What diagnostic tests are indicated for evaluating vertigo?

Diagnostic Tests for Vertigo

The diagnostic evaluation of vertigo is fundamentally clinical and relies on bedside positional maneuvers—specifically the Dix-Hallpike and supine roll tests—rather than laboratory or imaging studies, which should be reserved only for patients with red-flag features suggesting central pathology. 1

Essential Bedside Maneuvers (First-Line Diagnostic Tests)

Dix-Hallpike Maneuver (Gold Standard for Posterior Canal BPPV)

• Perform this test bilaterally on every patient presenting with positional vertigo by moving the patient from upright to supine with the head turned 45° to one side and neck extended 20° beyond horizontal. 1, 2
• Positive findings include: torsional upbeating nystagmus with 5-20 second latency, crescendo-decrescendo pattern lasting <60 seconds, fatigability with repeated testing, and accompanying subjective vertigo. 1, 2
• The test has 82% sensitivity and 71% specificity for posterior canal BPPV, though a negative result does not rule out BPPV and may require repeat testing at a separate visit. 1
• A negative Dix-Hallpike mandates proceeding to the supine roll test to evaluate for lateral canal BPPV. 1

Supine Roll Test (For Lateral Canal BPPV)

• Perform this test when the Dix-Hallpike is negative or shows horizontal nystagmus by rapidly rotating the patient's head 90° to each side while supine. 1, 2
• Lateral canal BPPV accounts for 10-15% of BPPV cases and is commonly missed when this test is skipped. 1, 2
• Observe for geotropic nystagmus (fast component toward the ground, most common) or apogeotropic nystagmus (fast component away from the ground). 1, 3

HINTS Examination (For Acute Vestibular Syndrome)

• Use the Head Impulse, Nystagmus, Test of Skew examination to differentiate vestibular neuritis from posterior circulation stroke in patients with continuous vertigo lasting days. 3
• This bedside test has 92.9% sensitivity and 83.4% specificity for central causes when performed by trained clinicians. 3

Nystagmus Assessment (Critical Diagnostic Feature)

Peripheral Vertigo Nystagmus Characteristics

• Horizontal with rotatory component, unidirectional, suppressed by visual fixation, fatigable with repeated testing, and has brief latency before onset. 4

Central Vertigo Nystagmus Characteristics (Red Flags)

• Pure vertical (upbeating or downbeating) without torsional component, direction-changing without head position changes, not suppressed by visual fixation, and does not fatigue with repeated testing. 4, 2
• Downbeating nystagmus on Dix-Hallpike without torsional component mandates urgent MRI. 4
• Baseline nystagmus present without provocative maneuvers is a red flag for central disease. 4, 2
• Gaze-evoked nystagmus (direction changes with eccentric gaze) is typical of central lesions, especially vertebrobasilar insufficiency. 4

Imaging Studies (Only When Red Flags Present)

When Imaging Is NOT Indicated

• Do not order radiographic imaging or vestibular testing in patients meeting diagnostic criteria for BPPV with typical nystagmus on Dix-Hallpike testing and no additional concerning symptoms. 1
• CT head has <1% diagnostic yield for isolated dizziness and misses posterior fossa strokes in the acute phase. 1, 3
• MRI has only 4% diagnostic yield in patients with isolated dizziness without neurologic findings. 1

When Urgent MRI Brain (With Diffusion-Weighted Imaging) Is Mandatory

• Severe postural instability with falling 1, 4, 3
• New-onset severe headache accompanying vertigo 4, 3
• Any additional neurologic symptoms (dysarthria, dysmetria, dysphagia, sensory/motor deficits, diplopia, Horner's syndrome) 4, 3
• Downbeating nystagmus on Dix-Hallpike without torsional component 4, 3
• Purely vertical nystagmus without torsional component 4, 3
• Failure to respond to appropriate peripheral vertigo treatments (e.g., canalith repositioning) 4, 3
• Baseline nystagmus without provocative maneuvers 4, 3
• Positive Romberg test (indicates central pathology requiring imaging before Dix-Hallpike) 3

Specialized Imaging

• MRI head and internal auditory canal without contrast is first-line for persistent vertigo with neurologic symptoms and can detect acute brain lesions in 11% of patients with acute persistent vertigo even without focal neurologic deficits. 3
• MRA head and neck can detect vertebrobasilar insufficiency in episodic vertigo that cannot be confidently categorized as peripheral. 3
• CT temporal bone without contrast is indicated for conductive hearing loss without middle-ear mass to detect otosclerosis, ossicular chain erosion, or superior semicircular canal dehiscence—not for routine vertigo evaluation. 1, 3

Audiometric Testing

• No recommendation for routine audiometry in diagnosed BPPV. 1
• Consider audiometry when auditory symptoms suggest Ménière's disease (fluctuating hearing loss, tinnitus, aural fullness) or other inner ear pathology. 3
• An abnormal Weber test mandates formal hearing evaluation to differentiate conductive from sensorineural loss. 4

Laboratory Testing

• Routine blood tests (CBC, serum chemistry) are not recommended as standard practice for BPPV diagnosis, which accounts for 85-95% of vertigo cases and is diagnosed clinically. 3
• Reserve laboratory tests for specific clinical scenarios: autoimmune panels for progressive fluctuating bilateral hearing loss with concurrent vision/skin/joint problems; serologic testing for suspected Lyme disease or otosyphilis presenting with vertigo and severe otalgia, fever, or sudden bilateral hearing loss. 3

Critical Pitfalls to Avoid

• Do not assume a normal neurologic examination excludes stroke: 75-80% of posterior circulation strokes causing vertigo lack focal neurologic deficits initially, and approximately 10% of cerebellar strokes present identically to peripheral vestibular disorders. 4, 2, 3
• Do not skip the supine roll test when Dix-Hallpike is negative, as lateral canal BPPV is commonly missed. 2, 3
• Do not rely solely on patient descriptions of "spinning" or "dizziness"—focus on timing and triggers to categorize into acute vestibular syndrome (days), spontaneous episodic (minutes-hours), triggered episodic (<1 minute), or chronic (weeks-months). 3, 5, 6
• Isolated transient vertigo may precede vertebrobasilar stroke by weeks to months, typically lasting <30 minutes without hearing loss, with gaze-evoked nystagmus and severe postural instability. 4
• Multiple peripheral vestibular disorders can coexist (e.g., BPPV with Ménière's disease or vestibular neuritis), requiring careful evaluation. 4

Follow-Up Protocol

• Reassess all patients within 1 month after initial observation or treatment to confirm symptom resolution or identify persistent BPPV or underlying peripheral vestibular/CNS disorders. 1, 3
• Repeat the Dix-Hallpike test at follow-up to confirm ongoing BPPV or other vestibular pathology if symptoms persist. 3