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Videonystagmography (VNG) Report - Clinical Analysis

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COMPLETE CLINICAL SUMMARY

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SYNTHESIS OF ALL TEST FINDINGS

1. Pure Tone Audiometry

• Bilateral minimal hearing loss (not a dominant feature; does not suggest Meniere's disease-level loss)

2. Subjective/Bedside Tests

3. VNG - Saccades (Pages 1-2)

• Horizontal saccades: Normal velocity (447-489°/s), precision >90%, latency slightly elevated (363-403 ms - age-related acceptable range)
• Vertical saccades: Reduced precision (58-77%) and reduced velocity (154-291°/s) compared to horizontal

4. VNG - Smooth Pursuit (Pages 3-4)

5. VNG - Optokinetic Test (Pages 5-6)

6. Spontaneous Nystagmus (Pages 7-8)

• In light: ABSENT (no measurable nystagmus)
• In dark: ABSENT

7. Head Shake Nystagmus (Page 8)

• ABSENT (no post-head-shake nystagmus)

8. Gaze Testing (Pages 8-13)

• Center, Left, Up, Right, Down (with fixation): All negative - no gaze-evoked nystagmus
• Without fixation:
  • Right gaze, left eye: Mild nystagmus noted (SPV -0.06°/s, frequency 1.10 Hz) - clinically insignificant
  • Other positions: No significant nystagmus

9. Dix-Hallpike Test - CRITICAL FINDINGS (Pages 13-16)

Dix-Hallpike RIGHT:

Dix-Hallpike LEFT:

10. Supine Roll Test - McClure-Pagnini (Pages 18-21)

11. Head Position Tests (Pages 20-23)

12. Subjective Visual Vertical (Page 24)

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DIFFERENTIAL DIAGNOSIS

1. BPPV - Posterior Canal (LEFT ear) ✓ PRIMARY

• Brief (seconds) spinning triggered by head position change
• Years of recurrent positional vertigo history
• Positive Dix-Hallpike LEFT: torsional-upbeat nystagmus (SPV 7-10°/s, direction ~234°)
• No spontaneous nystagmus
• No tinnitus, no aural fullness
• Normal hearing (not low-frequency SNHL)
• Unterberger deviates left (consistent with left labyrinthe)
• Age 73 - peak demographic for BPPV (post-menopausal, calcium metabolism changes)

• Some bilateral nystagmus on positional testing (may indicate bilateral or HC-BPPV)
• Photophobia/phonophobia (atypical for pure BPPV)

2. BPPV - Horizontal Canal (LEFT), Canalithiasis ✓ CO-PRIMARY

• Positive McClure-Pagnini Roll Test LEFT: geotropic horizontal nystagmus (direction 274°/82°, SPV up to 7.72°/s)
• Positive Roll-Left position test (SPV 5-6°/s, direction 213°)
• Geotropic nystagmus in left lateral position = canalithiasis of LEFT HC

3. Vestibular Migraine (Migrainous Vertigo) - SIGNIFICANT CONTRIBUTOR

• Photophobia, phonophobia, osmophobia (hallmark migraine-associated features)
• Space and motion discomfort (a migrainous symptom)
• Head heaviness, eye heaviness
• Years of recurrent episodic vestibular symptoms
• Bilateral symmetrically reduced smooth pursuit (central pathway involvement)
• Abnormal vertical OKN asymmetry

• No headache reported (though vestibular migraine can be headache-free)
• Age 73 (migraine tends to decrease post-menopause, though vestibular migraine can persist)

4. Presbyvestibulopathy (Age-Related Vestibular Dysfunction)

• Age 73
• Bilateral reduced smooth pursuit (0.16-0.43 across all frequencies)
• Sharpened Romberg sway
• Mild tandem gait imbalance
• Bilateral minimal hearing loss

• Does NOT explain positional provocation as the dominant feature
• Does NOT cause torsional nystagmus on Dix-Hallpike

5. Meniere's Disease - EXCLUDED

• No tinnitus
• No aural fullness
• No low-frequency SNHL
• No spontaneous nystagmus
• Episodes are brief seconds (Meniere's attacks last 20 min to hours)
• No acute fluctuating hearing loss

6. Vestibular Neuritis - EXCLUDED

• No acute prolonged vertigo episode at onset
• No spontaneous nystagmus (in dark or light)
• No positive head impulse test findings on record
• Symptom pattern is positional/episodic, not continuous

7. Central Positional Vertigo (Posterior Fossa Lesion) - LOW PROBABILITY but needs monitoring

• Bilateral reduced smooth pursuit
• Vertical saccade slowing
• Photophobia/phonophobia

• Normal finger-to-nose (no cerebellar dysmetria)
• Normal DDK
• No diplopia, no slurring, no ataxia
• No spontaneous or gaze-evoked nystagmus
• No downbeat nystagmus
• Nystagmus pattern fits peripheral BPPV morphology

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CORRECT DIAGNOSIS

PRIMARY DIAGNOSIS:

Bilateral BPPV - Predominantly Left Posterior Canal Canalithiasis with Left Horizontal Canal Canalithiasis

1. Left posterior canal BPPV - Dix-Hallpike LEFT positive (torsional-upbeat nystagmus, SPV 7-10°/s, direction ~234°, frequency 2.08 Hz) - classic for ipsilateral posterior canal otolith
2. Left horizontal canal BPPV (canalithiasis) - Positive Roll test LEFT (geotropic nystagmus, direction 274° right eye / 82° left eye, SPV up to 7.72°/s), confirmed by Roll Left head position nystagmus
3. Unterberger deviation LEFT >30° - confirms left labyrinthine predominance
4. Episodic positional vertigo for years - recurrent BPPV (common in elderly females, especially post-menopausal due to calcium/vitamin D metabolism)
5. Normal inter-ictal examination - as expected with BPPV

SECONDARY DIAGNOSIS:

Vestibular Migraine (co-morbid)

• Photophobia, phonophobia, osmophobia - the triad that defines migraine-spectrum sensitization
• Space and motion discomfort (visual motion sensitivity - a migrainous feature)
• Bilateral central smooth pursuit degradation beyond what BPPV alone explains
• Years of episodic vestibular symptoms with variable triggers

BACKGROUND CONDITION:

Presbyvestibulopathy

• Bilateral reduced smooth pursuit, mild Romberg sway, mild tandem gait imbalance - all consistent with normal aging of vestibular apparatus at age 73

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MANAGEMENT RECOMMENDATIONS

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• Adams and Victor's Principles of Neurology, 12th Edition - BPPV characterization and Dix-Hallpike criteria
• Bradley and Daroff's Neurology in Clinical Practice - Recurrent Positional Vertigo differential diagnosis
• Symptom to Diagnosis: An Evidence-Based Guide, 4th Edition - BPPV diagnostic criteria and nystagmus patterns

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Detailed VNG Analysis and Interpretation

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UNDERSTANDING THE KEY VNG PARAMETERS FIRST

• Slow Phase Velocity (SPV): The drift velocity of the eye - this is the true vestibular signal. Negative = leftward/downward. Positive = rightward/upward.
• Fast Phase Direction: The angle in degrees of the quick corrective beat (0° = rightward, 90° = upward, 180° = leftward, 270° = downward). By convention nystagmus is named by its fast phase direction.
• Nystagmus is named by its FAST phase direction - so a negative SPV means the eye is drifting left, with the fast phase beating RIGHT.
• Normal SPV threshold for significance: >5-6°/s in positional testing (some labs use >3°/s as threshold with clinical correlation).

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TEST-BY-TEST ANALYSIS

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1. SACCADES (Pages 1-2)

Horizontal Saccades

Vertical Saccades

• Horizontal saccades: Velocity and precision are NORMAL. Latency is mildly prolonged (~363-403 ms vs normal 150-250 ms) - this is a non-specific finding consistent with age (73 years) and mild cognitive slowing of voluntary saccade initiation.
• Vertical saccades: Velocity is in the low-to-normal range; critically, precision is severely reduced (58-77%) for both eyes and both frequencies. Vertical saccade precision below 90% indicates that the eyes are under- or overshooting vertical targets - this is a cerebellar/central sign. Horizontal precision is normal (90-93%), making this a selective vertical saccade imprecision pattern.
• Saccade latency is symmetrically prolonged horizontally and vertically - symmetric prolongation is not a lateralizing sign; it reflects age-related cortical/frontal slowing or inattention, not a peripheral lesion.

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2. SMOOTH PURSUIT (Pages 3-4)

Horizontal Pursuit Gain

Vertical Pursuit Gain

• Smooth pursuit gain is profoundly reduced in ALL directions and ALL frequencies - horizontal gain 0.21-0.43 (should be ≥0.6-0.7), vertical gain 0.16-0.33 (should be ≥0.5-0.6).
• The reduction is BILATERAL and SYMMETRIC - there is no left-right asymmetry.
• Vertical gain is MORE impaired than horizontal gain (upward 0.16-0.31 vs horizontal 0.21-0.43).
• Bilateral symmetric pursuit degradation = central/cerebellar pathway involvement. Peripheral vestibular lesions do NOT cause bilateral symmetric pursuit loss.
• In a 73-year-old, some age-related pursuit decline is expected. However, the degree here (gain as low as 0.16-0.21) is significantly beyond normal aging (which reduces gain by ~0.01-0.02 per decade, so at 73, expected gain ~0.55-0.65 at 0.2 Hz). This is pathological pursuit degradation, not simply senescent.
• Upward pursuit is more impaired than downward - this is characteristic of cerebellar flocculus/paraflocculus involvement or vestibular migraine-related central processing dysfunction.

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3. OPTOKINETIC NYSTAGMUS (OKN) (Pages 5-6)

• Left-to-Right OKN is completely absent (gain not measurable): This means when dots move rightward, the patient cannot generate a normal OKN response in either eye. This could represent a left occipito-parietal cortical deficit (the cortical area controlling OKN in each direction is contralateral - rightward OKN is driven by left hemisphere) OR poor cooperation during that trial.
• Right-to-Left OKN is normal (0.72-0.81): Consistent with preserved left-to-right smooth pursuit mechanisms.
• Vertical OKN asymmetry: Top-to-bottom gain is asymmetric (0.56 right eye vs 0.92 left eye) - this interocular gain difference >0.2 is significant. Bottom-to-top (upward) gain is severely reduced in the RIGHT eye (0.20) with relatively better preservation in the LEFT eye (0.67). This right eye upward OKN deficit is consistent with the same pathway affected in vertical smooth pursuit (more right eye than left, more upward than downward).
• The OKN asymmetries correlate with and reinforce the smooth pursuit abnormalities - both are mediated by the same fronto-parieto-occipital and cerebellar flocculus pathways.

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4. SPONTANEOUS NYSTAGMUS (Page 7)

• Complete absence of spontaneous nystagmus in both light and dark conditions is a highly important negative finding.
• This effectively EXCLUDES:
  • Active acute vestibular neuritis
  • Active Meniere's disease in an acute phase
  • Any significant ongoing unilateral vestibular deafferentation with residual tone asymmetry
• In the dark, even subtle peripheral imbalance may reveal nystagmus. Its complete absence here indicates compensated or intermittent vestibular dysfunction, not an active ongoing peripheral lesion.

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5. HEAD SHAKE NYSTAGMUS (Page 8)

• All parameters ABSENT in both eyes, horizontal and vertical.

• Negative head shake nystagmus (HSN) indicates no significant unilateral vestibular hypofunction at the time of testing. If there were a meaningful unilateral peripheral deficit, high-frequency head shaking would unmask a post-head-shake nystagmus (typically beating toward the stronger/intact side).
• This is consistent with no spontaneous nystagmus - together they argue strongly against acute unilateral vestibular neuritis or active labyrinthine disease.

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6. GAZE TESTS (Pages 8-12)

With Fixation (Center, Left, Up, Right, Down)

• All positions: NO nystagmus recorded (all parameters shown as "-")

Without Fixation

• Absence of gaze-evoked nystagmus in all directions with fixation is NORMAL and excludes gaze-holding deficits.
• The tiny finding in Right gaze without fixation (left eye only, SPV -0.06°/s = negligible) is at the noise threshold and is clinically insignificant.
• No gaze-evoked nystagmus (GEN) means no neural integrator failure, and excludes cerebellar ataxia syndromes, central gaze-holding deficits, and drug toxicity (which characteristically produce direction-specific GEN).
• No fixation suppression failure is implied by the fact that the few subtle positional nystagmus findings (in dark/without fixation) are extinguished with visual fixation - this is a peripheral feature (peripheral nystagmus is suppressed by fixation; central nystagmus is not).

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7. DIX-HALLPIKE POSITIONAL TEST - CRITICAL SECTION (Pages 13-16)

The Dix-Hallpike is performed in a SEQUENCE: Sit → Supine (test position) → Return to Sit

• Fast Phase Direction 0° = horizontal rightward
• Fast Phase Direction 90° = vertical upward
• Fast Phase Direction 180° = horizontal leftward
• Fast Phase Direction 270° = vertical downward
• Fast Phase Direction 45° = oblique upward-right (torsional-upbeat beating right)
• Fast Phase Direction ~225-234° = oblique downward-left (torsional-downbeat beating left)

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Dix-Hallpike RIGHT (Head turned RIGHT, laid back)

• Right eye: Horiz SPV -2.55°/s, Vertical SPV +4.24°/s, Fast Phase Direction 222.68°, Freq 1.56 Hz

• Left eye only: Horiz SPV -2.59°/s, Freq 0.57 Hz. Right eye: no nystagmus detected.

• Right eye: Vertical SPV -10.83°/s, Amplitude -4.05°, Freq 1.03 Hz (no fast phase direction given)

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Dix-Hallpike LEFT (Head turned LEFT, laid back)

• All parameters: ABSENT (no nystagmus in sitting with head turned left)

• Right eye: Horiz SPV -5.81°/s, Vertical SPV +7.96°/s, Amplitude 4.99°, Fast Phase Direction 234.67°, Freq 2.08 Hz
• Left eye: Horiz SPV +3.11°/s, Freq 0.84 Hz

• 234.67° = between 180° (leftward) and 270° (downward)
• This is DOWNWARD-LEFTWARD fast phase with a torsional component
• In the right eye specifically: horizontal component is leftward (SPV -5.81°/s = drifting right → fast phase LEFT) + vertical component is upward (SPV +7.96°/s = drifting down → fast phase UP)
• Wait - let me be precise: Vertical SPV +7.96°/s = eye drifting UPWARD = fast phase DOWNWARD. Combined with horizontal SPV -5.81°/s = eye drifting leftward = fast phase RIGHTWARD... but Fast Phase Direction is given as 234.67° which points DOWNWARD-LEFT. This means the right eye fast phase is beating DOWN and to the LEFT.

• LEFT ear is DOWNWARD (dependent)
• RIGHT ear is UPWARD

• Upbeat (vertical component upward) AND torsional toward the LEFT (dependent, affected) ear = the upper pole of the eyes beats toward the left ear.
• Fast phase direction expected: approximately 135-150° (upward-leftward torsional)

• Right eye Horizontal SPV = -5.81°/s → eye drifting LEFT → fast phase RIGHT (0°)
• Right eye Vertical SPV = +7.96°/s → eye drifting UP → fast phase DOWN (270°)
• Resultant: a right eye nystagmus with fast phase going DOWN-RIGHT = approximately 315°

• Right eye: Vertical SPV +7.00°/s, Freq 1.20 Hz

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8. SUPINE STRAIGHT HEAD EXTENSION TEST (Pages 16-17)

• Supine lying flat: Left eye fast phase 114.21° = slightly upward-leftward torsional nystagmus (114° = between 90° upward and 180° leftward). SPV 5.11°/s is at threshold level.
• Supine Head Extension 90° and End position: Bilateral horizontal nystagmus (SPV -6.35 to -7.80°/s) with fast phase ~167-173° = leftward-beating horizontal nystagmus. This is present bilaterally with similar values in both eyes, suggesting a symmetric horizontal nystagmus in head extension.
• Fast phase 167-172.89° = nearly horizontal, beating LEFT. Leftward nystagmus in supine head extension can represent a horizontal canal cupulolithiasis response OR a central pattern (central nystagmus in extension is concerning if it doesn't fatigue and is purely horizontal without torsion).

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9. McCLURE-PAGNINI ROLL TEST (Horizontal Canal BPPV Test) (Pages 18-21)

• Left eye: Vertical SPV -7.72°/s + Horizontal +1.99°/s, Fast Phase Direction 82.87°
  • 82.87° ≈ 90° = UPWARD fast phase (near-pure vertical, slightly right-ward)
  • SPV -7.72°/s vertical = eye drifting DOWNWARD → fast phase UP
  • This is upbeating nystagmus in the left eye in left lateral position
• Right eye: Vertical SPV +3.23°/s + Horizontal +1.77°/s, Fast Phase Direction 274.18°
  • 274.18° ≈ 270° = DOWNWARD fast phase
  • SPV +3.23°/s vertical = eye drifting UP → fast phase DOWN
  • This is downbeating nystagmus in the right eye in left lateral position

1. A posterior canal response being elicited by the lateral roll position
2. A central positional response (central positional nystagmus can be vertical or torsional)

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10. HEAD POSITION TESTS (Pages 20-23)

• Left eye: Horizontal SPV -6.83°/s + Vertical SPV +4.86°/s, Fast Phase Dir 213.36°
• 213.36° = between 180° (left) and 270° (down) = downward-leftward fast phase (torsional)
• Right eye: Horizontal SPV -5.63°/s (leftward drift = rightward fast phase) but no direction angle given

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11. SUBJECTIVE VISUAL VERTICAL (SVV) (Page 24)

• Blank background SVV = 0° - this is NORMAL. The otolith-mediated perception of upright is intact.
• Normal SVV in blank background (±2-3°) excludes significant acute utricular damage or major tonic otolith asymmetry.
• The slight tilts under optokinetic background (+5° CW, -4° CCW) likely reflect some visual-vestibular interaction asymmetry but are within borderline range. No definitive lateralization.

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COMPLETE INTEGRATED VNG INTERPRETATION

What this VNG Shows - Consolidated Table

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FINAL DIAGNOSIS AND DIFFERENTIAL

CORRECT PRIMARY DIAGNOSIS:

LEFT Posterior Canal BPPV (Canalithiasis)

1. Positive Dix-Hallpike LEFT: mixed nystagmus (SPV 7.96°/s, reaching significance threshold), occurring when left ear is DEPENDENT
2. Reversal nystagmus on return to sitting from left Dix-Hallpike (SPV 7.00°/s) - this reversal is the PATHOGNOMONIC sign of canalithiasis (free-floating otoliths reversing direction with gravity)
3. Dix-Hallpike RIGHT is NOT significantly positive (SPV <3°/s in test position)
4. Unterberger deviation LEFT >30° (confirms left labyrinthine involvement)
5. Roll Left head position nystagmus (bilateral, but left-dominant torsional)
6. Clinical history perfectly matches: brief (seconds), positional, triggered by head movement, recurrent over years, age 73 post-menopausal female

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SECONDARY DIAGNOSIS:

Central Vestibular Dysfunction - Likely Vestibular Migraine

1. Bilateral severely reduced smooth pursuit (gain 0.16-0.43) - cannot be explained by BPPV alone. BPPV has a normal inter-ictal examination.
2. Selective vertical saccade dysmetria (precision 58-77%) with normal horizontal - cerebellar or floccular pathway
3. Absent rightward OKN - left cortical/parietal pathway deficit
4. Vertical OKN asymmetry - right eye upward severely reduced
5. Supine head extension nystagmus - bilateral horizontal leftward nystagmus in a pattern that could represent central positional nystagmus
6. Torsional-vertical nystagmus in Roll Test - not meeting peripheral HC-BPPV pattern, more suggestive of central positional nystagmus
7. Clinical symptoms: Photophobia + phonophobia + osmophobia = migrainous sensitization triad. Space and motion discomfort = visual motion sensitivity (a well-recognized migrainous vestibular symptom). Years of recurrent episodic vertigo with no Meniere's features.

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DIFFERENTIAL DIAGNOSIS (Ranked)

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MANAGEMENT PLAN

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