A Study on the Lateral Dominance of Hands, Feet and Eyes in the Children with Brain Damages

Abstract

The incidence of the mixed dominance in relation to the age was studied in 1,009 healthy children aged 3 to 11 years, 59 children with severe mental retardation aged 4 to 16 years and 71 children with minimal brain dysfunction syndrome aged 4 to 12 years. Left-handedness, left-eyedness and mixed dominance were found in 5.5%, 29.2% and 28.2% of normal children respectively. These values decreased with age, but it became invariable after 7 years of age. The most important factor of mixed dominance was left-eyedness. The incidence of left-handedness in the children with severe mental retardation (32.2%) was significantly higher than that in the normal children (P< 0.01). The incidence of left-eyedness in the children with behavior disorders (48.1%) and with minimal brain dysfunction syndrome (45.1%) were significantly higher than that in the normal children (P< 0.01). There were no correlation between left-handedness and reading disabilities. The incidence of mixed dominance was significantly higher than that in the normal children in all the children with learning disabilities or mental retardation (34.4%), behavior disorder (44.9%), history of convulsive seizures (42.1%), history of delayed speech (47.2%), severe mental retardation (50.1%) and minimal brain dysfunction syndrome (44.4%). Mixed dominance was more frequent in the cases with severe brain damage. These findings suggested that the examination of lateral dominance in hands, “feet and eyes might be useful to evaluate the brain damage. © 1982, The Japanese Society of Child Neurology. All rights reserved.