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The relationship between eye stabilization reflexes, smooth pursuit eye movements and the
range of motion of the cervical spine in healthy individuals.
B.K Ischebeck1,2, J de Vries1, M Janssen1, G.J. Kleinrensink1, M.A. Frens1, .J.N. van der Geest1
1 Dept Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
2 Spine and Joint Centre, Rotterdam, the Netherlands.
Physicians currently do not have methods to objectively determine the severity of the
complaints of chronic neck pain patients. Earlier research has suggested that ocular
stabilization reflexes, used to stabilize the visual image on the retina, may have been altered
in patients with chronic neck pain.
Although straightforward measurement of (spinal) proprioception is still impossible,
neurophysiological research has revealed an alternative sensorimotor measurement via the
cervico-ocular reflex (COR), which receives sensory input from neck proprioception. Changes
in COR are therefore likely to reflect changes in neck proprioception-, and recording of eye
reflexes might help to objectively assess the severity of the complaints of neck pain patients.
Our hypothesis is that reflexive eye movement measurements can assist into making the
connection between functional impairments and symptoms for chronic neck pain patients.
As a start in determining the symptom-profile we measured healthy controls. Subjects were
restrained in a chair using seatbelts, and their head was fixed with a bite bar. Rotations of
the chair and/or head were controlled via computer. Eye movements were recorded with an
infrared eye-tracking device (EyeLink 2.04, SensoMotoric Instruments, Germany), and range
of motion were measured using a CROM-device. We correlated the characteristics of three
eye stabilization reflexes-, [the COR, vestibular-ocular reflex (VOR) and the optokinetic reflex
(OKR)], to the subject’s ability to track a moving target [Smooth Pursuit (SP) eye movements]
at different head positions over the (ROM) of the cervical spine. Preliminary results suggest
that the relationship between eye stabilization reflexes, SP and ROM and that this relation
depends on the orientation of the head, and we hypothesize that this relationship will vary
for patients with chronic neck pain.