Table 4: World Health Organisation Grades of Hearing Impairement
(WHO, 2008)
| Grade of impairment* |
Corresponding audiometric ISO value** |
Performance |
Recommendations |
* Grades 2, 3 and 4 are classified as disabling hearing impairment (for children, it starts at 31 dB)
** The audiometric ISO values are averages of values at 500, 1000, 2000, 4000 Hz.
|
| 0 - No impairment |
25 dB or better
(better ear) |
No or very slight hearing problems. Able to hear
whispers. |
|
| 1 - Slight impairment |
26-40 dB
(better ear) |
Able to hear and repeat words spoken in normal
voice at 1 metre. |
Counselling. Hearing aids may be needed. |
| 2 - Moderate impairment |
41-60 dB
(better ear) |
Able to hear and repeat words spoken in raised
voice at 1 metre. |
Hearing aids usually recommended. |
| 3 - Severe impairment |
61-80 dB
(better ear) |
Able to hear some words when shouted into better
ear. |
Hearing aids needed. If no hearing aids available,
lip-reading and signing should be taught. |
| 4 - Profound impairment including deafness |
81 dB or greater
(better ear) |
Unable to hear and understand even a shouted
voice. |
Hearing aids may help understanding words.
Additional rehabilitation needed. Lip-reading and sometimes signing
essential. |
Source: SCENIHR,
Potential health risks of exposure to noise from personal music players and mobile phones including a music playing function (2008)
,
Section 3.4.1, page 22
Related publication:
Other Figures & Tables on this publication:
Figure 1*: Normal equal-loudness-level contours for pure tones under free-field
listening conditions
Figure 2: The prevalence of hearing impairment
Figure 3: Estimated units sales in EU of all portable audio devices and MP3 devices over the period 2004–2007,
Figure 4: The number of unit sales for all portable audio devices for the ten countries and for the EU,
Figure 5: Number of unit sales (in thousands) for CD and MP3 devices in ten European countries* between 2001 and 2007
Figure 6: Cumulative numbers of MP3 players and all portable audio equipment in the EU
Figure 7: Percentage of each portable audio device sold in 2004-2007
Figure 8: Percentage of each portable audio device sold in 2007 and the estimated number of units sold in EU
Table 1: Examples of sound pressure levels in relation to hearing threshold and pain threshold (in dB SPL)The range of human ear’s audible sounds goes from 0 dB SPL (hearing threshold) to 120-140 dB SPL (pain threshold)
Table 2: Audiometric hearing thresholds of normal ears: conversion of dB SPL
into dB HL (Extracted from ISO, 2003)
Pure-tone audiometric thresholds are expressed in dB HL (hearing level). The differences between dB HL and dB SPL, arise from isophonic curves.
Table 3: The examples of equivalent time-intensity levels referred to the
action levels
according to the Directive 2003/10/EC
Table 4: World Health Organisation Grades of Hearing Impairement (WHO, 2008)
Low and high-pitched sounds appear less loud to the human ear
EU Action levels for noise protection at work
Table 5: Noise Induced Hearing Loss (NIHL) predicted from ISO 1999 as a function of noise exposure level for 45 years (adapted from Lutman et al. 2008) Extent of
hearing loss to be expected from a working lifetime of 45 years at daily
continuous noise levels of 80, 85, 90 and 95 dB(A).
Table 6 : Noise Induced Hearing Loss (NIHL) predicted from ISO 1999 as a function of noise exposure level for 3 years (adapted from Lutman et al. 2008) Extent of hearing
loss to be expected from a shorter exposure duration of 3 years at daily
continuous noise levels of 80, 85, 90 and 95 dB(A).
