[Clinical significance of general movements].

Human fetuses and young infants have a repertoire of distinct patterns of spontaneous movements. A set of these movement patterns are known as general movements (GMs), which were defined by Prechtl as gross movements involving the whole body, and lasting from a few seconds to several minutes, or longer. GMs are characterized by the variable sequence of arm, leg, neck and trunk movements which begin gradually, wax and wane in intensity, force and speed, and end gradually. Extension and flexion movements of the arms and legs are mostly complex and variable because of superimposed rotations and frequent, slight changes in direction, which make the movements fluent and elegant. Initially GMs are complex, and then differentiate into single movements. GMs show no change during the fetal period, but change in early infancy into writhing, fidgety, oscillating, saccadic and swipes & swaps. Hadders-Algra indicated that on EMG, burst duration of phasic activity shortens, burst amplitude attenuates and tonic background decreases with development. In contrast to normal GMs that are smaller and monotonous in trajectory, abnormal GMs include poor repertoire of GMs, cramped-synchronized GMs, chaotic GMs, absent fidgety, and abnormal fidgety, that are periodic and monotonous, showing no developmental change. For example, a normal twin showed elliptic or round trajectory of GMs that became smaller with age, whereas the other with periventricular leukomalacia and cerebral palsy had periodic and rectilinear trajectory showing no developmental change. GMs, especially fidgety, correlate with neurological prognosis of infants. Einspieler reported that GMs' sensitivity and specificity for neurological prognosis of high risk infants are 96% and 95%, respectively. Clinical significance of GMs 1. includes non-invasive, secure and easy observation, 2. high coincidence between trained observers, 3. high reliability 78-98%, mean 90% and, 4. correlation of abnormal GMs with the presence and degree of brain damage.