Case 04 of 8 · Trainee · Vestibular schwannoma

Asymmetric high-frequency hearing loss

A 58-year-old whose audiogram screen shows right-sided high-frequency loss.

CASE VIGNETTE

A 58-year-old man is referred from primary care because a routine occupational audiogram screen showed asymmetric high-frequency hearing loss in the right ear. He reports no clear hearing change subjectively, intermittent right-sided tinnitus over the past year, and a vague sense of unsteadiness when walking on uneven ground but no episodic vertigo, no headache, and no other neurological symptoms.

Formal pure-tone audiometry confirms a right-sided high-frequency sloping sensorineural hearing loss. Word recognition is 92% on the left, 76% on the right at 60 dB HL — a clinically significant asymmetry.

Bedside HIT is normal bilaterally. There is no spontaneous nystagmus. DVA loss is mild on rightward thrusts. Formal vestibular testing shows: vHIT gain 0.7 on the right horizontal canal (mildly reduced), 0.95 left; caloric weakness 28% right; cVEMP reduced amplitude on the right; oVEMP normal bilaterally.

Asymmetric high-frequency sensorineural hearing loss with reduced word recognition disproportionate to the pure-tone average is the classic audiometric signature that should prompt imaging for vestibular schwannoma. The 15+ dB asymmetry across 2-8 kHz meets most screening criteria.

DVA SIGNATUREMild

Vestibular schwannoma — right intracanalicular

DVA loss: Mild — 0.15 logMAR on rightward thrusts; not the primary diagnostic finding
Laterality: Subtle right asymmetry
Asymmetry: Mild rightward DVA asymmetry
Corroborating tests: Audiometric asymmetry (15+ dB at high frequencies) · reduced right word recognition · reduced right cVEMP · MRI IAC pending

Key signature: Schwannoma is imaging-led. DVA is supporting evidence — the principal diagnostic clue is the audiometric asymmetry with reduced word recognition. MRI with gadolinium of the IAC is the gold standard.

Test-battery findings

DVA — rightward thrust	0.15 logMAR (mild loss)
vHIT gain — right horizontal canal	0.7 (mildly reduced)
Caloric weakness — right	28%
cVEMP — right	Reduced amplitude
oVEMP — right	Normal
Audiogram	Right HF SNHL, 15+ dB asymmetry at 2-8 kHz
Word recognition — right	76% (vs 92% left — disproportionate)

Question

Which investigation is the most appropriate next step?

References

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Vestibular schwannoma — right intracanalicular

Test-battery findings

Question

Further reading

References