Cranio-Oculography (Extended Videonystagmography) Report - Bharat Singh

Section-by-Section Analysis

1. Saccades (Rapid Eye Movements)

2. Smooth Pursuit (Eye Tracking)

• Right eye smooth pursuit data is absent ("-") for all horizontal measurements, suggesting the right eye could not reliably track OR data acquisition was limited for that eye.
• Left eye gain values of 0.06-0.17 are drastically below the normal range of 0.9-1.0 - this is a major abnormal finding.
• Gain Asymmetry: 11.76% leftward at 0.2 Hz, 40% rightward at 0.4 Hz - indicating asymmetric pursuit deficit.

3. Optokinetic Nystagmus (OKN)

4. Gaze Testing (Static Eye Position)

• Slow Phase Velocity: "-"
• Frequency: "-"
• Amplitude: "-"
• Direction: "-"

5. Spontaneous Nystagmus

• In Light: All parameters "-" - No spontaneous nystagmus with fixation.
• In Dark: All parameters "-" but traces show subtle activity.
• High Frequency Head Shaking: All parameters "-" - No head-shake nystagmus.

6. Positional Testing

Bow and Lean Test

Supine Roll Test (McClure-Pagnini Maneuver)

Dix-Hallpike Right

Dix-Hallpike Left

Supine Straight Head Extension

Summary of All Findings

Diagnosis / Clinical Interpretation

Important notice: This interpretation is based solely on the VNG findings. A formal diagnosis requires clinical correlation, history, neurological examination, and additional imaging. The report itself is signed but the "Findings" and "Impression" sections on page 1 are blank, meaning the reporting physician has not yet filled in their clinical impression.

Primary Finding: Central Oculomotor Dysfunction

• The cerebellum (particularly the flocculus, which coordinates smooth pursuit and OKN)
• Brainstem ocular motor pathways (pontine/mesencephalic circuits)
• Possibly cortical/subcortical pursuit pathways (occipito-parietal cortex and its projections)

Differential Diagnosis (Most to Least Likely Based on VNG Pattern)

1. Cerebellar or cerebellar pathway dysfunction - The combination of severely impaired smooth pursuit + reduced OKN + mildly prolonged saccade latencies is highly characteristic. Causes in a 64-year-old male include:
   • Cerebellar atrophy (degenerative, alcohol-related, paraneoplastic)
   • Spinocerebellar ataxia
   • Posterior fossa mass/lesion (tumor, infarct)
   • Multiple System Atrophy (MSA)
2. Brainstem lesion - Pontine or mesencephalic pathology affecting the PPRF (paramedian pontine reticular formation) or MLF (medial longitudinal fasciculus) can produce similar oculomotor patterns.
3. Diffuse central nervous system process - In a 64-year-old, vascular disease (small vessel disease, posterior circulation TIA/stroke), demyelination, or neurodegenerative conditions should be considered.
4. Medication effect - Certain medications (anticonvulsants, sedatives, antidepressants) can cause symmetrical smooth pursuit impairment and should be excluded.
5. Normal aging causes mild smooth pursuit degradation but NOT to the degree seen here (gains of 0.06 are pathological at any age).

What Has Been Ruled Out

• Benign Paroxysmal Positional Vertigo (BPPV): Ruled out - both Dix-Hallpike and Supine Roll maneuvers are negative.
• Acute Peripheral Vestibular Lesion (Vestibular Neuritis/Labyrinthitis): No spontaneous nystagmus, no head shake nystagmus - not consistent.
• Meniere's Disease (active phase): No spontaneous low-frequency vestibular asymmetry pattern.

Recommended Next Steps

1. MRI Brain with gadolinium - especially focused on the posterior fossa (cerebellum, brainstem) to rule out structural lesions, infarct, or demyelination.
2. Full neurological examination - cerebellar signs (ataxia, dysmetria, dysdiadochokinesia), cranial nerve assessment.
3. Caloric testing / Video Head Impulse Test (vHIT) - These components are not present in this report. They would help assess peripheral canal function specifically and are important to complete the vestibular workup.
4. Review of medication list - exclude drug-induced oculomotor suppression.
5. Audiological evaluation - to assess for associated hearing loss (could suggest posterior fossa pathology or Meniere's).
6. If MRI normal: Consider paraneoplastic antibody panel (anti-Yo, anti-Ri, anti-Hu) given age profile, and screening for systemic malignancy.

Diagnosis Based on Bharat Singh's VNG Report

The VNG Pattern Points To: Central Oculomotor Dysfunction

Most Likely Diagnosis:

Central Vestibular / Cerebellar Oculomotor Dysfunction

1. Cerebellar atrophy or degeneration - top suspect given the symmetric bilateral pursuit failure
2. Posterior circulation stroke or TIA (vertebrobasilar territory) - must be urgently ruled out
3. Brainstem lesion (pontine/mesencephalic)
4. Multiple System Atrophy (MSA)
5. Drug effect (certain medications suppress pursuit)

What Has Been Definitively RULED OUT:

• ❌ BPPV - Dix-Hallpike Right and Left both negative; Supine Roll negative
• ❌ Vestibular Neuritis - No spontaneous nystagmus
• ❌ Meniere's Disease - No peripheral vestibular asymmetry pattern

What Must Be Done Immediately:

Important: The original report's "Findings" and "Impression" boxes on page 1 were left blank by the reporting doctor - meaning no formal clinical impression was filled in. This patient needs to be seen urgently by a neurologist or neurotologist for clinical correlation and MRI. Do not delay.