Case Study: The hearing will take place

It is common for eye care professionals to be the first to identify when a patient may have a hearing problem. This is particularly so when undertaking domiciliary visits to the elderly, all of whom would be expected to have suffered some form of presbycusis, the reduction in hearing of specified frequencies of sound with age. This is usually very apparent during the consultation, the patient showing some or all of the signs of hearing challenge listed on page 35 of this issue.

When recently, an elderly family member showed such difficulties and mentioned that she would like to have her hearing tested, I arranged for a home visit from an audiologist to undertake a test and to recommend appropriate hearing aids. I was given permission to sit in on the test and have the basics of the procedure explained to me.

The human ear is able to detect a wide range of frequencies of sound. For a young, healthy adult, the range of detectable frequencies is from 20Hz (the deepest, lowest sounds) up to 20,000Hz (the highest pitched sounds). Each of these frequencies is first detected once it is received at a certain level of loudness. Loudness is usually measured in decibels (dBs), with 0dB being inaudible and the loudest sounds a human ear might process being 180dB. Any sound over 85dB is likely to cause damage to the inner ear so is best avoided and certainly would not be used in any audiologist test.