2010 BC Guide in Determining Fitness to Drive

Chapter 16: Vestibular DisordersBACKGROUND16.1 About vestibular disordersThe vestibular system - or balance system - is a sensory apparatus localized in the inner ears. Itprovides information to the nervous system about a person’s movement and orientation in space.Vestibular input contributes to: control of balance gaze stabilization so that a person can see clearly while moving, and spatial orientation so that a person knows their position with reference to gravity.Vestibular disorders may result in: vertigo dizziness disturbed vision such as involuntary eye movement, and illusory movement of the visual world as a result of head movement.A hallmark of vestibular disorders is vertigo, a term that refers to the sensation of spinning orwhirling resulting from a disturbance in balance (equilibrium). Most commonly an attack ofvertigo generally lasts less than one minute (30 seconds is typical) but it may last up to 60minutes. A small number of people may experience vertigo lasting as long as 24 hours and aneven smaller number may experience vertigo lasting up to, or beyond, 30 days.Disorders of the vestibular system are classified as either peripheral or central.Peripheral vestibular disordersPeripheral disorders are characterized by episodic fluctuating symptoms; the dominant symptomis ‘true spinning vertigo’, that is the sensation of motion when no motion is occurring relative toearth’s gravity. Peripheral vestibular disorders typically occur as a single acute episode or asrecurrent acute episodes. However, complete bilateral hypofunction may result in severe andconstant disequilibrium and motion sensitivity.The most common peripheral vestibular disorders and the typical duration of an episodic eventare shown in the following table.Disorderbenign paroxysmal positioning vertigo (BPPV)vestibular neuronitis (labyrinthitis)Meniere’s DiseaseDuration20-30 secondsTends to be single attacklasting days to weeks20 minutes – 24 hours149