Journal of Dental Research, Vol 58, 1333-1336, Copyright © 1979 by International & American Associations for Dental Research Online Journals
Trend analysis of jaw jerk action potential-amplitude data
S. E. Widmalm, H. Gill and S. Widmalm
The amplitude of the jaw jerk action potential (MSP) is a parameter with
potential diagnostic value. It has apparently a large and irregular
variation which has not yet been subjected to a thorough analysis. It is
important to know if samples of MSP contain trends. The occurrence of
trends indicates that the average value is influenced in a principally
different way by changes in the number of observations per sample than if
trends do not occur. If, for instance, there is a positive linear trend in
the data, this means that the average value is larger if the number of
observations is small. Samples of MSPs therefore were recorded, using
surface EMG electrodes in the masseter and the anterior temporal muscles of
young and elderly subjects, and subjected to trend analysis. Trends of the
1--4th grade occurred in 51% of the samples. Both positive and negative
linear trends were found and had about the same frequency. The trend
components were, however, randomly distributed. Comparisons between groups
may therefore be made without the claim of trend-free samples. This
significantly facilitates the use of the parameter MSP-amplitude, since it
is difficult to obtain samples which have a normal and identical
distribution.
