Peripheral sensation. Vibration sense was measured with
an electronic device that generated a 200-Hz vibration of
varying intensity. The vibration was applied to the tibial tuberosity
via a rubber stopper of 1cm in diameter and was measured
in microns of motion perpendicular to the body surface. Three
readings in the ascending mode and 3 readings in the descending
mode were made, and an average of these 6 measurements
was recorded. Tactile sensitivity was measured with a
Semmes-Weinstein pressure aesthesiometer.b This instrument
contained 20 nylon filaments of equal length, with varying
diameter. The filaments were applied to the center of the lateral
malleolus, and measurements were expressed as logarithms of
the bending force in milligrams. Proprioception was measured
by a lower-limb matching task while subjects were seated.
Errors were recorded with a protractor inscribed on a vertical
clear acrylic sheet (60601cm) placed between the legs.24