Spectrum of developmental disabilities. Continuum of motor dysfunction

The spectrum of developmental disabilities encompasses a diverse group of interrelated disorders with multiple manifestations resulting from brain dysfunction. Motor disability has been highlighted, as it is the most frequent presenting sign of developmental disability. Such disability may vary from severe to minimal. Severe disability, or cerebral palsy, is well appreciated, as are the additional associated disabilities that affect habilitation. Mild to minimal motor disability (mild to minimal cerebral palsy), because it is usually nonhandicapping, is less frequently appreciated as a marker of brain dysfunction. Further delineation of the child's nonmotor abilities is necessary in order to define the scope of the disability. Cognitive limitation is not an important cause for the gross motor delay seen in children with mental retardation. It is our postulation that the motor deficit is on the basis of mild to minimal cerebral palsy. This diagnosis is frequently obscured by the mental retardation.