What are the central signs of vertigo?

Central Signs of Vertigo

The most important central signs of vertigo include downbeating nystagmus without torsional component, direction-changing nystagmus without changes in head position, baseline nystagmus without provocative maneuvers, and gaze-evoked nystagmus that doesn't fatigue or suppress with fixation. 1

Key Nystagmus Patterns Indicating Central Vertigo

• Downbeating nystagmus on Dix-Hallpike maneuver, particularly without the torsional component 1
• Direction-changing nystagmus occurring without changes in head position (periodic alternating nystagmus) 1
• Baseline nystagmus present without provocative maneuvers 1
• Gaze-evoked nystagmus that doesn't fatigue and isn't easily suppressed by gaze fixation 1
• Direction-switching nystagmus (beats to the right with right gaze and to the left with left gaze) 1
• Pure vertical or torsional nystagmus 2

Associated Neurological Signs

Central vertigo is frequently accompanied by additional neurological findings that help differentiate it from peripheral causes:

• Dysarthria (speech difficulties)
• Dysmetria (inaccurate movement)
• Dysphagia (swallowing difficulties)
• Sensory or motor deficits
• Horner's syndrome 1, 2
• Severe postural instability disproportionate to the vertigo 1
• Gaze holding abnormalities 3
• Saccade accuracy problems 3
• Impaired fixation-suppression of the vestibulo-ocular reflex 3

Response to Treatment

• Failure to respond to conservative management such as canalith repositioning procedures or vestibular rehabilitation should raise concern for a central cause 1

Common Central Causes of Vertigo

1. Vestibular migraine:

   • Accounts for approximately 14% of vertigo cases 1
   • Diagnostic criteria include:
     • ≥5 episodes of vestibular symptoms lasting 5 minutes to 72 hours
     • Current or history of migraine
     • ≥1 migraine symptoms during at least 50% of dizzy episodes (headache, photophobia, phonophobia, visual/other aura)
     • Other causes ruled out 1

2. Brainstem and cerebellar stroke:

   • About 10% of cerebellar strokes present similar to peripheral vestibular disorders 1, 3
   • Sudden onset of vertigo
   • May be the initial and only symptom of vertebrobasilar insufficiency 1
   • Attacks typically last less than 30 minutes without associated hearing loss 1

3. Intracranial tumors or disorders (e.g., multiple sclerosis) 1

Pitfalls in Diagnosis

• Cerebellar stroke can mimic peripheral vestibular disorders in approximately 10% of cases, making it a dangerous cause of vertigo that requires careful evaluation 1
• Isolated transient vertigo may precede a stroke in the vertebrobasilar artery by weeks or months 1
• Central positional nystagmus is nearly always purely vertical (upbeating or downbeating) 4
• MRI is indicated in any patient with acute vertigo and profound imbalance suspected to be the result of cerebellar infarct or hemorrhage 4

Differentiating Central vs. Peripheral Vertigo

Feature	Central Vertigo	Peripheral Vertigo
Nystagmus	Direction-changing, vertical, pure torsional	Unidirectional, mixed horizontal-torsional
Fixation	Not suppressed by fixation	Often suppressed by fixation
Associated symptoms	Neurological deficits common	Hearing loss, tinnitus, aural fullness may be present
Duration	Variable, can be brief or prolonged	Usually self-limited
Response to repositioning	No response to repositioning maneuvers	Often responds to repositioning (in BPPV)

Remember that careful evaluation of nystagmus characteristics and associated neurological symptoms is crucial for distinguishing central from peripheral causes of vertigo, as this distinction has significant implications for patient management and outcomes.