Section 10

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What type of hearing test is used in the newborn hearing test?

Oto-acoustic emissions

Name two infections which may result in sensorineural hearing loss?

  • Meningitis
  • Rubella
  • Cytomegalovirus
  • Toxoplasmosis
  • Herpes
  • Syphilis

Name the conditions and the type of hearing loss for photographs A, B and C.

  • A – Down’s syndrome / trisomy 21 – mainly conductive but can also have sensorineural hearing loss 
  • B -Waardenburg syndrome – progressive sensorineural hearing loss
  • C – Treacher Collin-syndrome – conductive hearing loss due to microtia and narrowing or absence of external auditory canal

What protein and gene is associated with the most common cause of congenital sensorineural hearing loss?

  • Connexin 26 (Cx26) is a protein found on the (GJB2) gene
  • Connexin 26 mutations are responsible for at least 20% of all genetic hearing loss and 10% of all childhood hearing loss.

Name two syndromic causes of hearing loss associated with ophthalmological manifestations and what are they?

  • Usher syndrome – retinitis pigmentosa
  • Laurence-Moon syndrome – retinitis pigmentosa
  • CHARGE – coloboma of eye

Supporting Information

Congenital hearing problems- Syndromic hearing loss:

NameType of lossGeneticsAssociation
Pendred’s syndromeSensorineuralAutosomal recessive

Thyroid goitre

Widened vestibular aqueduct bilateral

Treacher Collins syndromeConductiveAutosomal dominantUnderdevelopment of the mandible, maxilla and microtia and other ear problems
Pierre Robin syndrome Autosomal dominantHypoplastic mandible with cleft palate and ear abnormalities such as micro/anotia
Crouzon’s diseaseMixedAutosomal dominantHypoplastic mandible, maxilla and craniosynostosis, exophthalmos and ear abnormalities- narrow canal and menieres
Aperts syndrome Autosomal dominantSyndactyly, cleft palate, maxillary underdevelopment, stapes footplate fixation. 
CHARGE  

Coloboma of the eye

Heart defects

Atresia of nasal choanae

Retarded growth

Genitourinary problems

Ear defects- microtia

Branchio-oto-renal syndrome Autosomal dominantBranchial cleft defects, preauricular sinus, kidney disease, middle ear disease and anotia

Microtia (small underdeveloped ears) and anotia (no ear)- causes functional and cosmetic issues:

  • Conductive loss- 30-60dB
  • Must know whether it is unilateral/bilateral and if they have a syndrome
  • MDT approach
  • Associated with Treacher-Collins, Goldenhaar, CHARGE and Pierre Robin syndrome
  • CHARGE- coloboma of the eye, heart defects, atresia of nasal choanae, retardation of growth, genitourinary problems, ear defects such as microtia
  • Treated with bone conduction aids, first soft band and then BAHA
  • Cosmetic- 
    • Conservative with prosthesis if neonate will correct
    • 6-8 yrs – reconstruction with rib cartilage if bilateral can be difficult due to associated middle ear problems such as facial nerve or cholesteatoma
    • Wait until adult size if unilateral for comparison

Cochlear abnormalities- congenital- classified by Jackler:

Commonest– enlarged vestibular aqueduct seen in Pendred syndrome- SNHL avoid contact sports as head injury can worsen it. 

Pendred syndrome- 7.5% congenital deafness, AR inheritance- pendrin gene

  • Enlarged vestibular aqueduct
  • Enlarged endolymphatic system
  • Mondini deformity
  • Bilateral SNHL + goitre
  • CSF rhinorrhea from ear which via the eustachian tube may cause CSF rhinorrhoea 
  • Treat- thyroxine, cochlear implants, MDT

Other classification:

  1. Membranous labyrinth dysplasia
    1. Limited abnormality- Scheibe (saccular/cochlear)
    2. Complete abnormality- Usher, Javell and Lange Nelson, Bind Seebenman- SNHL- treated with cochlear implants
  2. Bony labyrinth dysplasia
    1. Limited abnormality- Mondini- 1.5 instead of 2.5 cochlear 
    2. Complete abnormality- Michel- no cochlear, brainstem implant

Waardenburg syndrome- associated with congenital progressive hearing loss (unilateral in 70% and bilateral 30%) and heterochromia irides (different iris colours), white forelock (front patch of white-poliosis) and skin pigmentation changes. 

It is an autosomal dominant inheritance and comes in 4 types:

  • Type 1+2- 
    • Dystopia canthorum- lateral inner canthi displacement
    • Hypertelorism- increased with between medial canthi from above
  • Type IV- 
    • Hirschsprung disease

Try with air conduction aid, if this doesn’t work could consider a cochlear implant.  

Paediatric hearing tests

  • Neonate – OAE
  • 7 months – distraction testing
  • 2-4 yrs – distraction testing or conditioned responses   UK screening=all children
  • >5 years –  PTA

Comprehensive list includes:

  • Otoacoustic emissions– measurement of distortion product OAEs is being developed as a universal tool for very young children. 
  • Auditory response cradle- monitors head turning, startle response and body/respiratory movements in response to voice. 
  • Distraction testing– the child’s response to none visible sounds when distracted with play
  • Conditioned response audiometry– trained to perform a task after hearing a sound. It is then made in various directions and volumes. 
  • Speech discrimination testing- asked to point to a number of objects with names designed to sound similar. 

Pure tone audiogram- 4 yrs and older

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