HEARING CATEGORISATION
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OM033-4 - CA850 Series 5 Operating Manual
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HEARING CATEGORISATION
Only suitably qualified practitioners should undertake the assessment of audiometric data produced by this
instrument.
As an aid to this assessment the audiometer produces hearing categorisations once hearing thresholds (based
on Manual, Computer or Bekesy testing) and other patient data are established.
Such hearing categorisations include those derived from the UK Health & Safety Executive (HSE) scheme
incorporated into the UK Control of Noise at Work Regulations 2005 (L108). These regulations define 5
categories of hearing as follows:
Category 1 - acceptable hearing ability
Category 2 - mild hearing impairment
Category 3 - poor hearing
Category 4 - rapid hearing loss (based on a previous test within 3 years)
Category U - unilateral hearing loss (based on a comparison of left & right ears)
Each ear of a patient is placed into one (or more) of the above categories based on the hearing threshold
results at a number of frequencies and the age and sex of the patient. Based on the resulting categorisation,
a patient may be warned about hearing ability or referred for further medical advice. For detail of the derivation
and application of these categories the user/operator is referred to the regulations.
As long as the required data is available (e.g. hearing thresholds have been established at the required
frequencies) the CA850 audiometer will perform this calculation and present the hearing categorisation results.
These are displayed at the bottom of the Test Details page (see Section 9.4) and are saved, printed or
transferred to computer with other data.
The category identifier (1, 2, 3, 4 and ‘U’) will be followed by an associated coding which shows which part of
the audiogram data caused the category identifier to be assigned. These codings are:
L (left)
R (right)
B (both)
no data (previous test data is not available)
Age < 18 (HSE tables do not cover this age range)
Data incomplete (required threshold data not available)
Examples of categorisations presented on the CA850 audiometer:
1
1 4-no data U Age < 18
2R 3L 4R U
2B 4R U
3B 4-no data U
2R 3L 4L Age < 18
2R 3L 4-no data U Age < 18
Data incomplete
No sex chosen
No sex chosen Age under 18
Invalid patient age (e.g. if date of birth age was not provided or is inconsistent)
As shown above, to differentiate each part of the categorisation, there is a space between category identifiers.
