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Cerebellar Exam




  • The term nystagmus is used mainly to refer to jerk nystagmus, abnormal rhythmic eye movements that may be a sign of cerebellar disease.

Jerk Nystagmus

    • How to Perform

    • Ask the patient to look at your finger, held ~50cm in front of their eyes (in primary position). Repeat in the extremes of left and right lateral gaze, as well as in superior and inferior gaze.
    • Look For

    • Slow drifting movements of the eye interspersed with corrective fast saccadic movements.Note whether these movements are horizontal, vertical or torsional.
  • The direction of the nystagmus is describes as the direction of the fast-beating movement.
    • Interpretation

    • Physiologic nystagmus - a few beats of horisontal nystagmus at the extremes of lateral gaze
    • Positional nystagmus - transient (
    • Upbeat nystagmus - downward slow movements with upward fast movements in primary position
    • Downbeat nystagmus - upward slow movements with downward fast movements
    • Causes of Jerk Nystagmus

    • Physiologic
    • Congenital
    • Central (brainstem / cerebellum) - multiple sclerosis, stroke, trauma, tumour
    • Visual impairment - intra-ocular, optic nerve (II), total blindness
    • Vestibular disturbance - Meniere’s, benign paroxysmal positional vertigo, labyrinthitis
    • Drugs - alcohol, sedatives, phenytoin

Pendular Nystagmus

  • Pendular nystagmus is less common, and manifests as equal movement to both sides (i.e. no fast or slow phase).
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