12/6/2013

12/6/2013

Answers:

Which category of presbycusis is only theoretical?
A) Strial Presbycusis 
B) Neural Presbycusis 
C) Sensory Presbycusis 
D) Conductive Presbycusis

Conductive Presbycusis is thought to be due to changes
in mechanical characteristics of basilar membrane which may cause gradually sloping high frequency hearing loss. No discernable pathology exists however and this hearing loss mechanism is only
theoretical.

What is the most common cause of sudden SNHL in the elderly?

Thrombotic/embolic events of the internal auditory artery is the most common cause. Partial losses may be reversible, but total losses rarely recover.

MC Questions:
What is the mode of transmission for most forms of hereditary hearing loss?
A) Autosomal Recessive 
B) Autosomal Dominant 
C) X-linked 
D) Mitochondrial 
E) Syndromic

Free Response Question:
What is the classic appearance on an audiogram for nonsyndromic congenital hearing loss?

Quick Facts:
Syndromic HHI
-can be conductive, sensorineural or mixed.
-Pendred = most common syndromic form of deafness (10%), SNHL + goiter, often before puberty. Hearing loss is congenital, bilateral, mod-profound and sloping in
higher frequencies. Often have enlarged vestibular aqueduct and mondini-type
malformations.
-Waardenburg = 2-5% of pts w/ congenital hearing loss. Dystopia canthorum, pigmentary abnormalities and SNHL.  
Four subtypes:
-Type I = + dystopia canthorum, PAX3
-Type II = no dystopia canthorum, MITF, SNA12
-Type III = + dystopia canthorum, + upper limb abnormalities, PAX3
-Type IV = - dystopia canthorum, + Hirschsprung disease, EDNRB, EDN3,
SOX10