated weaker abilities than children with typical language development (TLD) in reading, sentence recall, and phonological awareness. Dependent measures were word recognition, discrimination of spectral glides, and phonetic judgments based on spectral and temporal cues. All tasks were conducted in quiet and in noise. Children with PPD showed neither poorer auditory sensitivity nor greater masking than adults and children with TLD, but they did demonstrate an unanticipated deficit in category formation for nonspeech sounds. These results suggest that these children may have an underlying deficit in perceptually organizing sensory information to form coherent categories.     

The "temporal processing deficit" hypothesis in dyslexia: new experimental evidence

The notion that developmental dyslexia may result from a general, nonspecific, defect in perceiving rapidly changing auditory signals is a current subject of debate (so-called "temporal processing deficit" hypothesis). Thirteen phonological dyslexics (age 10-13 years) and 10 controls matched for chronological and reading age were compared on a temporal order judgment (TOJ) task using the succession of two consonants (/p/-/s/) within a cluster. In order to test the relevance of the temporal deficit hypothesis, the task also included two additional conditions where either the two stimuli were artificially slowed or the interstimulus interval was expanded. As expected, the TOJ performance was significantly poorer in dyslexics than in controls. Moreover, in the "slowed speech" condition dyslexics' performance improved to reach the normal controls' level, whereas no significant improvement occurred when increasing the interstimulus interval. Finally dyslexics' performances, especially on the slowed condition, were found correlated with several tests of phonological processing (phoneme deletion, rhyme judgment, and nonword spelling tasks). These results lend support to the general temporal deficit theory of dyslexia.