What are the clinical tests for vertigo, including the HINTS (Head Impulse Test, Nystagmus examination, and Test of Skew) exam?

Clinical Tests for Vertigo, Including HINTS Exam

HINTS Examination: The Primary Bedside Tool for Acute Vestibular Syndrome

The HINTS (Head Impulse, Nystagmus, Test of Skew) examination is the most powerful bedside diagnostic tool for differentiating central from peripheral causes of acute vestibular syndrome, with sensitivity of 94-96.7% and specificity of 86.9-94.8% when performed by trained specialists—superior to early MRI for detecting stroke. 1, 2, 3

When to Use HINTS

HINTS is specifically designed for patients with Acute Vestibular Syndrome (AVS), defined by: 1, 2

• Acute, persistent vertigo (not brief episodes)
• Nausea/vomiting
• Head motion intolerance
• Nystagmus present
• Gait unsteadiness

Critical caveat: HINTS should NOT be used for brief, positional vertigo (like BPPV) or chronic recurrent symptoms—it is only for acute, continuous vertigo lasting hours to days. 2, 4

The Three Components of HINTS

1. Head Impulse Test (HI)

• Rapidly rotate the patient's head horizontally while they fixate on your nose 5, 3
• Abnormal (corrective saccade) = peripheral cause 2, 6
• Normal (no saccade) in a dizzy patient = CENTRAL CAUSE—high concern for stroke 2, 7

2. Nystagmus Assessment (N)

• Observe direction of spontaneous nystagmus in primary gaze and lateral gaze 2, 3
• Unidirectional horizontal nystagmus = peripheral cause 6
• Direction-changing nystagmus OR pure vertical nystagmus = CENTRAL CAUSE 2, 6, 7
• Must assess with visual fixation removed (Frenzel goggles or video goggles) to avoid missing nystagmus suppressed by fixation 4

3. Test of Skew (TS)

• Perform alternate cover test while patient fixates on target 2
• Look for vertical corrective movement when uncovering either eye 2
• Any vertical misalignment = CENTRAL CAUSE 2

HINTS Plus: Enhanced Sensitivity

Add bedside hearing testing to standard HINTS, increasing sensitivity to 99.2% for detecting stroke, particularly anterior inferior cerebellar artery (AICA) territory infarcts. 2, 3

• Clinical HINTS Plus: 95.3% sensitive, 72.9% specific 3
• New unilateral hearing loss with AVS suggests AICA stroke 2

Critical Performance Requirements

Examiner Expertise Matters Dramatically

HINTS accuracy depends heavily on proper training—subspecialists achieve 97.6% specificity versus 89.1% for non-subspecialists. 2, 8

• Most emergency physicians lack adequate training to perform HINTS with sufficient accuracy as first-line test before MRI 2
• When performed by emergency physicians without specialized training, HINTS is not adequately sensitive to exclude stroke 2
• If performed by non-expert examiners, do not rely on HINTS alone—proceed with MRI for high-risk patients 2

Mandatory Imaging Regardless of HINTS Results

Proceed directly to MRI with diffusion-weighted imaging if ANY of the following: 2

• 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

Up to 75-80% of posterior circulation stroke patients lack focal neurologic deficits on standard examination, so normal neurologic exam does NOT exclude stroke. 6

Additional Bedside Tests for Vertigo

Dix-Hallpike Maneuver

• Primary test for benign paroxysmal positional vertigo (BPPV) 1, 5
• Triggers brief (<60 seconds) rotatory nystagmus with latency of 5-20 seconds 5
• Most common pitfall: Failing to perform this test systematically leads to misdiagnosis and inappropriate treatment 4

Positioning Examination

• Systematic evaluation for positional triggers is essential 5, 4
• Absence of typical positional nystagmus is concerning for alternative diagnosis 4

Advanced Vestibular Function Testing

When to Order Comprehensive Testing

Reserve ENG/VNG and other vestibular function tests for unclear diagnoses, atypical presentations, or failed initial treatment—NOT for straightforward BPPV or typical Ménière's disease. 9

Appropriate indications include: 9

• Diagnosis remains unclear after history and examination
• Atypical clinical presentation
• Equivocal or unusual nystagmus on positional testing
• Additional symptoms suggesting CNS or otologic disorders
• Multiple concurrent peripheral vestibular disorders suspected
• Patients remain symptomatic following treatment
• Frequent BPPV recurrences

Specific Advanced Tests

Video Head Impulse Test (vHIT)

• Assesses high-frequency vestibulo-ocular reflex for all three semicircular canals 9, 5
• Useful for vestibular neuritis and superior canal dehiscence syndrome 9

Vestibular Evoked Myogenic Potentials (VEMP)

• Cervical VEMP (cVEMP) tests sacculus function 9, 5
• Ocular VEMP (oVEMP) tests utriculus function 9, 5
• Evaluates otolith organs not assessed by traditional tests 9

Caloric Testing (ENG/VNG)

• Low-frequency stimulus testing horizontal semicircular canal 9, 5
• Records nystagmus in response to warm/cool water or air 9

Common pitfall: Unnecessary vestibular testing leads to delays in diagnosis, increased costs, and patient discomfort, while normal results do not rule out vestibular disorders like Ménière's disease. 9

Algorithmic Approach to Vertigo Evaluation

1. Determine symptom pattern: Brief positional episodes vs. acute continuous vs. chronic recurrent 1, 5

2. For acute continuous vertigo (AVS):

   • Check for high-risk features requiring immediate MRI 2
   • If no high-risk features and trained examiner available: perform HINTS/HINTS Plus 2, 3
   • Any central finding (normal head impulse, direction-changing nystagmus, skew deviation) = urgent MRI 2
   • If peripheral pattern but high-risk patient = still obtain MRI 2

3. For brief positional vertigo:

   • Perform Dix-Hallpike maneuver 1, 5
   • If positive = treat BPPV with canalith repositioning 9
   • If negative or atypical = consider comprehensive vestibular testing 9

4. For chronic recurrent vertigo:

   • With hearing loss/tinnitus = likely Ménière's disease 1
   • With brainstem symptoms = consider vertebrobasilar insufficiency 1
   • Consider comprehensive vestibular testing if diagnosis unclear 9