Signs of poor audiometry

If anyone has been unfortunate enough to wander through this entire health screening section you will no doubt have decided that I am generally a rather sarcastic chap, but it's only because I care, honest. Audiometry in heath screening is important as it is the fall-back which ensures people are being kept safe and not harmed by noise risks. Poor hearing has such a terrible impact on every element of a sufferer's life that the effects cannot be understated, but all too often I've seen audiometry so woefully done the provider should be thoroughly ashamed of it, and this applies equally to the big boys as well as the small ones. Some of the worst testing I've ever come across has been provided by a huge insurance company selling health screening services to its clients, although this was followed as a close second by a sole-trader occupational health nurse contracting out their screening services whom I have come across numerous times.

Some of the things I have seen in audiometry which scream out that the service is not good, and a client should not be paying for are: 

Lack of assigning date of birth

If no date of birth is assigned to the test then the appropriate category of result cannot be calculated, meaning the testing is incomplete. This is absolutely fundamental to a test and if a service provider is generating tests with no result because of this I humbly suggest that they should be thrown out and any money paid to them for the testing reclaimed.

Lack of assigning gender

This is the same as date of birth as no gender means no result can be calculated. It is a basic and fundamental part of any health screening programme that it cannot be omitted. That applies no matter how sensitive the situation - see the transgender section for more advice on this.

Skipping the otoscopic examination

It is far form uncommon for technicians providing audiometry screening to try and race through as many people as possible, and to do that they sometimes skip the visual otoscopic inspection of the ear. This is a basic part of the test as you need to look down the ears to see what state they are in as this can have a big impact on the results - infections, blockages, etc. This should be done and noted on the results.

Missing key audiometry frequencies

A screening test must include the 1, 2, 3, 4 and 6 kHz frequencies as these are needed to calculate the category of result and are the frequencies specific in L108 (Appendix 5, Table 13).

Most tests also include the 0.5 and 8kHz frequencies as this wider range can be helpful in identifying trends in the hearing, although these are not mandatory.

If any screening test doesn't include any of the five mandatory frequencies then it is incomplete and has not been done properly.

Flat audiometry results lines

Anything medical with a flat line is usually bad and means you are dead. Flat lines in an audiogram (the graphical result of a hearing test) are possible, but very very uncommon. If you see one in thousands of tests it is unusual, if you see several in a batch of results a technician has created then it is suspicious. The most common cause of this is that the technician has put the headphones on the attendee, pressed 'go' and then is either working on something else or playing on their phone, but either way they are not watching the test. If the attendee just keeps pressing the button repeatedly, chances are they will end up with a flat line at whatever the best sound level measured by the equipment is, usually -10 or -20dB depending on the audiometer. If the technician then compounds this by not identifying it at the end of the test as a potential problem then you should be very wary of their competence and wary of their results.

Audiometry result - just pressing button all time.png

I've also seen this result because the attendee could see the reflection of a little red light on the audiometer which came on every time a tone was presented, so the attendee pressed the button when that lit up rather than when they could hear something.

Suspiciously high audiometry results

This one is related to the flat lines above and is often indicative of an attendee guessing rather then responding when they can hear properly. Most of the time guesses are not registered as the attendee needs to be consistent in the level they guess at but every so often one of them gets it right. If you get a 50 year old chap with the hearing of a 20 year old woman, then that's great for him. He is unusual and could probably navigate by sonar. If you get a few 50 year old chaps with the hearing of 20 year old women then that is getting suspicious and is worth asking the technician what they did to verify the results to ensure that this pattern is indeed correct, including checking their equipment to make sure it is reading correctly. My guess is that they didn't verify at all, or even think about it.

 If this is a 20 year old woman then fine. If it is a 50 year old man then it is exceptional. If it is a few 50 year old men in a batch then that is getting suspicious and verification checks should be made.

If this is a 20 year old woman then fine. If it is a 50 year old man then it is exceptional. If it is a few 50 year old men in a batch then that is getting suspicious and verification checks should be made.

I raise this one again from experience where in the past we had a large client with several thousand employees. They did their Year 1 screening in-house as people started their employment, using a sole-trader occupational health nurse contracted to them, and we then did all the large-scale batch-testing for all subsequent tests. I saw crazily high audiometry results time after time there, to the point that in future screening tests we had a standing procedure to pretty much ignore their in-house results as they were just too unreliable.  

Not measuring the noise in the testing environment

This is especially critical for a mobile visiting service - you MUST know what the noise level is in the testing environment to have any future reliance on the audiometry test results as being valid. I raise this from my own experience where:

  1. Mobile units can be instructed to park anywhere on the site and there is often noise from vehicles, air handling units, etc. The scope of this has to be known to be sure that the tests are valid.
  2. When the employer's insurer is defending a claim for hearing loss they may rely on the audiometry undertaken as part of the noise risk management programme. I have been asked in the past by insurers how I can prove the test results were valid, which when you can respond with a copy of that day's calibration check and a measurement of the noise levels in the testing environment means the results can and will be used by the insurer in defending the claim.

Not doing the daily calibration check

The British Standard for Pure Tone Audiometry requires a daily calibration check to ensure that all parts of the equipment are functioning as they should be. This is used to prove the tests done that day were valid. 

This is not the same as the annual calibration check done by a specialist technician, the daily check is a test against a known standard (such as the technician's own hearing) to confirm there is no undue variance. From experience, all bits of the equipment fail at some point and if you don't do this check in the morning, not only is the testing not compliant with the required standards but all tests done that day are questionable and should really be binned and repeated.