Evoked Potential

Otosclerosis

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A hereditary disorder causing progressive deafness due to overgrowth of bone in the inner ear.

Practical Audiology

​Signs from the Case History
  • 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​
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