Visual processing and dyslexia: evidence from stress marker assignment in Greek

The present exploratory study investigated whether targeted visual intervention can improve stress assignment during oral reading in children with developmental dyslexia. The Greek orthography uniquely marks lexical stress with a diacritic visual mark, allowing testing in-text sensitivity to identify fine visual-linguistic information. A total of one hundred participants took part in the study. Seventy children with developmental dyslexia (Mean age = 9.3, SD = 1.07) were assigned to attend either a visual or an auditory single-session intervention. The visual stimuli consisted of visual discrimination and crowding tasks aiming to enhance visual processing abilities, whereas the auditory stimuli comprised matched discrimination and crowding tasks. Data were collected from pre- and post-test oral reading tests, and error types were analysed and compared to a control group (N = 30, Mean age = 9.7, SD = 0.8). Results revealed a significant improvement in lexical stress assignment after the visual single-session exposure, with no significant changes in segmental errors or fluency. These findings suggest that visual intervention may improve the decoding of fine orthographic features, especially in transparent orthographies where visual markers carry critical linguistic weight. The study highlights the role of visual-based interventions as a complementary approach to support the reading development of children with dyslexia.