mất thính giác dẫn truyền rung động âm thanh không được thực hiện thông qua ống tai, màng tympanic, hoặc các xương nhỏ. Tối đa 20-60 dB mất thính giác. Mất thính giác: rối loạn chức năng (cảm giác) ốc tai điện tử thành phần hoặc dây thần kinh thính giác. Có thể có sâu sắc 90 mất nghe dB. | 74 Hearing impairment CONDITIONS D Conductive hearing loss sound vibrations are not conducted via the ear canal tympanic membrane or the ossicles. Maximum 20-60dB hearing loss. Sensorineural hearing loss dysfunction of the cochlear sensory components or the auditory nerve. May have profound 90dB hearing loss. A Conductive hearing loss most cases due to secretory otitis media glue ear . Ear canal wax foreign body. Tympanic membrane perforation due to blow to ear pressure change in aircraft. Ossicles absent defective ossicles due to congenital malformation. Eustachian tube dysfunction cleft palate Down syndrome. Sensorineural hearing loss Genetic 50 autosomal recessive dominant or as part of a syndrome . Waardenburg syndrome. Intrauterine 10 congenital infections rubella CMV herpes aminoglycosides loop diuretics. Perinatal 10 birth asphyxia preterm delivery hyperbilirubinaemia. Postnatal 30 measles mumps meningitis encephalitis head injury neurodegenerative disorders. A R Recurrent otitis media URTIs atopy. E Severe 1 1000 children require special education may be sensorineural or mixed . Moderate 2 1000 children require hearing aids and educational support. Mild 1 100 school-age children affected usually 2 to glue ear and usually transient . _H Usually suspected by mother when the baby consistently fails to respond to loud noises. May report delayed language development behavioural or educational difficulties. Elicit family history consanguinity intrauterine perinatal or postnatal complications recurrent otitis media or URTIs. E Universal neonatal hearing screening programme currently being piloted in the UK. Use of otoacoustic emissions and or auditory brainstem-evoked responses at 4-6 weeks. In this test a computer-based system detects electrical activity in the cochlea and auditory pathways in the brain. Distraction test 4 months infant is held on parent s lap and distracted by a toy in front. The examiner stands behind parent and creates noises of different .
