What are the steps to perform the HINTS (Head Impulse Test, Nystagmus, Test of Skew) exam on a patient presenting with acute vertigo?

How to Perform the HINTS Exam

The HINTS exam consists of three sequential bedside tests—Head Impulse Test, Nystagmus assessment, and Test of Skew—performed specifically in patients with Acute Vestibular Syndrome (continuous vertigo lasting hours to days with nausea, head motion intolerance, nystagmus, and gait unsteadiness) to differentiate stroke from peripheral vestibular causes. 1, 2

Patient Selection Criteria

Only perform HINTS in patients with Acute Vestibular Syndrome (AVS), defined as: 1, 2

• Acute, persistent, continuous vertigo lasting hours to days
• Nausea and/or vomiting
• Head motion intolerance
• Spontaneous nystagmus present
• Gait unsteadiness

Do NOT use HINTS for: 2

• Brief, positional vertigo (like BPPV)
• Chronic recurrent symptoms
• Episodic vertigo

Step-by-Step Examination Technique

1. Head Impulse Test (HI)

This test assesses the vestibulo-ocular reflex: 1

• Have the patient fixate on your nose or a target directly in front of them
• Hold the patient's head firmly with both hands
• Deliver a rapid, small-amplitude (10-20 degrees), unpredictable head thrust to one side
• Observe whether the eyes stay fixed on target or require a corrective saccade

Interpretation: 1, 2

• Abnormal (positive) test: Eyes move off target with the head, then make a corrective saccade back to target = peripheral cause
• Normal (negative) test: Eyes remain fixed on target despite head movement = concerning for central/stroke

2. Nystagmus Assessment (N)

Evaluate the direction and characteristics of spontaneous nystagmus: 1

• Have patient look straight ahead, then 30 degrees left, then 30 degrees right
• Observe the direction of nystagmus in each gaze position
• Note whether nystagmus changes direction with gaze

Interpretation: 1, 2

• Unidirectional horizontal nystagmus (beats in same direction regardless of gaze) = peripheral cause
• Direction-changing nystagmus (beats left on left gaze, right on right gaze) = central cause
• Pure vertical nystagmus = central cause

3. Test of Skew (TS)

This detects vertical misalignment of the eyes: 1

• Have patient fixate on your nose or a target
• Cover one eye with your hand for 2-3 seconds
• Uncover that eye and observe for any vertical corrective movement
• Repeat with the other eye

Interpretation: 1, 2

• Any vertical corrective movement when uncovering either eye = skew deviation present = central cause
• No vertical movement = no skew = peripheral pattern

Critical Interpretation Rules

Any ONE central finding indicates stroke risk and requires urgent MRI: 1, 2

• Normal head impulse test (no corrective saccade), OR
• Direction-changing or vertical nystagmus, OR
• Skew deviation present

All three findings must be peripheral to suggest benign vestibular neuritis: 1

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

Examiner Training Requirements and Accuracy

HINTS accuracy depends critically on examiner expertise: 1

• Trained specialists achieve sensitivity of 96.7% and specificity of 94.8% for detecting stroke 1
• Subspecialists achieve significantly higher specificity (97.6%) compared to non-subspecialists (89.1%) 1
• Most emergency physicians have not received adequate training to perform HINTS with sufficient accuracy as a first-line test before MRI 1

If performed by non-expert examiners in the emergency department, do not rely on HINTS alone to exclude stroke—proceed with MRI for high-risk patients. 1

Mandatory Imaging Regardless of HINTS Results

Proceed directly to MRI with diffusion-weighted imaging if any of these high-risk features are present: 1, 2

• Age over 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

Common Pitfalls to Avoid

A normal neurologic examination does NOT exclude stroke—up to 75-80% of posterior circulation stroke patients lack focal neurologic deficits on standard examination. 1, 3

HINTS is more sensitive than early MRI when performed correctly—MRI has a false-negative rate of approximately 15% within the first 48 hours, particularly for small posterior fossa strokes. 1, 4

Beware of false reassurance from peripheral HINTS patterns—one study found that 54% of confirmed peripheral vestibulopathy cases showed positive (central-appearing) HINTS signs, particularly normal head impulse tests. 5 This emphasizes the importance of considering the entire clinical context and risk factors.

For suspected anterior inferior cerebellar artery (AICA) stroke, add bedside hearing testing to HINTS, which increases sensitivity to 99.2%. 1