Management of Patients with Negative Dix-Hallpike Test Without Nystagmus
For patients with suspected BPPV who have a negative Dix-Hallpike test without nystagmus, neuroimaging (preferably MRI brain) should be performed to rule out central causes of positional vertigo, as these patients are at increased risk of having acute central pathology.
Diagnostic Considerations
When a patient presents with symptoms suggestive of BPPV but has a negative Dix-Hallpike test without nystagmus, several important steps should be taken:
1. Repeat the Dix-Hallpike Test
- A single negative Dix-Hallpike test does not rule out BPPV (negative predictive value of only 52%) 1
- Consider repeating the Dix-Hallpike test after testing the horizontal canals, as this may allow canaliths to collect and produce a positive test on repeat examination 2
2. Test for Horizontal Canal BPPV
- Perform the supine roll test to assess for lateral canal BPPV when posterior canal testing is negative 1
- This involves laying the patient supine and quickly turning the head 90° to each side while observing for nystagmus 1
3. Consider BPPV Without Nystagmus
- Some patients may have subjective vertigo without observable nystagmus during positioning tests 3
- This condition is recognized as "subjective BPPV" or "BPPV without nystagmus" 3
Imaging Recommendations
When to Image
According to the American College of Radiology guidelines:
- Patients with symptoms of triggered episodic vertigo but negative or atypical Dix-Hallpike testing are at increased risk of having an acute central cause of vertigo identified on imaging 4
- These central causes may include mass lesions, hemorrhage, infarct, and demyelinating disease 4
Preferred Imaging Modality
- MRI brain is preferred over CT due to superior soft tissue contrast
- In a retrospective study, MRI detected acute brain lesions in 11% of cases compared with only 6% detection rate with CT in patients with central positional vertigo 4
Treatment Approach
For Subjective BPPV (Without Nystagmus)
- Consider empiric canalith repositioning procedures (CRPs) despite negative testing 3
- The Epley maneuver has shown success rates of 50-97.1% in patients with BPPV without nystagmus 3
For Suspected Central Causes
- If imaging reveals central pathology, management should be directed at the underlying cause
- Referral to neurology may be warranted
Special Considerations
When to Consider Additional Vestibular Testing
Vestibular function testing is warranted in patients with:
- Atypical nystagmus
- Suspected additional vestibular pathology
- Failed response to CRP
- Frequent recurrences of BPPV 4, 1
Common Pitfalls to Avoid
- Failure to test all semicircular canals
- Inadequate technique during positioning tests
- Premature termination of treatment
- Relying solely on medications
- Unnecessary imaging in typical BPPV cases 1
Algorithm for Management
- Repeat Dix-Hallpike test if initially negative
- Perform supine roll test to assess horizontal canals
- If all tests remain negative but symptoms are highly suggestive of BPPV, consider:
- Empiric CRP treatment (Epley or Semont maneuver)
- Neuroimaging (preferably MRI) to rule out central causes
- If symptoms persist despite treatment, or if atypical features are present, proceed with comprehensive vestibular testing and neurological evaluation
Remember that a negative Dix-Hallpike test without nystagmus in a patient with positional vertigo symptoms requires careful evaluation to distinguish between subjective BPPV and potentially serious central causes of vertigo.