The vertical posture of patients with impaired sensorimotor integration was compared with that in healthy subjects before and after 30 sec of involuntary cervical muscle contraction. Studies were performed on seven patients with impaired sensorimotor integration. The movement trajectories of the center of mass were recorded for 30 sec in the standing position with the eyes open and closed and on foam rubber with the eyes open before and after involuntary contraction of the cervical muscles. The areas of oscillation of patients standing with the eyes open and on foam rubber were greater than those in healthy subjects, while the mean positions of the center of mass standing with the eyes open and closed were closer to the axis of the talocrural joints. Closing of the eyes had a smaller destabilizing effect on patients than on healthy subjects. Contraction of the cervical muscles for 30 sec in healthy subjects led to a backward displacement of the center of pressure toward the axis of the talocrural joints, especially on standing with the eyes open, along with a decrease in the length of the center of pressure curve, especially its frontal components, on standing on foam rubber. In patients, the aftereffects of involuntary cervical muscle contraction consisted of a reduction in the area of oscillations on foam rubber and a relative increase in frontal oscillations while standing with the eyes closed. These results lead to the conclusion that standing in patients with impaired sensorimotor integration was more sensitive to changes in proprioceptive than visual afferentation, while 30-sec involuntary cervical muscle contraction brought measures of vertical stability in patients closer to age-normal values.