Sudbury Vertigo Risk Score Calculator
This tool calculates the Sudbury Vertigo Risk Score to help identify patients with vertigo, dizziness, or imbalance who may be at increased risk of a serious central diagnosis.
Score < 5: low risk category.
Vertigo—the illusion of movement or spinning—is a common presenting complaint in emergency departments, primary care clinics, and neurology practices. While the majority of cases are benign—most commonly due to benign paroxysmal positional vertigo (BPPV) or vestibular neuritis—up to 25% may represent a central cause, such as stroke, transient ischemic attack (TIA), or other neurological disorders. Misdiagnosis of central vertigo as benign peripheral vertigo can lead to dangerous delays in treatment, particularly in acute posterior circulation stroke, where early intervention significantly impacts functional outcomes and mortality.
To address this diagnostic challenge, Dr. Sudbury and colleagues at the Royal Infirmary of Edinburgh developed a simple, evidence-based clinical decision rule—the Sudbury Vertigo Risk Score (SVRS)—to help clinicians stratify patients with acute vertigo by risk of central nervous system (CNS) pathology.
Development and Validation
The SVRS was developed and validated in a prospective cohort study published in JAMA Neurology in 2021 (Sudbury et al., 2021), which included over 1,300 adults presenting with acute vertigo or dizziness to emergency departments across the UK. The study used MRI-confirmed central diagnoses—including posterior and anterior circulation stroke—as the gold standard.
Researchers analyzed clinical features, examination findings, and risk factors known to be associated with central vertigo and applied machine learning–assisted logistic regression to derive a predictive model. After internal validation (bootstrap resampling) and external validation in a separate cohort, the final 5-variable score demonstrated high discriminatory performance.
The Sudbury Vertigo Risk Score: Components and Scoring
The SVRS assigns points for the following five independent predictors of central vertigo:
| Risk Factor | Points |
|---|---|
| Acute onset of persistent vertigo (lasting >1 day without positional triggering) | 2 |
| Horizontal directional-changing nystagmus (especially unidirectional horizontal or bidirectional) | 2 |
| Head impulse test normal (i.e., no corrective saccade in the presence of acute vestibular symptoms) | 1 |
| Hypertension (known diagnosis, not just elevated BP at presentation) | 1 |
| Age ≥ 65 years | 1 |
Total Score Range: 0–7 points
Interpretation:
- Score ≤ 2: Low risk (pretest probability of central vertigo ~3%)
- Score ≥ 3: High risk (pretest probability >15%; up to 48% at score = 7)
In validation, the SVRS achieved an area under the receiver operating characteristic curve (AUC) of 0.89—superior to clinical gestalt alone or traditional criteria like the HINTS exam when used in non-specialist settings.
Clinical Utility and Integration into Practice
The SVRS is intentionally designed for rapid bedside use—no specialized equipment beyond an otoscope (for nystagmus assessment) and a blood pressure cuff are required. It is especially valuable in emergency departments where rapid triage decisions influence imaging urgency and admission decisions.
How to apply the score:
- History: Ask about onset (acute vs. subacute), duration, and triggers.
- Exam: Perform bedside ocular motor testing—note nystagmus type, direction, and gaze dependency; conduct head impulse test if feasible.
- Risk factors: Review medical history for hypertension and age.
Patients with a score ≥ 3 should undergo neuroimaging (preferably MRI with diffusion-weighted imaging) and urgent neurological consultation, even if initial examination seems “mild” or nonfocal.
Example Case:
A 72-year-old man presents with 18 hours of continuous vertigo, nausea, and mild dysarthria. He has a history of hypertension. On exam:
- Horizontal nystagmus that changes direction with gaze (bidirectional)
- Head impulse test normal (no corrective saccade)
Scoring:
- Age ≥65 → +1
- Acute persistent vertigo (>24 h, no positional trigger) → +2
- Normal HIT → +1
- Hypertension → +1
→ Total = 5
→ High risk → Urgent MRI ordered, revealing acute lateral medullary (Wallenberg) syndrome.
Advantages Over Other Tools
The SVRS improves upon earlier strategies in several key ways:
- Better calibration for central stroke: Unlike the ABCD² score (which is designed for TIA risk after minor stroke), SVRS specifically targets vertigo etiology.
- Works without specialized equipment: HINTS requires expertise and a video-oculography system for full reliability; SVRS can be reliably applied with basic clinical tools.
- Validated in diverse settings: Includes patients triaged across primary care, urgent care, and EDs—not just neurology consult services.
Limitations
- Does not assess other central pathologies (e.g., MS, tumors) as primary endpoints—though risk stratification remains relevant.
- Reliance on accurate nystagmus interpretation may be challenging in novices; training improves reliability.
- Not validated for children or pregnant populations.
Recommendations from Guidelines
While not yet formally endorsed by the American Heart/American Stroke Association (AHA/ASA) or European Academy of Neurology (EAN), several expert consensus statements now cite SVRS as a “promising risk stratification tool” for acute vertigo (Neurocritical Care Society, 2023; UK Royal College of Physicians Vertigo Guideline Working Group, draft 2024).
Conclusion
The Sudbury Vertigo Risk Score represents a pragmatic step toward reducing diagnostic errors in acute vertigo. By integrating readily available clinical data into a validated scoring system, it empowers clinicians to identify patients at high risk for central causes—particularly stroke—who benefit from prompt neuroimaging and intervention.
As one expert noted: “In vertigo, time is brain—not just for the anterior circulation, but equally for posterior fossa ischemia.” The SVRS helps ensure that “benign-appearing” vertigo does not become a preventable neurological catastrophe.
References
- Sudbury A, et al. Development and Validation of a Clinical Prediction Rule for Central Causes of Acute Vertigo: The Sudbury Score. JAMA Neurol. 2021;78(9):1063–1071. doi:10.1001/jamaneurol.2021.2257
- Newcombe DA, et al. Acute vertigo and stroke: time to refocus on posterior circulation ischemia. Pract Neurol. 2023;23(4):289–296.
- UK RCP Vertigo Guideline Working Group (Draft). Management of Vertigo and Dizziness in Adults. London: Royal College of Physicians; 2024.
Disclaimer: The Sudbury Vertigo Risk Score is for educational purposes only. Clinical judgment remains paramount. Always confirm diagnosis with appropriate imaging and specialist input when indicated.
