Adelina Estévez

An anatomical signature for literacy

Language is a uniquely human ability that evolved at some point in the roughly 6,000,000 years since human and chimpanzee lines diverged. Even in the most linguistically impoverished environments, children naturally develop sophisticated language systems. In contrast, reading is a learnt skill that does not develop without intensive tuition and practice. Learning to read is likely to involve ontogenic structural brain changes, but these are nearly impossible to isolate in children owing to concurrent biological, environmental and social maturational changes. In Colombia, guerrillas are re-integrating into mainstream society and learning to read for the first time as adults. This presents a unique opportunity to investigate how literacy changes the brain, without the maturational complications present in children. Here we compare structural brain scans from those who learnt to read as adults (late-literates) with those from a carefully matched set of illiterates. Late-literates had more white matter in the splenium of the corpus callosum and more grey matter in bilateral angular, dorsal occipital, middle temporal, left supramarginal and superior temporal gyri. The importance of these brain regions for skilled reading was investigated in early literates, who learnt to read as children. We found anatomical connections linking the left and right angular and dorsal occipital gyri through the area of the corpus callosum where white matter was higher in late-literates than in illiterates; that reading, relative to object naming, increased the interhemispheric functional connectivity between the left and right angular gyri; and that activation in the left angular gyrus exerts top-down modulation on information flow from the left dorsal occipital gyrus to the left supramarginal gyrus. These findings demonstrate how the regions identified in late-literates interact during reading, relative to object naming, in early literates.

Brain Activation for Lexical Decision and Reading Aloud: Two Sides of the Same Coin?

This functional magnetic resonance imaging study compared the neuronal implementation of word and pseudoword processing during two commonly used word recognition tasks: lexical decision and reading aloud. In the lexical decision task, participants made a finger-press response to indicate whether a visually presented letter string is a word or a pseudoword (e.g., paple). In the reading-aloud task, participants read aloud visually presented words and pseudowords. The same sets of words and pseudowords were used for both tasks. This enabled us to look for the effects of task (lexical decision vs. reading aloud), lexicality (words vs. nonwords), and the interaction of lexicality with task. We found very similar patterns of activation for lexical decision and reading aloud in areas associated with word recognition and lexical retrieval (e.g., left fusiform gyrus, posterior temporal cortex, pars opercularis, and bilateral insulae), but task differences were observed bilaterally in sensorimotor areas. Lexical decision increased activation in areas associated with decision making and finger tapping (bilateral postcentral gyri, supplementary motor area, and right cerebellum), whereas reading aloud increased activation in areas associated with articulation and hearing the sound of the spoken response (bilateral precentral gyri, superior temporal gyri, and posterior cerebellum). The effect of lexicality (pseudoword vs. words) was also remarkably consistent across tasks. Nevertheless, increased activation for pseudowords relative to words was greater in the left precentral cortex for reading than lexical decision, and greater in the right inferior frontal cortex for lexical decision than reading. We attribute these effects to differences in the demands on speech production and decision-making processes, respectively.

Test anxiety and comprehension efficiency: The role of prior knowledge and working memory deficits

Abstract The hypotheses that test anxiety is associated with a deficit in prior knowledge and/or working memory capacity, that anxiety impairs comprehension efficiency, and that deficits in knowledge and capacity underlie the efficiency impairment, were tested. In Study 1, high-anxiety students were characterized by lower scores in several vocabulary measures, compared with low-anxiety students. In Study 2, high-anxiety individuals showed inferior working memory capacity to low-anxiety individuals under evaluative stress conditions, but not under non-stress conditions. In Study 3 high-anxiety subjects exhibited lower efficiency scores than low-anxiety subjects in expository texts without a summary: The former employed a greater amount of reading time than the latter to acquire an equivalent amount of information. In addition, the disadvantage in efficiency associated with anxiety was removed when differences in vocabulary knowledge were partialled out statistically. Instead, that disadvantage was only red...

Ego-threat interpretive bias in test anxiety: on-line inferences

Abstract The hypothesis that test anxiety is associated with an on-line bias towards threatening interpretations of ambiguous information was explored by means of a lexical decision task. Ambiguous sentences (concerned with ego-threat, physical-threat, or non-threat events) were presented to high- and low- test-anxiety subjects. Sentences were followed by a disambiguating word or a very wordlike corresponding nonword, which either confirmed or disconfirmed the threat implied by the sentence. A control condition involved the presentation of words and nonwords alone, without being primed by the sentences. Results indicated that there were no differences in lexical decision times as a function of test anxiety when words and nonwords were presented alone. In contrast, when they were primed, high-anxiety subjects took longer to respond correctly to the ego-threat confirming nonword, and to the ego-threat disconfirming word, compared with low-anxiety subjects; likewise, high-anxiety subjects responded faster to...

On-line predictive inferences in reading: Processing timeduring versusafter the priming context

Prior research suggests that predictive inferences take time to construct on-line. The present study examines the relative contribution of time available during and after reading an inducing context. In six experiments, we manipulated the presentation rate of the context and the delay between the onset of the last word in the context and a target word. A predicting, or a control, sentence context was followed by a target word, which represented the predicted event or an unlikely event. The results indicated that increasing the time available during reading of the context improved comprehension of explicit information, but it did not affect construction of inferences. In contrast, increasing the delay at the end of the context did not affect explicit comprehension, but it enhanced the probability of inferences, as revealed by shorter latencies in naming the predictable target word after the inducing context, relative to the control context. These findings show that readers defer making predictive inferences until 1 sec after the sentence context has been read, regardless of the time available when they are processing the context.

Do the Effects of Computer-Assisted Practice Differ for Children with Reading Disabilities With and Without IQ—Achievement Discrepancy?

This study was designed to assess whether the effects of computer-assisted practice on visual word recognition differed for children with reading disabilities (RD) with or without aptitude—achievement discrepancy. A sample of 73 Spanish children with low reading performance was selected using the discrepancy method, based on a standard score comparison (i.e., the difference between IQ and achievement standard scores). The sample was classified into three groups: (1) a group of 14 children with dyslexia (age M = 103.85 months; SD = 8.45) who received computer-based reading practice; (2) a group of 31 “garden-variety” (GV) poor readers (age M = 107.06 months; SD = 6.75) who received the same type of instruction; and (3) a group of 28 children with low reading performance (age M = 103.33 months; SD = 9.04) who did not receive computer-assisted practice. Children were pre- and posttested in word recognition, reading comprehension, phonological awareness, and visual and phonological tasks. The results indicated that both computer-assisted intervention groups showed improved word recognition compared to the control group. Nevertheless, children with dyslexia had more difficulties than GV poor readers during computer-based word reading under conditions that required extensive phonological computation, because their performance was more affected by low-frequency words and long words. In conclusion, we did not find empirical evidence in favor of the IQ—achievement discrepancy definition of reading disability, because IQ did not differentially predict treatment outcomes.

Transposed-letter similarity effects in naming pseudowords: Evidence from children and adults

There is growing empirical evidence that shows that transposed-letter pseudowords (e.g., relovution) are perceptually very similar to their base words. This is a finding that has important implications for the choice of an input coding scheme in visual word recognition and naming. In the present experiment, we examined the presence of transposed-letter effects for pseudowords by using the naming task in a transparent orthography (Spanish): The pseudowords were created by transposing two letters or by replacing two letters (e.g., relovución vs. retosución). Since it has been suggested that transposed-letter effects may be greater for developing than for adult readers (Castles, Davis, & Forster, 2003), we recruited beginning readers (second graders, i.e., 7-year-olds), intermediate readers (fourth graders, i.e., 9-year-olds), and adult readers (college students). Results showed that developing and adult readers frequently mispronounced transposed-letter pseudowords (lexicalisations, mostly). Interestingly, the difference between the transposed-letter pseudowords and the replacement-letter pseudowords vanished when measuring the correct naming times. We examine the implications of these findings for models of visual word recognition and naming.

Computer Speech-Based Remediation for Reading Disabilities: The Size of Spelling-to-Sound Unit in a Transparent Orthography

This study was designed to assess the effects of four reading-training procedures for children with reading disabilities (RD) in a transparent orthography, with the aim of examining the effects of different spelling-to-sound units in computer speech-based reading. We selected a sample of 83 Spanish children aged between 7 years 1 month and 10 years 6 months (M = 105.2, SD = 7.8) whose pseudoword reading performance was below the 25th percentile and IQ > 90. The participants were randomly assigned to five groups: (a) the whole-word training group (WW) (n = 17), (b) the syllable training group (S)(n = 16), (c) the onset-rime training group (OR) (n = 17), (d) the phoneme training group (P) (n = 15), and (e) the untrained control group (n = 18). Children were pre- and post-tested in word recognition, reading comprehension, phonological awareness, and orthographic and phonological tasks. The results indicate that experimental groups who participated in the phoneme and syllable conditions improved their word recognition in comparison with the control group. In addition, dyslexics who participated in the phoneme, syllable, and onset-rime conditions made a greater number of requests during computer-based word reading under conditions that required extensive phonological computation (low frequency words and long words). Reading time, however, was greater for long words in the phoneme group during computer-based reading. These results suggest the importance of training phonological processes in improving word decoding in children with dyslexia who learn in a consistent orthography.

Locus and Nature of Perceptual Phonological Deficit in Spanish Children With Reading Disabilities

The aims of this study were (a) to determine whether Spanish children with reading disabilities (RD) show a speech perception deficit and (b) to explore the locus and nature of this perceptive deficit. A group of 29 children with RD, 41 chronological age—matched controls, and 27 reading ability—matched younger controls were tested on tasks of speech perception. The effect of linguistic unit (word vs. syllable) and type of phonetic contrast (voicing, place and manner of articulation) were analyzed in terms of the number of errors and the response time. The results revealed a speech perception deficit in Spanish children with RD that was independent of the type of phonetic contrast and of linguistic unit.

Is the deficit in phonological awareness better explained in terms of task differences or effects of syllable structure

The primary purpose of the study reported here was to explore the effects of the complexity of syllable structure and the effects of task differences in the explanation of deficit in phonological awareness (PA). A sample of 97 subjects was selected and organized into three different groups: 29 reading-disabled (RD) children, 41 normal readers matched in age with the former, and 27 younger normal readers at the same reading level as those with reading disabilities. We administered PA tasks which included items with different complexity of syllable structure. The results showed that the complexity of syllable structure had no particularly marked effect on the dyslexic children. Rather, the isolation task revealed the phonological deficit across all syllable structures.