Methods for evaluation of postural control adaptation

New methods were developed to determine the dynamic changes of postural con trol during the initial exposure to large perturbances of stance. The adjus tments of postural control over time in measured anteroposterior torque, we re investigated in ten normal subjects. Perturbations of stance were evoked by two high intensity vibrators applying pseudorandom stimulation either t o the calf muscles or the paravertebral muscles of the neck. The new method s use a system identification approach, which distinguishes between feedbac k control, adaptation of postural responses and adaptation to stimulus. Thi s approach makes it possible to quantify motion dynamics and complexity, st imulus impact and adjustments of postural control. Quantification of the di fferent adaptive responses could be useful for diagnostic purposes, in eval uating treatment efficacy and patient progress in rehabilitation programs. (C) 2000 Elsevier Science B.V. All rights reserved.