LV R2X(%) R2X(cum)(%) R2Y(%) R2Y(cum)(%) Q2Y(%) Q2Y(cum)(%) 1 14.24 14.24 88.95 88.95 73.56 73.56 2 11.49 25.72 6.73 95.68 18.37 78.42 3 8.40 34.12 2.38 98.06 -10.87 76.07 R2X, R2Y: fraction of the variance of descriptor matrix (X) and class response (Y) explained by each latent variable (LV) in %, Q2Y: fraction of the variance predicted (cross-validated) in %; R2X(cum), R2Y(cum): cumulative explained variation and Q2Y(cum) predicted variation in %.

Table 2: Summary statistics of PLS-DA model for the ALS vs CN comparison. A three component model utilizes 34.12% of X for modeling 98.06% and predicting 76.07% of the response variation.