Effects of a structured multisensory phonics-based intervention on children identified as showing risk signs for dyslexia: a longitudinal study in Brazilian public schools

Introduction This study evaluated the effects of a structured intervention protocol, grounded in systematic and multisensory phonics instruction, on reading development in children identified as showing risk signs for dyslexia through a multifactorial protocol. Methods Seventy-six preschool and early elementary students were classified into three risk levels (mild, moderate, significant) based on phonological awareness, rapid automatized naming (RAN), and short-term/working memory. The intervention consisted of four progressive cycles (28 sessions in total). Cycles I and II involved small-group preventive sessions targeting phonological awareness, oral language, and early literacy concepts, supported by phonics-based materials and multisensory activities. From Cycle III onward, students were divided into two support groups: Risk Level 1 (small-group prevention) and Risk Level 2 (individual intensive support). Literacy development was monitored at five timepoints (T1–T5). Analyses included chi-square tests ( χ 2 ), adjusted standardized residuals, Cramér’s V, and multinomial logistic regression. Results The intervention significantly increased the number of children achieving initial and consolidated literacy stages, with a reduction in those remaining at the pre-literacy stage. By T5, no significant differences remained between risk groups and the comparison group, indicating effectiveness of the intervention in promoting similar developmental trajectories. A small subset of students showed persistent difficulties, underscoring the need for ongoing individualized support. Differentiated response patterns across risk levels confirmed the predictive validity of the early identification protocol, demonstrating its utility for selecting children most in need of preventive and intensive intervention. Conclusion A structured multisensory and systematic phonics-based intervention applied to children identified through early risk identification effectively supported those at risk for dyslexia. Findings highlight the potential of preventive and intensive interventions to reduce literacy gaps and the importance of sustained individualized support for students with persistent challenges, offering practical implications for inclusive education policies in public schools.