Behavioral Indices of Brain Injury in School Children12

Behavioral diagnosis of brain damage in children rests on the assumption that such damage will be reflected in an impairment in behavioral efficiency and that appropriate observational methods will bring this impairment to light. It is well for us to realize, at the outset of this discussion, that this assumption is by no means always supported in practice. Whatever be the reasons for the phenomenon, it must be conceded that one can and does encounter children with obvious cerebral defects whose behavior appears to be well within normal limits. It may be that these children have not suffered behavioral disturbance as a consequence of their brain damage. Or it may be that behavioral impairment will be disclosed in them as advances in our understanding of brain-behavior relations and further refinements in our techniques of observation are made. In either case, one must accept the fact that not every child with brain damage will show demonstrable behavioral impairment and hence that not all children with cerebral defects can be identified by current methods of behavioral diagnosis. It is impossible to say what proportion of brain-damaged children are in this category. Since, by its very nature, the category consists of children whose behavior gives no cause for complaint, it is probably larger than most of us suspect. In this connection, it is worth bearing in mind that experimental ablation studies on infant animals indicate that early brain damage may result in very little or no specific behavioral deficit and that when such deficit does appear, it is always less severe than that caused by a comparable lesion in adult animals. Many years ago, Kennard (i9) showed that the end result of ablation of the motor areas in infant primates was limited to some impairment in fine motor skills while comparable lesions in older animals led to much more severe deficit. Recently, Benjamin and Thompson (4) com