Reading disability (RD) and math disability (MD) frequently co-occur, but what factors contribute to their comorbidity (RDMD) still need to be explored. Most existing studies are conducted in Western context, while research on RDMD in a Chinese sample was scarce. The present study aimed to investigate the cognitive profiles of Chinese children (Mage = 9.16, SD = 0.61; 48 % girls). The sample consisted of four groups: groups with RD only (N = 71), MD only (N = 76), RDMD (N = 75), and a control group with neither disorder (N = 87). The results revealed that RD and MD shared common deficits. The cognitive profiles of RDMD generally showed additive patterns, with under-additive effects observed in graphic sequence reasoning, numerical magnitude comparison Stroop, and symbolic magnitude comparison tasks. Phoneme deletion and non-symbolic magnitude comparison were significant predictors of the comorbidity. These findings indicated that the cognitive profiles of comorbid RDMD in Chinese children exhibited a complex pattern.
Educational relevance and implications statement
This study investigated the cognitive profiles of RD, MD, and RDMD in Chinese children. Four learning disability groups were screened out from 1517 Chinese children (Grades 2–3). Utilizing 16 cognitive tasks, we investigated the cognitive profiles of RD, MD, and RDMD. The current research revealed RD and MD share common cognitive deficits. The profiles of comorbid RDMD demonstrated a complex pattern, supporting the multi-deficit model. Specifically, the profile of RDMD is characterized by the sum of language- and math-specific deficits, along with additional cognitive factors related to RD and MD (additivity). Meanwhile, in tasks like graphic sequence reasoning, numerical magnitude comparison Stroop, and symbolic magnitude comparison, significant interactions between RD and MD were observed, indicating under-additivity. Phoneme deletion and non-symbolic magnitude comparison emerged as unique predictors of the comorbidity. These findings are crucial for designing educational interventions, particularly in preventing and treating RDMD. Interventions should address these cognitive deficits through both formal and informal educational curricula, with a focus on graphic sequence reasoning, numerical magnitude comparison Stroop, and symbolic magnitude comparison. Furthermore, it is crucial to address cognitive deficits like phonological awareness and non-symbolic numerical processing early in the educational process to prevent further comorbid RDMD. These are especially important for some Chinese primary school children, who have started formal education and suffered from learning disabilities.