ZDROJ: http://www.biap.org/biapanglais/rec021eng.htm

BIAP Recommendation n° 02/1 bis

AUDIOMETRIC CLASSIFICATION OF HEARING IMPAIRMENTS

In most cases, hearing impairments are due to the loss of sound perception and, particularly, of
speech perception.

Speech is made up of both acute and low-pitched sounds of highly-varied acoustic power. It cannot
be measured by means of a single average acoustic level.

After a clinical examination has been realized, an audiometric measuring can be done in
satisfactory acoustic conditions. It shows a loss in dB, compared with normal hearing level (dB
H.L.), with reference to ISO standards. An average tone loss is calculated, taking as a starting
point the loss in dB at various frequencies: 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. A frequency
which is not perceived is considered as a loss of 120 dB. The total amount is calculated, divided
by 4 and rounded up to the nearest unit. In the event of an assymetric hearing loss, the average
loss level, expressed in dB, is multiplied by 7 for the " good " ear and by 3 for the " bad " ear.
The total is then divided by 10.

I. Normal or subnormal hearing

The average tone loss is below 20 dB. Mild tone disorder with no social consequences.

II. Mild hearing loss (lehké/mírné sluchové postižení ztráty sluchu)

Average tone loss between 21 and 40 dB. Speech is perceived if the voice is normal, difficulties
arise if the voice is low-pitched or distant from the subject. Most of the daily life noises are
perceived.

III. Moderate hearing loss (střední sluchové postižení – ztráty sluchu) – rozděleno na 2 stupně

- 1st degree: average tone loss between 41 and 55 dB.

- 2nd degree: average tone loss between 56 and 70 dB. Speech is perceived if the voice is loud. The
subject understands better what is being said if he can see his/her interlocutor. Some daily life
noises are still perceived.

IV. Severe hearing loss (těžké sluchové postižení – ztráty sluchu) – rozděleno na 2 stupně

- 1st degree: average tone loss between 71 and 80 dB.

- 2nd degree: avergae tone loss between 81 and 90 dB. Speech is perceived is the voice is loud and
close to the ear. Loud noises are perceived.

V. Very severe hearing loss (velmi těžké sluchové postižení – ztráty sluchu) – rozděleno na 3
stupně

- 1st degree: average tone loss between 91 and 100 dB.

- 2nd degree: average tone loss between 101 and 110 dB.

- 3rd degree: average tone loss between 111 and 119 dB. Speech is not perceived. Only very loud
noises are perceived.

VI. Total hearing loss – Cophosis (totální hluchota – při ztrátě sluchu více než 120dB)

Average tone loss over 120 dB. Nothing is perceived.

October 26th, 1996



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