Rinne’s Test and Weber’s Test

Rinne’s Test

• Procedure:
  • Place a vibrating 512 Hz tuning fork firmly on the mastoid process to test bone conduction. Ensure firm contact by applying pressure to the opposite side of the head.
  • Ask the patient to indicate when they can no longer hear the sound.
  • Move the tuning fork in front of the external auditory meatus to test air conduction.
  • Ask the patient if they can hear the sound again.
• Interpretation:
  • Normal Hearing (Rinne’s Positive):
    • Air conduction (AC) is better than bone conduction (BC).
    • The patient hears the sound when the tuning fork is moved in front of the ear after it can no longer be heard on the mastoid.
  • Conductive Hearing Loss (Rinne’s Negative):
    • Bone conduction (BC) is better than air conduction (AC).
    • The patient hears the tuning fork longer on the mastoid than in front of the ear.
  • Sensorineural Hearing Loss:
    • Rinne’s test remains positive (AC > BC), but the patient may have a ‘false negative’ if they cannot hear anything in the affected ear; bone vibrations might be transmitted to the unaffected ear.

Weber’s Test

• Procedure:
  • Tap a 512 Hz tuning fork and place it in the midline of the forehead.
  • Ask the patient “Where do you hear the sound?”
• Interpretation:
  • Normal Hearing:
    • Sound is heard equally in both ears (midline).
  • Conductive Hearing Loss:
    • Sound localizes to the affected ear.
    • The affected ear has less environmental noise and low-frequency sounds are trapped within the inner ear, increasing loudness.
  • Sensorineural Hearing Loss:
    • Sound localizes to the unaffected ear.

• Additional Notes
  • The 512 Hz tuning fork is preferred due to its balance between decay time and minimizing tactile vibration.
  • Rinne’s Test Sensitivity: While useful, it has low sensitivity, and results should be interpreted in conjunction with other clinical findings.
  • Demonstration of Conductive Loss: Speaking or humming and then occluding one ear can illustrate how conductive loss causes increased loudness in the occluded ear.

	Rinne’s test	Weber’s test
Normal	Air conduction > bone conduction  (Positive Rinne’s)	Heard in the midline
Conductive hearing loss	Bone conduction > Air conduction (Negative Rinne’s)	Heard in the bad ear
Sensorineural hearing loss	Air conduction > bone conduction (Positive Rinne’s)	Heard in the good ear

Causes of Conductive Hearing Loss

Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane (eardrum), or middle ear (ossicles). The causes can be divided into external and middle ear causes:

External Ear Causes:

1. Earwax (Cerumen) Impaction: Accumulation of earwax blocking the ear canal.
2. Otitis Externa: Infection or inflammation of the ear canal.
3. Foreign Bodies: Objects stuck in the ear canal.
4. Exostoses and Osteomas: Bony growths in the ear canal.
5. Congenital Atresia: Absence or closure of the ear canal.

Middle Ear Causes:

1. Otitis Media: Infection or inflammation of the middle ear.
   • Acute Otitis Media: Often due to bacterial or viral infections.
   • Chronic Suppurative Otitis Media: Persistent infection leading to perforation of the tympanic membrane.
2. Otosclerosis: Abnormal bone growth in the middle ear, usually affecting the stapes bone.
3. Eustachian Tube Dysfunction: Improper functioning of the tube that connects the middle ear to the back of the nose, leading to fluid accumulation and pressure issues.
4. Tympanic Membrane Perforation: Hole or tear in the eardrum.
5. Cholesteatoma: Abnormal skin growth in the middle ear leading to destruction of the middle ear structures.
6. Barotrauma: Injury to the ear due to changes in pressure, such as during flying or diving.

Causes of Sensorineural Hearing Loss

Sensorineural hearing loss (SNHL) occurs due to damage to the inner ear (cochlea) or the nerve pathways from the inner ear to the brain. The causes can be divided into congenital (present at birth) and acquired causes:

Congenital Causes:

1. Genetic Factors: Inherited conditions like Usher syndrome, Waardenburg syndrome, and Pendred syndrome.
2. Prenatal Infections: Infections during pregnancy such as rubella, cytomegalovirus (CMV), and syphilis.
3. Birth Complications: Low birth weight, prematurity, and lack of oxygen (hypoxia) during birth.

Acquired Causes:

1. Aging (Presbycusis): Gradual loss of hearing due to aging.
2. Noise Exposure: Prolonged exposure to loud noises (e.g., industrial noise, music concerts).
3. Ototoxic Medications: Certain medications that can damage the inner ear, such as aminoglycoside antibiotics, chemotherapy drugs (e.g., cisplatin), loop diuretics, and high doses of aspirin.
4. Infections: Meningitis, measles, mumps, and labyrinthitis (infection of the inner ear).
5. Head Trauma: Injury to the head that damages the inner ear or auditory nerve.
6. Meniere’s Disease: A disorder of the inner ear causing vertigo, tinnitus, and fluctuating hearing loss.
7. Acoustic Neuroma: A benign tumor on the auditory nerve that can cause hearing loss and balance issues.
8. Autoimmune Inner Ear Disease: An autoimmune condition where the body’s immune system attacks the inner ear.
9. Sudden Sensorineural Hearing Loss (SSNHL): Rapid loss of hearing, often with unknown cause, potentially related to viral infections, vascular issues, or immune responses.