How do you interpret the results of the Rinne (Rinne test) and Weber (Weber test) tests in assessing hearing loss?

Interpreting Rinne and Weber Tests for Hearing Loss Assessment

The Rinne and Weber tests are essential bedside tools for differentiating between conductive hearing loss (CHL) and sensorineural hearing loss (SNHL), with proper technique being critical for accurate diagnosis and subsequent management decisions.

Proper Technique for Tuning Fork Tests

Weber Test

• Vibrate a 256 or 512 Hz tuning fork by striking it on your covered elbow or knee (not on hard surfaces) 1
• Place the vibrating tuning fork at the midline of the forehead or on maxillary teeth (not false teeth) 1
• Ask the patient where the sound is heard; normally it should be heard at midline or "everywhere" 1
• Interpretation:
  • If sound lateralizes to one ear, either there is CHL in that ear OR SNHL in the opposite ear 1
  • Lateralization occurs with as little as 2.5 dB difference between ears 2

Rinne Test

• Vibrate a 256 or 512 Hz tuning fork by striking it on your covered elbow or knee 1
• Place the vibrating tuning fork over the mastoid bone of one ear, then move it to the entrance of the ear canal (without touching the ear) 1
• Ask the patient where the sound is louder 1
• Interpretation:
  • Normal result (positive Rinne): Sound is heard louder via air conduction (at ear canal) 1
  • Abnormal result (negative Rinne): Sound is heard louder via bone conduction (at mastoid) indicating CHL in that ear 1
  • If sound is heard better by bone conduction but in the opposite ear, there is SNHL in the test ear 1
• Repeat for the other ear 1

Diagnostic Interpretation

Conductive Hearing Loss (CHL)

• Weber test: Sound lateralizes to the affected ear 1
• Rinne test: Negative (bone conduction > air conduction) in the affected ear 1
• Common causes: Cerumen impaction, middle ear fluid, otitis media, foreign bodies, perforated tympanic membrane, otosclerosis, cholesteatoma 1

Sensorineural Hearing Loss (SNHL)

• Weber test: Sound lateralizes to the unaffected ear 1
• Rinne test: Positive (air conduction > bone conduction) in both ears 1
• Otoscopic examination is typically normal 1

Mixed Hearing Loss

• Combination of both CHL and SNHL components 1
• Requires careful interpretation of both tests in conjunction with audiometry 1

Important Considerations and Limitations

• Tuning fork tests should be used as preliminary diagnostic tools and do not replace formal audiometric testing 1, 3
• The sensitivity and specificity of the Rinne test for detecting CHL varies considerably:
  • For 256 Hz fork: 43-91% sensitivity, 50-100% specificity 4
  • For 512 Hz fork: 16-87% sensitivity, 55-100% specificity 4
• Rinne test accuracy decreases with higher frequency tuning forks; most reliable at 256 Hz 5
• Air-bone gaps of 25-40 dB are typically needed for the Rinne test to reliably detect CHL 5, 6
• Tester experience significantly affects test reliability; experienced testers achieve better results 6
• The use of masking improves test reliability when testing patients with asymmetric hearing 6
• The hum test is a reasonable alternative to the Weber test when a tuning fork is unavailable—patient hums and if they hear their own hum louder in the affected ear, it suggests CHL 1

Clinical Significance

• Early differentiation between CHL and SNHL is crucial as they have markedly different management strategies and prognoses 1
• CHL often has treatable causes (e.g., cerumen impaction) that can improve hearing when addressed 1
• Misdiagnosis of SNHL as CHL can lead to delays in appropriate treatment, particularly in cases of sudden sensorineural hearing loss 1
• These tests are particularly valuable in settings where audiometry is not immediately available 1