This concurrent minimum SD includes a subject's best performance even if he or she had episodes of greater unsteadiness at other times during the test, and therefore is a conservative measure for comparison between groups having varying balance stability. According to Schenkman, et.al. The normal elderly male's trace depicts all four stages, as expected. Stage 1 begins at the beginning of motion to the inflection point of the second positive peak as the head accelerates forward. Momentum transfer ends at the bottom of the negative peak as the subject's center of mass travels anteriorly and upward.
Extension ends and stabilization begins after the rise of the negative peak.
The female stroke subject's trace is similar to the normal elderly male's trace in form. Each of the significant peaks are present, except with less amplitude and more frequent fluctuations throughout the activity. The settling period also extends further than that for the normal subject. This subject has left hemiparesis. She has also been diagnosed with diabetes, high blood pressure, and arthritis.