Directed Acyclic Graph (DAG) Representing Variables and Their Relationships. Arrows denote the direction of assumed relationships among selected variables. Note that the baseline Fugl-Meyer Assessment (FMA) for upper extremity (FMA-UE; outcome, circled in red) is not included in the DAG because it was used as a fixed adjustment variable in the model. BBT = box & blocks test; CST = corticospinal tract; FIM = functional independence measure; FMA-s = FMA for sensation; MAS = Modified Ashworth Scale (at biceps brachii); MEP = motor evoked potential; MRI = magnetic resonance imaging; NIHSS = National Institutes of Health Stroke Scale; Rehab = rehabilitation (exposure in hours, blue); SAFE = shoulder abduction and finger extension; TCT = trunk control test; TMS = transcranial magnetic stimulation.