The influence of phonetic component position, lexicality, and word length on omission and substitution errors in Chinese neglect dyslexia

Background Neglect dyslexia (ND) is an acquired reading disorder that is associated with unilateral spatial neglect (USN), typically resulting from right hemisphere damage. While the majority of related research has focused on alphabetic written languages, identifying omission and substitution errors linked to specific cognitive mechanisms, it remains unclear whether similar error patterns appear in Chinese ND, given the unique structural characteristics of the Chinese reading system.Aim This study aimed to determine (1) whether phonetic component position in pictophonetic characters modulates error types, (2) how lexicality and word length influence errors in compound words, and (3) how first versus last characters contribute to omission and substitution errors in Chinese ND.Methods and Procedures Sixteen right-hemisphere stroke patients with left USN completed a tailored reading battery comprising pictophonetic characters (left/right phonetic components), two-/three-character real words and pseudowords, and three-character real word pairs with first- or last-character substitutions. Omission and substitution error rates were quantified. Analyses included mixed-effects models, and Fisher’s exact tests.Outcomes and Results The position of the phonetic component in pictophonetic characters influenced omission errors but had no effect on substitution errors. In compound words, omission errors increased with word length and for pseudowords, reflecting attentional and lexical demands. Substitution errors showed a strong lexicality effect (near-absent in real words) but no word length effect, indicating a pre-lexical origin. The first character was critical for error patterns.Conclusions and Implications The findings reveal a double dissociation between error types in Chinese ND. Substitution errors appear to be driven by visual crowding, while omission errors are affected by structural and lexical factors. This supports error-based subtyping and tailored interventions: perceptual training for substitution errors, and spatially-guided attention training for omission errors.