Rinne test

**Technique:** Strike a 512 Hz tuning fork. Place the base on the mastoid process (bone conduction) until the patient no longer hears it. Then move the prongs about 1-2 cm from the external auditory canal (air conduction). Ask which is louder, or have the patient say when the sound stops.

**Interpretation:** - **Normal (Rinne positive):** AC > BC. The ossicular chain amplifies sound about 20-30 dB, so air conduction is normally about 2x as long as bone conduction. - **Conductive hearing loss (Rinne negative):** BC > AC. Sound bypasses the external or middle ear defect and goes through bone to the cochlea. - **Sensorineural hearing loss (SNHL):** AC > BC is still preserved (Rinne positive), but both are reduced. This is sometimes called a "false-normal" result. - **Severe unilateral SNHL:** A false-negative Rinne can occur from cross-over (transcranial transmission) to the opposite, normal cochlea. Masking the opposite ear solves this.

**Pairing with the Weber test (256-512 Hz fork on midline forehead/vertex):** - Conductive loss: Weber lateralizes to the **affected** ear. Rinne is negative in that ear. - SNHL: Weber lateralizes to the **normal** ear. Rinne is positive (AC > BC) in both ears. - Mnemonic: conductive loss makes the affected ear louder, because it is less masked by ambient noise. SNHL means the good ear hears better.

**Causes of conductive loss (negative Rinne):** - Cerumen impaction or foreign body - Otitis media with effusion - Tympanic membrane perforation - Otosclerosis (stapes fixation; classically young adult women, may worsen in pregnancy) - Cholesteatoma - Ossicular discontinuity (e.g., trauma)

**Causes of SNHL (positive Rinne, with Weber toward the good ear):** - Presbycusis - Noise-induced hearing loss - Ototoxic drugs (aminoglycosides, loop diuretics, cisplatin) - Acoustic neuroma (vestibular schwannoma) - Ménière disease

**Clinical pearls:** - A 512 Hz fork is preferred. Lower frequencies (e.g., 128 Hz) cause vibration sensation, and higher frequencies decay too quickly. - A negative Rinne generally implies an air-bone gap of at least about 20-30 dB (some sources say 15-30 dB). - Tuning fork tests are screening tools. Audiometry confirms and quantifies the loss. - In otosclerosis, a paradoxical ability to hear better in noisy environments (paracusis of Willis) can occur.