Which planes are used in the smooth pursuit neck torsion test when following the moving target?

• A. Vertical and diagonal
• B. Horizontal and vertical
• C. Horizontal only
• D. All planes

Answer: (B)

Smooth pursuit neck torsion tests how neck proprioception during torsion can influence the eyes’ ability to smoothly track a moving target. The moving target is used in the two principal ocular motor planes—horizontal and vertical—because tracking in these directions relies on distinct neural pathways and can reveal how cervical input affects pursuit differently across axes. Testing in just one plane might miss deficits, and moving in diagonal or all planes isn’t necessary to evaluate the primary smooth pursuit control during neck torsion. Horizontal and vertical tracking together provide a full enough picture of the eye–neck coordination involved.