Lexical Orthographic Representations Research Articles

White matter associations with spelling performance.

Multiple neurocognitive processes are involved in the highly complex task of producing written words. Yet, little is known about the neural pathways that support spelling in healthy adults. We assessed the associations between performance on a difficult spelling-to-dictation task and microstructural properties of language-related white matter pathways, in a sample of 73 native English-speaking neurotypical adults. Participants completed a diffusion magnetic resonance imaging scan and a cognitive assessment battery. Using constrained spherical deconvolution modeling and probabilistic tractography, we reconstructed dorsal and ventral white matter tracts of interest, bilaterally, in individual participants. Spelling associations were found in both dorsal and ventral stream pathways. In high-performing spellers, spelling scores significantly correlated with fractional anisotropy (FA) within the left inferior longitudinal fasciculus, a ventral stream pathway. In low-performing spellers, spelling scores significantly correlated with FA within the third branch of the right superior longitudinal fasciculus, a dorsal pathway. An automated analysis of spelling errors revealed that high- and low- performing spellers also differed in their error patterns, diverging primarily in terms of the orthographic distance between their errors and the correct spelling, compared to the phonological plausibility of their spelling responses. The results demonstrate the complexity of the neurocognitive architecture of spelling. The distinct white matter associations and error patterns detected in low- and high- performing spellers suggest that they rely on different cognitive processes, such that high-performing spellers rely more on lexical-orthographic representations, while low-performing spellers rely more on phoneme-to-grapheme conversion.

Investigating L2 reading aloud and silent reading in typically developing readers and dyslexic adolescents from grades 6 to 9.

The goal of this study was to examine the reading performance of French typically developing readers and dyslexic adolescents from grades 6 to 9 in English as a second language (L2) learned in a school context. Lexicality effects and the impact of two sub-lexical variables, that is cross-language orthographic markedness and congruency of grapheme-to-phoneme correspondences (GPCs), were investigated in three tasks: L2 reading aloud and lexical decision, and L2-to-L1 translation. English words and nonwords were divided into three conditions: (a) marked condition in which items have an L2-specific orthographic pattern (e.g., town), (b) unmarked congruent condition in which items have an L1/L2 shared orthography and similar GPCs across languages (e.g., fast) and (c) unmarked incongruent condition that contains incongruent GPCs across languages (e.g., dirt). The results yielded a significant deficit in dyslexic readers in all three tasks, suggesting poor decoding but also poor lexical orthographic representations in L2 and difficulties in connecting form to semantic representations. This deficit was mostly observed for the unmarked incongruent conditi-on, highlighting the need to carefully manipulate the sub-lexical features of items when examining L2 reading. The results are discussed in relation to the cross-language transfer hypothesis and to mono- and bilingual models of reading.

Further evidence for a late locus of holistic word processing: Exploring vertex effect in the word composite task.

Previous studies have shown a rather late and lexical level for holistic word processing. In the present study, we evaluated whether there are early effects in holistic processing of words, taking into consideration the role of lower-level visual processes that are critical in the hierarchy of visual word recognition: the extraction of viewpoint-invariant line junctions/vertices. We used contour-deleted words in two conditions: preservation of the vertices versus preservation of midsegments and an all-contour condition. We found evidence of a composite effect that was equivalent for all materials. Thus, we found no evidence of an early contribution of holistic processing to word recognition, and confirmed that holistic word processing is related to late lexical orthographic representations.

Holistic word processing is correlated with efficiency in visual word recognition.

Holistic processing of visual words (i.e., obligatory encoding of/attending to all letters of a word) could be a marker of expert word recognition. In the present study, we thus examined for the first time whether there is a direct relation between the word-composite effect (i.e., all parts of a visual word are fully processed when observers perform a task on a word part) and fast access to the orthographic lexicon by visual word experts (i.e., fluent adult readers). We adopted an individual differences approach and used the word-frequency effect (i.e., faster recognition of high- than low-frequency words) in an independent lexical decision task as a proxy of fast access to lexical orthographic representations. Fluent readers with larger word-composite effect showed smaller word-frequency effect. This correlation was mainly driven by an association between a larger composite effect and faster lexical decision on low-frequency words, probably because these lexical representations are less stable and integrated/unitized, hence allowing differentiating among fluent readers. We thus showed that holistic processing of visual words is indeed related to higher efficiency in visual word recognition by skilled readers.

Cross-script phonological priming with Japanese Kanji primes and English targets

Two experiments investigated whether Japanese–English bilinguals have integrated phonological stores for their two languages using a masked phonological priming task with Japanese Kanji (logographic) primes and English targets. In both experiments, lexical decisions for English target words were facilitated by phonologically similar Kanji primes. Furthermore, the size of the phonological priming effect was uninfluenced by the participants' English proficiency or target word frequency, which suggests that the priming effect arose from feedback from sublexical phonological representations to lexical orthographic representations. Because of the orthographic and phonological differences between Japanese and English, these findings provide particularly strong support for the Bilingual Interactive Activation (BIA+) model's assumption that representations are integrated across languages.

The locus of Katakana–English masked phonological priming effects

Japanese–English bilinguals completed a masked phonological priming study with Japanese Katakana primes and English targets. Event related potential (ERP) data were collected in addition to lexical decision responses. A cross-script phonological priming effect was observed in both measures, and the effect did not interact with frequency. In the ERP data, the phonological priming effect was evident before the frequency effect. These data, along with analyses of response latency distributions, provide evidence that the cross-script phonological priming effects were the consequence of the activation of sublexical phonological representations in a store shared by both Japanese and English. This activation fed back to sublexical and lexical orthographic representations, influencing lexical decision latencies. The implications for the Bilingual Interactive Activation (BIA+) model of word recognition are discussed.

Do children who acquire word reading without explicit phonics employ compensatory learning? Issues of phonological recoding, lexical orthography, and fluency

Two studies were conducted across three countries to examine samples of beginning readers without systematic explicit phonics who had reached the same level of word reading accuracy as comparison samples with high and moderate explicit phonics. Had they employed any compensatory learning to reach that level? Four hypotheses of compensatory learning or performance were tested on the samples, all of which represented the lower half of the normative distribution of word reading accuracy. The two samples without explicit phonics received teaching that centered on story text reading and some receptive phonics that arose from this text reading. They did not compensate by relatively greater use of a larger psycholinguistic grain size in the form of rime units. Nor did they compensate by trading off comprehension for text word reading accuracy. In a microtraining study, they showed no compensation in proficiency of initial learning of lexical orthographic representations. For all samples, this initial learning was less effective with spelling than reading training trials. In reading text, the samples without explicit phonics did not compensate by trading off speed for accuracy, or comprehension. On the contrary, they read text faster than the explicit phonics samples. The extra classroom instruction time available to them for text reading, with the consequential extra exposure and practice of word reading, would explain this result.

LÉXICO ORTOGRÁFICO Y COMPETENCIA LECTORA

Se presenta un estudio en el que se analizan las relaciones entre la lectura eficiente y la disponibilidad de representaciones ortográficas léxicas en dos muestras de estudiantes universitarios españoles y uruguayos. Mediante el uso de una metodología de análisis de regresión tratamos de explicar los resultados de una prueba de lectura eficiente (TECLE) a partir de una prueba de conocimiento ortográfico (TECOR). Los resultados permiten confirmar el importante papel que juega el léxico ortográfico en la lectura eficiente en español. Esta relación se revela más intensa en la muestra uruguaya que en la española. El patrón de resultados se interpreta en el marco de los efectos de la transparencia ortográfica en el aprendizaje de la lectura y el procesamiento lector.

The Crucial Role of Posterior Frontal Regions in Modality Specific Components of the Spelling Process

Although it is commonly assumed that posterior temporo-parietal regions are the regions of the brain essential for accessing orthographic representations for written output, patients with lesions in these areas also have reading and/or naming impairments at least early after stroke onset. This observation raises the possibility that these regions are important for components of spelling that are not specific to written output. The goal of the present study was to identify any regions of the brain that, when damaged, result in selective impairment in accessing orthographic representations for written output. We studied 54 consecutive right-handed patients with acute, left hemisphere ischemic stroke, who were able to perform the motor aspects of writing with the right hand and had at least a 10th grade education, on a battery of lexical tasks designed to identify impaired and spared cognitive processes underlying spelling and with advanced magnetic resonance imaging. Only five patients had pure agraphia, and had evidence of impaired access to lexical-orthographic representations for output; and all five had infarct or ischemia in Brodmann’s area 44 and 45. Analysis of performance across tasks of three of these patients, whose performance has not been previously reported, provides evidence for additional impairment in converting graphemes to letter shapes or letter-specific motor programs. These three patients, unlike previously reported patients with lexical-orthographic impairment and compromised function in Brodmann’s area 44 and 45, also had infarcts in Brodmann’s area 6. On the basis of these cases, and those in the literature, we propose a network of brain regions involved in writing words, each with a separate function. This proposal emphasizes the role of left posterior frontal regions in modality-specific output processes.

A mechanism of implicit lexicalized phonological recoding used concurrently with underdeveloped explicit letter-sound skills in both precocious and normal reading development

These are findings of theoretical interest from: (i) follow-up of a case study of a precocious reader; and (ii) normally developing readers who served as comparison groups. The precocious reader was first reported when 2–3 years of age ( Cognition 74 (2000) 177). From 3 to 7 years of age her precocious reading development continued, her word reading accuracy increasing from the 8- to the 16-year-level, although her phonemic awareness skills remained underdeveloped relative to word reading. Nonword reading continued to develop rapidly. Her word reading, however, was more than phonological recoding. At 5 years of age, in comparison with reading-level matched normal 11-year-olds she exhibited strong effects of semantic characteristics of words and evidence of well-specified lexical orthographic representations. In common with normal comparison 11-year-olds, who had not received instruction in explicit phonics, her explicit letter-sound skills were underdeveloped but she possessed high speed and accuracy in nonword reading, a result most theories of the acquisition of reading fail to explain. Her responses to irregularly spelt nonwords indicated higher proficiency than the 11-year-olds in acquiring lexical orthographic representations not predictable from prior phonological recoding knowledge. It is considered that this proficiency contributes to an explanation of her precocious reading development. A mechanism of implicit lexicalized phonological recoding is involved which explains the dissociation of skills in both the precocious reader and normally developing readers.

A Third Route for Reading? Implications from a Case of Phonological Dyslexia

Models of reading in the neuropsychological literature sometimes only include two routes from print to sound, a lexical semantic route and a sublexical phonological route. Other researchers hypothesize an additional route that involves a direct connection between lexical orthographic representations and lexical phonological representations. This so-called ‘third route’ has been invoked to account for the preserved oral reading of some patients who show severe semantic impairments and a disruption of the sublexical phonological route. In their summation hypothesis, Hillis and Caramazza proposed that reading in these cases could result from a combination of partial lexical semantic information and partial sublexical phonological information, thus obviating the need for the third route. The present study examined the case of a phonological dyslexic patient (ML) who exhibited preserved word reading, even for items he could not name, along with a non-word reading impairment. The relationship between ML’s naming and reading, and the influence of semantic variables on his reading were examined. The results of this examination are interpreted as supporting the existence of the third route.

A Third Route for Reading? Implications from a Case of Phonological Dyslexia

Models of reading in the neuropsychological literature sometimes only include two routes from print to sound, a lexical semantic route and a sublexical phonological route. Other researchers hypothesize an additional route that involves a direct connection between lexical orthographic representations and lexical phonological representations. This so-called ‘third route’ has been invoked to account for the preserved oral reading of some patients who show severe semantic impairments and a disruption of the sublexical phonological route. In their summation hypothesis, Hillis and Caramazza proposed that reading in these cases could result from a combination of partial lexical semantic information and partial sublexical phonological information, thus obviating the need for the third route. The present study examined the case of a phonological dyslexic patient (ML) who exhibited preserved word reading, even for items he could not name, along with a non-word reading impairment. The relationship between ML’s naming and reading, and the influence of semantic variables on his reading were examined. The results of this examination are interpreted as supporting the existence of the third route.

Sequential and parallel letter processing in letter-by-letter dyslexia

Four experiments are reported that focus on the issue of sequential vs. parallel letter processing in letter-by-letter (LBL) dyslexia; these were conducted on patient IH. Expt. 1 showed a large linear reduction of word naming times with an increase in the number of orthographic neighbours of the target (i.e., words of the same length differing by just one letter; N size). Given the large negative linear correlation existing between word length and N size, this result raises the possibility that the large word length effect diagnostic of LBL dyslexia may be, in fact, an artefact of uncontrolled N size. Expt. 2 falsified this possibility by showing that the word length effect is unaffected by whether N size is controlled for or not. This result also suggested that the facilitatory effect of increased N size in LBL dyslexia is based on the parallel processing of the constituent letters of the target. Further supporting a contribution of parallel letter processing to overt word recognition performance in the disorder, Expt. 3 showed significant but independent effects of word length and letter confusability (i.e., similarity of the constituent letters of the target word with other letters of the alphabet). The letter confusability effect therefore appears to rest on the parallel analysis of the letters in the target word. Finally, Expt. 4 showed that the facilitatory effect of N size is prevented with high letter-confusability targets. These observations suggest that LBL dyslexia rests on an impairment of letter encoding that results in an excessive level of background noise in the activation of lexical-orthographic representations when letters are processed in parallel. This prevents overt identification of the target and forces sequential letter processing in order to achieve this goal.

Superior Written Over Spoken Picture Naming in a Case of Frontotemporal Dementia

Two main hypotheses have been proposed regarding the role of phonology in written word production. According to the phonological mediation hypothesis, the retrieval of the lexical phonological representation of a word is an obligatory prerequisite to the retrieval of its spelling. Therefore, deficits to the phonological lexicon should affect both spoken and written picture naming. In contrast, the orthographic autonomy hypothesis posits that the lexical orthographic representations of words can be accessed without any necessary phonological mediation. In support of this view, cases of preserved written naming despite impaired lexical phonology have been reported following brain damage. In this report, we replicate this basic pattern of performance in case YP, a 60-year-old woman with a pattern of frontotemporal dementia. As her disease progressed, YP’s ability to write down the names of pictures remained very good despite a severe decline in oral naming. Further testing indicated that this deficit was not primarily due to an articulatory or post-lexical phonological deficit. YP’s case provides strong additional support for the orthographic autonomy hypothesis. The significance of this case with respect to the characterization of dementia syndromes is discussed.

When a Rose is a Rose in Speech but a Tulip in Writing

We report the pattern of performance on language tasks by a neurologically impaired patient, RCM, who makes semantic errors in writing to dictation and in written naming, but makes very few errors at all (and no semantic errors) in spoken naming, oral reading, or spontaneous speech. RCM also shows a significant effect of concreteness on spelling accuracy and other features of so-called “deep dysgraphia.” However, it is shown that, unlike previously reported patients described as deep dysgraphic, RCM has intact semantic processing but impairment in accessing lexical-orthographic representations, at least for the items tested. These results demonstrate that the collection of features labelled as “deep dysgraphia” can arise from damage to different cognitive processes. Detailed analyses of RCM's performance across lexical tasks, at two different time periods of recovery, provide evidence that lexical orthographic representations can be either directly activated by lexical semantic representations, or activated by the interaction of lexical semantic and sublexical information from phonology-to-orthography conversion mechanisms.

Serial Position Effects and Lexical Activation in Spelling: Evidence from a Single Case Study

A single case study of a 'deep dysgraphic' patient is reported. The majority of her errors consist of non-word and fragment responses in which initial letters tend to be correctly produced (e.g. book ? b, dentist ? dentant). The probability of making an error at a given position increases linearly from word beginning to word end for all spelling tasks requiring lexical access. This serial position effect cannot be attributed to damage to the graphemic buffer, since a different pattern is found in a buffer-taxing task which does not require lexical access. It is also unlikely to reflect a neglect deficit, since the serial position effect is related to ordinal positions rather than positions left or right of word-centre. It is argued that the patient's pattern reflects incomplete activation of lexical-orthographic representations. Our data are consistent with models of lexical activation in which the activation of letter nodes is a function of ordinal position.

Serial position effects and lexical activation in spelling: Evidence from a single case study

A single case study of a ‘deep dysgraphic’ patient is reported. The majority of her errors consist of non-word and fragment responses in which initial letters tend to be correctly produced (e.g. book b, dentist dentant). The probability of making an error at a given position increases linearly from word beginning to word end for all spelling tasks requiring lexical access. This serial position effect cannot be attributed to damage to the graphemic buffer, since a different pattern is found in a buffer-taxing task which does not require lexical access. It is also unlikely to reflect a neglect deficit, since the serial position effect is related to ordinal positions rather than positions left or right of word-centre. It is argued that the patient's pattern reflects incomplete activation of lexical-orthographic representations. Our data are consistent with models of lexical activation in which the activation of letter nodes is a function of ordinal position.

PERCEPTUA.ND LEXICA.ACTORS IN A CAS.F LETTER-BY-LETTER READING

We report the case of a letter-by-letter reader (MJ) who showed normal processing of single letters and who could normally access the orthographic input lexicon when presented with letter names for aural recognition, or when allow ed enough tim e to process a visually presented letter string. However, MJ showed severe difficulties in simultaneously processing multiple letters and other simple visual stimuli. Furthermore, she does not have normal access to lexical orthographic representations and their meanings when stimuli are presented for too brief a time to allow for serial processing of the letter string. We found no evidence of (partial) lexical or semantic access without corresponding recognition of the letters in a word: No signs of implicit reading were observed w hen the input stimuli were controlled for the relevant visual features; “implicit reading” was only obtained under conditions that allowed sophisticated guessing. This pattern of results is interpreted as indicating that LBL reading (at least in MJ) results from damage to prelexical processing mechanisms. In MJ's case, the deficit reflects the degraded transfer of information from a normal visual processing system in the right hemisphere to a normal language processing system in the left hemisphere.

Distinguishing Representation Deficits and Processing Deficits in a Case of Acquired Dysgraphia

The same acquired disorder of spelling may be due to deficits affecting lexical representations of word spelling or deficits affecting the mechanisms that process those representations. This study sought to distinguish these possibilities in a dysgraphic patient. The integrity of the patient's lexical orthographic representations was assessed by having him decide whether or not pairs of words presented auditorily rhymed. Although the patient was impaired on a variety of spelling tasks and with all types of stimulus material, he showed a normal effect of spelling on the rhyme task. Like normal subjects, he was faster at deciding that words rhymed when they were spelled similarly (e.g. tool-cool) than when they were spelled dissimilarly (e.g. rule-cool) and slower at deciding that words did not rhyme when they were spelled similarly (e.g. toad-broad) than when they were spelled dissimilarly (e.g. code-broad). Therefore, as the patient's lexical representations of word spelling seemed to be generally intact, his spelling problems were probably due to difficulty in processing those representations.