How to Perform the HINTS Examination
The HINTS examination consists of three sequential bedside tests—Head Impulse Test, Nystagmus assessment, and Test of Skew—performed specifically in patients with Acute Vestibular Syndrome to differentiate stroke from peripheral vestibular causes, and when performed by trained specialists, it is more sensitive than early MRI for detecting posterior circulation stroke. 1
Patient Selection Criteria
HINTS is only valid for patients with Acute Vestibular Syndrome (AVS), defined by: 1
- Acute, persistent vertigo (not episodic)
- Nausea/vomiting
- Head motion intolerance
- Nystagmus present on examination
- Gait unsteadiness
Critical pitfall: Do not use HINTS for episodic vertigo or patients without nystagmus—the test is invalid in these populations. 1
Step 1: Head Impulse Test
Technique: 1
- Patient fixates on examiner's nose
- Examiner holds patient's head and rapidly rotates it 10-20 degrees to one side
- Observe if eyes stay fixed on target or require a corrective saccade
- Repeat for the opposite side
Interpretation:
- Abnormal (peripheral): Eyes drift off target, requiring a visible corrective saccade back to the examiner's nose 1
- Normal (concerning for central cause): Eyes remain fixed on target throughout the movement—this suggests stroke in a dizzy patient 1
Step 2: Nystagmus Assessment
Technique: 1
- Observe nystagmus in primary gaze (straight ahead)
- Test nystagmus in lateral gaze positions
- Note the direction and whether it changes with gaze position
Interpretation:
- Peripheral pattern: Unidirectional horizontal nystagmus that beats away from the affected ear, does not change direction with gaze 1, 2
- Central pattern (stroke): Direction-changing nystagmus in different gaze positions, pure vertical nystagmus (upbeat or downbeat), or bidirectional gaze-evoked nystagmus 1, 2
Critical red flag: Any downbeat component without torsional features strongly suggests a central lesion requiring immediate imaging. 2
Step 3: Test of Skew
- Patient fixates on a distant target
- Cover one eye, then uncover it while watching for vertical corrective movement
- Repeat for the opposite eye
- Look for any vertical realignment movement when uncovering
Interpretation:
- Abnormal (central): Any vertical corrective movement when uncovering either eye indicates skew deviation, suggesting brainstem or cerebellar pathology 3, 1
- Normal (peripheral): No vertical correction movements 1
HINTS Result Interpretation Algorithm
Any ONE central finding = stroke until proven otherwise: 1
- Normal head impulse test (no corrective saccade) OR
- Direction-changing or vertical nystagmus OR
- Skew deviation present
→ Urgent MRI with diffusion-weighted imaging required 1
All three peripheral findings = likely benign peripheral vestibular disorder: 1
- Abnormal head impulse test (corrective saccade present) AND
- Unidirectional horizontal nystagmus AND
- No skew deviation
Enhanced Sensitivity for AICA Stroke
Add bedside hearing testing to HINTS in all AVS patients, which increases sensitivity to 99.2% for detecting stroke. 1 Test for unilateral hearing loss, as anterior inferior cerebellar artery (AICA) strokes often affect the inner ear.
Mandatory Imaging Regardless of HINTS Results
Proceed directly to MRI 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
Critical Limitations and Pitfalls
Examiner expertise is paramount: Subspecialists achieve 97.6% specificity versus 89.1% for non-subspecialists. 1 Emergency physicians without specialized training should not rely on HINTS alone to exclude stroke—proceed with MRI for high-risk patients. 1
Common errors to avoid: