Otosclerosis
A hereditary disorder causing progressive deafness due to overgrowth of bone in the inner ear.
Practical Audiology
Signs from the Case History
Site of Lesion
Severity of Loss
Tympanometry
Acoustic Reflexes
OAEs
Pure Tone Audiometry
Speech Audiometry (SRT/WRS/QuickSIN)
Recommendations
- Maternal Family Hx/Pregnancy
- Occlusion effect while talking or chewing
- Swartzes Sign; red bulge on medial wall of ME Space
Site of Lesion
- Middle Ear; Conductive
- Mixed loss w/ Inner Ear involvement
Severity of Loss
- Starts as low frequency conductive loss
- Progression toward flatter and more severe CHL
- Mixed loss will show abnormal high frequency bone conduction thresholds
- Carhart's Notch; dip in bone sensitivity at 2kHz, typically bilateral loss
Tympanometry
- Type A or As
Acoustic Reflexes
- Absent reflexes with probe to the affected ear
- If disease is unilateral, contralateral reflex may be present but elevated by the amount of the conductive loss
OAEs
- Absent with a significant conductive loss
Pure Tone Audiometry
- Unilateral or Conductive loss
Speech Audiometry (SRT/WRS/QuickSIN)
- SRT/PTA in agreement
- Word Recognition Scores when intensity can overcome conductive component
Recommendations
- Refer to ENT for imaging and medical management (fusion of ossicles, potential stapedectomy)
- Amplification after medical clearance