Otosclerosis

Question 1

What is Otosclerosis?

Answer 1

• This is a condition whereby you have remodelling of the bones in the middle ear
• This Leads to conductive hearing loss
• Oto means ear
• Sclerosis means hardening

Question 2

How is Otosclerosis inherited?

Answer 2

• In an Autosomal Dominant Pattern
• No specific genetic mutations
• More Common in women

Question 3

What are the bones of the middle ear?

Answer 3

• Malleus
• Incus
• Stapes

Question 4

What is connected to the stapes?

Answer 4

• Connected to the Oval Window of the cochlea
• Transmits vibrations into the cochlea

Question 5

What is the Pathophysiology of Otosclerosis?

Answer 5

• The small bones of the middle ear are affected by the bone remodelling and formation
• This typically affects the base of the stapes which attaches to the oval window
• This causes stiffening and fixation which prevents it from transmitting sound effectively
• This causes conductive hearing loss

Question 6

How does Otosclerosis present?

Answer 6

• Hearing Loss
• Tinnitus

Question 7

Which pitch of sounds typically is affected more?

Answer 7

• lower pitched sounds are affected more than higher pitched sounds
• This is the opposite compared to Presbycusis

Question 8

Why does the patient tend to talk quietly?

Answer 8

• Due to conductive hearing loss with intact sensory hearing
• The patient can experience their voice as loud as the environment
• This Leads to them talking more quietly

Question 9

What examinations would you consider for Otosclerosis?

Answer 9

• Otoscopy
• Weber’s Test ( conductive hearing loss)
• Rhinne’s test ( conductive hearing loss)

Question 10

What investigations would you do for Otosclerosis?

Answer 10

• Audiometry ( shows conductive hearing loss - Bone conduction will be normal, air conduction will be greater than 20 dB on the chart, hearing loss is worse at lower frequencies)
• Tympanometry (will show reduced admittance, the tympanic membrane e is stiff and non-compliant and does not absorb sound, reflecting most of it back)
• High resolution CT scans ( these can detect bones changes associated with otosclerosis, these aren’t always required)

Question 11

What is the Management for Otosclerosis?

Answer 11

• Conservative ( hearing aids)
• Surgical ( stapedectomy or stapedotomy)
• Stapedectomy - involves removing the entire stapes bone and replacing it with a prosthesis. The prosthesis attaches to the oval window and hooks around the incus, allowing for normal transmission of the sounds from the incus to the cochlea
• Stapedotomy - involves removing part of the stapes bone the foot plate attached to the oval window. A small hole is made at the base of the stapes window for the prosthesis to enter. This transmits sound from the incus to the cochlea