In evaluating patients with acute vestibular syndrome to distinguish between a potential stroke and a benign cause such as vestibular neuritis, the HINTS examination relies on three clinical tests to interpret the results in a systematic manner.

The interpretation stems from a combination of:

- Horizontal head impulse test:
  - "Abnormal" indicates a likely benign cause.
  - "Normal/untestable" raises suspicion for a dangerous cause, such as a stroke.

- Observation of nystagmus:
  - "Direction-fixed horizontal nystagmus" aligns with a benign condition.
  - "Direction-changing horizontal nystagmus/untestable" may indicate a dangerous condition.

- Test of skew:
  - "Absent skew deviation" suggests a benign outcome.
  - "Skew deviation/untestable" points towards a dangerous pathology.

For the assessment to conclude with a benign interpretation—the HINTS examination being benign—all three observations must align:
- The head impulse test is "Abnormal."
- The nystagmus is "Direction-fixed horizontal."
- The skew test shows "Absent skew deviation."

If any of the following are observed:
- A "Normal/untestable" response in the horizontal head impulse test,
- "Direction-changing horizontal nystagmus/untestable" during the observation of nystagmus,
- "Skew deviation/untestable" in the test of skew,

The examination concludes with a "HINTS exam is dangerous" result, warranting further investigation to rule out a stroke.

This systematic approach helps clinicians in making prompt decisions based on the combinations of these specifically observed clinical signs.

The HINTS (Head-Impulse, Nystagmus, Test of Skew) examination is a clinical tool used in the evaluation of patients presenting with acute vestibular syndrome (AVS). AVS is characterized by sudden onset of prolonged, continuous vertigo, unsteady gait, nausea or vomiting, nystagmus, and head-motion intolerance. The HINTS examination is used to differentiate between a central cause of AVS, such as a stroke, and a peripheral cause, such as vestibular neuritis.

The HINTS examination consists of three components: the head impulse test, observation for nystagmus, and the test of skew. A "central" pattern on the HINTS examination (normal head impulse test, direction-changing nystagmus, or skew deviation) is highly suggestive of a stroke, while a "peripheral" pattern (abnormal head impulse test, horizontal or horizontal-torsional nystagmus, and no skew deviation) suggests a peripheral cause.

The HINTS examination is particularly useful in the emergency department setting, where rapid differentiation between central and peripheral causes of AVS is critical. It has been shown to be more sensitive than early MRI in detecting strokes in patients with AVS.

Exclusion

HINTS examination for stroke in acute vestibular syndrome

HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging.