VNG Report Analysis - Patient Mitravesh Choudhary (Age 35, Male)

Patient Summary

• Age/Sex: 35-year-old male
• Chief Complaint: Dizziness lasting several minutes to hours
• Test: Videonystagmography (VNG) - a full vestibular battery

Section-by-Section VNG Findings

1. Saccade Testing (Pages 1-2)

2. Smooth Pursuit Testing (Pages 3-4)

• Left eye leftward gain at 0.2 Hz: 0.36 - markedly reduced
• Left eye rightward gain at 0.4 Hz: 0.37 - markedly reduced
• Both eyes at 0.4 Hz horizontal show gains around 0.5, which is consistent with the frequency-related reduction but borderline
• Vertical pursuit at 0.4 Hz shows reduced gains bilaterally (0.50-0.71)

3. Optokinetic Testing (Pages 5-7)

4. Spontaneous Nystagmus (Page 8)

5. Head Shake Nystagmus (Page 9)

6. Hyperventilation-Induced Nystagmus (Page 9)

7. Gaze Testing (Pages 10-14)

• Center without fixation: Horizontal SPV 1.91 °/s, Amplitude 0.70°, Frequency 1.07 Hz (right eye)
• All other gaze-without-fixation positions: No nystagmus

8. Positional Testing - Dix-Hallpike (Pages 15-17)

Right Dix-Hallpike:

Left Dix-Hallpike:

1. Canalolithiasis involving multiple canals (multi-canal BPPV)
2. Horizontal canal BPPV with posterior canal involvement
3. A central positional disorder

9. Positional Testing - McClure-Pagnini (Roll Test) (Pages 18-20)

• Positive nystagmus in both Right Lateral and Left Lateral positions, with fast phases between 34-43°
• Nystagmus persists in Supine Head Neutral (SPV up to 10.97 °/s right, 7.34 °/s left)
• The vertical components are prominent and consistent across positions

10. Subjective Visual Vertical (SVV) (Page 21)

1. Patient reversal of the luminous bar (mistaking 180° for vertical - a response error, where the patient set the bar 180° from the perceived vertical, essentially "upside down")
2. Severe otolith dysfunction - though a true 180° SVV tilt is not physiologically meaningful as it would represent complete disorientation
3. Test artifact or equipment issue

Synthesis and Diagnosis

Primary Diagnosis

• Strongly positive McClure-Pagnini (Roll Test) with nystagmus in both lateral positions
• Dix-Hallpike positional nystagmus bilaterally with atypical (non-classic) morphology
• Symptoms of dizziness lasting minutes to hours fit BPPV episodes (though typically seconds to < 1 minute for classic PC-BPPV; HC-BPPV can be more prolonged)
• Patient age (35 years) and sex (male) consistent with BPPV demographics

Contributing/Complicating Findings

• Persistent nystagmus in supine neutral position
• SVV deviations (borderline at -3°)
• Oblique fast-phase directions (34-43°) indicating mixed canal-otolith generation of nystagmus
• Vertical component in Head Shake Nystagmus

• Vertical post-head-shake nystagmus (13.40 °/s) - atypical for peripheral-only lesion
• Hyperventilation-induced vertical nystagmus - associated with central demyelinating disease or schwannoma
• Reduced smooth pursuit in one eye at 0.2 Hz (left eye leftward gain 0.36)
• Oblique fast-phase direction in OKN (164-165°)

Red Flag Findings Requiring Further Evaluation

1. Vertical post-head-shake nystagmus (13.40 °/s) - should prompt MRI of the posterior fossa
2. Hyperventilation-induced nystagmus (vertical) - can indicate 8th nerve compression (schwannoma) or demyelination
3. Asymmetric smooth pursuit (left eye) - central pathway consideration
4. SVV blank background 180° - needs repeat testing to confirm/exclude true otolith dysfunction

Recommended Further Workup

Management Recommendations

Immediate - Canalith Repositioning

• Perform the Gufoni maneuver or Barbecue roll (360° rotation) for horizontal canal BPPV
• If geotropic: Gufoni maneuver toward the unaffected ear, or 270° roll toward healthy side
• If apogeotropic: Forced prolonged position or Casani maneuver
• Monitor response and repeat if nystagmus persists

Medical Management

• Vestibular suppressants (e.g., betahistine 8-16 mg TID) may help if Meniere's component suspected
• Avoid benzodiazepines and antihistamines long-term (impair vestibular compensation)

Referral

• Neurotology / Otoneurology consultation given the atypical central signs
• Neurology if MRI reveals posterior fossa pathology

Summary

Disclaimer: This analysis is provided for clinical educational purposes. All findings should be correlated with the patient's full clinical history, physical examination, and interpreted by a qualified neurotologist or otolaryngologist before clinical decisions are made.

PPPD vs BPPV: Are They Contradictory?

Why I Cannot Confirm PPPD as the Sole Diagnosis

The Correct Clinical Framework: BPPV as Precipitant, PPPD as Secondary Overlay

"BPPV causes transient vertigo with head movements, while PPPD involves persistent dizziness and unsteadiness. Both significantly impact quality of life... effective treatment must address both physical and psychological aspects."

BPPV episode  →  frightening vertigo  →  anxiety & maladaptive postural strategies
              →  PPPD develops as a secondary functional overlay
              →  Patient continues to feel dizzy even after BPPV resolves

What the VNG Tells Us That PPPD Cannot Explain

My Position

Recommended Clinical Approach

1. Step 1 - Treat the BPPV first: Perform the Gufoni or Barbecue Roll maneuver. If the nystagmus resolves and symptoms improve, this confirms BPPV was driving the picture.
2. Step 2 - Reassess at 4-6 weeks: If symptoms persist even after successful repositioning (VNG normalized), then PPPD as a secondary, maintained functional disorder becomes a much stronger and justifiable diagnosis.
3. Step 3 - Screen for PPPD triggers: Ask specifically about:
   • Duration ≥ 3 months
   • Worsening in supermarkets, crowds, scrolling screens
   • Anxiety, avoidance behaviors, obsessional traits
   • History of panic attacks or anxiety disorder
4. Step 4 - If PPPD confirmed: Vestibular rehabilitation (habituation-based) + SSRI/SNRI (sertraline, venlafaxine) + Cognitive Behavioural Therapy (CBT)

BPPV vs CPPV: Where Does This Patient Stand?

The Core Distinguishing Criteria

Point-by-Point Analysis of THIS Patient's VNG

Features Favoring BPPV

• Positive Dix-Hallpike - both sides provoke nystagmus
• Positive McClure-Pagnini (Roll Test) - the specific test for HC-BPPV
• Horizontal nystagmus is a prominent component, consistent with horizontal canal involvement
• No gaze-evoked nystagmus in any direction
• No spontaneous nystagmus in darkness
• Saccade metrics normal (no cerebellar dysmetria)

Features Favoring CPPV (Central)

1. Vertical post-head-shake nystagmus at 13.40 °/s - cannot be explained by any peripheral canal. This is the single most compelling central sign in this VNG.
2. Bilateral positive Dix-Hallpike AND bilateral positive Roll Test - BPPV is typically unilateral. Bilateral involvement on multiple tests is a central feature.
3. Persistent nystagmus in Supine Head Neutral (SPV up to 10.97 °/s) - in pure BPPV, returning to neutral should stop nystagmus. Persistence is a central sign.
4. Oblique fast-phase directions 22-43° - do not fit cleanly into any single canal plane, which Scott-Brown's identifies as: "Central positional nystagmus is not attributable to the stimulated canal plane"
5. Hyperventilation-induced vertical nystagmus - associated with 8th nerve compression (schwannoma), demyelination (MS), or brainstem lesion
6. Unilateral smooth pursuit deficit (left eye 0.36 at 0.2 Hz) - points to an ipsilateral central pathway
7. OKN fast phase at 164-165° (oblique/posterior vector) - atypical for a purely peripheral response

The Definitive Distinguishing Test: Canalith Repositioning Maneuver Response

Perform Gufoni / Barbecue Roll (for HC-BPPV)
           ↓
Nystagmus RESOLVES → BPPV confirmed
           ↓
Nystagmus PERSISTS / RETURNS IMMEDIATELY → CPPV highly likely → URGENT MRI

Where This Patient Sits: My Assessment

Immediate Action Required

Do NOT assume this is simple BPPV and perform repositioning as the only intervention.

Possible Diagnoses - Complete Differential Analysis

Patient Profile Recap (Key VNG Features)

Ranked Differential Diagnoses

🥇 Diagnosis 1: Vestibular Migraine (Most Probable)

• "Central, spontaneous, or positional nystagmus may be present during the attack" - Symptom to Diagnosis
• Bilateral positional nystagmus is well recognized in vestibular migraine
• Vertical post-head-shake nystagmus is a documented feature - Localization in Clinical Neurology notes it can occur with vestibular migraine
• Vestibular migraine is "the second most common cause of recurrent spontaneous vertigo after BPPV" - Localization in Clinical Neurology
• Duration of minutes to hours is exactly the vestibular migraine window (5 min to 72 h)
• Tinnitus and ear fullness occur in up to 40% - overlaps with Meniere's
• Hac & Gold 2024 specifically highlight: vestibular migraine "overlaps clinically with BPPV, Meniere's, PPPD, and cerebrovascular etiologies" - exactly this patient's picture

"Do you have a personal or family history of migraine? During your dizzy spells, do you get headache, sensitivity to light, sensitivity to sound, or visual disturbances?"

🥈 Diagnosis 2: Horizontal Canal BPPV (HC-BPPV) - Secondary/Concurrent

• Positive McClure-Pagnini in both lateral positions
• Bilateral Dix-Hallpike nystagmus (atypical but possible in multi-canal BPPV)
• Horizontal component to nystagmus

• Duration minutes to hours (HC-BPPV cupulolithiasis can be prolonged but not typically hours)
• Vertical post-head-shake nystagmus - not explainable by HC-BPPV alone
• Persistence in supine neutral

🥉 Diagnosis 3: Meniere's Disease (Early/Possible)

• Episode duration (hours)
• Age of onset (Meniere's peaks in 3rd-6th decade)
• Otolith involvement suggested by SVV deviations
• Persistence of nystagmus suggesting endolymphatic pressure

• No audiometry to confirm sensorineural hearing loss
• No reported tinnitus or aural fullness in the available history
• Bilateral positional findings (Meniere's is typically unilateral)
• Vertical post-head-shake nystagmus is atypical

Diagnosis 4: Posterior Fossa Lesion (Must Exclude)

• "Ageotropic central positional nystagmus"
• "Perverted head-shaking nystagmus" (i.e., vertical HSN after horizontal head shake - exactly what this patient has)
• "Paroxysmal positional nystagmus"
• Normal HIT (head impulse test)

• Acoustic neuroma / Vestibular schwannoma (hyperventilation nystagmus is a known sign)
• Demyelinating plaque (MS) in the vestibular pathways
• Cerebellar hemangioblastoma or meningioma

Diagnosis 5: BPPV + PPPD (Secondary Functional Overlay)

• Prolonged perception of dizziness between acute episodes
• Worsening in busy visual environments
• Chronic disability beyond what the structural lesion alone would cause

Summary Diagnostic Probability Table

The Diagnostic Pathway Forward

STEP 1 - Clinical History (TODAY)
 Ask about: migraine history / headache type / photophobia / phonophobia / 
 aura / tinnitus / ear fullness / hearing fluctuation / family history

      ↓
STEP 2 - Repositioning Trial (TODAY)
 Perform Gufoni / Barbecue Roll
 → Resolves = HC-BPPV confirmed (± vestibular migraine as co-cause)
 → Does NOT resolve = Central cause rises in probability

      ↓
STEP 3 - Investigations (THIS WEEK)
 • MRI Brain + Posterior Fossa + IAM with gadolinium
 • Pure Tone Audiogram
 • cVEMP + oVEMP (otolith function)
 • vHIT (canal-by-canal VOR gain)

      ↓
STEP 4 - Diagnosis Confirmed
 Vestibular Migraine → Migraine prophylaxis + vestibular rehab
 Meniere's → Low sodium, betahistine, diuretics
 Posterior fossa lesion → Neurosurgery/neuro-oncology referral
 Pure HC-BPPV → Repositioning + follow-up
 PPPD component → SSRI/SNRI + CBT + vestibular rehab

The Significance of Nystagmus WITHOUT Subjective Dizziness

What It Definitively Rules Out

BPPV is NOW Eliminated as the Primary Diagnosis

Recurrent episodes of vertigo provoked by changes in head position - subjective symptom is mandatory

What the Literature Says About This Exact Scenario

"When central positional nystagmus without vertigo occurs as an isolated finding, imaging is often negative and a specific diagnosis cannot be made."

"CPN is caused by cerebellar and/or brainstem dysfunction... pathophysiologically believed to reflect abnormal integration of semicircular canal signals by the cerebellar nodulus, uvula and/or tonsil."

Revised Diagnostic Framework

Column A: Objective Nystagmus Findings (Asymptomatic)

• Positional nystagmus on Dix-Hallpike - both sides - NO symptoms
• Positional nystagmus on Roll Test - both lateral + supine neutral - NO symptoms
• Spontaneous nystagmus in light (0.60 °/s) - likely not felt
• Nystagmus Center-without-fixation (1.91 °/s) - likely not felt

Column B: Tests That DID Provoke Sensation

• Head Shake Nystagmus - vertical, 13.4 °/s - this is the highest-intensity finding and the one most likely to correlate with the patient's actual dizziness complaint
• Hyperventilation - produced vertical nystagmus (3.4 °/s) - may correspond to episodic symptoms

Revised Diagnosis: Central Positional Nystagmus (CPN) with Probable Vestibular Migraine

Now - What Is CAUSING the CPN?

Most Probable: Vestibular Migraine

• Spontaneous dizziness lasting minutes to hours - perfectly matches
• CPN is a documented interictal (between-attack) finding in vestibular migraine
• Asymmetric smooth pursuit fits
• Vertical HSN fits
• No structural lesion needed - the migraine-related cortical spreading depression and brainstem sensitization alone can generate CPN
• Importantly: Imaging is often normal in vestibular migraine-related CPN

Must Exclude: Posterior Fossa Structural Lesion

• Cerebellar nodulus / uvula lesion - these structures specifically generate asymptomatic positional nystagmus
• Demyelinating plaque (MS) - hyperventilation nystagmus is a red flag for this
• Acoustic neuroma / vestibular schwannoma
• Small cerebellar or brainstem infarct

Lower on the List Now: Meniere's Disease

• Meniere's does NOT typically produce asymptomatic positional nystagmus
• Positional nystagmus in Meniere's is usually accompanied by pressure/fullness sensation
• Moves DOWN the differential with this new information

Eliminated Now: BPPV as Primary Diagnosis

• Cannot be the explanation for these VNG findings
• The positional nystagmus is CPN, not canalith-generated BPPV nystagmus

Critical Diagnostic Action - Now Urgent

1. CPN (nystagmus without vertigo)
2. Vertical post-head-shake nystagmus
3. Hyperventilation-induced nystagmus
4. Smooth pursuit deficit

Summary in One Sentence

This patient has Central Positional Nystagmus (CPN) - not BPPV - with the most likely cause being vestibular migraine, but posterior fossa pathology must be excluded urgently by MRI before any final diagnosis is assigned.