Prediction matrix based on multinomial regression.

Observed classes are in rows, predicted in columns. Overall correct classification rate was 86.1%. Class 3 was omitted because of small sample size. Classes 1, 2 and 4 show a very high predictive probability using diagnostic delay and bulbar onset. However the predicted Class 2 appears to include cases that appeared in Class 1. This may require the use of other variables not included in this study to better distinguish between Classes 1 and 2.