DEVELOPMENT OF NEW MUSCLE SYNERGIES IN POSTURAL CONTROL IN SPINAL-CORD INJURED SUBJECTS

The development of new patterns of postural control in patients with a complete thoracic spinal cord injury (SCI) during their active clinic al rehabilitation was studied. Especially the role of non-postural mus cles, like the latissimus dorsi (LD) and the trapezius pars ascendens (TPA), in maintaining and restoring sitting balance during standardize d bimanual task performance was investigated. Twelve patients, diagnos ed with an acute complete thoracic SCI between spinal cord level T2 an d T12, participated in a longitudinal experimental study. Changes in t he centre of pressure (CP) and electromyographic activity of the erect or spinae (ES) at level L3, T9 and T3, the LD, the TPA, the pectoralis major (PM), the serratus anterior and the oblique abdominal muscles w ere investigated at several moments in the rehabilitation process. Res ults show a gradual development of specific muscle activation patterns for both high and low thoracic SCI patients. These patterns seem to b e related to a combination of restoration of function of the ES-L3 and ES-TB in the low thoracic SCI subjects and increased compensatory mus cle use of the LD, TPA and PM in high SCI patients. The range in which low thoracic SCI patients can actively vary their CP increased slight ly during rehabilitation. (C) 1998 Elsevier Science Ltd. All rights re served.