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VNG (Videonystagmography) Report - Mrs. Akanccha Parveen

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1. SACCADES

• Horizontal saccade velocities are generally within expected ranges, though there is a consistent asymmetry with the right eye faster than the left in horizontal movements.
• Vertical saccade precision is reduced (especially at 0.6 Hz: 34/29), which may indicate some difficulty with vertical eye movement accuracy.
• Latencies are within broadly normal range (150-350 ms is typical).

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2. SMOOTH PURSUIT

• At low frequencies (0.2 Hz) - gain is normal (~0.84-0.90), as expected.
• Bilateral smooth pursuit gain reduction is clearly present at higher frequencies (0.4 Hz and especially 0.6 Hz) for both horizontal and vertical directions. Gain as low as 0.12-0.19 at 0.6 Hz vertically is markedly reduced.
• This pattern of frequency-dependent gain reduction (normal at slow speeds, reduced at higher speeds) is consistent with a central or age-related smooth pursuit deficit, though central pathology (cerebellar or cerebral) needs to be considered given the degree of vertical reduction.

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3. OPTOKINETIC TEST (OKN)

• OKN gains are generally within normal limits (>0.75) for horizontal directions.
• Several vertical OKN tests returned no gain ("--"), possibly due to technical issues or inadequate response generation.
• One test (R→L 40°) showed fast phase directions at 172° and 161°, suggesting presence of a nystagmus fast phase, which warrants attention.

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4. NYSTAGMUS TESTS

• No spontaneous nystagmus in light or dark - this is a normal and reassuring finding.
• No post-head-shake nystagmus - suggests no significant unilateral vestibular weakness.

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5. GAZE TEST

• No gaze-evoked nystagmus with fixation - normal.
• A very mild nystagmus detected at center without fixation (right eye only, slow phase velocity 2.98°/s, amplitude 4°) - this is borderline and clinically may or may not be significant. Values <5°/s are generally considered borderline.

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6. POSITIONAL TESTS

• Right Dix-Hallpike: No nystagmus recorded in any position.
• Left Dix-Hallpike: No nystagmus recorded in any position.
• BPPV (posterior canal) - NEGATIVE bilaterally.

• No nystagmus in any position (sit to supine, right lateral, supine, left lateral).
• Horizontal canal BPPV - NEGATIVE.

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7. SUBJECTIVE VISUAL VERTICAL (SVV)

• A -3° left tilt in the anticlockwise condition is mildly outside the normal range. This may suggest a subtle left otolith (utricle) dysfunction or mild tilt perception bias. The blank background result of -1° is within normal limits.

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SUMMARY AND CLINICAL INTERPRETATION

Overall Impression:

• No evidence of BPPV (all positional tests negative).
• No peripheral vestibular dysfunction (no spontaneous nystagmus, no post-head-shake nystagmus).
• Smooth pursuit gain is reduced in a frequency-dependent manner, more pronounced for vertical movements. This pattern is more consistent with central pathway involvement (cerebellum, brainstem, or cortical pursuit pathways) than peripheral vestibular disease. Age-related pursuit decline may contribute but vertical involvement to this degree warrants further evaluation.
• SVV mildly tilted left - may indicate subtle left utricular dysfunction, though borderline.
• The overall VNG profile suggests a central vestibulo-ocular processing issue rather than a peripheral (inner ear) disorder.

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Note: The report's "Impression" and "Signature" fields on page 1 are blank - this interpretation above is based on the raw VNG data values. The attending clinician should provide the final clinical impression.