An association between dyslexia, left-handedness, and immune disorders was investigated in 734 Norwegian grade 6 children, aged 12 years, at the Center for Reading Research, Stavanger, Norway, and the Department of Psychology, University of Bergen. In the sample studied, 10% of students were dyslexic, 8% were left-handed, 35% had allergic symptoms, and 6% were asthmatics. 67% of left-handed dyslexic children had immune disorders(P>.05); 42% of left-handed children with immune disorders had dyslexia(P<.01); and 32% of dyslexic children with immune disorders were left-handed(P<.05). Of the three factors, handedness was the most important association. [1]
COMMENT. The Geschwind theory postulates a single factor underlying dyslexia, left-handedness, and immune disorders. The results of this study suggest that left-handedness and dyslexia are more important than immune disorders in a possible three-way association of these conditions.