Hearing impairment classification: Difference between revisions

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!MIXED
!MIXED
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|CHL occurs when sound is not conducted efficiently through the [[external ear]] canal to the middle ear.
|CHL occurs when sound is not conducted efficiently through the [[external ear|outer ear]] canal to the middle ear.
|SNHL occurs when there is damage to the [[inner ear]] or to the nerve pathways from the inner ear to the brain. So loss at the point of the [[cochlea]] or proximal to the cochlea is considered SNHL.
|SNHL occurs when there's damage to the [[inner ear|internal ear]] or to the nerve pathways from the internal ear to the brain. So loss at the point of the [[cochlea]] or proximal to the cochlea is considered SNHL.
|Mixed HL is defined as CHL and SNHL.
|Mixed HL is defined as CHL and SNHL.
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|-
|CHL accounts for 90%–95% of all childhood HL.
|CHL accounts for 90%–95% of all childhood HL.
|SNHL is far more common in adults
|SNHL is far more common in adults.
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|With pure conductive hearing loss, the ''quality'' of hearing and [[Speech communication|speech discrimination]] is good.
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|Often only mild and is never worse.
|It can be mild, moderate, or severe, including total deafness.
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*[[Cholesteatoma]]
*[[Cholesteatoma]]
*[[Otitis media|Otitis media with effusion.]]
*[[Otitis media|Otitis media with effusion.]]
*[[Ear canal]] obstruction
*Middle-ear abnormalities
**[[Tympanic membrane]]
**[[Ossicles]]
|If SNHL takes hours or days to develop it can be due to:
|If SNHL takes hours or days to develop it can be due to:


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*[[Autoimmune]]: Systemic diseases that cause hearing loss include [[Systemic lupus erythematosus CT|systemic lupus erythematosus]], [[rheumatoid arthritis]], [[myasthenia gravis]], and [[Hashimoto's thyroiditis]]
*[[Autoimmune]]: Systemic diseases that cause hearing loss include [[Systemic lupus erythematosus CT|systemic lupus erythematosus]], [[rheumatoid arthritis]], [[myasthenia gravis]], and [[Hashimoto's thyroiditis]]


*[[Neoplastic]]: Direct compression of the cochlear nerve by the [[tumor]], occlusion or vascular compression of the [[Internal auditory artery|internal auditory]] artery, intratumor bleeding, internal auditory canal occlusion, and [[toxic substances]] produced by the tumor that causes degeneration of the inner ear.
*[[Neoplastic]]: Direct compression of the cochlear nerve by the [[tumor]], occlusion or vascular compression of the [[Internal auditory artery|internal auditory]] artery, intratumor bleeding, internal auditory channel occlusion, and [[toxic substances]] produced by the tumor that causes degeneration of the inner ear.
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===Conductive===
{{main|}}
Conductive hearing loss occurs when sound is not normally conducted through the outer or middle ear (or both)<ref>
{{cite web|url=http://www.asha.org/public/hearing/disorders/types.htm|title=Types of Hearing Loss|accessdate=2007-09-24}}
 
</ref>. Since sound can be picked up by a normally sensitive inner ear even if the ear canal, ear drum, and ear ossicles are not working, conductive hearing loss is often only mild and is never worse than a moderate impairment. Hearing thresholds will not rise above 55-60 dB from outer or middle ear problems alone. Generally, with pure conductive hearing loss, the ''quality'' of hearing (speech discrimination) is good, as long as the sound is amplified loud enough to be easily heard.
 
A conductive loss can be caused by any of the following:
 
*[[Ear canal]] obstruction
*Middle-ear abnormalities
**[[Tympanic membrane]]
**[[Ossicles]]
 
===Sensorineural===
{{main|Sensorineural hearing loss}}
 
A sensorineural hearing loss is due to insensitivity of the [[inner ear]] (the [[cochlea]]), or to impairment of function in the auditory nervous system.  It can be mild, moderate, or severe, including total deafness.  This is classified as a disability under the [[Americans with Disabilities Act of 1990|ADA]] and if unable to work is eligible for disability payments.<ref>http://www.eeoc.gov/facts/deafness.html Hearing impairment and the Americans with Disabilities Act</ref>
 
The great majority of human sensorineural hearing loss is caused by abnormalities in the [[hair cells]] of the [[organ of Corti]] in the cochlea. There are also very unusual sensorineural hearing impairments that involve the VIIIth [[cranial nerve]] (the [[Vestibulocochlear nerve]]) or the auditory portions of the brain. In the rarest of these sorts of hearing loss, only the auditory centers of the brain are affected. In this situation, [[central hearing loss]], sounds may be heard at normal thresholds, but the quality of the sound perceived is so poor that speech can not be understood.
 
Most sensory hearing loss is due to poor hair cell function. The hair cells may be abnormal at birth, or damaged during the lifetime of an individual. There are both external causes of damage, like noise trauma and infection, and intrinsic abnormalities, like deafness genes.
 
Sensory hearing loss (also called sensorineural hearing loss) may also result from abnormalities of the VIII cranial nerve.
 
Sensory hearing loss that results from abnormalities of the central auditory system in the brain is called Central Hearing Impairment. Since the auditory pathways cross back and forth on both sides of the brain, deafness from a central cause is unusual.


==References==
==References==

Revision as of 20:36, 20 April 2021

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Classification

Hearing losses can be classified according to:[1]

  1. Laterality,
  2. Symmetry,
  3. Clinical characteristic (syndromic or not),
  4. Time of onset (congenital, perinatal, or postnatal),
  5. Hereditary (genetic or not),
  6. Time of manifestation (prelingual, perilingual, or post-lingual),
  7. Intensity (mild, moderate, severe, and profound)
CLASSIFICATION BASED OF SEVERITY OF DISEASE[2]
MILD MODERATE SEVERE DISABLING
HEARING LOSS 26–40 dB HL 41–60 dB HL 61–80 dB HL >80 dB HL
DESCRIPTION Patient hears fine Hear with some difficulty.

People Mumble.

Difficulty in hearing. Patients relies on reading lips.

The term deaf is often used by persons

with profound hearing loss with >80 dB HL.

INTERVENTION Communication strategies Communication strategies

Amplification

Communication strategies

Hearing aids

Cochlear implant

Communication strategies

Hearing aids

Cochlear implant

Sign language

Lip reading


CLASSIFICATION BASED ON ANATOMY OF EAR[3]
CONDUCTIVE SENSORINEURAL MIXED
CHL occurs when sound is not conducted efficiently through the outer ear canal to the middle ear. SNHL occurs when there's damage to the internal ear or to the nerve pathways from the internal ear to the brain. So loss at the point of the cochlea or proximal to the cochlea is considered SNHL. Mixed HL is defined as CHL and SNHL.
CHL accounts for 90%–95% of all childhood HL. SNHL is far more common in adults.
With pure conductive hearing loss, the quality of hearing and speech discrimination is good.
Often only mild and is never worse. It can be mild, moderate, or severe, including total deafness.
Common causes in adults include: If SNHL takes hours or days to develop it can be due to:

If hearing loss develops in weeks:

If happens in years:

CLASSIFICATION BASED ON CAUSE[4][5]
CONGENITAL ACQUIRED
  • Neoplastic: Direct compression of the cochlear nerve by the tumor, occlusion or vascular compression of the internal auditory artery, intratumor bleeding, internal auditory channel occlusion, and toxic substances produced by the tumor that causes degeneration of the inner ear.

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References

  1. ↑ Nieman CL, Oh ES (2020). "Hearing Loss". Ann Intern Med. 173 (11): ITC81–ITC96. doi:10.7326/AITC202012010. PMID 33253610 Check |pmid= value (help).
  2. ↑ Nieman CL, Oh ES (2020). "Hearing Loss". Ann Intern Med. 173 (11): ITC81–ITC96. doi:10.7326/AITC202012010. PMID 33253610 Check |pmid= value (help).
  3. ↑ Kral A (2017). "[Pathophysiology of hearing loss : Classification and treatment options]". HNO. 65 (4): 290–297. doi:10.1007/s00106-016-0183-1. PMID 27299892.
  4. ↑ Kral A (2017). "[Pathophysiology of hearing loss : Classification and treatment options]". HNO. 65 (4): 290–297. doi:10.1007/s00106-016-0183-1. PMID 27299892.
  5. ↑ Kenna MA (2015). "Acquired Hearing Loss in Children". Otolaryngol Clin North Am. 48 (6): 933–53. doi:10.1016/j.otc.2015.07.011. PMID 26452421.

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