VNG Report Analysis: BPPV vs. Central Paroxysmal Positional Vertigo (CPPV)

Summary of Key Findings from the Report

1. Saccades

2. Smooth Pursuit

3. Optokinetic (OKN)

• All gains near 1.0 (0.86-1.10) - normal and symmetric
• No fast-phase direction abnormality documented
• Normal OKN - this is reassuring against a major cortical or brainstem lesion

4. Spontaneous Nystagmus (Light & Dark)

• No spontaneous nystagmus in either condition
• No head-shake nystagmus
• No hyperventilation or Valsalva-induced nystagmus
• Normal - rules out active peripheral decompensation or perilymph fistula

5. Gaze Testing (Critical Findings)

6. Positional Testing (The Core Question)

• Supine Head Ext. & Right: No measurable nystagmus (SPV -, Amplitude -)
• Return to Sit (Head Right): Right eye SPV 8.23°/s, Amplitude 5.09°, Freq 0.91 Hz - nystagmus appeared on SITTING UP, not during the provocative Hallpike position itself

• Supine Head Ext. & Left: Both eyes - Right SPV -10.84°/s, Left SPV -10.11°/s; Freq 1.27 Hz (R), 0.93 Hz (L)
• Return to Sit (Head Left): No measurable nystagmus

• Yaw Right: Both eyes - R: SPV -2.09°/s, L: SPV -3.06°/s, Freq 0.55 Hz bilaterally
• Pitch Backward: Both eyes - R: SPV -5.68°/s, L: SPV -8.40°/s; Freq 1.22/1.16 Hz
• Pitch Forward, Yaw Left, Roll Right/Left: No nystagmus

BPPV vs. CPPV: Analysis

What Does the Textbook Say?

"The most reliable criterion to distinguish BPPV from central positioning vertigo is the direction of nystagmus... Purely vertical or torsional nystagmus... should always raise the suspicion of a central lesion... Central positional nystagmus often persists as long as the precipitating head position is maintained... Central positional vertigo and nystagmus usually does not fatigue with repetitive positioning."

"Suggestive features include unusual nystagmus that may be short latency, atypical direction, not fatigable, and not responsive to the Epley maneuver... The symptoms often spontaneously resolve within a few days."

1. Nystagmus is atypical for any of the BPPV syndromes
2. Brainstem or cerebellar signs are present
3. Positional vertigo does not resolve with repeated therapeutic manoeuvres

Conclusion and Recommendation

1. Dysmetric saccades (hypermetric left eye, high precision values) - cerebellar sign
2. Gaze-evoked nystagmus without fixation (right gaze) - brainstem/cerebellar sign
3. Nystagmus provoked in multiple head positions (DH-Left, Pitch Backward, Yaw Right) - not canal-specific
4. Bilateral simultaneous eye involvement in the positional tests
5. Nystagmus occurring on return to sitting rather than in the classic Hallpike supine position (atypical timing)
6. Predominantly downward (negative) slow-phase velocity in provocative positions - downbeat nystagmus in positional testing is a classic central sign (nodulus/uvula lesion)

Urgent Next Steps

• MRI brain with posterior fossa protocol (not CT - small cerebellar/brainstem lesions are CT-invisible) - looking for: cerebellar nodulus/uvula infarct, demyelination, cerebellar mass
• Neurology referral - do not treat this as simple BPPV
• Avoid the Epley as definitive treatment without central pathology ruled out
• Consider: posterior circulation TIA/infarct, MS, cerebellar degeneration, or drug effect (e.g., amiodarone)

This patient should NOT be discharged with a BPPV diagnosis until MRI posterior fossa is performed.

• Cummings Otolaryngology, Central Positional Vertigo section
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery Vol. 2, p. 877 (Differential Diagnosis)

VNG Report Interpretation

Saccades

Smooth Pursuit

Optokinetic Testing

Spontaneous Nystagmus

Gaze Testing - Important Finding

Positional Testing - The Key Section

• No nystagmus was triggered during the actual head-hanging (supine) position.
• Nystagmus appeared only when the patient sat back up (SPV 8.23°/s, Freq 0.91 Hz in right eye).
• In classic BPPV, nystagmus is provoked during the Hallpike position itself - not on return to sitting. This is an atypical and suspicious finding.

• Clear nystagmus was triggered in the supine head-extended-left position (R eye SPV -10.84°/s, L eye SPV -10.11°/s).
• Importantly, both eyes were involved simultaneously with comparable velocities and frequencies.
• In typical BPPV, nystagmus follows a canal-specific pattern (torsional + upbeat). Bilateral symmetric eye involvement does not fit this picture.

• Pitch Backward (head tilted back): Nystagmus in both eyes (SPV -5.68°/s right, -8.40°/s left) - this is a downbeat pattern in a static position, which is a recognized sign of central (nodular/uvular cerebellar) pathology.
• Yaw Right (head turned right): Nystagmus in both eyes (SPV ~2°/s bilaterally).
• Pitch Forward, Yaw Left, Roll Right and Left: No nystagmus.

Subjective Visual Vertical (SVV)

BPPV vs. CPPV - Comparison Table

Overall Impression

Recommended Next Steps

1. MRI brain - posterior fossa protocol (not CT - small lesions in the cerebellum and brainstem are frequently missed on CT).
2. Urgent neurology referral - this should not be managed as routine BPPV.
3. Do not rely on Epley maneuver as the sole treatment without first ruling out central pathology.
4. Consider workup for: posterior circulation stroke/TIA, multiple sclerosis, cerebellar atrophy, or drug-induced cerebellar toxicity.

Bottom line: The Epley maneuver and a BPPV label are not appropriate for this patient until MRI of the posterior fossa has been reviewed by a neurologist or neurotologist.