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
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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 Middle ear abnormalities (ossicular anomalies) are rare and can be part of first arch syndrome.
- familial expansile osteolysis
- malleus/incus fixation
- absence of the long process of the incus
- congenital fixation of stapes (stapes anchored to oval window)
- failure of annular ligament development
- cholesteatoma
Familial Expansile Osteolysis (FEO)
A rare congenital (autosomal dominant, 18q21.1-q22) disorder similar to Paget's disease of bone. Osteolytic lesions occur in all bones (mainly long bones) causing medullar expansions and lead eventually to middle ear and jaw abnormalities.[4]
Malleus/Incus Fixation
Congenital absence of the long process of the incus.[5]
Congenital Fixation of Stapes
In this condition the stapes is anchored to oval window often by growth of bone around the stapes (otosclerosis). Surgicallly treated by stapedectomy, where the bone and stapes is removed and replaced by a prosthesis.[6]
Cholesteatoma
Squamous epithelium that has been trapped within the skull base during development (congenital) and also occurs in an acquired form. The presence of this abnormality leads to erosion of the bones (temporal bone, middle ear, or mastoid) in which the epithelium is embedded.
Persistent Stapedial Artery
The fetal stapedial artery initially lies between the foramen of the stapes and is lost before birth. If this regression fails, a persistent stapedial artery will affect conduction through the middle ear ossicle chain.
The condition can be seen in hemifacial microsomia (14q32), a reasonably common sporadic and rare familial autosomal dominant abnormality of the first and second pharyngeal arch derivatives.[7][8]
Outer Ear Abnormalities
Several genetic effects and syndromes can include impacts on developmental of the external ear either directly or by altering development of the skull or face. Several developmental environment effects can be indicated by changes in the relative position or appearance of the external ear at birth. (More? Abnormal Development - Fetal Alcohol Syndrome.
- 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
Microtia
The condition in humans of an abnormally small external ear is called "microtia".
This abnormality can generally be surgically repaired by use of rib cartilage to reconstruct the external ear.[9]
A recent study has identified a genetic mouse model for this condition with the knockout of the Pact gene.[10]
Preauricular Sinus
Preauricular sinus occurs in 0.25% births, is bilateral (hereditary) in 25-50% of cases and unilateral (mainly the left). They are developmental and generally occur on the surface in anterior margin of the ascending limb of the helix, and the duct runs inward to the perichondrium of the auricular cartilage and in some cases extend into the parotid gland. Postnatally they are a site for infection.
Search PubMed: Preauricular Sinus
Links: Medline Plus - Preauricular tag or pit
Preauricular Tag
Skin tags in front of the external ear opening are common in neonates and in most cases are normal, though in some cases are indicative of other associated abnormalities.
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Search PubMed: Preauricular Tag
Links: Medline Plus - Preauricular tag or pit
External Meatus Stenosis
Stenosis (narrowing) of the external auditory meatus is uncommon and can be due to chronic otitis externa or acquired atresia. The condition can be treated surgically by meatoplasty (reconstructive surgery of the canal) alone, though acquired atresia requires removal of the soft tissue plug and a split skin graft.
Search PubMed: external meatus stenosis
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 [11]
- 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
Australia
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).
Links: NSW Statewide Infant Screening - Hearing (SWISH) Program
Germany
Multicenter newborn hearing screening project[1] "From the actual point of view, the "sensitive period" for the effects of hearing impairment on speech and language development is within the first year of life. Early exposure to acoustic or electric stimulation can compensate for the acoustic deficit. A regional-based, specifically designed concept of a universal newborn hearing screening (UNHS) was started in Hamburg in the year 2002. ...Sixty-three thousand, four hundred fifty-nine out of 65,466 births were registered during the period August 2002 to July 2006, 93% were primarily screened. 3.3% failed the test and 31.3% were lost to follow-up. A total of 118 children were diagnosed with hearing loss in the follow-up."
Nigeria
Very low birthweight infants and universal newborn hearing screening[12] "very low birth weight (VLBW) infants in resource-poor settings are associated with the risk of sensorineural hearing loss and other perinatal outcomes that may potentially compromise their optimal development in early childhood."
Cochlear Implant
The "Bionic Ear" was pioneered in development by Professor Graeme Clark in Australia (1960s) and first successfully used in 1978, there are now a variety of different implant devices.[13] By the year 2000 more than 13,000 children worldwide have received these implants. The medical device consists of an array of electrodes implanted within cochlea, that directly electrically stimulate the auditory nerve fibres.
The sound used to test persons with cochlear implants can be delivered by two methods, referred to as ‘‘HL’’ (hearing level) and ‘‘SPL’’ (sound pressure level), both of these methods are expressed in dB, but a specific dB HL is not the same level of loudness as the same dB SPL.
- Young children with cochlear implants compared with children with normal hearing.[14]
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
References
- ↑ 1.0 1.1 <pubmed>20549232</pubmed>
- ↑ <pubmed>20513039</pubmed>
- ↑ <pubmed>20015469</pubmed>
- ↑ <pubmed>15793411</pubmed>
- ↑ <pubmed>10890764</pubmed>
- ↑ <pubmed>15353993</pubmed>
- ↑ <pubmed>10037288</pubmed>
- ↑ <pubmed>10730654</pubmed>
- ↑ <pubmed>14515077</pubmed>
- ↑ <pubmed>1657165</pubmed>
- ↑ <pubmed>20500943</pubmed>
- ↑ <pubmed>20450464</pubmed>
- ↑ <pubmed>18816421</pubmed>JRRD
- ↑ <pubmed>20452685</pubmed>
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
<pubmed>19132125</pubmed> <pubmed>18345839</pubmed>
Search Pubmed
Search Pubmed: Abnormalities | Microtia | Middle ear ossicular anomalies | familial expansile osteolysis | cholesteatoma | | cochlear implant |
OMIM Database Search: Microtia
Additional Images
Inner ear hair cells
External ear anatomy
Preauricular tag
Preauricular tag
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
- Cochlear - Commercial Cochlear Implants | Cochlear implants for children
Glossary Links
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Cite this page: Hill, M.A. (2024, April 18) 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
