For a study, the researchers assessed the diagnostic usefulness of flexion-extension central motor conduction time. About 227 patients with CSM were taken under consideration. Researchers acquired CMCT recorded from the abductor pollicis Brevis muscle. All patients underwent a dynamic CMCT outcome during neck flexion and extension and a static analysis during the neutral neck. CMCT was delayed with flexion (P<0.01) and extension (P<0.01) compared with neutral neck position. Patients with MC grades 1 and 2 showed significant lag in CMCT during flexion and extension. No considerable lag by neck motion was noted for those in the MC grade 3. Researchers also calculated the amount of CMCT variation according to MC grade change (G0, G1, G2) by neck motion. Delta-CMCT of both G1 and G2 were significantly larger than those of G0 in both flexion and extension. In the neutral neck, the CMCT showed a difference between MC grades 1 and 3. Researchers also displayed significant delay with high signal intensity on T2 MRI. More than one-third of the patients whose CMCT was within the normal range in the neutral neck presented abnormal CMCT in neck flexion (35.3%) and extension (37.8%). CMCT was observed to be slower in both neck flexion and neck extension than in the neutral neck position.