Childhood Deafness Flashcards
What can cause genetic conductive hearing loss?
Congenital anomalies of pinna, external ear canal, drum or ossicles
Treacher-Collins
Pierre Robin
Goldenhar syndrome
What can cause genetic sensorineural hearing loss?
40+ dB hearing loss
Autosomal dominant: Alport syndrome, Waardenburg syndrome
Autosomal recessive
Non-syndromic SNHL
X-linked: Turner’s
What are non-genetic causes of hearing loss in children?
Intrauterine TORCH infection - CMV, rubella, toxoplasmosis, HIV, syphilis
Perinatal causes - prematurity, hypoxia, kernicterus, infection, intraventricular haemorrhage
Infections: meningitis, encephalitis, measles, mumps
Other: Ototoxic drugs, acoustic/cranial trauma
What tests are used in universal newborn hearing screening? When?
Screening within weeks of birth
Otoacoustic emissions
Audiological brainstem responses
What is an otoacoustic emission test? Results?
Microphone placed in the external meatus detects tiny cochlear sounds produced my movement of outer hair cells which occur spontaneously or in response to an auditory stimulus.
OAE evaluates the function of the peripheral auditory system, there area most invoeled in SNHL - i.e. the sensory part of the cochlea and not the neural pathway.
OAE is abnormal or equivocal in 3-8%
Most of these can external ear canal obstruction - repeat and arrange Audiological brainstem responses
What is an audiological brainstem responses test? What does this test?
The ears are covered with earphones that emit a series of soft clicks
Electrodes on the infants forehead and neck measure brain wave activity in response to the clicks.
ABR tests the auditory neural pathway from CNVIII to the lower brainstem
Describe distraction testing?
An assistant in front the the child attracts their attention while a tester attempts to distract the child by making noises behind and beside the child
6-18 months
Describe visually reinforced audiometry
6months to 2.5 years
Child turns their head to a sound stimulus and a toy lights up to reward the listening behaviour
Describe speech discrimination test
2 years to 5 years
Child touches selected objects cued by acoustically similar phrases - key/tree
What is management for childhood deafness?
Support
Advice
Information
Maximise hearing a deaf child may have by using hearing aids or cochlear implants
Support to develop spoken or signed communication
Who are cochlear implants for? How do they work?
Cochlear implants are for children/adults with profound sensorineural deafness who do not benefit from conventional hearing aid.
Normal cochlear structure is required
Cochlear implants are a multichannel electrode surgically inserted into the cochlea that directly stimulates the auditory nerve when signals are applied.
Signal is not normal sound an intensive therapy is needed to understand the new sounds.
Implants allow better lip reading, provision and recognition of environmental sounds and relief of isolation
Quality is not sufficient for deaf people to have excellent hearing
What is a bone anchored hearing aid? Indications? Complications? Contraindications?
BAHA - sound is transmitted to the cochlea via bone conduction.
Intolerance of conventional hearing aids, congenital malformations
Complications: skin regrowth around titanium screw
Contraindicaiotns: average bone threshold worse than 45 dB, non-ompliance, poor hygiene
