What is the procedure for performing the HINTS (Head Impulse, Nystagmus, Test of Skew) exam?

How to Perform the HINTS Exam

The HINTS exam is a three-step bedside oculomotor examination performed in patients with acute vestibular syndrome to differentiate central (stroke) from peripheral causes of vertigo, and should only be used in patients with continuous vertigo, spontaneous nystagmus, nausea/vomiting, head motion intolerance, and gait unsteadiness. 1

Patient Selection Criteria (Critical First Step)

Before performing HINTS, confirm the patient has Acute Vestibular Syndrome (AVS) with ALL of the following: 1, 2

• Acute, persistent, continuous vertigo (not episodic or positional)
• Spontaneous nystagmus visible without provocation
• Nausea/vomiting
• Head motion intolerance
• Gait unsteadiness

Do NOT use HINTS for patients with intermittent or positional symptoms—this is a common pitfall that dramatically reduces accuracy. 3

The Three Components (Performed in Order)

1. Head Impulse Test (HI)

Technique: 1, 2

• Have the patient fixate on your nose
• Grasp the patient's head firmly with both hands
• Instruct the patient to keep their eyes locked on your nose
• Rapidly rotate the head 10-20 degrees to one side (unpredictable timing and direction)
• Observe if the eyes stay fixed on target or require a corrective saccade

Interpretation:

• Abnormal (peripheral): Eyes move with the head and require a visible corrective saccade back to target 1
• Normal (concerning for central): Eyes remain fixed on target throughout the maneuver, indicating intact vestibulo-ocular reflex 1, 2

2. Nystagmus Assessment (N)

Technique: 1, 2

• Observe spontaneous nystagmus in primary gaze (straight ahead)
• Have patient look 30 degrees to the right, then 30 degrees to the left
• Document the direction of the fast phase in each gaze position

Interpretation:

• Unidirectional horizontal nystagmus (peripheral): Fast phase beats in the same direction regardless of gaze position 1
• Direction-changing nystagmus (central): Fast phase changes direction with gaze (e.g., right-beating in right gaze, left-beating in left gaze) 1, 2
• Vertical or purely torsional nystagmus (central): Always suggests central pathology 1

3. Test of Skew (TS)

Technique: 1, 2

• Have patient fixate on your nose at distance
• Cover one eye for 2-3 seconds
• Uncover that eye and observe for vertical corrective movement
• Repeat with the other eye
• Look for any vertical misalignment requiring correction

Interpretation:

• Skew deviation present (central): Either eye makes a vertical corrective movement when uncovered, indicating brainstem involvement 1, 2
• No skew deviation (peripheral): No vertical correction movements 1

Overall HINTS Interpretation

ANY ONE of the following indicates CENTRAL cause (stroke until proven otherwise): 1, 2

• Normal head impulse test (eyes stay fixed on target)
• Direction-changing nystagmus in eccentric gaze
• Skew deviation present

ALL THREE of the following suggest PERIPHERAL cause: 1

• Abnormal head impulse test (corrective saccade)
• Unidirectional horizontal nystagmus
• No skew deviation

Critical Caveats and Pitfalls

Examiner expertise is paramount: When performed by trained specialists (neuro-ophthalmologists, neuro-otologists), HINTS achieves 96.7% sensitivity and 94.8% specificity, but non-specialists achieve significantly lower accuracy (89.1% specificity). 1, 4

Emergency physicians without specialized training should NOT rely on HINTS alone to exclude stroke—proceed with MRI for high-risk patients regardless of HINTS results. 1, 3

Proceed directly to MRI (bypass HINTS) if ANY of the following are present: 1

• Age >50 years with vascular risk factors (hypertension, diabetes, smoking, atrial fibrillation)
• Focal neurologic deficits (diplopia, dysarthria, dysphagia, limb weakness)
• New severe headache or neck pain
• Severe imbalance disproportionate to vertigo

False reassurance from peripheral HINTS: Up to 54% of peripheral vestibulopathy cases can show "positive" (central-appearing) HINTS findings, particularly normal head impulse tests. 5 When in doubt, image.

HINTS Plus Enhancement

Add bedside hearing testing (finger rub or whisper test) to increase sensitivity to 99.2% for detecting AICA (anterior inferior cerebellar artery) stroke, which can present with acute hearing loss. 1

Imaging Recommendations

If HINTS suggests central cause: Obtain urgent MRI with diffusion-weighted imaging (DWI), which is superior to CT for detecting posterior circulation stroke. 1, 6

Note: Early MRI (<24-48 hours) can be falsely negative in 12-15% of posterior circulation strokes, making properly performed HINTS more sensitive than early imaging when done by experts. 1, 2