Linear Discriminant Analysis in contiguous 3 severity groups. (O = Mild; Δ = Moderate; + = Severe). DA was used to derive the direction in space (a vector), associated with the difference between the groups. DF 1 for mild vs moderate and DF 2 for moderate vs severe. Note: Circles represent regions where each groups mean can be found. The size of the circle indicates each group's variability.