The Role of Orthographic Knowledge, Vocabulary Size, and Reading Experience in Orthographic Processing during Reading: Evidence from Event-Related Potentials

Temporal dynamics of letter processing revealed by multivariate pattern analysis of EEG data.

Abstract This paper outlines the design and development of an experimental test intended to evaluate the cognitive-linguistic factors that influence the acquisition of Chinese as a second language (L2) literacy among native (L1) Italian secondary school students. The study focuses specifically on learners with reading and writing impairments, as well as learners with diagnosed developmental dyslexia. These learners form a group known as “impaired readers”. The performance of this group is then compared with that of typically developing learners (TDLs). The theoretical framework is based on the multiple deficit model of developmental dyslexia and research on Chinese native (L1) readers. The battery includes tasks targeting phonological awareness, orthographic processing, rapid automatised naming (RAN), working memory, visual attention and morphological awareness. These tasks have been adapted from assessments used with L1 Chinese learners and meticulously tailored for L1 Italian learners of L2 Chinese. This manuscript presents the comprehensive rationale, structure and detailed adaptation process of the assessment battery, alongside its data collection methodology. This foundational work establishes a robust methodological tool for future empirical investigations, with the ultimate aim of informing targeted interventions and educational strategies through analysis of the collected dataset. A subsequent publication will present a comprehensive report of the findings from administering the battery and their implications.

Insights into the multi-factorial nature of reading difficulties: exploring phonological, visual, and attentional challenges in children.

Mirror invariance is the cognitive tendency to perceive mirror-image objects as identical. Mirrored letters, however, are distinct orthographic units and must be identified as different despite having the same shape. Consistent with this phenomenon, a small, localized region in the ventral visual stream, the Visual Word Form Area (VWFA), exhibits repetition suppression to both identical and mirror pairs of objects but only to identical, not mirror, pairs of letters (Pegado et al., 2011), a phenomenon named mirror invariance “breaking”. The ability of congenitally blind individuals to “break” mirror invariance for pairs of mirrored Braille letters has been demonstrated behaviorally (de Heering et al., 2018, Korczyk et al., 2024). However, its neural underpinnings have not yet been investigated. Here, in an fMRI repetition suppression paradigm, congenitally blind individuals (8 males and 10 females) recognized pairs of everyday objects and Braille letters in identical (“p” and “p”), mirror (“p” and “q”), and different (“p” and “z”) orientations. We found repetition suppression for identical and mirror pairs of everyday objects in the parietal and ventral-lateral occipital cortex, indicating that mirror-invariant object recognition engages the ventral visual stream in tactile modality as well. However, repetition suppression for identical but not mirrored pairs of Braille letters was found not in the VWFA, but in broad areas of the left parietal cortex and the lateral occipital cortex. These results suggest that reading-related orthographic processes in blind individuals depend on different neural computations than those of the sighted.

Efficient written word recognition is crucial for effective reading and comprehension. However, whether deaf people recognize written words through the same psychological mechanisms as those of hearing individuals remains controversial. The present study utilized mouse-tracking technology to examine the differences in the transposed-character effect and the substituted-character effect during the recognition of four-character Chinese words between prelingually deaf adults (PDAs) and their hearing counterparts. The PDAs were found to experience greater difficulties in recognizing Chinese written pseudowords although both groups exhibited significant transposed-character effects with lower accuracies, longer response times, and larger areas under the curve in transposed-character pseudoword conditions. Furthermore, the PDAs demonstrated more pronounced substituted-character effects in the substituted-character pseudoword conditions compared with hearing people. These results revealed that Chinese written word recognition of the hearing participants followed the multiple-route model derived from alphabetic languages, while PDAs tend to rely more on whole-word and orthographic processing due to their limited access to phonological information. This study can provide theoretical guidance and potential targeted intervention measures for enhancing the reading abilities of deaf individuals. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

ABSTRACT Phonewriting involves a unique multitasking demand: writers monitor suggestions above the keyboard while typing and deciding whether to select them. We investigated how word suggestions affect orthographic processing during word production. French young adults wrote dictated words on a smartphone, in conditions with and without suggestions. Keystroke data revealed that word suggestions influenced processing time during movement execution, increasing production time for short words but reducing it for long words. Suggestions slowed down writing due to the concurrent execution of keystrokes and preparation for a potential shift to suggestion selection. The presence of suggestions also decreased the number of errors and corrections, particularly in long words. The participants did not rely on suggestions systematically but followed strategies: they used them more frequently for orthographically inconsistent and long words, often at syllable boundaries. These findings highlight the dual nature of word suggestions—as sources of interference and as external supports that relieve memory load and improve accuracy.

One of the critical benchmarks for understanding orthographic processing during word recognition and reading is the transposed-letter effect (e.g., in lexical decision, CHOLOCATE [created by transposing two letters from CHOCOLATE] produces slower and more error responses than CHOTONATE). Two main theoretical frameworks explain this phenomenon: positional uncertainty models, which attribute the effect to uncertainty in letter position encoding that diminishes over time, and open bigram models, which propose a level of ordered pairs of letters between the letter and word levels that may be more resilient to decay. We designed two delayed lexical decision experiments to test whether the transposed-letter effect vanishes or persists at two time delays (750ms and 1,500ms). In Experiment 1, a robust transposed-letter effect in accuracy emerged at 750ms (9.6%) but diminished to a small (2.9%) yet reliable effect at 1,500ms. Experiment 2 replicated this pattern with a contrast manipulation on the critical letters (e.g., CHOLOCATE vs CHOTONATE), yielding a slightly smaller transposed-letter effect (2.0%) at 1,500ms. These findings demonstrate that positional uncertainty diminishes over time, yet residual orthographic overlap persists, particularly for a subset of participants, supporting hybrid accounts that combine bottom-up perceptual refinement with top-down contributions from shared sublexical codes (e.g., open bigrams).

Source reconstruction of clinical resting-state EEG reveals differences in power and functional connectivity in children with developmental dyslexia.

A similarity-based memory retrieval model to orthographic processing

Blindness has been shown to induce changes in the structural and functional organization of the brain. However, few studies have investigated the relationship between these structural and functional changes. In this study, we examined cortical thickness within occipital regions of interest in 38 early blind individuals and explored its relationship to functional activation during linguistic processing. Participants engaged in tactile Braille reading and auditory processing tasks involving words, pseudowords, and control conditions to assess various aspects of linguistic processing. Linear mixed models revealed a significant association between cortical thickness and functional activation in the occipital cortex during linguistic tasks. Specifically, lower cortical thickness in the middle occipital gyrus, the calcarine sulcus, and the parieto-occipital sulcus were linked to increased activation during orthographic processing in blind participants (Braille pseudowords vs. Braille nonsense-symbols). Similarly, lower cortical thickness in the calcarine sulcus and parieto-occipital sulcus was associated with greater functional activation during phonological processing (auditory pseudowords vs. auditory control). These findings align with prior research suggesting that structural and functional adaptations in the visual cortex of blind individuals may be influenced by developmental mechanisms such as pruning or myelination. This study highlights the interplay between cortical structure and functional reorganization in the blind brain.

Reversal errors (e.g., confusing b with d, or R with Я) are common in beginning readers and often persist in individuals with developmental dyslexia due to mirror invariance—an evolutionary-old perceptual tendency of processing mirror images as equivalent. This study investigated whether dyslexic adults still struggle with mirror-image discrimination when processing reversible letters (i.e., differing only by orientation; e.g., d, b, p) and nonreversible letters (i.e., differing also in shape; e.g., f, t, r). In a masked priming lexical decision task, one letter of the prime was manipulated by letter-type (reversible, nonreversible) and prime-condition: identity (e.g., judo, zero), control (judo, zero), mirrored-letter (jubo, zero), or rotated-letter (jupo, zero). Both dyslexic and neurotypical readers showed identity priming effects: faster recognition of target-words preceded by identity than control primes. Neurotypical readers also showed mirror and rotation costs, regardless of letter-type: slower word recognition after mirrored- or rotated-letter primes than an identity prime. In contrast, and for nonreversible letters only, dyslexics were as fast in recognizing target-words preceded by identity as by mirrored-letter primes (qualified by Bayesian statistics). These findings suggest that, despite extensive reading experience, orthographic processing by dyslexic college students remains residually sensitive to mirror invariance.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21092-5.

ABSTRACT Aim This study aimed to examine the benefits of combining spoken and written approaches in treating naming deficits in Chinese-speaking people with aphasia (C-PwA). Specifically, it examined whether participants’ naming accuracy would be improved by three different approaches – repetition approach (REP), repetition + written Chinese characters approach (REP+WC), and repetition + written Chinese Pinyin approach (REP+WP). Method & Procedures A single-subject experimental design was conducted with four post-stroke aphasia participants. 72 items were allocated across three treatment conditions and one control condition (18 items each). Each participant received 10 sessions per treatment condition, delivered five times weekly in randomized order. Treatment effects were analyzed using the contrastive dual-criteria method and effect size calculations. Outcomes & Results Visual analyses revealed naming improvements across all participants and treatment conditions. Effect size analysis showed meaningful improvements for all participants overall, with differential patterns across approaches. REP+WC demonstrated effectiveness in all four participants, while REP was effective in three participants and REP+WP in two participants. The control condition showed no meaningful effects except for one participant. Conclusions Chinese character writing combined with repetition (REP+WC) produced better outcomes compared to repetition alone or combined with Pinyin writing. These findings suggest the therapeutic value of orthographic processing in Chinese character writing for improving spoken naming in C-PwA, suggesting that REP+WC represents a viable clinical intervention for addressing naming deficits in this population.

Dysgraphia is a disorder that affects children's ability to write legibly and can impact overall written expression, spelling, and composition skills. Traditionally, dysgraphia is assessed through various tests that measure working memory, cognitive ability, and orthographic processing. These assessments are time-consuming and may require significant effort and resources to administer. This study presents two novel frameworks based on Deep Learning (DL) architectures, such as Spatially Enhanced SegNet (SE-SegNet) and Self-Attention U-Net (SAU-Net), to identify children with dysgraphia using handwritten text images based on gender. The proposed frameworks were trained and tested on a collected dataset, comprising 1,853 text images, and their performance was evaluated using accuracy, recall, precision, and the Mathew Correlation Coefficient (MCC). According to performance analysis, the SAU-Net framework was superior, achieving maximum accuracy at 99%, recall at 99.1%, precision at 98.5%, and MCC at 98.3%. The proposed approach provides an efficient and accurate method for identifying dysgraphia in children, supporting early detection for effective interventions and improving children's academic progress.

Letter processing plays a key role in visual word recognition. However, word recognition models typically overlook or greatly simplify early perceptual processes of letter recognition. We suggest that optimal transport theory may provide a computational framework for describing letter shape processing. We use representational similarity analysis to show that optimal transport cost (Wasserstein distance) between pairs of letters aligns with neural activity elicited by visually presented letters <225 ms after stimulus onset, outperforming an existing approach based on shape overlap. We additionally show that optimal transport can capture the emergence of geometric invariances (e.g., to position or size) observed in letter perception. Finally, we demonstrate that Wasserstein distance predicts neural activity similarly well to features from artificial networks trained to classify images and letters. However, whereas representations in artificial neural networks emerge in a computationally unconstrained manner, our proposal provides a computationally explicit route to modeling the earliest orthographic processes.

Abstract How does bilingualism affect orthographic processing across languages with different structures? This study investigates masked transposed-letter (TL) priming in Arabic-English bilinguals, comparing Arabic (a Semitic language with rigid orthography and weak TL effects) with English (an Indo-European language with flexible letter coding and strong TL effects). Using lexical decision tasks, we tested whether exposure to English enhances letter-coding flexibility in Arabic. Results showed robust TL priming in both languages, indicating that bilingual experience with English modifies Arabic orthographic processing, traditionally seen as resistant to letter transpositions. These findings suggest that bilingual orthographic processing is adaptable, with language-specific exposure reshaping letter-position encoding and enabling flexible word recognition across languages.

This study aimed to investigate the changes and deterioration in lexical processing caused by Alzheimer's disease (AD). It analyzed the differences in lexical processing between individuals with healthy controls, mild AD, and moderate AD as well as how these groups processed varying lexical aspects. A total of 180 older adults participated in the experiment, including 60 healthy controls, 60 with mild AD, and 60 with moderate AD. Each group was further divided into two subgroups, with each subgroup assigned to one of two different experiments. The experiments assessed the speed and accuracy of lexical processing in both orthography and meaning using compound words. Individuals with mild and moderate AD showed significant differences in the speed and accuracy of lexical processing, both in orthography and meaning, compared to healthy controls. When the prime character shared character-level units with the target word, it enhanced the accuracy of lexical processing in AD patients. Mild AD patients demonstrated a significant advantage in both the speed and accuracy of processing high-frequency words in terms of orthography and meaning, while moderate AD patients only showed a significant advantage in orthographic processing accuracy. The AD group showed no significant differences in the speed and accuracy of processing high- and low-transparency words in terms of orthographic and meaning processing. Lexical processing significantly deteriorated in individuals with AD, with a greater decline observed in those with moderate AD. Differences in lexical processing between mild and moderate AD patients highlighted the varying impact of the disease's severity.

Background/Objectives: Previous research has demonstrated that the initial letters of a word likely play a privileged role in visual word recognition, such that reading and visual recognition errors reflecting changes in this position are much less likely. For example, prior case studies of attentional dyslexia reported that participants were most accurate at rejecting nonwords formed by transposing a word’s first two letters (e.g., WONER from OWNER) compared to transpositions in later positions. The current study aimed to replicate and extend this finding in patients with posterior cortical atrophy (PCA), a neurodegenerative condition associated with visuospatial and attentional impairments. Methods: Two PCA patients completed lexical decision tasks involving five-letter real words and nonwords created either by transposing adjacent letters (in positions 1 + 2, 2 + 3, 3 + 4, or 4 + 5) or using matched nonword controls. To assess robustness, tasks were repeated across test–retest sessions. Stimuli were presented in both canonical horizontal and non-canonical vertical (marquee) formats. Accuracy, response bias, and sensitivity (d′) were estimated, with 95% confidence intervals derived from a nonparametric bootstrap procedure. Within-case logistic regressions were also conducted to illustrate the findings. Results: Both patients showed significantly higher accuracy and lower response bias for 1 + 2 transposition nonwords relative to other positions. This early-letter advantage persisted across test–retest observations and was maintained when words were presented in the vertical format, suggesting orientation-invariant effects. The bootstrap and regression analyses provided convergent support for these results. Conclusions: The findings provide novel evidence in PCA that the encoding of early letter positions operates independently of visual orientation and persists despite attentional deficits. This supports models in which the initial letters serve as a key anchor point in orthographic processing, highlighting the privileged and resilient status of early letter encoding in visual word recognition.

Electrophysiological activity predicts children's reading ability through orthographic awareness: Evidence from a cross-sectional and longitudinal study

This dataset captures responses from a lexical generation task designed to examine word production under structural constraints. Native Spanish speakers were presented with three-consonant strings and instructed to generate valid five-to-seven-letter Spanish words by inserting only vowels, maintaining the consonants in their original relative order. The task was conducted under time pressure and without semantic cues, allowing researchers to explore lexical access, phonotactic preferences, and the role of consonants and vowels in word formation processes. The dataset includes both item-level and participant-level files. Item-level data comprise individual responses with lexical frequency, word length, and response time. Participant-level data summarize age, gender, and aggregate lexical metrics per individual. This resource enables a range of investigations, including analyses of syllabic structures, relative consonant positioning, lexical diversity, and frequency effects. The dataset is encoded in UTF-8 CSV format and is directly compatible with standard data analysis environments. It offers a valuable tool for researchers studying lexical creativity and orthographic processing in Spanish.