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What is Michel’s Aplasia?
- complete failure of the development of the inner ear
- Autosomal Dominant
- Normal middle and outer ear
- CT –hypoplastic petrous pyramid and absent cochlea and labyrinth
What is Mondini Aplasia?
- developmental arrest of the bony and membranous labyrinth
- Autosomal Dominant
- progressive or fluctuating unilateral or bilateral hearing loss
- increased risk of perilymphatic gushers and meningitis
- CT – single turn of curved cochlea, cystic dilatation of the cochlea, SCC may be absent or wide
What is Scheibe Aplasia
- partial or complete aplasia of the pars inferior (cochlea and saccule) and normal pars superior (SCC and utricle)
- Autosomal recessive
- assoc. w other diseases ie. Usher syndrome and Waardenburg syndrome
What is Alexander Alexander Aplasia?
- abnormal cochlear duct, primarily a membranous defect
- autosomal recessive
- mild high frequency loss
What is the most common syndromic form of hereditary sensorineural hearing loss?
- Pendred syndrome
- inherited in an autosomal recessive fashion
- affected individuals also have goiter
What is Branchio-oto-renal Syndrome?
- A wide variety of otologic findings, can involve the external, middle, or inner ear.
- Hearing impairment (CHL, SNHL, or mixed) is the most common feature of BOR syndrome and is reported in almost 90% of affected individuals.
- Branchial anomalies occur in the form of laterocervical fistulas, sinuses, and cysts
- renal anomalies ranging from agenesis to dysplasia (25%
Diagnostic criteria for neurofibromatosis, type 2?
(1) bilateral vestibular schwannomas that usually develop by the second decade of or (2) a family history of NF2 in a first-degree relative, plus one of the following: unilateral vestibular schwannomas at less than 30 years of age, or any two of meningioma, glioma, schwannoma, or juvenile posterior subcapsular lenticular opacities/juvenile cortical cataract
Diagnostic criteria for Stickler syndrome?
- (1) congenital vitreous anomaly
- and (2) any three of myopia with onset before age 6 years, rhegmatogenous retinal detachment or paravascular pigmented lattice degeneration, joint hypermobility with abnormal Beighton score, SNHL (audiometric confirmation), or midline clefting.
Which type of Stickler has worst HL? Best vision?
- SS type 3 tend to have moderate to severe hearing lss, patients with SS type 1 have either normal hearing or only a mild impairment, and patients with SS type 2 fall in between
- SS type 2 is due to missense or in-frame deletion mutations in COL11A2, and is unique in that there are no ocular abnormalities because COL11A2 is not expressed in the vitreous
Describe the 4 types of Waardenburg syndrome?
- WS type 1 is recognized by SNHL, white forelock, pigmentary disturbances of the iris, and dystopia canthorum, a specific displacement of the inner canthi and lacrimal puncti.
- WS type 2 is like WS type 1 with absence of dystopia canthorum
- WS type 3 is like WS type 1 with the addition of hypoplasia or contracture of the upper limb
- WS type 4 involves Hirschsprung disease
Describe Treacher-Collins syndrome
- autosomal dominant
- characterized by maldevelopment of the maxilla and mandible, with abnormal canthi placement, ocular colobomas, choanal atresia, and conductive hearing loss secondary to ossicular fixation.
Describe Pendred's syndrome
- hearing loss is usually congenital and severe to profound, although progressive mild to moderate SNHL is sometimes seen
- B/L dilation of the vestibular aqueduct is common
- Euthyroid goiter, Thyroid dysfunction can be shown with a perchlorate discharge test
Describe Jervell and Lange-Nielsen syndrome
- Prolonged QT
- Hearing impairment is due to changes in endolymph homeostasis caused by malfunction of this channel and is congenital, bilateral, and severe to profound
- Effective treatment with β-adrenergic blockers reduces mortality from 71% to 6%
Describe 3 types of Usher Syndrome
- Type 1 (profound), severe to profound congenital hearing loss, vestibular dysfunction, and retinitis pigmentosa that develops in childhood
- type 2 (severe), moderate to severe congenital hearing loss, with uncertainty related to progression, no vestibular dysfunction, and retinal degeneration that begins in the third to fourth decade
- type 3 (variable), progressive hearing loss, variable vestibular dysfunction, and variable onset of retinitis pigmentosa
Describe the heritability of Alport's syndrome
- predominantly X-linked (approximately 80%), can be autosomal recessive or dominant
- disease of type IV collagen that is manifested by hematuric nephritis, hearing impairment, and ocular change
Disability in these four areas have been associated with presbycusis
- sensory, characterized by hair cell loss (audiometric findings in this type of presbycusis include an abrupt, steep, and high-frequency sensorineural loss with slow, symmetric bilateral progression)
- neural, which is associated with the loss of spiral ganglion cells and axons (audiometric findings include gradual hearing loss with a moderate slope toward the high frequencies with a disproportionately severe decrease in speech discrimination metabolic, which is characterized by strial atrophy (audio shows a flat sensory loss beginning during the third through sixth decades and progressing slowly with good SD.
- mechanical or conductive.
Diagnosis and prognosis of SSNHL?
- Acute hearing loss, occurs over less than 3 day period, at least 30db, over 3 contiguous frequencies.
- Recovery often spontaneous.
- Prognosis depends on severity of hearing loss, but is often good.
- Better prognosis associated with hearing loss in a high or low pitch frequency and not across broad frequency spectrum.
- 50% improve within 10 daysif no improvement within 3 months, further improvement is not likely.