Sensory - Hearing Abnormalities
Introduction
How and why do things go wrong in development? Developing of hearing requires a complex origin, organisation, and timecourse means that abnormal development of any one system can impact upon the development of hearing. There are many different abnormalities of hearing development that can result in hearing loss and can broadly be divided into either conductive or sensorineural loss. These abnormalities can have genetic, environmental or unknown origins. In addition, abnormalities of the external ear (position and structure) is used as a clinical diagnostic tool for developmental abnormalities in other systems.
In Australia, there is now an early postnatal screening of neonatal hearing as part of a NSW State Wide Infant Screening Hearing (SWISH) Program using Automated Auditory Brainstem Response (AABR).
Abnormality Links: abnormal development | abnormal genetic | abnormal environmental | Unknown | teratogens | ectopic pregnancy | cardiovascular abnormalities | coelom abnormalities | endocrine abnormalities | gastrointestinal abnormalities | genital abnormalities | head abnormalities | integumentary abnormalities | musculoskeletal abnormalities | limb abnormalities | neural abnormalities | neural crest abnormalities | placenta abnormalities | renal abnormalities | respiratory abnormalities | hearing abnormalities | vision abnormalities | twinning | Developmental Origins of Health and Disease | ICD-11 | ||
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Some Recent Findings
- Review - The etiology of otosclerosis[1] "Otosclerosis is a common form of hearing loss characterized by abnormal bone remodeling in the otic capsule. It is a complex genetic disease, caused by a combination of genetic and environmental factors. During the past decade, several attempts have been made to identify factors for otosclerosis."
Inner Ear Abnormalities
Common cavity, severe cochlear hypoplasia
Cholesteatoma
Epithelium trapped within skull base in development, erosion of bones: temporal bone, middle ear, mastoid
Middle Ear Abnormalities
Rare and can be part of first arch syndrome.
Fixation of the middle ear ossicles Malleus, Incus and Stapes
Outer Ear Abnormalities
Several genetic effects and syndromes, Environmental Effects
- Microtia - abnormally small external ear
- Preauricular sinus - occurs in 0.25% births, bilateral (hereditary) 25-50%, unilateral (mainly the left), duct runs inward can extend into the parotid gland, Postnatally sites for infection
Fetal Alcohol Syndrome
- Postion- Lower or uneven height, "railroad track” appearance, curve at top part of outer ear is under-developed, folded over parallel to curve beneath
Congenital Deafness
Sensorineural - cochlear or central auditory pathway Conductive - disease of outer and middle ear
Sensorineural
Cochlear or central auditory pathway
- Hereditary
- recessive- severe
- dominant- mild
- can be associated with abnormal pigmentation (hair and irises)
- Acquired
- rubella (German measles), maternal infection during 2nd month of pregnancy, vaccination of young girls
- cytomegalovirus [2]
- streptomycin
- antibiotic
- thalidomide
Conductive
Disease of outer and middle ear
- produced by otitis media with effusion, is widespread in young children.
- temporary blockage of outer or middle ear
Newborn Hearing Screening
In Australia, there is now an early postnatal screening of neonatal hearing as part of a NSW State Wide Infant Screening Hearing (SWISH) Program using Automated Auditory Brainstem Response (AABR).
- Very low birthweight infants and universal newborn hearing screening in a developing country[3]
Links: NSW Statewide Infant Screening - Hearing (SWISH) Program
Bionic Ear
The "Cochlear Implant" was pioneered in development by Professor Graeme Clark (1960s, Australia).[4] It consists of an array of electrodes implanted within cochlea, that directly electrically stimulate the auditory nerve fibres.
- Young children with cochlear implants compared with children with normal hearing.[5]
References
Online Textbooks
- Clinical Methods 63. Cranial Nerves IX and X: The Glossopharyngeal and Vagus Nerves | The Tongue | 126. The Ear and Auditory System | An Overview of the Head and Neck - Ears and Hearing | Audiometry
- Health Services/Technology Assessment Text (HSTAT) Bethesda (MD): National Library of Medicine (US), 2003 Oct. Developmental Disorders Associated with Failure to Thrive
- Search Bookshelf hearing development
Reviews
- The International Journal of Developmental Biology Vol. 51 Nos. 6/7 (2007) Ear Development
Articles
Search Pubmed
Search Pubmed: Abnormalities
Additional Images
External Links
- Embryo Images - Hearing
- NIDCD - Balance Disorders
- NSW Health - NSW Statewide Infant Screening - Hearing (SWISH) Program
- American Academy of Audiology - American Academy of Audiology | In Memoriam: Judy Gravel
Glossary Links
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Cite this page: Hill, M.A. (2024, May 1) Embryology Sensory - Hearing Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Sensory_-_Hearing_Abnormalities
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G