182 normal children from 6 to 14 years old presenting learning difficulties were neurologically examined. A 149 items questionaire covering the intrauterine, peri and post partum life were answered by parents and afterwards detailed in interview consultation. Special procedures on motor skill were added to the usual neurological examination, to text motor performance differences between antimeres. Dextrallity appeared in 156 cases (85.71%), sinistrality in 8 (4.39%) and in 18 cases (9.89%) the lateral dominance could not be determined. The concept of ambidextrallity was rejected for the bilateral equivalence in motor competence was not found in the subjects. The results lead to interpret the lateral dominance as a proportional distribution of motor performances in the right and left halves of the body in a process of constant improvement of motor skills which takes place in and belongs to the development of interdependence between the individuals and their environment. It is by way of such interrelationships that the significant motor activity (praxias) is acquired. Lateral dominance is considered a dynamic mechanism resulting from this interactive process which aim is directed together with other mechanisms to provide and improve the human being survival.
lateral dominance; praxias; struture-performance relation; facilitation; automatism