Brain Activity During Performance of Naming Tasks: Comparison Between Dyslexic and Regular Readers

This research was aimed at contributing to the current understanding of the underlying factors of naming speed and the causes of naming speed deficits. Forty regular readers and 40 dyslexic university students participated in the study. Electrophysiological (Event-Related Potentials [ERPs]) and behavioral measures were employed. Behavioral baseline tasks assessed general ability, reading skills, reading-related cognitive abilities, and standard Rapid Automatized Naming (RAN) and Rapid Alternating Stimulus tests. ERP tasks included letter and object naming tasks adapted for electrophysiological research presentation. The dyslexics were significantly slower and less accurate than the controls on most of the baseline measures. On all the naming tasks, the peak ERP latencies were elicited later, reaction times were longer, and the P300 latency width was wider among the dyslexics as compared to the regular readers. On the choice reaction time naming tasks, accuracy for both groups was almost perfect. When naming presentation time was controlled by the experiment, the dyslexics were significantly less accurate than the controls. Our data indicated that effective naming speed was related to an earlier P200 latency peak among regular readers and to an earlier P300 latency peak and narrower area component activation in the dyslexic group. The results from this study suggest that effective RAN speed among regular readers might be a result of efficient processing of RAN information at the input stage of stimulis perception and evaluation as well as of updating and processing the information in short-term memory among dyslexics.     

The development of reading speed in Italians with dyslexia: a longitudinal study

The development of reading speed in Italian children with dyslexia was estimated using individualized growth curves for a group of 38 children with dyslexia tested longitudinally from the second to the eighth grade and compared with typical readers. Their reading speed development followed a linear trend of .3 syllables per second per grade, approximately half the increment observed in typical children reading a passage and similar to typical children's reading of nonword lists. These findings give support to the deficit hypothesis versus the lag hypothesis and to reading speed as the core deficit in dyslexia with transparent orthographies.     

Persistence of phonological processing deficits in college students with dyslexia who have age-appropriate reading skills

This study investigated the phonological processing skills of university students with dyslexia. Fifty-nine students participated in this study: 28 with reading disabilities based on recent psychological assessments and a history of early and persistent reading problems; and 31 controls. The two groups did not differ on estimates of verbal and nonverbal abilities. The dyslexia group performed significantly less well on standardized measures of reading and spelling. However, the dyslexia group scores on these measures fell within the average range. The main dependent variables were subsumed under three areas of phonological processing: phonological awareness, phonological recoding in lexical access, and phonological recoding in working memory. The control group performed significantly better on all phonological processing measures, particularly those measures involving accuracy and response times. Despite age-appropriate performances on standardized reading and spelling measures, phonological processing deficits persisted in the dyslexia group. These findings support the causal role of phonological awareness in the acquisition of reading skills and indicate that differences in phonological processing skills are still evident in a sample of university students with dyslexia compared a group matched on age and education.     

Short-term memory for order but not for item information is impaired in developmental dyslexia

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory (Szmalec et al. Journal of Experimental Psychology: Learning, Memory, & Cognition 37(5): 1270-1279, 2011). At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing (Majerus et al. Cognition 107: 395-419, 2008). The current study is aimed to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order and whether this impairment also affects processing beyond the verbal domain. A sample of 26 adults with dyslexia and a group of age and IQ-matched controls participated in a 2?×?2?×?2 experiment in which we assessed short-term recognition performance for order and item information, using both verbal and nonverbal material. Our findings indicate that, irrespective of the type of material, participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexia group. We conclude that dyslexia is characterized by a selective impairment of short-term memory for serial order, but not for item information, and discuss the integration of these findings into current theoretical views on dyslexia and its associated dysfunctions.     

Naming difficulties in children with dyslexia: application of the tip-of-the-tongue paradigm

The present study used the tip-of-the-tongue (TOT) experimental paradigm in a picture naming task to explore the source of the naming deficits of children with dyslexia. Compared with a control group of typically developing readers, the children with dyslexia showed fewer correct responses and spontaneous recalls, more don't know (DK) and TOT responses, and less accurate feeling of knowing (FOK) judgments. When they failed to retrieve a target word, the children with dyslexia did not differ from the control group in the partial semantic information they provided, but they gave less valid and more invalid partial phonological information. The children with dyslexia also benefited less from phonological cues. The phonologically related responses of the children with dyslexia elicited during the administration of the TOT procedure were related to their performance on a phonological awareness test. These findings suggest that the naming problems of children with dyslexia arise because of their difficulty in accessing the phonological word forms after the corresponding abstract lexical representation has been successfully accessed. The results are discussed in relation to the claim that two-stage models of naming can be profitably used in the early identification and treatment of reading disabilities.     

P300 event-related potentials in children with dyslexia

To elucidate the timing and the nature of neural disturbances in dyslexia and to further understand the topographical distribution of these, we examined entire brain regions employing the non-invasive auditory oddball P300 paradigm in children with dyslexia and neurotypical controls. Our findings revealed abnormalities for the dyslexia group in (i) P300 latency, globally, but greatest in frontal brain regions and (ii) decreased P300 amplitude confined to the central brain regions (Fig. 1). These findings reflect abnormalities associated with a diminished capacity to process mental workload as well as delayed processing of this information in children with dyslexia. Furthermore, the topographical distribution of these findings suggests a distinct spatial distribution for the observed P300 abnormalities. This information may be useful in future therapeutic or brain stimulation intervention trials.     

Spatial selective attention and asynchrony of cognitive systems in adult dyslexic readers: an ERPs and behavioral study

The aim of this study was to gain additional knowledge about the asynchrony phenomenon in developmental dyslexia, especially when spatial selective attention is manipulated. Adults with developmental dyslexia and non-impaired readers underwent two experimental tasks, one including alphabetic stimuli (pre-lexical consonant–vowel syllables) and the other containing non-alphabetic stimuli (pictures and sounds of animals). Participants were instructed to attend to the right or left hemifields and to respond to all stimuli on that hemifield. Behavioral parameters and event-related potentials were recorded. The main finding was that the dyslexic readers demonstrated asynchrony between the auditory and visual modalities when alphabetic stimuli were presented on the right hemifield. These results suggest that intact reading is linked to a synchronized auditory and visual speed of processing even when spatial selective attention is manipulated. The findings of the current study are discussed in terms of asynchrony between modalities as a neurocognitive marker in developmental dyslexia.     

Atypical predictive processing during visual statistical learning in children with developmental dyslexia: an event-related potential study

Previous research suggests that individuals with developmental dyslexia perform below typical readers on non-linguistic cognitive tasks involving the learning and encoding of statistical-sequential patterns. However, the neural mechanisms underlying such a deficit have not been well examined. The aim of the present study was to investigate the event-related potential (ERP) correlates of sequence processing in a sample of children diagnosed with dyslexia using a non-linguistic visual statistical learning paradigm. Whereas the response time data suggested that both typical and atypical readers learned the statistical patterns embedded in the task, the ERP data suggested otherwise. Specifically, ERPs of the typically developing children (n?=?12) showed a P300-like response indicative of learning, whereas the children diagnosed with a reading disorder (n?=?8) showed no such ERP effects. These results may be due to intact implicit motor learning in the children with dyslexia but delayed attention-dependent predictive processing. These findings are consistent with other evidence suggesting that differences in statistical learning ability might underlie some of the reading deficits observed in developmental dyslexia.     

The impact of early institutional rearing on the ability to discriminate facial expressions of emotion: an event-related potential study

Event-related potentials (ERPs), in response to 4 facial expressions of fear, angry, happy, and sad, were collected from 72 institutionalized children (IG), ages 7 to 32 months, in Bucharest, Romania, and compared with ERPs from 33 children, ages 8 to 32 months, who had never been institutionalized (NIG). The NIG and IG exhibited different patterns of responding in early latency components. Moreover, group differences in amplitude were evident across all components. Such differences may point to the role of early deprivation in disrupting the development of the neural circuitry involved in the recognition of facial expressions.     

A systematic review and Bayesian meta-analysis of the development of turn taking in adult–child vocal interactions

Fluent conversation requires temporal organization between conversational exchanges. By performing a systematic review and Bayesian multi-level meta-analysis, we map the trajectory of infants’ turn-taking abilities over the course of early development (0 to 70 months). We synthesize the evidence from 26 studies (78 estimates from 429 unique infants, of which at least 152 are female) reporting response latencies in infant–adult dyadic interactions. The data were collected between 1975 and 2019, exclusively in North America and Europe. Infants took on average circa 1 s to respond, and the evidence of changes in response over time was inconclusive. Infants’ response latencies are related to those of their adult conversational partners: an increase of 1 s in adult response latency (e.g., 400 to 1400 ms) would be related to an increase of over 1 s in infant response latency (from 600 to 1857 ms). These results highlight the dynamic reciprocity involved in the temporal organization of turn-taking. Based on these results, we provide recommendations for future avenues of enquiry: studies should analyze how turn-by-turn exchanges develop on a longitudinal timescale, with rich assessment of infants’ linguistic and social development.     

Cognitive brain potentials in kindergarten children with subtyped risks of reading retardation

Cognition-related brain responses to meaningful and meaningless figures were registered in 5-year-old kindergarten children who either had been subtyped as being at-risk of developing an L- or P-type dyslexia (LAL versus LAP) or who were not at-risk. While identifying, naming, or categorizing pictures, event-related potentials (ERP) were registered. Three cognition-related components were found: the N460, the P780, and the Slow Wave (SW). LAP-children produced weak N460 activity across tasks, whereas LAL children, and to a lesser degree, non-risk children produced robust task-dependent activity. This finding may indicate that LAP-children lack semantic input while processing the figures. P780 latencies to frequently occurring figures were found hemisphere-dependent: LAP-children showed longer latencies in the right than in the left hemisphere, whereas the distribution was reversed in the LAL and non-risk children. It was also found that the right hemisphere is generally responsible for a lion's share of the processing of figures and therefore it seems that the right hemisphere of LAP-children invests ample time in doing so. Whereas LAP-children showed largest SW amplitude differences between frequent and infrequent stimuli at posterior locations, LAL children did so at frontal locations. Assuming that the SW represents working-memory processes, it may be that working-memory in LAP-children deals with figure-relevant visual-spatial information and with figure-derived concepts in LAL children. Overall, the findings suggest that LAL and LAP represent two different groups of kindergartners at risk of dyslexia and that these differences, to some degree, fit with the presumed etiology of L- and P-type dyslexia.     

Are RAN deficits in university students with dyslexia due to defective lexical access,impaired anchoring,or slow articulation?

The purpose of this study was to examine different hypotheses in relation to RAN deficits in dyslexia. Thirty university students with dyslexia and 32 chronological-age controls were assessed on RAN Digits and Colors as well as on two versions of RAN Letters and Objects (one with five items repeated 16 times and one with 20 items repeated four times). In addition, participants were tested on discrete letter and object naming, phonological awareness, orthographic knowledge, and speed of processing, and the RAN Letters and Objects total times were partitioned into pause times and articulation times. Results showed first that the dyslexia group was slower than the control group on all RAN tasks and the differences remained significant after controlling for discrete naming time. Second, both groups were slower in the large item set condition (20 ×?4) than in the small set condition (5 ×?16). Third, the dyslexia group was slower than the control group in both the pause and the articulation times. Although none of the processing skills was sufficient on its own to eliminate group differences in RAN Letters components, phonological awareness, and orthographic processing were sufficient on their own to eliminate group differences in the RAN Objects pause time. Taken together, our findings suggest that the deficits in RAN are not due to impaired anchoring, but rather due to subtle impairments in lexical access (specific to alphanumeric RAN), serial processing, and articulation.     

安康方言形容词的重叠式

安康市位于陕西南部,地处川、陕、鄂、渝交界之地。安康方言形容词的重叠式非常丰富,其构成形式主要有：AA儿式、AA子式、A的A式、ABB式、A不BB式、ABB儿式、AABB式、ABAB式、A里AB式、A里A气式、A头A脑式、A眉A眼式、乌A八A式、到A不A式。     

Naming speed in dyslexia and dyscalculia

In four carefully selected samples of 8- to 10-year old children with dyslexia (but age adequate arithmetic skills), dyscalculia (but age adequate reading skills), dyslexia/dyscalculia and controls a domain-general deficit in rapid automatized naming (RAN) was found for both dyslexia groups. Dyscalculic children exhibited a domain-specific deficit in rapid naming of quantities. This finding is in line with recent assumptions that dyscalculia is associated with a neurobiological deficit in the processing of numerosities. In the dyslexia/dyscalculia group, RAN deficits were additive, that is, the dyslexia/dyscalculia group exhibited the sum of the deficits found in the dyslexia only and dyscalculia only groups. This finding suggests that the cognitive bases of dyslexia and dyscalculia are independent from each other. Within the naming speed paradigm no differential impact of special demands on the executive functions inhibition and shifting was found for any of the four groups.     

发展性阅读障碍亚类型的研究

发展性阅读障碍是关系人类健康和发展的重要课题。多年来研究者试图寻找这个群体中发生困难的真正原因,希望从根本上解决阅读落后问题和消除阅读障碍。但是研究者发现阅读障碍群体内部具有很大的变异性。文章在简介了当今具有代表性的两种流派对阅读障碍原因的解释和相应的研究证据后,着重阐述了阅读障碍的亚类型的发展历史、研究者对亚类型的划分以及不同亚类型在语言技能上、一般感知能力和生理机制方面的差异,并且阐述了亚类型研究对阅读障碍早期预测的作用,为根本消除阅读障碍提供了新的视角。     

Timing precision and rhythm in developmental dyslexia

Current research on the etiology ofdevelopmental dyslexia is generally informed byeither of two major hypotheses. One of theseassumes that the phonological processing ofconsonants and vowels at a segmental levelidentifies the core deficit in developmentaldyslexia and that it cannot be reduced todomain-general deficits of temporal informationprocessing. The other hypothesis holds thatphonological processing deficits aresymptomatic of an underlying, domain-generaldysfunction; and that at least some dyslexiasubtypes are causally related to domain generaldeficits of temporal information processing forauditory and visual stimuli. This report startsfrom the assumption that the terms temporal information processing andphonological processing as applied in currentdyslexia research, are frequently conflated. Further, it assumes that the conflated termsmust be decomposed into their concretebehavioral referents before the causalsignificance of either can be investigatedsystematically.The studies to be summarized in thisreport represents one step toward suchdecomposition. The findings indicated thatduring a motor sequencing task, dyslexicstudents anticipated the signal of anisochronic pacing metronome by intervals thatwere two or three times as long as those ofage matched normal readers or normal adults.These group differences were significant whenparticipants tapped with the preferred indexfinger alone or with both fingers in unison.Dyslexic students also took significantlylonger than normal readers did to recalibratetheir tapping responses when the metronome ratewas experimentally changed in the middle of atrial.In addition, dyslexic students, bycontrast to normal readers, had inordinatedifficulty reproducing simple motor rhythms byfinger tapping, and similar difficultyreproducing the appropriate speech rhythm oflinguistically neutral nonsense syllables.These difficulties were exaggerated whenparticipants had to synchronize theirperformance to an external pacing metronome.The implications of the findings for temporalinformation processing deficits on one hand,and impaired phonological processing on theother, are discussed.     

儿童阅读障碍神经科学研究对早期教育的启示

对儿童阅读障碍的研究逐渐从心理发展和认知加工角度转向利用神经科学方法来对阅读障碍的神经机制(包括脑区定位和时间进程等)进行研究。在评析阅读障碍神经机制研究的基础上分析了儿童阅读障碍研究对早期教育的启示:应重视阅读障碍对儿童发展和学业成绩的影响;应及早发现阅读障碍并利用神经可塑性研究成果制定出相关矫治计划;利用脑成像技术可检测阅读障碍矫正效果。同时,本文对汉语阅读障碍提出预防措施。     

Cognitive processing skills and developmental dyslexia in Chinese

The purpose of the present study was twofold: (a) to examine the extent to which Chinese dyslexic children experience deficits in phonological and orthographic processing skills and (b) to examine if Chinese dyslexia is associated with deficits in Planning, Attention, Simultaneous, and Successive (PASS) processing. A total of 27 Grade 4 children with dyslexia (DYS), 27 Grade 4 chronological age (CA) controls, and 27 Grade 2 reading age (RA) controls were tested on measures of phonological awareness, rapid naming, phonological memory, PASS, reading accuracy, and reading fluency. The results indicated that the DYS group performed significantly poorer than the CA and RA groups on both measures of phonological awareness and on a measure of orthographic processing but comparably to the RA group on a measure of rapid naming and both measures of phonological memory. In regard to the PASS processing skills, the DYS group performed worse than the CA controls on Successive and Simultaneous processing but comparably to the RA group on all PASS processing skills. Implications of these findings for early identification and intervention of reading difficulties are discussed.     

Dyslexia and dysgraphia: more than written language difficulties in common

A dual-task paradigm involving concurrent finger tapping and line orientation judgment was used to investigate brain processing differences in early adolescent good readers/poor spellers (dysgraphia), poor readers/poor spellers (dyslexia) and good readers/good spellers. Whereas all groups were similarly affected during the left-hand tapping condition, in the right-hand tapping condition the good spelling group displayed significantly less tapping disruption than both poor spelling groups, who did not differ significantly from each other. From these results, it can be inferred that individuals with dyslexia and dysgraphia share a left-hemisphere processing limitation that is not confined to written language. In light of other relevant research findings, I suggest that this limitation is due to the absence of a disembedding scanning mechanism for converting spatial arrays (e.g., spelling patterns) to temporal form-an impairment putatively caused by attempting to teach written language to children who are late in establishing left-hemisphere motor dominance.