Event-related brain potentials elicited by rhyming and non-rhyming pictures differentiate subgroups of reading disabled adolescents

Auditory pseudoword rhyming effects in bilingual children reflect second language proficiency: An ERP study

This study investigated second language (L2-English) phonological processing in 31 Spanish-English bilingual, 6- to 8-year-old schoolchildren in an event-related potential (ERP) auditory pseudoword rhyming paradigm. In addition, associations between ERP effects and L2 proficiency as measured by standardized tests of receptive language and receptive vocabulary were explored. We found a classic posterior ERP rhyming effect that was more widely distributed in children with higher L2 proficiency in group analyses and was larger for children with better L2 proficiency in correlation analyses. In contrast, the amplitude of an early (75-125 ms) auditory positivity was larger in children with lower L2 proficiency. This pattern suggests differential use of early and late auditory/phonological processing resources in the pseudoword rhyme task associated with L2 proficiency, which is consistent with the predictions of the lexical restructuring model in a bilingual context.

Evidence from ERP and Eye Movements as Markers of Language Dysfunction in Dyslexia

Developmental dyslexia is a complex reading disorder involving genetic and environmental factors. After more than a century of research, its etiology remains debated. Two hypotheses are often put forward by scholars to account for the causes of dyslexia. The most common one, the linguistic hypothesis, postulates that dyslexia is due to poor phonological awareness. The alternative hypothesis considers that dyslexia is caused by visual-attentional deficits and abnormal eye movement patterns. This article reviews a series of selected event-related brain potential (ERP) and eye movement studies on the reading ability of dyslexic individuals to provide an informed state of knowledge on the etiology of dyslexia. Our purpose is to show that the two abovementioned hypotheses are not necessarily mutually exclusive, and that dyslexia should rather be considered as a multifactorial deficit.

A Picture Is Worth… Both Spelling and Sound

In an event-related potential (ERP) study using picture stimuli, we explored whether spelling information is co-activated with sound information even when neither type of information is explicitly provided. Pairs of picture stimuli presented in a rhyming paradigm were varied by both phonology (the two images in a pair had either rhyming, e.g., boat and goat, or non-rhyming, e.g., boat and cane, labels) and orthography (rhyming image pairs had labels that were either spelled the same, e.g., boat and goat, or not spelled the same, e.g., brain and cane). Electrophysiological picture rhyming (sound) effects were evident in terms of both N400/N450 and late effect amplitude: Non-rhyming images elicited more negative waves than rhyming images. Remarkably, the magnitude of the late ERP rhyming effect was modulated by spelling - even though words were neither explicitly seen nor heard during the task. Moreover, both the N400/N450 and late rhyming effects in the spelled-the-same (orthographically matched) condition were larger in the group with higher scores (by median split) on a standardized measure of sound awareness. Overall, the findings show concomitant meaning (semantic), sound (phonological), and spelling (orthographic) activation for picture processing in a rhyming paradigm, especially in young adults with better reading skills. Not outwardly lexical but nonetheless modulated by reading skill, electrophysiological picture rhyming effects may be useful for exploring co-activation in children with dyslexia.

Auditory perception of non-sense and familiar Bengali rhyming words in children with and without SLD

BACKGROUND

Rhyming ability is among the earliest metaphonological skills to be acquired during the process of speech and language acquisition. Metalinguistic skills, particularly metaphonological skills, greatly influence language learning during early, school grades and reportedly children with learning disorders are poor at these skills.

AIM AND OBJECTIVES

To develop and validate a Bengali rhyming checklist and study the auditory perception of non-sense and familiar Bengali rhyming words in children with and without specific learning disability (SLD).

METHOD

60 children, age range 8-11years, participated in two groups; group-A included children with SLD and group-B, typically developing children (TDC). All participants were native Bengali speakers, attending regular school, with hearing sensitivity less than 25dBHL, no history of ear discharge and middle socioeconomic background. A rhyming checklist was developed in Bengali, consisting of familiar (section-A) and non-sense (section-B) words. Test-retest reliability and validity measures were obtained. The items on the checklist were audio recorded and presented to the participants in a rhyming judgment task in one to one set up. Scores were obtained and statistically analyzed using SPSS software (version-11.0).

RESULT

Children with SLD scored significantly low on the rhyming judgment task as against TDC (p<.05) for both familiar and non-sense words. Children with SLD performed significantly better on familiar word rhyming judgment task against non-sense words (p<.05). TDC showed no significant difference on familiar and non-sense words rhyming judgment tasks (p>.05).

CONCLUSION

Semantic content influences rhyming perception in children with SLD but has no significant effect on TDC. The developed rhyming checklist may be used as a screening tool for children at risk of SLD at primary school grades. Rhyming activities may be utilized by teachers and parents, to promote language learning in young learners.

Electrocortical Measures During a Lexical Decision Task: A Comparison Between Elementary School-Aged Normal and Dyslexic Readers and Adult Normal and Dyslexic Readers

The authors examined the differences in performance between 30 dyslexic readers in 4th grade, 30 dyslexic readers attending university, and age-matched normal readers for both groups on a lexical decision task to evaluate the underlying factors of dyslexia that persist into adulthood. In both age groups, the dyslexic readers were significantly less accurate and slower than were the normal readers when reading word lists and in connected text. Electrophysiological data showed 2 main distinguishing components. Results supported the hypothesis that the dyslexia phenomenon is characterized by inaccurate and slow word-recognition skills. In addition, the authors found slow performance speed among all dyslexic readers in all stages of processing.

Predicting Reading Growth with Event-Related Potentials: Thinking Differently about Indexing "Responsiveness"

The purpose of this study was to determine if event-related potential (ERP) data collected during three reading-related tasks (Letter Sound Matching, Nonword Rhyming, and Nonword Reading) could be used to predict short-term reading growth on a curriculum-based measure of word identification fluency over 19 weeks in a sample of 29 first-grade children. Results indicate that ERP responses to the Letter Sound Matching task were predictive of reading change and remained so after controlling for two previously validated behavioral predictors of reading, Rapid Letter Naming and Segmenting. ERP data for the other tasks were not correlated with reading change. The potential for cognitive neuroscience to enhance current methods of indexing responsiveness in a response-to-intervention (RTI) model is discussed.

Orthographic and phonological processing in Chinese dyslexic children: An ERP study on sentence reading

An event-related potential (ERP) experiment was conducted to explore the differences between Chinese-speaking dyslexic children and normal school children in orthographic and phonological processing during Chinese sentence reading. Participants were visually presented with sentences, word-by-word and were asked to judge whether the sentences were semantically acceptable. The crucial manipulation was on the sentence-final two-character compound words, which were either correct or incorrect. For the incorrect compounds, the second characters of the base words were replaced by homophonic or orthographically similar characters. It was found that, for the normal controls, the orthographic and phonological mismatches elicited more negative ERP responses, relative to the baseline, over a relatively long time course (including the time windows for P200 and N400) at the central-posterior scalp regions. In contrast, the dyslexic children in general showed no differences between experimental conditions for P200 and N400, although the more detailed time course analyses did reveal some weak effects for the N400 component between experimental conditions. In addition, the mean amplitude of N400 in the homophonic condition was less negative-going for the dyslexics than for the controls. These findings suggest that Chinese dyslexic children have deficits in processing orthographic and phonological information conveyed by characters and, compared with normal children, they rely more on phonological information to access lexical semantics in sentence reading.

Semantic, syntactic, and phonological processing of written words in adult developmental dyslexic readers: an event-related brain potential study

Background

The present study used event-related brain potentials to investigate semantic, phonological and syntactic processes in adult German dyslexic and normal readers in a word reading task. Pairs of German words were presented one word at a time. Subjects had to perform a semantic judgment task (house – window; are they semantically related?), a rhyme judgment task (house – mouse; do they rhyme?) and a gender judgment task (das – Haus [the – house]; is the gender correct? [in German, house has a neutral gender: das Haus]).

Results

Normal readers responded faster compared to dyslexic readers in all three tasks. Onset latencies of the N400 component were delayed in dyslexic readers in the rhyme judgment and in the gender judgment task, but not in the semantic judgment task. N400 and the anterior negativity peak amplitudes did not differ between the two groups. However, the N400 persisted longer in the dyslexic group in the rhyme judgment and in the semantic judgment tasks.

Conclusion

These findings indicate that dyslexics are phonologically impaired (delayed N400 in the rhyme judgment task) but that they also have difficulties in other, non-phonological aspects of reading (longer response times, longer persistence of the N400). Specifically, semantic and syntactic integration seem to require more effort for dyslexic readers and take longer irrespective of the reading task that has to be performed.

Event-related brain potentials elicited during word recognition by adult good and poor phonological decoders

Cognitive processing of lexical and sub-lexical stimuli was compared for good and poor adult phonological decoders. Sixteen good decoders and 16 poor decoders, average age 19 years, silently read 150 randomly computer presented sentences ending in incongruous regular, irregular, or nonwords and 100 congruent filler sentences. Electro-encephalographic recordings were made from the final word of each incongruous sentence. Although no significant group differences were found, good decoders showed specialised hemispheric word recognition processing at P200 and P300. Nonwords elicited greater N200 and P300 amplitudes for both good and poor decoders. Larger amplitude P200s were elicited by poor decoders when processing nonwords. These findings provide evidence for separable lexical and sub-lexical procedures and support a psychophysiological basis for a core phonological deficit in poor phonological decoders.

Does dyslexia develop from learning the alphabet in the wrong hemisphere? A cognitive neuroscience analysis

A new perspective is described which views developmental dyslexia as the outcome of learning to write the alphabet in the nondominant (right) hemisphere. The letter-level and whole-word subtypes of dyslexia are seen as differing responses adopted to cope with this predicament. Striking similarities between dyslexics and callosotomy patients in the allocation of covert attention to lateralized stimuli provide direction for integrating a diversity of dyslexic research within this framework. This synthesis, together with information from pure alexia, brain activation, and reading research, lends insight into the neural circuitry of the compensatory strategies adopted by the two dyslexic subtypes.

Electrophysiological dissociation between verbal and nonverbal semantic processing in learning disabled adults

Event-related potentials (ERPs) were recorded as 16 adults with learning disabilities (LD) and 16 controls were presented with two sets of stimuli. The first set comprised pairs of line drawings and environmental sounds (nonverbal condition); the second consisted of printed and spoken words (verbal condition). In the controls, semantically related items elicited smaller N400s than unrelated items in both conditions, with opposing hemispheric asymmetries for spoken words and environmental sounds. The LD group did not show a significant difference between related and unrelated words, despite a robust context effect for nonspeech sounds. The results suggest anomalous processing limited to the verbal domain in a simple semantic association task in the LD group. Semantic deficits in this group may reflect a relatively specific deficit in forming verbal associations rather than a more general difficulty that spans both verbal and nonverbal domains.

The relationship between language-processing and visual-processing deficits in developmental dyslexia

Some research on developmental dyslexia focuses on linguistic abnormalities such as poor reading of nonwords or poor reading of exception words. Other research focuses on visual abnormalities such as poor performance on psychophysical tasks believed to assess the functioning of the magnocellular and parvocellular layers of the lateral geniculate nucleus (LGN). Little is known about what the relationships are between these two types of abnormalities. We measured nonword reading, exception word reading, and performance with Ternus apparent movement displays (the perception of which is believed to depend upon the magnocellular and parvocellular pathways) in dyslexic children and children without reading difficulties. Our results indicate that performance on the Ternus task is related to nonword reading ability but not to exception word reading ability. We offer two alternative interpretations of these findings. According to the first of these, nonword reading requires a serial left-to-right allocation of covert attention across the letter string being read and the neural systems involved in this attentional process also play a part in responses to the Ternus display. According to the second, poor nonword reading and abnormal Ternus performance are not directly related: perinatal/neurodevelopmental insult has affected the LGN (influencing Ternus performance) and the adjacent medial geniculate nucleus (MGN; affecting phonological ability) and the MGN abnormalities may be more functionally related to poor nonword reading.

Event-related brain potentials elicited during phonological processing differentiate subgroups of reading disabled adolescents

Visual and auditory rhyme judgment tasks were administered to adolescent dyslexics and normal readers while event-related brain potentials were recorded. Reading disabled subjects were split into two groups based on a median split of scores on a visual non-word decoding test. The better decoders were called Phonetics and the poorer decoders were referred to as Dysphonetics. Single syllable, real word stimuli were used, and both rhyming and non-rhyming targets had a 50% chance for matching orthography. In the visual paradigm the normal readers exhibited a left frontal CNV before targets, a large reduction in frontal N400 for matching orthography (orthographic priming), and a large reduction in parietal N400 for rhyming targets (phonological priming). Dysphonetics had an intact CNV and orthographic priming, but the group's phonological priming was very reduced. Phonetics showed both orthographic and phonological priming but had a marked reduction in their CNV. In the auditory task, controls showed a left parietal N400 priming effect for rhyming targets. Dysphonetics showed a similar bilateral effect. The Phonetics did not show a normal priming effect, but produced evidence for priming at a longer latency. Additionally, the Phonetic group responded more slowly than either of the other two groups, who responded with similar latencies. These results support the separation of the reading disabled into a group that has difficulty translating orthography into phonology, and a group that is slower functioning and has reduced capacity in preparing for a response.