Treatment of irregular word spelling in developmental surface dysgraphia

Developmental surface dyslexia and dysgraphia in a child with corpus callosum agenesis: an approach to diagnosis and treatment

We present a case study detailing cognitive performance, functional neuroimaging, and effects of a hypothesis-driven treatment in a 10-year-old girl diagnosed with complete, isolated corpus callosum agenesis. Despite having average overall intellectual abilities, the girl exhibited profound surface dyslexia and dysgraphia. Spelling treatment significantly and persistently improved her spelling of trained irregular words, and this improvement generalized to reading accuracy and speed of trained words. Diffusion weighted imaging revealed strengthened intrahemispheric white matter connectivity of the left temporal cortex after treatment and identified interhemispheric connectivity between the occipital lobes, likely facilitated by a pathway crossing the midline via the posterior commissure. This case underlines the corpus callosum's critical role in lexical reading and writing. It demonstrates that spelling treatment may enhance interhemispheric connectivity in corpus callosum agenesis through alternative pathways, boosting the development of a more efficient functional organization of the visual word form area within the left temporo-occipital cortex.

The Modularity of Dysgraphia

Research regarding dysgraphia, an impairment in writing, is attaining more attention in recent times. The existing studies on dysgraphia draw insights from cognitive, behavioural, neurological, and genetic fields of knowledge. However, these multiple studies on dysgraphia fail to illustrate how these cognitive, behavioural, neurological, and genetic systems interact and intersect in dysgraphia. Therefore, the studies could not offer a comprehensive understanding of dysgraphia. In order to fill this gap, the review attempts to study dysgraphia using the notion of modularity by accommodating insights from cognitive, behavioural, neurological, and genetic aspects of dysgraphia. Such a profound understanding could facilitate an early diagnosis and holistic intervention towards dysgraphia.

Two types of developmental surface dysgraphia: to bee but not to bea

We report on two types of developmental surface dysgraphia. One type, exhibited by 8 participants, is orthographic lexicon surface dysgraphia, which involves an impairment in the orthographic output lexicon, leading to nonword phonologically-plausible misspellings. The other type, shown by 3 participants, is disconnection surface dysgraphia. In this type, the orthographic output lexicon is disconnected from the semantic system and from the phonological input lexicon, but still contributes to spelling via support to the orthographic output buffer, resulting in mainly lexical phonologically-plausible misspellings (writing be as "bee" but not "bea").The specific localization of the impairment in spelling, in the lexicon or in its connections, allowed us to examine the question of one or two orthographic lexicons; four participants who had a deficit in the orthographic output lexicon itself in writing had intact orthographic-input-lexicon in reading. They made surface errors in writing but not in reading the same words, supporting separate input and output orthographic lexicons.

The effect of an integrated reading and anxiety intervention for poor readers with anxiety

A recent systematic review has reported that poor reading is reliably associated with anxiety. However, we currently lack evidence-based intervention for children who have both poor reading and anxiety (PRAX). In this study, we tested a new PRAX intervention in 8- to 12-year-old children using a double-baseline intervention case series design. Analyses of both group and individual data revealed that 12 weeks of PRAX intervention significantly improved children's reading and spelling accuracy, and significantly reduced both anxiety disorders and symptoms. These results support PRAX intervention as a treatment for comorbid reading and anxiety problems in children and pave the way to a randomised controlled trial.

Videoconferencing Interventions for Children with Reading and Spelling Difficulties: A Pilot Study

Background: Many children in rural and remote areas do not have access to professionals providing literacy interventions. However, delivery of services through videoconferencing would increase access and choice for end users. Introduction: This pilot study investigated the efficacy of videoconferencing literacy interventions. As videoconferencing platforms become easier and cheaper to use, this form of telehealth delivery is increasing in popularity. However, there is currently no strong evidence base to support this practice. Materials and Methods: We studied 18 children, aged 7-12 years, with poor reading and/or spelling, and whose literacy interventions were videoconferenced into their homes and/or schools. Children were tested on three reading measures: (1) reading words, (2) reading nonwords, and (3) letter-sound knowledge, twice before their interventions commenced and once after their intervention concluded. Results: Children's raw and standardized scores on 2 of 3 outcome measures increased significantly more during the intervention than in the no-intervention period before their training commenced. Discussion and Conclusions: This study demonstrates that videoconferencing is a promising delivery mode for literacy interventions, and the results justify running a larger, randomized controlled trial.

The development of working memory spatialization revealed by using the cave paradigm in a two-alternative spatial choice

When Western participants are asked to keep in mind a sequence of verbal items, they tend to associate the first items to the left and the last items to the right. This phenomenon, known as the spatial-positional association response codes effect, has been interpreted as showing that individuals spatialize the memoranda by creating a left-to-right mental line with them. One important gap in our knowledge concerns the development of this phenomenon: when do Western individuals start organizing their thought from left to right? To answer this question, 274 participants in seven age groups were tested (kindergarten, Grades 1, 2, 3, 4, and 5, and adults). We used a new protocol meant to be child-friendly, which involves associating two caves with two animals using a two-alternative spatial forced choice. Participants had to guess in which cave a specific animal could be hidden. Results showed that it is from Grade 3 on that participants spatialize information in working memory in a left-to-right fashion like adults.

The Link Between Language and Spelling: What Speech-Language Pathologists and Teachers Need to Know

Purpose Speech-language pathologists (SLPs) working within the pediatric field will find themselves working with school-age children and consequently collaborating with teaching staff. Knowledge of the links between language, speech, and literacy can support and inform successful collaboration between the SLP and the teacher and their shared goal of facilitating the school-age child in accessing the curriculum. To facilitate and develop the collaborative working practices of SLPs working with school-age children and teaching staff, it is helpful, to both parties, to develop and extend their explicit understanding of the link between language, speech, and spelling. Method In this tutorial, I describe how verbal and written speech and language skills are inextricably linked and key to spelling development and progress. I will (a) discuss the complexities of spelling in the English language; (b) describe the links between language, speech, and spelling; and (c) propose a linguistically informed approach to spelling intervention. Conclusion SLPs have expertise in the key speech and language domains such as phonology, morphology, and semantics and are therefore well placed to play an important role in supporting learners in making links between these domains in relation to spelling development and intervention.

Too harts, won sole: Using dysgraphia treatment to address homophone representation

Previous spoken homophone treatment in aphasia found generalization to untreated homophones and interpreted this as evidence for shared phonological word form representations. Previous written treatment of non-homophones has attributed generalization to orthographic neighbours of treated items to feedback from graphemes to similarly spelled orthographic word forms. This feedback mechanism offers an alternative explanation for generalization found in treatment of spoken homophones. The aim of this study was to investigate the mechanism underpinning generalization (if any) from treatment of written homophones. To investigate this question a participant with acquired dysgraphia and impaired access to orthographic output representations undertook written spelling treatment. Generalization to untreated items with varying degrees of orthographic overlap was investigated. Three experimental sets included homographs (e.g., bank-bank), heterographs (e.g., sail-sale), and direct orthographic neighbours (e.g., bath-path). Treatment improved written picture naming of treated items. Generalization was limited to direct neighbours. Further investigation of generalization found that items with a greater number of close neighbours in the treated set showed greater generalization. This suggests that feedback from graphemes to orthographic word forms is the driving force of generalization. The lack of homograph generalization suggests homographs do not share a representation in the orthographic lexicon.

Developmental surface dysgraphia without surface dyslexia

The case is reported of an individual (N.K.) with a developmental spelling impairment (dysgraphia) who has no apparent problems in reading. His performance therefore provides further evidence of a classical dissociation between impaired spelling and preserved reading in individuals with developmental literacy problems. The dissociation is observed when N.K. is asked to read and spell in either his first (Greek) or his second language (English). An investigation of his spelling performance revealed that his impairment was more selective than that of P.J.T. Although his spelling of regular words and nonwords was normal, N.K. had a problem in spelling words with atypical sound-letter associations despite having no problems in reading aloud or understanding the meaning of words of this kind. It is argued that N.K.'s pattern of performance can be best explained in terms of normal development of an orthographic system that allows access to the meaning and pronunciation of written words during reading. In terms of a dual-route model of spelling, his poor spelling appears to be the result of a developmental impairment that impedes access to the orthographic system from phonology and semantics. In terms of the triangle model, his poor spelling appears to be the result of a developmental impairment that affects activation of orthography from semantics.

Intervention for a lexical reading and spelling difficulty in two Greek-speaking primary age children

An intervention study was carried out with two nine-year-old Greek-speaking dyslexic children. Both children were slow in reading single words and text and had difficulty in spelling irregularly spelled words. One child was also poor in non-word reading. Intervention focused on spelling in a whole-word training using a flashcard technique that had previously been found to be effective with English-speaking children. Post-intervention assessments conducted immediately at the end of the intervention, one month later and then five months later showed a significant improvement in spelling of treated words that was sustained over time. In addition, both children showed generalisation of improvement to untrained words and an increase in scores in a standardised spelling assessment. The findings support the effectiveness of theoretically based targeted intervention for literacy difficulties.

Do reading and spelling share orthographic representations? Evidence from developmental dysgraphia

Both spelling and reading depend on knowledge of the spellings of words. Despite this commonality, observed dissociations between spelling and reading in cases of acquired and developmental deficits suggest some degree of independence between the cognitive mechanisms involved in these skills. In this paper, we examine the relationship between spelling and reading in two children with developmental dysgraphia. For both children, we identified significant deficits in spelling that affected the processing of orthographic long-term memory representations of words. We then examined their reading skills for similar difficulties. Even with extensive testing, we found no evidence of a reading deficit for one of the children. We propose that there may be an underlying difficulty that specifically affects the learning of orthographic word representations for spelling. These results lead us to conclude that at least some components of lexical orthographic representation and processing develop with considerable independence in spelling and reading.

Developmental graphemic buffer dysgraphia in English: A single case study

A single case study is reported of a 10-year-old, English-speaking boy, L.S., who presented with spelling errors similar to those described in acquired graphemic buffer dysgraphia (GBD). We used this case to evaluate the appropriateness of applying adult cognitive models to the investigation of developmental cognitive disorders. The dual-route model of spelling guided this investigation. L.S. primarily made "letter errors" (deletions, additions, substitutions, transpositions, or a combination of these errors) on words and nonwords and in all input (aural and visual) and output modalities (writing, typing, oral spelling); there was also some evidence of a length effect and U-shaped serial position curve. An effect of lexical variables on spelling performance was also found. We conclude that the most parsimonious account is an impairment at the level of the graphemic buffer and without systematic cognitive neuropsychological investigation, the nature of L.S.'s spelling difficulty would likely have been missed.

Developmental dysgraphia: An overview and framework for research

Developmental deficits in the acquisition of writing skills (developmental dysgraphias) are common and have significant consequences, yet these deficits have received relatively little attention from researchers. We offer a framework for studying developmental dysgraphias (including both spelling and handwriting deficits), arguing that research should be grounded in theories describing normal cognitive writing mechanisms and the acquisition of these mechanisms. We survey the current state of knowledge concerning developmental dysgraphia, discussing potential proximal and distal causes. One conclusion emerging from this discussion is that developmental writing deficits are diverse in their manifestations and causes. We suggest an agenda for research on developmental dysgraphia, and suggest that pursuing this agenda may contribute not only to a better understanding of developmental writing impairment, but also to a better understanding of normal writing mechanisms and their acquisition. Finally, we provide a brief introduction to the subsequent articles in this special issue on developmental dysgraphia.

Do reading and spelling share a lexicon?

In the reading and spelling literature, an ongoing debate concerns whether reading and spelling share a single orthographic lexicon or rely upon independent lexica. Available evidence tends to support a single lexicon account over an independent lexica account, but evidence is mixed and open to alternative explanation. In the current work, we propose another, largely ignored account--separate-but-shared lexica--according to which reading and spelling have separate orthographic lexica, but information can be shared between them. We report three experiments designed to competitively evaluate these three theoretical accounts. In each experiment, participants learned new words via reading training and/or spelling training. The key manipulation concerned the amount of reading versus spelling practice a given item received. Following training, we assessed both response time and accuracy on final outcome measures of reading and spelling. According to the independent lexica account, final performance in one modality will not be influenced by the level of practice in the other modality. According to the single lexicon account, final performance will depend on the overall amount of practice regardless of modality. According to the separate-but-shared account, final performance will be influenced by the level of practice in both modalities but will benefit more from same-modality practice. Results support the separate-but-shared account, indicating that reading and spelling rely upon separate lexica, but information can be shared between them.

A sublexical training study for spelling in a biliterate Greek- and English-speaking child

RI is an emergent trilingual boy, literate in Greek and English, with difficulties in reading and spelling in both languages. Assessment with non-literacy tests revealed a deficit in phonological ability and in visual memory for sequentially presented characters. RI took part in a training programme that targeted sublexical spelling processes. Post-intervention assessment revealed improvement in reading and spelling in Greek but not in English. Assessments of lexical and sublexical skills showed improvement in nonword spelling and nonword reading for Greek. For English, there was some indication of improvement in nonword reading at delayed post-intervention testing, but no evidence of improvement in nonword spelling. Possible reasons for the difference in outcome for the two languages are considered, including the level of transparency of written Greek and English.

Thinking outside the boxes: Using current reading models to assess and treat developmental surface dyslexia

Improving the reading performance of children with developmental surface dyslexia has proved challenging, with limited generalisation of reading skills typically reported after intervention. The aim of this study was to provide tailored, theoretically motivated intervention to two children with developmental surface dyslexia. Our objectives were to improve their reading performance, and to evaluate the utility of current reading models in therapeutic practice. Detailed reading and cognitive profiles for two male children with developmental surface dyslexia were compared to the results obtained by age-matched control groups. The specific area of single-word reading difficulty for each child was identified within the dual route model (DRM) of reading, following which a theoretically motivated intervention programme was devised. Both children showed significant improvements in single-word reading ability after training, with generalisation effects observed for untrained words. However, the assessment and intervention results also differed for each child, reinforcing the view that the causes and consequences of developmental dyslexia, even within subtypes, are not homogeneous. Overall, the results of the interventions corresponded more closely with the DRM than other current reading models, in that real word reading improved in the absence of enhanced nonword reading for both children.

Sight Word and Phonics Training in Children With Dyslexia

The aims of this study were to (a) compare sight word training and phonics training in children with dyslexia, and (b) determine if different orders of sight word and phonics training have different effects on the reading skills of children with dyslexia. One group of children (n = 36) did 8 weeks of phonics training (reading via grapheme-phoneme correspondence rules) and then 8 weeks of sight word training (reading irregular words as a whole), one group did the reverse (n = 36), and one group did phonics and sight word training simultaneously for two 8-week periods (n = 32). We measured the effects of phonics and sight word training on sight word reading (trained irregular word reading accuracy, untrained irregular word reading accuracy), phonics reading (nonword reading accuracy, nonword reading fluency), and general reading (word reading fluency, reading comprehension). Sight word training led to significant gains in sight word reading measures that were larger than gains made from phonics training, phonics training led to statistically significant gains in a phonics reading measure that were larger than gains made from sight word training, and both types of training led to significant gains in general reading that were similar in size. Training phonics before sight words had a slight advantage over the reverse order. We discuss the clinical implications of these findings for improving the treatment and assessment of children with dyslexia.

An Analysis of Reading Skill Development using E-Z Reader

Previously reported simulations using the E-Z Reader model of eye-movement control suggest that the patterns of eye movements observed with children versus adult readers reflect differences in lexical processing proficiency (Reichle et al., 2013). However, these simulations fail to specify precisely what aspect(s) of lexical processing (e.g., orthographic processing) account for the concurrent changes in eye movements and reading skill. To examine this issue, the E-Z Reader model was first used to simulate the aggregate eye-movement data from 15 adults and 75 children to replicate the finding that gross differences in reading skill can be accounted for by differences in lexical processing proficiency. The model was then used to simulate the eye-movement data of individual children so that the best-fitting lexical-processing parameters could be correlated to measures of orthographic knowledge, phonological-processing skill, sentence comprehension, and general intelligence. These analyses suggest that orthographic knowledge accounts for variance in the eye-movement measures that is observed with between-individual differences in reading skill. The theoretical implications of this conclusion will be discussed in relation to computational models of reading and our understanding of reading skill development.

Generalisation after treatment of acquired spelling impairments: A review

This paper provides a comprehensive review of treatment studies of acquired dysgraphia and the occurrence of generalisation after this treatment. The aim is to examine what determines the occurrence of generalisation by investigating the link between the level of impairment, the method of treatment, and the outcome of therapy. We present the outcomes of treatment with regard to generalisation in 40 treatment studies. We derive general principles of generalisation which provide us with a better understanding of the mechanism of generalisation: (1) Direct treatment effects on representations or processes; (2) interactive processing and summation of activation; and (3) strategies and compensatory skills. We discuss the implications of these findings for our understanding of the cognitive processes used for spelling. Finally, we provide suggestions for the direction of further research into this important area, as a better understanding of the mechanism of generalisation could maximise treatment effects for an individual with acquired dysgraphia.

New insights on developmental dyslexia subtypes: heterogeneity of mixed reading profiles

We examined whether classifications based on reading performance are relevant to identify cognitively homogeneous subgroups of dyslexic children. Each of the 71 dyslexic participants was selected to have a mixed reading profile, i.e. poor irregular word and pseudo-word reading performance (accuracy and speed). Despite their homogeneous reading profile, the participants were found to split into four distinct cognitive subgroups, characterized by a single phonological disorder, a single visual attention span disorder, a double deficit or none of these disorders. The two subgroups characterized by single and contrasted cognitive disorders were found to exhibit a very similar reading pattern but more contrasted spelling performance (quantitative analysis). A qualitative analysis of the error types produced in reading and spelling provided some cues about the participants' underlying cognitive deficit. The overall findings disqualify subtyping based on reading profiles as a classification method to identify cognitively homogeneous subgroups of dyslexic children. They rather show an opaque relationship between the cognitive underpinnings of developmental dyslexia and their behavioral manifestations in reading and spelling. Future neuroimaging and genetic studies should take this issue into account since synthesizing over cognitively heterogeneous children would entail potential pitfalls.

Reading impairment in an adolescent with temporo-occipital epilepsy. Pre- and post-surgical evaluation

We present a 16 year-old right-handed case who underwent a left temporo-occipital resection to treat intractable epilepsy. Pre- and post-surgical evaluations showed an average intellectual quotient, preserved abilities in language and visuo-spatial functions and increased reading and spelling deficits (difficulties with irregular words, homophones and phonologically valid spelling errors of irregularly spelled words, associated with preserved performances in non-words). This pattern of characteristic lexical route deficits highlights the major role of the temporo-occipital areas in reading acquisition. We discussed the consequences of temporo-occipital dysfunction on reading.

Intervention for a multi-character processing deficit in a Greek-speaking child with surface dyslexia

A case study with a 12-year-old boy, R.F., who was a monolingual speaker of Greek is reported. R.F. showed slow word reading and a difficulty in spelling irregular words but not nonwords. Assessments revealed that R.F. did not appear to have a phonological deficit, but indicated impaired multicharacter processing ability for visually presented letter arrays. On the basis of previous research linking multicharacter processing and reading we developed an intervention aimed at improving R.F.'s ability to report letter arrays of increasing length. Following a 9-week programme, improvement was observed, and investigation of R.F.'s reading revealed gains in single word reading speed and accuracy. The findings support the significance of intervention studies for testing hypotheses regarding causal relationships among cognitive processes and the notion of specific profiles of developmental dyslexia/dysgraphia in both opaque and transparent orthographies.

Rehabilitation of executive functions in a real-life setting: goal management training applied to a person with schizophrenia

The aim was to assess the efficacy of a modified version of Goal Management Training (GMT) in a person with schizophrenia who had difficulties in attaining the final goal for new and multitasking daily-life situations. GMT is designed to improve abilities in establishing goal-directed plans and carrying them out effectively. Beneficial effects of GMT were measured for several clinical questionnaires, laboratory tasks, and three real-life situations: meal preparation (trained, familiar); washing (nontrained, familiar); meeting preparation (nontrained, unfamiliar). The results revealed improvement in planning and on trained laboratory and meal preparation tasks and a generalization of GMT effects on nontrained laboratory and everyday tasks. Self-esteem also improved. Finally, a two-year followup indicated the durability of the beneficial effects.

The Effectiveness of the Attention Training Technique in Reducing Intrusive Thoughts in Schizophrenia

The aim of this study was to investigate the effectiveness of the attention training technique (ATT) on the frequency of intrusive thoughts experienced by a person with schizophrenia in her daily life. The attentional procedure was designed to attenuate self-focused attention and to reinforce attentional control and consisted of auditory external exercises. Homework practice was included to promote transfer to everyday life. The efficacy and specificity of the ATT were assessed with cognitive, functional, and control measures. The impact of ATT on symptomatology, work functioning, and self-esteem was also measured. Postrehabilitation results showed that, after nine training sessions, there was a reduction in intrusive thoughts for the cognitive and ecological outcome measures. Selective attention, attention switching, and resistance to distractive interference specifically improved. The person reported a reduction in intrusive thoughts in her daily life. In addition, positive symptoms decreased. Finally, a 6-month follow-up assessment revealed the maintenance of most of the beneficial effects in daily life.

Inflectional spelling deficits in developmental dyslexia

The goal of this study was to examine past-tense spelling deficits in developmental dyslexia and their relationship to phonological abilities, spoken morphological awareness and word specific orthographic memory. Three groups of children (28 9-year-old dyslexic, 28 chronological age-matched and 28 reading/spelling age-matched children) completed a battery of tests including spelling regularly inflected words (e.g., kissed) and matched one-morpheme words (e.g., wrist). They were also assessed on a range of tests of reading and spelling abilities and associated linguistic measures. Dyslexic children were impaired in relation to chronological age-matched controls on all measures. Furthermore, they were significantly poorer than younger reading and spelling age-matched controls at spelling inflected verbs, supporting the existence of a specific deficit in past-tense spelling in dyslexia. In addition to under-using the -ed spelling on inflected verbs, the dyslexic children were less likely to erroneously apply this spelling to one-morpheme words than younger controls. Dyslexics were also poorer than younger controls at using a consistent spelling for stems presented in isolation versus as part of an inflected word, indicating that they make less use of the morphological relations between words to support their spelling. In line with this interpretation, regression analyses revealed another qualitative difference between the spelling and reading age-matched group and the dyslexic group: while both spoken morphological awareness and orthographic word specific memory were significant predictors of the accuracy of past-tense spelling in the former group, only orthographic memory (irregular word reading and spelling) was a significant factor in the dyslexic group. Finally, we identified a subgroup of seven dyslexic children who were severely deficient in past-tense spelling. This subgroup was also significantly worse than other dyslexics and than younger controls on scores of orthographic memory. The implications of our findings for teaching and remediation strategies are discussed.

Single or dual orthographic representations for reading and spelling? A study of Italian dyslexic-dysgraphic and normal children

Italian children with surface dyslexia and dysgraphia show defective orthographic lexical processing in both reading and spelling. It is unclear whether this parallelism is due to impairment of separate orthographic input and output lexicons or to a unique defective lexicon. The main aim of the present study was to compare the single- versus dual-lexicon accounts in dyslexic/dysgraphic children (and in normal but younger children). In the first experiment, 9 Italian children with surface dyslexia and dysgraphia judged the orthographic correctness (input lexicon) of their phonologically plausible misspellings (output lexicon) and of phonologically plausible spellings experimentally introduced for words they consistently spelt correctly. The children were generally impaired in recognizing phonologically plausible misspellings. Parallel deficits in reading and spelling also emerged: Children were more impaired in judging items they consistently misspelt and more accurate in judging items they always spelt correctly. In a second experiment, younger normal children with reading/spelling ability similar to that of the dyslexic/dysgraphic children in the first experiment (but younger) were examined. The results confirmed a close parallelism between the orthographic lexical representations used for reading and spelling. Overall, findings support the hypothesis that a single orthographic lexicon is responsible for reading and spelling performance in both dyslexic/dysgraphic and normal (but younger) children.

Spelling and reading: using visual sensitivity to explore shared or separate orthographic representations

Do we use the same neurocognitive mechanisms to spell that we do to read? There is a considerable number of conflicting findings, such that evidence has been provided to support common mechanisms for reading and spelling, while other research supports the proposal that reading and spelling utilise unique neurocognitive resources. Sensitivity to visual spatial-frequency doubling (FD) has been demonstrated to correlate with and specifically predict orthographic processing when reading; therefore, if spelling and reading share some elements of orthographic representation, sensitivity to FD should similarly correlate with, and predict, spelling ability by virtue of this shared association. A double dissociation between reading and spelling was found such that sensitivity to the FD task, as mediated by the visual dorsal stream, predicted reading ability but not spelling, while the visual control task predicted spelling but not reading ability, in poor readers/spellers. The results support a dual-orthographic model with separate orthographic representations for reading and spelling.

Mrs. Malaprop's Neighborhood: Using Word Errors to Reveal Neighborhood Structure

Many theories of language production and perception assume that in the normal course of processing a word, additional non-target words (lexical neighbors) become active. The properties of these neighbors can provide insight into the structure of representations and processing mechanisms in the language processing system. To infer the properties of neighbors, we examined the non-semantic errors produced in both spoken and written word production by four individuals who suffered neurological injury. Using converging evidence from multiple language tasks, we first demonstrate that the errors originate in disruption to the processes involved in the retrieval of word form representations from long-term memory. The targets and errors produced were then examined for their similarity along a number of dimensions. A novel statistical simulation procedure was developed to determine the significance of the observed similarities between targets and errors relative to multiple chance baselines. The results reveal that in addition to position-specific form overlap (the only consistent claim of traditional definitions of neighborhood structure) the dimensions of lexical frequency, grammatical category, target length and initial segment independently contribute to the activation of non-target words in both spoken and written production. Additional analyses confirm the relevance of these dimensions for word production showing that, in both written and spoken modalities, the retrieval of a target word is facilitated by increasing neighborhood density, as defined by the results of the target-error analyses.

Comparison of phonological and whole-word treatments for two contrasting cases of developmental dyslexia

This study compared the effectiveness of two reading treatment programmes for two contrasting developmental dyslexics. W.B. demonstrated "pure" phonological dyslexia (deficient nonword reading but normal irregular-word reading) and N.S. "pure" surface dyslexia (the converse pattern). Both participants completed: (a) a phonological programme, which targeted the sublexical reading procedure through repeated exposure to word "families" with the same grapheme-phoneme correspondence (GPC; e.g., frail, raid, bait); and (b) a whole-word programme, which targeted the lexical reading procedure through tasks that emphasize whole-word visual analysis (e.g., speeded identification of visually degraded words). Both participants improved after training on the targeted words and/or GPCs. However, W.B. demonstrated reliable generalization only following the phonological programme and only in his reading of nonwords. In contrast, N.S. showed generalization across all types of word materials following both programmes. Although the whole-word programme (in particular the degraded-images technique) resulted in numerically greater improvement for N.S., this difference was not significant. Practical and theoretical implications of these results are discussed.

Developmental dyslexia: The visual attention span deficit hypothesis

The visual attention (VA) span is defined as the amount of distinct visual elements which can be processed in parallel in a multi-element array. Both recent empirical data and theoretical accounts suggest that a VA span deficit might contribute to developmental dyslexia, independently of a phonological disorder. In this study, this hypothesis was assessed in two large samples of French and British dyslexic children whose performance was compared to that of chronological-age matched control children. Results of the French study show that the VA span capacities account for a substantial amount of unique variance in reading, as do phonological skills. The British study replicates this finding and further reveals that the contribution of the VA span to reading performance remains even after controlling IQ, verbal fluency, vocabulary and single letter identification skills, in addition to phoneme awareness. In both studies, most dyslexic children exhibit a selective phonological or VA span disorder. Overall, these findings support a multi-factorial view of developmental dyslexia. In many cases, developmental reading disorders do not seem to be due to phonological disorders. We propose that a VA span deficit is a likely alternative underlying cognitive deficit in dyslexia.

The effects of length and transposed-letter similarity in lexical decision: evidence with beginning, intermediate, and adult readers

Do length and transposed-letter effects reflect developmental changes on reading acquisition in a transparent orthography? Can computational models of visual word recognition accommodate these changes? To answer these questions, we carried out a masked priming lexical decision experiment with Spanish beginning, intermediate, and adult readers (N=36, 44, and 39; average age: 7, 11, and 22 years, respectively). Target words were either short or long (6.5 vs. 8.5 letters), and transposed-letter primes were formed by the transposition of two letters (e.g. aminal-ANIMAL) or by the substitution of two letters (orthographic control: arisal-ANIMAL). Children showed a robust length effect (i.e. long words were read slower than short words) that vanished in adults. In addition, both children and young adults showed a transposed-letter priming effect relative to the control condition. A robust transposed-letter priming effect was also observed in non-word reading, which strongly suggests that this effect occurs at an early prelexical level. Taken together, the results reveal that children evolve from a letter-by-letter reading to a direct lexical access and that the lexical decision task successfully captures the changing strategies used by beginning, intermediate, and adult readers. We examine the implications of these findings for the recent models of visual word recognition.

Treatment of irregular word spelling in acquired dysgraphia: selective benefit from visual mnemonics

In contrast to the numerous treatment studies of spoken language deficits, there have been relatively few studies concerned with the treatment of spelling disorders. Among these, there have been only a small number that have targeted specific components of the spelling process. We describe a successful single case treatment study for FME, a woman with acquired dysgraphia, which was conducted within a cognitive neuropsychological framework. Pre-treatment assessment revealed a semantic deficit, impaired access to output orthography and probable additional degradation of the actual representations within the orthographic output lexicon. The treatment study was therefore directed towards relearning spellings by strengthening, and facilitating access to, specific orthographic representations for writing. In order to maximise the functional outcome for FME, treatment was focused on high frequency, irregular words. The treatment programme was carried out in two phases, one without and one with the use of mnemonics, and the results showed a selective training effect with the mnemonics alone. Treatment benefits were item specific but long lasting, and a significant improvement in FME's spelling performance was still evident at 2 months post-treatment. The current study confirms how cognitive neuropsychological theories and methods can be successfully applied to the assessment of acquired spelling impairments, and exemplifies how treatment with carefully designed mnemonics is of benefit if the inability to retrieve orthographic representations for writing is aggravated by a semantic deficit.