How can I differentiate sensorineural hearing loss from conductive hearing loss using the tuning‑fork Weber and Rinne tests?

Differentiating Sensorineural from Conductive Hearing Loss Using Tuning Fork Tests

Use the Weber and Rinne tests with a 512 Hz tuning fork to distinguish between conductive and sensorineural hearing loss: in conductive hearing loss, the Weber test lateralizes to the affected ear and the Rinne test shows bone conduction louder than air conduction in that ear; in sensorineural hearing loss, the Weber test lateralizes to the unaffected ear and the Rinne test remains positive (air conduction louder than bone conduction) in both ears. 1, 2

Proper Testing Technique

Weber Test

• Strike the 512 Hz tuning fork on a covered elbow or knee (never on hard surfaces, as this creates nonharmonic frequencies that invalidate results) 2, 3
• Place the vibrating fork at the midline of the forehead or on maxillary teeth (not on false teeth) 1, 2
• Ask the patient where they hear the sound 1, 2
• Normal response: sound heard at midline or "everywhere" 1, 2

Rinne Test

• Strike the 512 Hz tuning fork on a covered elbow or knee 2, 3
• Place the vibrating fork over the mastoid bone, then move it to the entrance of the ear canal (without touching the ear) 1, 2
• Ask where the sound is louder: behind the ear (bone conduction) or in front of the ear (air conduction) 2, 3
• Normal response: air conduction louder than bone conduction 1, 2
• Repeat for the other ear 1

Interpretation Patterns

Conductive Hearing Loss

• Weber test: sound lateralizes to the affected ear 1, 2
• Rinne test: negative result (bone conduction > air conduction) in the affected ear 1, 2
• The Rinne test typically becomes abnormal at an air-bone gap of approximately 13 dB 2, 4
• Otoscopic examination will often show abnormalities (cerumen impaction, middle ear fluid, tympanic membrane perforation, canal edema) 1, 5

Sensorineural Hearing Loss

• Weber test: sound lateralizes to the unaffected (better hearing) ear 1, 2
• Rinne test: positive result (air conduction > bone conduction) in both ears 1, 2
• Otoscopic examination will almost always be normal 1
• Patients often report tinnitus, ear fullness, or vertigo (though these can also occur in conductive hearing loss) 1

Critical Clinical Considerations

Essential Pre-Test Steps

• Remove impacted cerumen before establishing any diagnosis, as cerumen impaction causes conductive hearing loss and must be cleared first 1, 2, 5
• Perform testing in a quiet environment to minimize ambient noise interference 2
• Complete otoscopic examination to identify visible causes of conductive hearing loss 1, 5

Frequency Selection

• Use a 512 Hz tuning fork as the standard for optimal balance between sensitivity and specificity 2, 6
• While 256 Hz forks are more sensitive for detecting conductive hearing loss, they have higher false-positive rates 6
• For suspected sudden sensorineural hearing loss specifically, 500 Hz shows the highest sensitivity (94.49%) 7

Important Limitations and Pitfalls

• Never assume the diagnosis without audiometric confirmation—tuning fork tests provide preliminary screening information only and do not replace formal audiometry 2, 5
• Tuning fork tests have poor accuracy for mild conductive hearing loss (air-bone gaps of 5-35 dB show unreliable results) 2, 4
• Misdiagnosing sensorineural hearing loss as conductive can delay critical treatment, particularly for sudden sensorineural hearing loss which requires urgent evaluation 2, 5
• Sensitivity of the Rinne test ranges from 43-91% and specificity from 50-100%, with significant variability in test accuracy 8
• Even if the Weber test lateralizes to the affected ear, this does not preclude sensorineural hearing loss—formal audiometry is still required 7

Immediate Next Steps After Abnormal Results

When Tests Suggest Conductive Hearing Loss

• Perform comprehensive otoscopic examination and pneumatic otoscopy to identify treatable causes 1, 5
• Order formal audiometry with pure-tone testing including both air and bone conduction to definitively confirm the type and severity 2
• Treat reversible causes immediately (remove cerumen, manage middle ear effusion) 2, 5
• Consider tympanometry to assess middle ear function 1, 5

When Tests Suggest Sensorineural Hearing Loss

• Assess urgently for sudden sensorineural hearing loss, which requires immediate evaluation and potential treatment 2
• Order formal audiometry to confirm diagnosis and severity 2
• Refer to audiology and otolaryngology for comprehensive management 2
• Look for bilateral involvement, recurrent episodes, or focal neurologic findings that suggest specific underlying disorders 1

Alternative When Tuning Fork Unavailable

• The "hum test" can substitute for the Weber test: have the patient hum and report if they hear their own hum louder in one ear (suggests conductive hearing loss in that ear) 2, 3