Hearing loss
- Conductive hearing loss
- Impaired conduction of sound through outer ear, tympanic membrane or middle ear
- Children and young adults
- Etiology
- Tympanic membrane perforation
- Otitis media with effusion
- Barotrauma
- Otosclerosis
- Diagnosis
- Pure tone audiometry
- Auditory threshold increased for air conduction
- Auditory threshold normal for bone conduction
- Speech audiometry
- Increasing loudness eventually leads to 100% speech comprehension
- Rinne test
- Unable to hear tuning fork after moving it from mastoid to outer ear
- Pure tone audiometry
- Sensorineural hearing loss
- Lesion of cochlea, vestibulocochlear nerve or central auditory pathways
- Adults and elderly
- Etiology
- Congenital
- Acquired
- Presbycusis (aging) (most common cause)
- Especially high frequencies
- Ototoxicity
- Meniere disease
- Acoustic neuroma
- Noise-induced hearing loss
- Trauma
- Otitis interna
- Diabetic otopathy
- Presbycusis (aging) (most common cause)
- Diagnosis
- Pure tone audiometry
- Auditory threshold increased for both air and bone conduction
- Speech audiometry
- Increasing loudness never leads to 100% speech comprehension
- Pure tone audiometry
- Combined hearing loss
- Diagnosis
- Pure tone
- Auditory threshold is increased for both air and bone conduction, but it is increased more for air conduction
- Pure tone
- Diagnosis
- Tuning fork tests
- Distinguish conductive and SNHL
- Weber test
- Tests for lateralization (sound is louder in one ear)
- Base of tuning fork on the middle of forehead – bone conduction to cochlea
- Interpretation
- Lateralization to one ear = contralateral sensorineural HL or ipsilateral conductive HL
- No lateralization = normal hearing or bilateral HL
- Rinne test
- Tests for air conduction and bone conduction
- Base of tuning fork on the mastoid process
- -> which side is louder?
- -> when the patient no longer hears the tone, move front of the fork to the outer ear and ask if the patient still hears it
- Air conduction is greater than bone, so patient should still hear the fork
- Interpretation
- Sound is louder with air than bone conduction (positive Rinne) = no conductive HL in examined ear
- Sound is louder with bone than with air conduction (negative Rinne) = conductive HL in examined ear