A COMPARISON OF STANDING STEADINESS MEASUREMENTS FROM 2 DEVICES - COVARIATES AND NORMAL VALUES

A comparison of standing steadiness measurements from two devices: Cov ariates and normal values. NEUROTOXICOL TERATOL 18(1) 83-88, 1996.-Qua ntifying standing steadiness may be a useful method of detecting neuro toxicity in epidemiological studies. Unfortunately, use of quantitativ e standing steadiness outcomes in epidemiologic studies has been limit ed by lack of standardization of methods, insufficient availability of normative data, and inadequately characterized effects of covariates. Additionally, the current gold standard method, the force platform (F P), has been expensive and unwieldy for use in field studies. A relati vely inexpensive and portable head position monitor (HPM) has been int roduced as an alternate method for measuring standing steadiness. In t his study 211 subjects were tested with one or both devices using a co mmon testing protocol. The correlations between measurements obtained with the FP and the HPM were high and similar to those obtained during repeated measurements with each device separately. The effects of pot ential covariates on outcome measures were investigated. There was a s ignificant age x sex interaction in the FP standing steadiness measure ments in this population with decreased steadiness among older men but not older women. Information for estimating normal values for the out come measures is provided. This study suggests that measures of standi ng steadiness obtained with the HPM are similar, but not identical, to measures obtained with a conventional FP and that the HPM may be usef ul in field studies of occupational exposure to neurotoxicants.