HINTS exam

Definition

• A three-part physical exam test to rule out posterior/cerebellar stroke in patients presenting with acute vertigo, distinguishing peripheral (acute vestibular syndrome, i.e. labyrinthitis and vestibular neuritis) from central (stroke) pathology
  • Head impulse: tests vestibulo-ocular reflex (VOR)
  • Nystagmus
  • Test-of-Skew deviation: most commonly affected in brainstem strokes

Technique

• Preparation: patient seated across from examiner
• Examination
  • Head impulse, where the head is held by the examiner and rotated suddenly and sharply in one direction (patient's eyes should remain focussed on examiner's nose)
    • Peripheral: VOR may be impaired
    • Central: VOR usually preserved
  • Nystagmus
    • Peripheral: horizontal unidirectional nystagmus, increasing in intensity when the patient looks in the direction of the nystagmus fast phase
    • Central: may present as above, but also can present as bidirectional horizontal, or vertical or torsional nystagmus
  • Skew deviation, using the cover-uncover test to
    • Peripheral: normal cover-uncover test
    • Central: abnormal test

Interpretation

• If any of the three tests is not consistent with peripheral lesion (impaired head impulse, horizontal unidirectional nystagmus, and no skew deviation), then further investigations for cerebellar disease is warranted
• Mnemonic for danger signs is INFARCT (Impulse Normal, Fast-phase Alternating, Refixation on Cover Test)

Further Reading

• Kattah JC, et al.HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504-10.