Can the Error Detection Mechanism Benefit from Training the Working Memory? A Comparison between Dyslexics and Controls — An ERP Study

BACKGROUND:Based on the relationship between working memory and error detection, we investigated the capacity of adult dyslexic readers' working memory to change as a result of training, and the impact of training on the error detection mechanism. METHODOLOGY:27 dyslexics and 34 controls, all university students, participated in the study. ERP methodology and behavioral measures were employed prior to, immediately after, and 6 months after training. The CogniFit Personal Coach Program, which consists of 24 sessions of direct training of working memory skills, was used. FINDINGS:Both groups of readers gained from the training program but the dyslexic readers gained significantly more. In the dyslexic group, digit span increased from 9.84+/-3.15 to 10.79+/-3.03. Working memory training significantly increased the number of words per minute read correctly by 14.73%. Adult brain activity changed as a result of training, evidenced by an increase in both working memory capacity and the amplitude of the Error-related Negativity (ERN) component (24.71%). When ERN amplitudes increased, the percentage of errors on the Sternberg tests decreased. CONCLUSIONS:We suggest that by expanding the working memory capacity, larger units of information are retained in the system, enabling more effective error detection. The crucial functioning of the central-executive as a sub-component of the working memory is also discussed

Does the Reading of Different Orthographies Produce Distinct Brain Activity Patterns? An ERP Study

Orthographies vary in the degree of transparency of spelling-sound correspondence. These range from shallow orthographies with transparent grapheme-phoneme relations, to deep orthographies, in which these relations are opaque. Only a few studies have examined whether orthographic depth is reflected in brain activity. In these studies a between-language design was applied, making it difficult to isolate the aspect of orthographic depth. In the present work this question was examined using a within-subject-and-language investigation. The participants were speakers of Hebrew, as they are skilled in reading two forms of script transcribing the same oral language. One form is the shallow pointed script (with diacritics), and the other is the deep unpointed script (without diacritics). Event-related potentials (ERPs) were recorded while skilled readers carried out a lexical decision task in the two forms of script. A visual non-orthographic task controlled for the visual difference between the scripts (resulting from the addition of diacritics to the pointed script only). At an early visual-perceptual stage of processing (∼165 ms after target onset), the pointed script evoked larger amplitudes with longer latencies than the unpointed script at occipital-temporal sites. However, these effects were not restricted to orthographic processing, and may therefore have reflected, at least in part, the visual load imposed by the diacritics. Nevertheless, the results implied that distinct orthographic processing may have also contributed to these effects. At later stages (∼340 ms after target onset) the unpointed script elicited larger amplitudes than the pointed one with earlier latencies. As this latency has been linked to orthographic-linguistic processing and to the classification of stimuli, it is suggested that these differences are associated with distinct lexical processing of a shallow and a deep orthography

Untersuchung des Aneignungsprozesses von visuellen Wortrepräsentationen bei Kindern mit Dyslexie

Skilled reading relies on the ability to access word representations, conceptualized as connections established between a word’s orthography, phonology and meaning in memory. This study set out to explore the process of acquisition of these representations. The central hypothesis was that dyslexic readers would present difficulties in forming and maintaining word representations in memory, presumably due to instability in processes of decoding. Their performance was compared to the performance of age-matched and reading-level-matched typical readers (n = 20 per group). The hypothesis was tested by repeatedly exposing the readers to the same target words embedded in word-lists and meaningful texts. The targets were words which the dyslexic participants had difficulty to read in a pre-test, while being part of their spoken vocabulary. The output of each encounter with a target word was analyzed. The results indicate reduced accuracy rates of dyslexic readers compared to typical readers, despite the repeated exposures to the same targets. In addition, dyslexic readers showed larger variability in types of output and higher rates of inconsistency in producing the same output across encounters with the same target. The results therefore uphold the hypothesis of a deficiency of dyslexic readers in forming and retaining word representations in reading, and point to instability in processes of decoding orthography to phonology. (DIPF/Orig.)Kompetentes Lesen stützt sich auf die Fähigkeit, auf Wortrepräsentationen, d. h. die im Gedächtnis hergestellten Verbindungen zwischen der Orthographie eines Wortes, seiner Phonologie und seiner Bedeutung, zugreifen zu können. Ziel der vorliegenden Studie ist es, den Aneignungsprozess dieser Repräsentationen zu untersuchen. Die zentrale Hypothese ist dabei, dass Kinder mit Dyslexie Probleme haben, diese Repräsentationen aufzubauen und im Gedächtnis zu speichern, wobei angenommen werden kann, dass dies auf Grund einer Instabilität während des Prozesses der Wortdekodierung erfolgt. Die Leseleistung von Kindern mit Dyslexie wurde dafür verglichen mit der Leistung von Leserinnen und Lesern gleichen Alters sowie mit Leserinnen und Lesern, die auf demselben Niveau lesen (n = 20 pro Gruppe). Getestet wurde die Hypothese, indem den Leserinnen und Leser mehrmals dieselben Zielwörter vorgelegt wurden, welche in Wortlisten und sinnvolle Texte eingebettet waren. Dabei handelte es sich um Worte, bei denen die Kinder mit Dyslexie in einem Pre-Test Leseschwierigkeiten hatten, die jedoch Teil ihres gesprochenen Vokabulars waren. Analysiert wurden die Ergebnisse der jeweiligen Konfrontationen mit einem Zielwort. Die Befunde zeigen für Kinder mit Dyslexie auch bei einer wiederholten Auseinandersetzung mit denselben Zielworten geringere Genauigkeitsraten im Vergleich zu typischen Leserinnen und Lesern. Darüber hinaus ergeben sich bei den Kindern mit Dyslexie stärkere Schwankungen in der Art der Ergebnisse und mehr Inkonsistenzen, wenn es darum geht, dasselbe Ergebnis bei mehreren Konfrontationen mit demselben Zielwort wiederzugeben. Insofern stützen die Ergebnisse die Hypothese eines Defizits beim Aufbau und der Speicherung von Wortrepräsentationen während des Lesens bei Leserinnen und Leser mit Dyslexie und weisen auf eine Instabilität im Prozess des Dekodierens von Orthographie zu Phonologie hin. (DIPF/Orig.

都市計画支援システムに関する研究

博士（学術）神戸大

ERN and CRN amplitudes in tests 1, 2 and 3 in dyslexics and controls.

<p>A grand average for the ERN-CRN (response-locked) components for correct response (CRN) and for error response (ERN), represented by the dashed and the solid lines, respectively, for tests 1 (A,D), 2 (B,E) and 3 (C,F) in dyslexics (left column, A,B,C) and controls (right column, D,E,F) at the Cz electrode. The ERN is seen between 30 and 150 ms after response denoted by the vertical line at time 0. Note that the negative Y axis is plotted up.</p

Accuracy rate and reaction times for the experimental measures.

<p>*<i>P</i><.05; **<i>P</i><.01; ***<i>P</i><.001.</p><p>Means (M) and standard deviation (SD) of dyslexics versus controls on the Sternberg task: accuracy rate (in percentage) and reaction times (in milliseconds).</p

Scalp Topographies of the N170 Component and of the Amplitudes Elicited by the Different Stimuli around 340 (P3) and 400 (P4) ms.

<p>Scalp topographies in response to the presentation of words, pseudowords (N170, P3 and P4) and squares (N170) with and without diacritics. Red represents positive electrophysiological activity and blue represents negative electrophysiological activity.</p

Reading Proficiency and Adaptability in Orthographic Processing: An Examination of the Effect of Type of Orthography Read on Brain Activity in Regular and Dyslexic Readers

<div><p>Regular readers were found to adjust the routine of reading to the demands of processing imposed by different orthographies. Dyslexic readers may lack such adaptability in reading. This hypothesis was tested among readers of Hebrew, as Hebrew has two forms of script differing in phonological transparency. Event-related potentials were recorded from 24 regular and 24 dyslexic readers while they carried out a lexical decision task in these two forms of script. The two forms of script elicited distinct amplitudes and latencies at ∼165 ms after target onset, and these effects were larger in regular than in dyslexic readers. These early effects appeared not to be merely a result of the visual difference between the two forms of script (the presence of diacritics). The next effect of form of script was obtained on amplitudes elicited at latencies associated with orthographic-lexical processing and the categorization of stimuli, and these appeared earlier in regular readers (∼340 ms) than in dyslexic readers (∼400 ms). The behavioral measures showed inferior reading skills of dyslexic readers compared to regular readers in reading of both forms of script. Taken together, the results suggest that although dyslexic readers are not indifferent to the type of orthography read, they fail to adjust the routine of reading to the demands of processing imposed by both a transparent and an opaque orthography.</p></div