INTRODUCTION

When the development of motor patterns in normal or abnormal infants and children is studied longitudinally, such investigations are always carried out within a theoretical concept, which is sometimes made explicit. Often, however, which theories and views on development and neural functions are held by the authors can only be conjectured. Since the methods of investigation and interpretation of results are closely related to the theoretical frame of reference in which these studies are carried out, it is useful to review new findings on early motor development as they contain certain new aspects for the theoretical approach to longitudinal studies. This chapter deals with empirical and mostly longitudinally collected data within the framework of development neurology, and is restricted to early human development.

The build-up of a movement repertoire in the fetus

An excellent illustration of the above-mentioned importance of theoretical background is represented by the history of fetal studies. A scientific interest in fetal movements has existed for more than 100 years. Preyer, in his famous book Die spezielle Physiologie des Embryo (1885), reports that fetal movements can be heard with the stethoscope at 12 to 16 weeks of pregnancy, i.e. before fetal movements are felt by the expectant mother. His comparative studies of embryonic and fetal motility were very much in the mould of nineteenth century natural historians, but they led him to a full acceptance of spontaneous motor activity in the human fetus. This idea became lost for nearly a century, with the rapidly growing dominance of reflex theory.