BODY SWAY AND VIBRATION PERCEPTION THRESHOLDS IN NORMAL AGING AND IN PATIENTS WITH POLYNEUROPATHY

Body sway and vibration perception in the lower limbs were measured in 32 normal subjects and 25 patients with peripheral neuropathies; nerv e conduction studies were also performed in the patients with neuropat hies. Body sway was measured by means of force-plate posturography, an d three methods were used to assess vibration perception: a neurothesi ometer, a semiquantitative tuning fork, and the bone vibrator of a con ventional audiometer. Body sway and vibration perception were increase d in the patients with peripheral neuropathies, and there was signific ant correlation between these measures. These findings, together with the lack of correlation between sway and muscle strength, indicate tha t the main source of unsteadiness in these patients is the loss of pro prioceptive information. Vibration perception and body sway did not co rrelate with the electrophysiological variables, indicating that these measures assess different aspects of peripheral nerve function. In al l subjects there was close correlation between vibration perception as assessed by the neurothesiometer and the audiometer, indicating that the audiometer could be used to screen proprioceptive function in pati ents with balance disorders. In normal subjects age correlated with vi bration perception (measured with the neurothesiometer and audiometer) and also with body sway standing on foam. This suggests that the incr eased body sway in elderly people may partly be due to reduced proprio ception in the lower limbs.