Standardization of rotational chair testing across laboratories has not bee
n achieved because of differences in test protocol and analysis algorithms.
The Interlaboratory Rotational Chair Study Group was formed to investigate
these differences, Its first study demonstrated significant variability in
calculated results using actual patient data files, No estimation of accur
acy could be made, however, because the "true" values of response parameter
s were unknown. In this study we used simulated "patient" data files to fur
ther explore the differences among analysis algorithms. We found a high deg
ree of agreement and accuracy across laboratories using automated analysis
of high signal-to-noise/low-artifact data for gain, phase, and asymmetry, V
ariability increased significantly for the lower signal-to-noise ratio/high
er artifact files, Operator intervention generally improved accuracy and de
creased variability, but there were cases in which operator intervention re
duced accuracy.