What bedside tests differentiate central from peripheral vertigo?

Bedside Tests to Differentiate Central from Peripheral Vertigo

The most reliable bedside approach combines nystagmus examination with the Dix-Hallpike maneuver and HINTS testing (when performed by trained specialists), prioritizing specific red-flag nystagmus patterns that mandate immediate neuroimaging. 1

Nystagmus Characteristics: The Primary Discriminator

Peripheral Vertigo Nystagmus

• Horizontal with rotatory (torsional) component, unidirectional regardless of gaze direction, suppressed when the patient fixates on a visual target, fatigable with repeated testing, and has a 5–20 second latency before onset. 1
• The nystagmus beats away from the affected ear and resolves within 60 seconds during positional testing. 1

Central Vertigo Nystagmus (Red Flags)

• Pure vertical nystagmus (up-beating or down-beating) without any torsional component is the single strongest indicator of central pathology and mandates urgent MRI. 1, 2
• Direction-changing nystagmus that switches direction with changes in gaze (left-beating when looking left, right-beating when looking right) without any change in head position. 1
• Baseline nystagmus present without any provocative maneuvers (spontaneous nystagmus at rest). 1
• Nystagmus that does not fatigue with repeated testing and is not suppressed by visual fixation. 1

Dix-Hallpike Maneuver: Positional Testing

Technique

• Move the patient from seated to supine, turning the head 45° to the side being tested and extending the neck approximately 20° backward; perform bilaterally. 1

Peripheral Pattern (BPPV)

• Torsional and up-beating nystagmus with 5–20 second latency, crescendo-decrescendo intensity, fatigues with repeat testing, and resolves within 60 seconds. 1

Central Pattern (Red Flag)

• Immediate onset (no latency), persistent nystagmus that does not resolve, purely vertical without torsional component, or down-beating nystagmus—all require urgent neuroimaging. 1

HINTS Examination: For Acute Vestibular Syndrome Only

Critical caveat: HINTS achieves 96.7% sensitivity and 94.8% specificity only when performed by trained neuro-specialists; emergency physicians without specialized training should not rely on HINTS alone to exclude stroke. 3

When to Use HINTS

• Reserved for patients with acute vestibular syndrome: continuous vertigo lasting days, nausea/vomiting, head-motion intolerance, nystagmus, and gait unsteadiness. 3
• Approximately 25% of acute vestibular syndrome cases are stroke, and 75–80% of posterior-circulation strokes lack focal neurologic deficits on standard examination. 3

HINTS Components

1. Head Impulse Test (HIT)

• Abnormal (corrective saccade) = peripheral vestibular dysfunction. 3
• Normal in a dizzy patient = raises concern for central cause (stroke). 3

2. Nystagmus Assessment

• Unidirectional horizontal nystagmus = peripheral. 3
• Direction-changing or vertical nystagmus = central. 3

3. Test of Skew

• Cover and uncover each eye while the patient fixates on a target; any vertical corrective movement indicates skew deviation and suggests brainstem or cerebellar pathology. 3

HINTS Interpretation

• Any one central finding (normal head impulse, direction-changing/vertical nystagmus, or skew deviation) mandates urgent MRI with diffusion-weighted imaging. 3
• In emergency settings without specialist expertise, maintain a low threshold for MRI in patients over 50 years or with vascular risk factors, even if HINTS appears peripheral. 3

Associated Neurologic Symptoms

Central Vertigo Red Flags

• Dysarthria, dysmetria, dysphagia, sensory or motor deficits, diplopia, or Horner's syndrome frequently accompany central vertigo. 1, 2
• Severe postural instability with actual falling during gait testing is a red flag for cerebellar or brainstem lesions. 1
• New-onset severe headache with vertigo may indicate vertebrobasilar stroke or hemorrhage. 1

Peripheral Vertigo Features

• Auditory symptoms—tinnitus, fluctuating hearing loss, aural fullness—are hallmarks of peripheral pathology (Ménière's disease, labyrinthitis). 2
• Patients maintain some degree of postural control despite vertigo. 1

Additional Bedside Tests

Head-Shaking Test

• Shake the patient's head horizontally 20 times, then observe for nystagmus. 4
• Horizontal head-shaking nystagmus (hHSN) that is suppressed by tilting the head = peripheral. 4
• Perverted head-shaking nystagmus (pHSN)—vertical or torsional nystagmus after horizontal head-shaking—that is not suppressed by head tilt = central (72.7% of central cases). 4

Supine Roll Test

• With the patient supine, rapidly turn the head 90° to each side; positive if horizontal nystagmus and vertigo occur. 1
• Used to detect lateral-canal BPPV (10–15% of BPPV cases). 1

Episode Duration and Triggers

Peripheral Causes

• BPPV: <1 minute, triggered by specific head-position changes. 1
• Ménière's disease: hours, with fluctuating hearing loss, tinnitus, and aural fullness. 1
• Vestibular neuritis: days to weeks of continuous vertigo. 1

Central Causes

• Vertebrobasilar insufficiency: <30 minutes, no hearing loss, severe postural instability, may precede stroke by weeks. 1
• Posterior-circulation stroke: continuous vertigo (acute vestibular syndrome). 3

Mandatory Neuroimaging Criteria

Proceed directly to urgent MRI with diffusion-weighted imaging if any of the following are present: 1

• Pure vertical or down-beating nystagmus without torsional component
• Direction-changing nystagmus without head-position change
• Baseline nystagmus without provocative maneuvers
• Nystagmus not suppressed by visual fixation or not fatiguing with repeat testing
• Severe postural instability with falling
• New-onset severe headache
• Any focal neurologic deficit (dysarthria, dysphagia, diplopia, limb weakness, sensory loss)
• Failure to respond to appropriate peripheral vertigo treatment (e.g., Epley maneuver for BPPV)
• Age >50 years with vascular risk factors (hypertension, diabetes, smoking, atrial fibrillation), even with peripheral-appearing findings

Common Pitfalls to Avoid

• Do not assume a normal neurologic examination excludes stroke—up to 75–80% of posterior-circulation strokes lack focal deficits. 3
• Do not rely on HINTS performed by non-specialists to exclude stroke; meta-analyses show inadequate sensitivity when performed by emergency physicians without specialized training. 3
• Do not overlook subtle neurologic signs such as mild dysmetria, gaze-evoked nystagmus, or skew deviation. 1
• Do not order routine CT for isolated vertigo—diagnostic yield is <1%; MRI with diffusion-weighted imaging is required for suspected central causes. 1
• Approximately 10% of cerebellar strokes mimic peripheral vestibular disorders; maintain high vigilance for red-flag features. 1