vestibulo-ocular reflex; sinusoidal vertical axis rotational testing

Indications

• balance disorder
• assessment of accidental falls
• falls in the elderly

Clinical significance

• test of neural mechanism that keeps a visual image registered on the fovea during head movement
• evaluates the 3 components of the vestibulo-ocular reflex
  • labyrinth
  • vestibular nuclei in the brain stem
  • higher central vestibular connections

Procedure

• the patient shakes his/her head 'no' & 'yes' while wearing electrodes that monitor eye position & a small angular velocity sensor that measures head velocity
• 3 characteristics of the vestibulo-ocular reflex are computed
  • gain (ratio of eye velocity to head velocity)
  • phase (degrees by which the eye misses the target)
  • asymmetry (comparing gain moving right with gain moving left)

More general terms

• clinical procedure
• reflex