A modern representation of neuromuscular excitability in the form of intensity-duration curve or line.

In 1939 Katz had mathematically defined the intensity-duration curve, and it has been used in this form to this day. In 1990, Ljubin and Knesaurek proposed the new mathematical and graphic form of the intensity-duration curve as a line. The new form, both graphic and mathematical, is considered to be more accurate and it is a new contribution to research into neuromuscular excitability. Besides, this method also makes possible a modern, numerical presentation of the clinical results and gives a new insight into observation of neuromuscular excitability, both in physiological conditions and pathology. Stephen's graphs, as well as of other authors, showing the intensity duration curves can also be transformed into lines, by translating them into the coordinate system with both logarithmic axes.