Effect of positioning of the feet in posturography.

Static posturography has been developed from a basic research test to a widely used clinical tool for evaluating dizzy patients. Before any actual standardization can be achieved, however, several aspects of the test situations have to be evaluated, including the position of the feet. The quantitative significance of the standing position in posturographic measurements was evaluated with healthy volunteers studied under visual and nonvisual conditions, using 4 foot positions: heels together with the toes 30 degrees apart or at an angle of the volunteer's own choice, and the feet parallel and either 0 or 10 cm apart were studied separately. Each measurement was characterized in terms of 5 parameters (body sway velocity, vibration-induced shift of centre of force in anteroposterior and lateral directions, and maximum displacement of centre of force in the same directions). Body sway velocities were smallest when the feet were parallel and 10 cm apart. Although the position chosen by the subject was usually more stable than that with the toes 30 degrees apart, the difference was nonsignificant. According to our results, the standing position is not crucial in posturographic measurements provided that the distance between the heels is determined, and the subject can just as well choose the angle between the feet if the heels are kept together.