What is the management and evaluation approach for a patient with torsional nystagmus on the supine head roll test?

Management and Evaluation of Torsional Nystagmus on Supine Head Roll Test

Torsional nystagmus on the supine head roll test indicates either posterior canal BPPV that has converted to lateral canal involvement during positioning, or a central nervous system pathology requiring urgent neuroimaging—you must immediately distinguish between these by assessing for red flag features and performing a Dix-Hallpike maneuver to confirm the diagnosis. 1, 2

Immediate Diagnostic Clarification

Determine the Type of Nystagmus Present

• Pure torsional nystagmus without horizontal component: This is atypical for lateral canal BPPV and raises concern for central pathology, particularly if it persists or lacks the characteristic features of BPPV 2, 3

• Torsional-vertical downbeating nystagmus: This pattern suggests either anterior canal BPPV or apogeotropic posterior canal BPPV, and requires specific diagnostic maneuvers to differentiate 4

• Torsional upbeating nystagmus converting to horizontal: This indicates posterior canal BPPV converting to lateral canal BPPV during positioning, with the same ear remaining affected 1, 2

Perform Dix-Hallpike Maneuver First

• The Dix-Hallpike test should be performed before the supine roll test to identify posterior canal BPPV, which classically produces torsional upbeating nystagmus 1, 2

• If posterior canal BPPV converts to horizontal nystagmus during positioning, the affected ear remains the same 1

Red Flags Requiring Urgent Neuroimaging

Central Nervous System Warning Signs

• Downbeat nystagmus without torsional component: This strongly suggests bilateral floccular lesion or cervicomedullary junction pathology requiring immediate MRI 2, 3

• Direction-changing nystagmus that does not follow typical BPPV patterns: This indicates central pathology rather than peripheral vestibular disease 2, 3

• Baseline nystagmus present in primary position: This suggests central nervous system involvement 2

• Associated cerebellar signs: Ataxia, dysmetria, or dysdiadochokinesia indicate central lesions 2

Imaging Protocol When Central Pathology Suspected

• MRI of the brain is the preferred imaging modality, as CT scans may not adequately visualize posterior fossa structures 3

• Do not obtain radiographic imaging if the patient meets diagnostic criteria for BPPV without additional signs or symptoms inconsistent with BPPV 1

Management Algorithm for Peripheral BPPV

If Geotropic Horizontal Nystagmus Present

• The side with the strongest nystagmus is the affected ear in geotropic lateral canal BPPV 1, 2

• Treat with canalith repositioning procedure specific to lateral canal BPPV 1

• The geotropic variant is most common and most amenable to treatment 1

If Apogeotropic Horizontal Nystagmus Present

• The side opposite the strongest nystagmus is the affected ear in apogeotropic lateral canal BPPV 1, 2

• This suggests calcium carbonate debris is located adherent to or close to the ampulla of the semicircular canal 1

If Lateralization Remains Unclear

• Clear lateralization remains unclear in about 20% of cases despite standard testing 1

• Perform the bow and lean procedure to add diagnostic certainty: in geotropic BPPV, bowing (face down) produces nystagmus toward the affected ear, while leaning (face up) produces nystagmus away from the affected ear 1

• Alternatively, treat one side and then the other if lateralization cannot be determined 1

Prognostic Factors

Nystagmus Parameters Predicting Treatment Resistance

• Longer latency in the affected side during supine roll test indicates higher risk of persistent BPPV after repositioning maneuver 5

• Slower slow phase velocity on the healthy side predicts treatment resistance 5

• These parameters may represent characteristics of the canalith that affect treatment success 5

Common Pitfalls to Avoid

• Missing lateral canal BPPV: Performing only the Dix-Hallpike test without the supine roll test will miss lateral canal involvement, which occurs in a significant proportion of BPPV cases 1, 2

• Misdiagnosing central positional nystagmus as BPPV: This occurs when proper diagnostic maneuvers are not performed or central features are overlooked 2, 3

• Confusing vestibular migraine with BPPV: Vestibular migraine can produce geotropic horizontal nystagmus during supine roll test that mimics lateral canal BPPV, but typically has additional features including spontaneous nystagmus in upright position 6

Contraindications to Positional Testing

• Exercise care in patients with cervical stenosis, severe kyphoscoliosis, limited cervical range of motion, Down syndrome, severe rheumatoid arthritis, cervical radiculopathies, Paget's disease, ankylosing spondylitis, low back dysfunction, spinal cord injuries, and morbid obesity 1

Follow-Up Assessment

• Reassess patients within 1 month after initial treatment to document resolution or persistence of symptoms 1

• Evaluate patients with persistent symptoms for unresolved BPPV and consider alternative diagnoses 1