Development of spontaneous leg movements in infants with and without periventricular leukomalacia

The main question asked in the present study was whether support could be f ound for the notion that supraspinal influences on the generation of sponta neous kicking movements become increasingly apparent in the first half-year after birth. In comparing groups of infants with and without damage in tra cts connected with the cortex surrounding the central sulcus, such support would consist of the finding that similar patterns of spontaneous kicking a re observed early in development, whereas differences between groups should occur with increasing age. Using 3-D registrations, the spontaneous kickin g movements of 19 infants with differing degrees of periventricular, lobar, and subcortical leukomalacia based on white matter CWM) abnormalities on u ltrasound were compared to those of 10 healthy control infants at 6, 12, 18 . and 26 weeks of corrected age. Magnetic resonance imaging recordings were used to identify the location and severity of the brain lesions. Infants w ith extensive lesions in the periventricular and lobar WM with or without d iffuse lesions in the subcortical WM showed a decreased variability on some spatial and temporal parameters of kicks. More importantly, these infants showed a different developmental course for intralimb couplings when compar ed to the other infants; they were unable to dissociate tight intralimb cou plings at 18 and 26 weeks. As all of these infants had substantial damage o f the corticospinal tracts, these findings suggest that these tracts are in volved in the regulation of intralimb joint dissociations between 4 and 6 m onths of age. However, caution is needed as areas outside those in which th e corticospinal tracts are located could be damaged as well and most of the infants with moderate to severe lesions in the corticospinal tract had add itional psychomotor problems. For interlimb couplings and most of the spati al and temporal parameters of kicks, no differences were found between grou ps. This strengthens the claim that inter- and intralimb couplings are orga nized in fundamentally different ways.