Standing posture of craniocerebral injured patients: Bi-lateral reactive force patterns

Bi-lateral force measurements on the supporting limbs in postural sway while standing still were carried out to evaluate postural stability of craniocerebral injured (CCI) patients. Brain pathology of these patients was characterised by CT scans and MRI, as well as by their cognitive and behavioural disturbances. Normal subjects of the same age group were tested as controls. From the force tracings obtained, three oscillation frequencies were identified, of which the middle frequency, (corresponding to 1.5 Hz) was selected for subsequent processing and analysis. Weight-bearing imbalance was defined in the vertical direction. In the horizontal plane, two parameters were defined: Sway Total Activity to represent the vector summation of the absolute values of the horizontal force components acting on both legs; and Asymmetry, to express the difference in activities between the two legs. The results presented disclose the reactive force patterns acting on each of the legs of CCI individuals, in comparison with normal individuals. Sway activity was found to be significantly higher in the CCI group as compared with that of the normal controls. These results justify the necessity to study the activity of each of the legs, rather than that corresponding to the resultant forces acting on the whole body.