Subjects wore a light bicycle helmet with an attached laser light. This was shone on a wall target and zeroed in the neutral cervical position by the researchers. Patients and control subjects were then instructed to turn to the side and then return to the neutral starting position. CAD patients had significantly more repositioning error, suggesting a deficit in proprioceptive input from the cervical spine. The authors also noted correlations between repositioning errors, reduced range of motion and oculomotor dysfunction, but no details were provided.
Smooth pursuit is a measurement of the ability to smoothly track a moving object.
Overshoot and undershoot are the ocular neurological equivalents of pastpointing. Again, a consecutive series of CAD patients was compared to matched controls. Smooth pursuit gain was measured after turning the head 45 degrees to the right and left. Based on the differences between dizzy and non-dizzy patients, the authors surmised the former. It is in the upper cervical spine where most proprioceptive activity is generated.