SNHL

• 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

• 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

• 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
• SNHL

• abnormal cochlear duct, primarily a membranous defect
• autosomal recessive
• mild high frequency loss

• Pendred syndrome
• inherited in an autosomal recessive fashion
• affected individuals also have goiter

• 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%

(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

• (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.

• 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

• 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

• 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.

• hearing loss is usually congenital and severe to profound, although progressive mild to moderate SNHL is sometimes seen
• recessive
• B/L dilation of the vestibular aqueduct is common
• Euthyroid goiter, Thyroid dysfunction can be shown with a perchlorate discharge test

• Recessive
• 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%

• 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

• 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

• 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.

• 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.