Evaluation of the double-deficit hypothesis in college students referred for learning difficulties

The present study explored the double-deficit hypothesis (DDH) in a sample of 146 college students with and without reading disabilities (RD). The results indicated that although both phonological awareness (PA) and visual naming speed (VNS) contributed to performance on measures of decoding and comprehension, their relative contribution was influenced both by the nature of the stimulus (word vs. nonword vs. text) and by the conditions of the task (timed vs. untimed). Similar results were obtained using an individual differences approach, or when between-group comparisons were made of individuals with deficits in PA or VNS. The relative representation of DDH subgroups in groups of adults with RD varied based on the classification criteria used to define RD. These results support the DDH, extend its applicability to adults, and have implications for diagnostic decision making.     

Testing the double-deficit hypothesis in an adult sample

The double-deficit hypothesis of dyslexia posits that reading deficits are more severe in individuals with weaknesses in phonological awareness and rapid naming than in individuals with deficits in only one of these reading composite skills. In this study, the hypothesis was tested in an adult sample as a model of reading achievement. Participants were parents of children referred for evaluation of reading difficulties. Approximately half of all participants reported difficulty learning to read in childhood and a small subset demonstrated ongoing weaknesses in reading. Structural equation modeling results suggest that the double-deficit hypothesis is an accurate model for understanding adult reading achievement. Better reading achievement was associated with better phonological awareness and faster rapid automatized naming in adults. Posthoc analyses indicated that individuals with double deficits had significantly lower reading achievement than individuals with single deficits or no deficits.     

The double-deficit hypothesis: a comprehensive analysis of the evidence

The double-deficit hypothesis of developmental dyslexia proposes that deficits in phonological processing and naming speed represent independent sources of dysfunction in dyslexia. The present article is a review of the evidence for the double-deficit hypothesis, including a discussion of recent findings related to the hypothesis. Studies in this area have been characterized by variability in methodology--how dyslexia is defined and identified, and how dyslexia subtypes are classified. Such variability sets limitations on the extent to which conclusions may be drawn with respect to the double-deficit hypothesis. Furthermore, the literature is complicated by the persistent finding that measures of phonological processing and naming speed are significantly correlated, resulting in a statistical artifact that makes it difficult to disentangle the influence of naming speed from that of phonological processing. Longitudinal and intervention studies of the double-deficit hypothesis are needed to accumulate evidence that investigates a naming speed deficit that is independent of a phonological deficit for readers with dyslexia. The existing evidence does not support a persistent core deficit in naming speed for readers with dyslexia.     

Investigating the double-deficit hypothesis of developmental dyslexia in an orthography of intermediate depth

The present study aimed to investigate the double-deficit hypothesis (DDH) in an orthography of intermediate depth. Eighty-five European Portuguese-speaking children with developmental dyslexia, aged 7 to 12, were tested on measures of phonological awareness (PA), naming speed (NS), reading, and spelling. The results indicated that PA and NS were not significantly correlated, and that NS predicts reading fluency (but not reading accuracy and spelling) beyond what is accounted for by PA. Although the majority of the children with developmental dyslexia have double deficit (62.4%), some children have a single phonological deficit (24.7%) or a single NS deficit (8.2%). Children with a double deficit were not more impaired in reading fluency, reading accuracy, and spelling than both single-deficit subtypes. In conclusion, the findings of the present study are partially consistent with the DDH and provide evidence for the multifactorial model of developmental dyslexia. Implications of the DDH for an orthography of intermediate depth are emphasized.

     

Neurodevelopmental characteristics of children with learning impairments classified according to the double-deficit hypothesis

The double-deficit model has been examined primarily in relation to reading. We investigated whether children classified according to the double-deficit model would exhibit differences in other neuropsychological domains. Children referred for learning problems (N = 188), ages 7 to 11, were classified by double-deficit subtype. Only three of the four groups predicted by the model could be identified. There were no group differences in IQ or attention problems. The three groups showed different neuropsychological profiles, involving functional domains other than reading and language. Differences also emerged in nonverbal low-level information processing. The double-deficit group was generally most severely affected. The double-deficit groupings identify children with different neuropsychological profiles and variation in the efficiency of basic online information processing, extending beyond the oral and written language domain.     

Naming speed deficits in adults with reading disabilities: a test of the double-deficit hypothesis

The present study investigated the persistent nature of naming speed deficits within the context of the double-deficit hypothesis in a university sample of adults with reading disabilities (RD). Twenty-five university students with RD were compared to 28 typically achieving readers on measures of reading skill, phonological processing, and naming speed. The results indicated that both naming speed and phonological processing deficits characterized the RD group. In a regression analysis, neither naming speed nor phonological processing were important variables in explaining comprehension when reading rate was in the model. The results of the present study are mixed at best and are consistent with earlier conclusions that support for the double-deficit hypothesis of dyslexia remains limited.     

Relationship of rapid automatized naming and phonological awareness in early reading development: implications for the double-deficit hypothesis

It is widely accepted that deficits in phonological awareness skills are related to reading difficulties. Recently, another source of reading difficulty has been identified that involves naming speed, and combined impairments in phonological skills and naming speed will produce more severe reading deficits than single deficits in either of these cognitive skills. The purpose of this study was to investigate the consequences of grouping children based on the presence or absence of deficits in these skills. We demonstrate that the greater severity of reading impairment found in children with a double deficit could be due in part to a statistical artifact caused by grouping children based on their performance on two correlated continuous variables. This artifact also makes it difficult to establish the relative impact of deficits in naming speed on reading ability independent of deficits in phonological awareness.     

The influence of lexical and sublexical variables in normal and poor Spanish readers

The main aim of our study was to find out the effect of several lexical and sublexical variables (lexical category, lexical frequency, syllabic structure, and word length) in the acquisition of reading in a transparent language such as Spanish. The second goal of our study was the comparison of the effect of these variables in normal and poor Spanish readers. One hundred and forty children (aged between 6 and 12), twenty of whom were poor readers, were tested using a reading test of 306 items in which we balanced all the variables. The dependent variable was the percentage of correct responses in a decontextualized word reading test. Our results showed that all the above mentioned variables produced a significant effect on the number of errors made by the children. This pattern of results suggests no difference between the processes involved in the reading acquisition of Spanish and those implicated in deep orthographies such as English. Our results also showed no qualitative differences between normal and poor readers. The four variables studied showed the same behaviour in their effect on reading performance for both normal and poor readers, indicating that poor readers also use both the lexical and the phonological route. Our data suggest the universality of the dual route model, independent of the transparency or opaqueness of the different alphabetical languages.     

Differences in eye movements control among dyslexic,retarded and normal readers in the Spanish population

This paper reports a research which examined the relationship between dyslexia and eye movement control in Spanish speaking children. The study compared the eye movements recordings of 30 dyslexic, 30 retarded and 30 normal readers, aged between 7 and 14, in one ocular tracking task and two reading tasks which differed in their degree of reading difficulty. Within each group the subjects were divided into 3 subgroups of 10 in accordance with the following chronological ages: 7–9, 10–11 and 12 years and above. Dependent variables were saccadics (number, size and fixation pause), regressives (number, size and fixation pause), total number of movements and percentage of regressives over the total number of movements. The following results were obtained: (1) In the two reading tasks significant differences were found between dyslexic and normal readers and between retarded and normal readers in most of the parameters, no differences being found between dyslexic and retarded readers except in a few parameters; (2) in the ocular tracking task significant differences both between dyslexic and normal readers and between dyslexic and retarded readers were found in all dependent variables, no differences being found between retarded and normal readers at all, and (3) the age factor produced a significant main effect in the two reading tasks indicating a general improvement of eye movements as age increases but an interaction effect with reading disability in the ocular tracking task-indicating a deterioration in eye movements in the dyslexic group as a function of age-was also found. The results are discussed in the context of alternative theoretical explanations of developmental dyslexia.This research was supported by grant PR82-1933 from the Spanish Consulting Committee for Scientific and Technological Research (CAYCIT). Requests for reprint should be sent to F. J. Martos, Departamento de Psicologia Experimental y Fisiologia del Comportamiento. Campus de Cartuja, Universidad de Granada. 18071 Granada, Spain.     

Remediating the core deficits of developmental reading disability: a double-deficit perspective

The double-deficit hypothesis (Wolf, 1997; Wolf & Bowers, 1999, this issue) contends that deficits in phonological awareness and deficits in visual naming speed represent two independent causal impediments to reading acquisition for children with developmental reading disabilities (RD). One hundred and sixty-six children with severe RD from 7 to 13 years of age were classified into three deficit subgroups according to a double-deficit framework. A total of 140 children with RD, 84% of the sample, were classified; 54% demonstrated a double deficit (DD), 22% a phonological deficit only (PHON), and 24% a visual-naming speed deficit only (VNS). Diagnostic test profiles highlighted the joint contributions of the two core deficits in depressing written language acquisition. The children in the DD group were more globally impaired than those in the other subgroups, and the VNS group children were the highest achieving and most selectively impaired readers. Following 35 hours of word identification training, sizable gains and significant generalization of training effects were achieved by all subgroups. A metacognitive phonics program resulted in greater generalized effects across the domain of real English words, and a phonological training program produced superior outcomes within the phonological processing domain. The greatest non-word reading gains were achieved by children with only phonological deficits.     

新生入馆教育引导是关键

通过揭示新生入馆教育的重要性和新生在利用图书馆时存在的一些问题,提出加强新生入馆教育的一些措施,进一步提高图书馆读者服务质量.     

谈阅览服务中的素质教育

阅览在素质教育中占有重要的地位，阅览室的工作人员应充分利用这块阵地，以富有成效的方法，促进读专业知识的精进和化素养的提高，为落实素质教育尽一份责任。     

Structural invariance in the associations of naming speed,phonological awareness,and verbal reasoning in good and poor readers: A test of the double deficit hypothesis

The associations of multiple measures of speeded naming, phonological awareness, and verbal intelligence with word reading were examined in 51 poor readers and 74 good readers in third and fourth grade. Structural equation modeling was used to determine the extent to which these two groups exhibited structurally invariant patterns of associations among the constructs. Results revealed that for poor readers, both speeded naming and phonological awarencess were significantly associated with word reading, but verbal intelligence had no association with it. In contrast, for good readers, phonological awareness and verbal intelligence were significantly associated with word reading, but naming speed was not. Findings are discussed in light of the double deficit hypothesis.     

Improving the comprehension of disabled readers

Students with learning disabilities (LD) often have difficulty comprehending what they read. Although reading comprehension problems frequently are associated with inadequate word recognition, students also have difficulties related to comprehension itself—a passive approach to the reading task, insensitivity to text structure, and poor metacognitive skills. The reading and language arts curricula that have emerged from today’s constructivist paradigm can pose problems for these students. Whereas the new curricula emphasize personal interpretations of text and relatively unstructured teaching strategies, students with LD do well with explicit, highly structured instruction. This paper introduces an instructional program designed to teach students with serious learning disabilities how to identify a story theme, and how to relate it to their own real-life experiences. The program focused on understanding a text as a whole, and integrating text meaning with concepts and experiences that are personally meaningful, goals shared by a constructivist approach. At the same time, the program incorporates the explicit, structured instruction that these students also need. A study to evaluate the program’s effectiveness is described, as are current efforts to refine the program to promote transfer of comprehension strategies.     

解释学视野下阅读者的自我建构

施莱尔马赫之后的解释学对主体问题给予了关注。在解释学的视野下,阅读者要进行直面传统、文本和自我的三重活动。以此,阅读者得以建构超越二元对立的自我,并融入到整体的意义世界。     

Evaluation bias against work in progress: evidence from a Spanish marketing conference

Traditionally, the literature has analyzed the existence of bias in the evaluation of papers submitted to scientific journals, but it has not considered any possible bias in the evaluation of studies submitted to conferences. In this sense we can ask whether the conferences provide an adequate service for researchers. This study examines whether there is bias in the evaluation of work in progress submitted to a conference, and also examines the explanatory factors of the evaluation. To address these questions we use information from a marketing conference. The results show that completed work receives higher reviewer ratings than work in progress; a bias that is specifically present in the evaluation of information sources, methodology and results. This bias can be explained by the simple fact of being work in progress. Additionally, the results reveal that the number of references from journals listed in the Social Citation Index Report positively influences the evaluation of research studies.     

当前高校图书馆引领读者经典阅读的几点思考

我国改革开放三十多来,综合国力取得长足进步。"硬实力"提升较快,但"软实力"的发展却大大滞后。面对理性主义沉沦,媚俗主义张场的现今中国文化生态;面对国内体制转型和生存焦虑的社会现实,民众渴望找到精神家园,纷纷走进阅读的世界,期望从中重塑人格精神美,同时使自己的知识结构层次得进一步的提升,进而找回生活的自信,最终构建起民族的精神高地。