October 17, 2010

Q&A: Diagnosis of Hearing Loss

Hearing loss is a common problem that everyone experiences from time to time. Most commonly it occurs when flying or traveling up a mountain, and a full sensation develops in the ears, leading to the feeling of wanting to pop the ears open in order to hear better. Diminished hearing also may occur during an ear infection. These causes of hearing loss are usually short-lived.

This article is for Medical Students & Professionals
This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the The Ears, Hearing and Balance article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.
In this article:
Classification of hearing loss
MCQ: clinical scenario
MCQ: answer
MCQ: explanation

Classification of hearing loss

Hearing loss may be classified into three types:
  • Sensorineural, involving the inner ear, cochlea, or the auditory nerve. 
  • Conductive, involving any cause that in some way limits the amount of external sound from gaining access to the inner ear. Examples include cerumen impaction, middle ear fluid, or ossicular chain fixation (lack of movement of the small bones of the ear). 
  • Mixed loss, which is a combination of conductive and sensorineural hearing loss. 
A number of abnormalities may lead to hearing loss of each type. It is useful to begin the evaluation by classifying the loss as sensorineural or conductive, since this helps focus the remainder of the patient assessment. Conductive hearing loss is usually related to abnormalities of the outer or middle ear; sensorineural hearing loss is related to inner ear pathology.

MCQ: clinical scenario

An 80 year old develops bilaterally symmetric hearing loss which is gradual in onset. On examination he is found to have a predominantly high frequency loss.

A likely diagnosis is:

a) Meniere's disease
b) Presbycusis
c) Multiple sclerosis
d) Acoustic neuroma
e) Alport's syndrome
f) Usher's syndrome

MCQ questions & answers on medicalnotes.info

MCQ: answer

The correct answer is B

MCQ: explanation

Presbycusis is hearing loss associated with aging and is the most common cause of diminished hearing in the elderly. The hearing loss is bilaterally symmetric and gradual in onset. The majority of cases begin with a loss of the high frequencies with slow progression. Eventually, middle- and low-frequency sounds also become difficult to perceive. There are four types of presbycusis, distinguished according to the correlated pathologic changes in the cochlea. Hair cell loss and cochlear neuron degeneration are the most widely recognized changes.

Reference(s)
1). UpToDate: Evaluation of hearing loss in adults. Available online: https://www.uptodate.com/contents/evaluation-of-hearing-loss-in-adults

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