Hearing Loss

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Introduction

Hearing loss is a raised hearing threshold, measured as decibels, relative to the normal population. It becomes a problem when communication by speech is affected. This level is commonly defined as a hearing level loss of 16 dB at frequencies of 500, 1000, and 2000 Hz.

Deafness is defined when the above three frequencies are lost at or above 82 dB.

Ten percent of the population is hard of hearing or deaf. It is detectable (by audiology) in greater than 1/3 of people over 65, and is associated with significant physical, functional, and mental health consequences.

The speech banana is between 250-4000 Hz.

 

People don't enjoy conversations and can become intimidated in many settings.

It shrinks one's world.

 

Conductive hearing loss

is caused by problems with the outer and inner ear. Otoscopy is often abnormal, and problems are often amenable to surgery. These are usually aidable.

Causes:

Diagnosis

 

Sensorineural hearing loss

Sensorineural hearing loss is caused by problems with the inner ear, the cochlear nerve through to auditory nuclei. It is most commonly caused by damage to hair cells. Often the higher frequency is lost.

 

Progressive bilateral SNHL is the commonest impairment in the adult population

causes:

 

Assymetrical sensorineural

 

 

Diagnosis

 

 

 

The Case of...

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Differential Diagnosis

 

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History and Physical Exam

  • history
  • physical exam

History

Diagnosing Hearing Loss

Rinne - base of tuning fork on mastoid until it is no longer heard, then placed beside ear

Weber - base of tuning fork is placed on on forehead

 

 

Conductive hearing loss

Sensorimotor hearing loss

 

noisy environment helps

noisy environment makes it more difficult

onset

childhood/young

middle/old age

 

visible abnormality with eardrum

no visible abnormality

Webber test

lateralizes to damaged ear

lateralizes to good ear

Rinne

BC > AC

BC < AC

 

 

 

 

 

 

 

 

 

 

 

 

 

Physical Exam

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Diagnostic Imaging

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Management

As with most conditions, prevention is the best medicine. Counsel patients about noise control and hearing protection.

Refer patients with hearing loss on screening for complete audiological examination.

 

Hearing amplification can dramatically improve quality of life

 

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Pathophysiology

 

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Resources and References

 

 

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Topic Development

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