Comorbidity Between Reading Disability and Math Disability Concurrent Psychopathology, Functional Impairment, and Neuropsychological Functioning

• Published in: Journal of learning disabilities Vol. 46; no. 6; pp. 500 - 516
• Main Authors: Willcutt, Erik G., Petrill, Stephen A., Wu, Sarah, Boada, Richard, DeFries, John C., Olson, Richard K., Pennington, Bruce F.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.11.2013; SAGE Publications and Hammill Institute on Disabilities; SAGE PUBLICATIONS, INC
• Subjects: Adolescent; Behavior Disorders; Child; Cognition Disorders - epidemiology; Cognition Disorders - physiopathology; Cognitive Ability; Colorado; Comorbidity; Comprehension; Consciousness; Control Groups; Diagnostic Tests; Disability; Diseases in Twins - epidemiology; Diseases in Twins - physiopathology; Dyscalculia - epidemiology; Dyscalculia - physiopathology; Dyslexia - epidemiology; Dyslexia - physiopathology; Etiology; Experimental Groups; Female; Functional impairment; Humans; Impaired control; Internalization; Learning disabilities; Male; Mathematical Aptitude; Mathematics Achievement; Memory; Mental Disorders; Multiple Disabilities; Multiple Regression Analysis; Naming; Neuropsychological functioning; Neuropsychological Tests - statistics & numerical data; Neuropsychology; Outcome Measures; Participant Characteristics; Phonemes; Physical Disabilities; Predictor Variables; Psychopathology; Reading Achievement; Reading comprehension; Reading Difficulties; Reading disabilities; Regression analysis; Screening Tests; Short term memory; Social Cognition; Special education; Stroop Color Word Test; Twins; Verbal memory; Wisconsin Card Sorting Test; Colorado; reading; BD; mathematics; behavior disorders
• ISSN: 0022-2194; 1538-4780; 1538-4780
• DOI: 10.1177/0022219413477476

Reading disability (RD) and math disability (MD) frequently co-occur, but the etiology of this comorbidity is not well understood. Groups with RD only (N = 241), MD only (N = 183), and RD + MD (N = 188) and a control group with neither disorder (N = 411) completed a battery of measures of internalizing and externalizing psychopathology, social and academic functioning, and 10 neuropsychological processes. Groups with RD only, MD only, and RD + MD were significantly impaired versus the control group on nearly all measures, and the group with RD + MD was more impaired than the groups with MD and RD alone on measures of internalizing psychopathology, academic functioning, and 7 of 10 neuropsychological constructs. Multiple regression analyses of the neuropsychological measures indicated that deficits in reading and math were associated with shared weaknesses in working memory, processing speed, and verbal comprehension. In contrast, reading difficulties were uniquely associated with weaknesses in phoneme awareness and naming speed, and math deficits were uniquely associated with weaknesses in set shifting. These results support multiple-deficit neuropsychological models of RD and MD and suggest that RD and MD are distinct but related disorders that co-occur because of shared neuropsychological weaknesses in working memory, processing speed, and verbal comprehension.