1. This annex establishes guidelines for the evaluation and surveillance of the hearing of employees exposed to elevated sound pressure levels.
2. All employees who perform or will perform their activities in environments with sound pressure levels above the action levels, as indicated in the organization’s Risk Management Program (PGR), must undergo reference and sequential audiometric exams, regardless of the use of hearing protectors.
2.1. The reference and sequential audiological exams consist of:
a) Clinical-occupational anamnesis;
b) Otological examination;
c) Audiometric examination conducted according to the terms outlined in this Annex;
d) Other complementary audiological exams as requested at the physician’s discretion.
3. Audiometric Examination
3.1 The audiometric examination will be conducted in an audiometric booth, where sound pressure levels do not exceed the maximum permissible levels according to ISO 8253-1 technical standard.
3.1.1 In companies with an acoustically treated environment that meets ISO 8253-1 standards, the audiometric booth may be dispensed with.
3.2 The audiometer must undergo periodic verification and control procedures, including:
I – Annual acoustic calibration;
II – Acoustic calibration:
a) Whenever acoustic calibration indicates a change;
b) When recommended by the manufacturer;
c) Every 5 (five) years, if there is no manufacturer indication.
III – Biological calibration preceding the audiometric exams.
3.2.1 Procedures listed in items “a” and “b” above must follow the guidelines in ISO 8253-1, and the results must be included in a calibration certificate accompanying the equipment.
3.2.1.1 If it is impossible to conduct the audiometric exam under the conditions outlined in item 3.1, the examiner will assess the feasibility of conducting it in a quiet environment by performing an audiometric test on 2 (two) individuals with known auditory thresholds detected in current reference audiometric exams, and ensuring there is no threshold difference above 5 (five) dB (HL) (hearing level in decibels) in any frequency for either individual.
3.3 The audiometric exam must be conducted by a physician or speech therapist, according to the resolutions of their respective federal professional councils.
3.4 The employee must undergo a minimum of 14 hours of auditory rest before the audiometric exam.
3.5 The audiometric exam results must be recorded and include, at minimum:
a) Employee’s name, age, CPF, and role;
b) Organization’s corporate name and CNPJ or CPF;
c) Duration of auditory rest before the audiometric exam;
d) Manufacturer’s name, model, and date of the audiometer’s last acoustic calibration;
e) Audiometric tracing and symbols as indicated in this Annex;
f) Name, regional council registration number, and signature of the professional responsible for the audiometric exam.
3.6 The audiometric exam must always be conducted via air conduction at frequencies of 500, 1,000, 2,000, 3,000, 4,000, 6,000, and 8,000 Hz.
3.6.1 If an alteration is detected in the air conduction test, audiometry must also be conducted via bone conduction at frequencies of 500, 1,000, 2,000, 3,000, and 4,000 Hz, or as assessed by the professional conducting the exam.
3.6.2 Segundo a avaliação do profissional responsável, no momento da execução do exame, podem ser determinados os Limiares de Reconhecimento de Fala – LRF.
4. Frequency of Audiometric Exams
4.1 4.1. The audiometric exam must be conducted, at minimum:
a) Pre-employment;
b) Annually, with the hiring exam as a reference;
c) Termination.
4.1.1 At termination, an audiometric exam conducted up to 120 (one hundred and twenty) days before the contract termination date may be accepted.
4.2 The interval between audiometric exams may be reduced at the discretion of the occupational physician responsible for the PCMSO.
4.3 The employee must undergo a reference audiometric exam and sequential audiometric exams as described in the following subitems.
4.3.1 A reference audiometric exam is the one against which sequential exams will be compared and must be conducted:
a) When there is no previous reference audiometric exam;
b) When any sequential audiometric exam shows significant changes compared to the reference exam.
4.3.2 A sequential audiometric exam is the one compared to the reference exam and applies to any employee with a previous reference audiometric exam.
5. Interpretation of Audiometric Exam Results
5.1 Cases where audiograms show hearing thresholds of 25 (twenty-five) dB (HL) or lower at all tested frequencies are considered within acceptable limits for this Annex.
5.2 Cases where audiograms at frequencies of 3,000 and/or 4,000 and/or 6,000 Hz show hearing thresholds above 25 (twenty-five) dB (HL) and higher than other tested frequencies, whether or not these frequencies are affected, in air conduction and bone conduction tests, in one or both ears, are considered suggestive of Noise-Induced Hearing Loss (NIHL).
5.2.1 Changes not meeting the criteria defined in item 5.2 above are not considered suggestive of NIHL.
5.3 Cases where hearing thresholds at all tested frequencies in both reference and sequential audiometric exams remain 25 (twenty-five) dB (HL) or lower, but the comparison between sequential and reference audiograms shows evolution meeting one of the following criteria, are considered suggestive of NIHL onset:
a) The difference between the arithmetic means of hearing thresholds in the group of frequencies of 3,000, 4,000, and 6,000 Hz equals or exceeds 10 (ten) dB (HL);
b) The worsening in at least one frequency of 3,000, 4,000, or 6,000 Hz equals or exceeds 15 (fifteen) dB (HL).
5.3.1 Cases where only the reference audiometric exam shows hearing thresholds at all tested frequencies of 25 (twenty-five) dB (HL) or lower, and the comparison between sequential and reference audiograms meets one of the following criteria, are also considered suggestive of NIHL onset:
a) The difference between the arithmetic means of hearing thresholds in the group of frequencies of 3,000, 4,000, and 6,000 Hz equals or exceeds 10 (ten) dB (HL);
b) The worsening in at least one frequency of 3,000, 4,000, or 6,000 Hz equals or exceeds 15 dB (HL).
5.4 Cases already confirmed in the reference audiometric exam, where the comparison between sequential and reference audiograms shows evolution meeting one of the following criteria, are considered suggestive of NIHL worsening:
a) The difference between the arithmetic means of hearing thresholds in the group of frequencies of 500, 1,000, and 2,000 Hz, or in the group of frequencies of 3,000, 4,000, and 6,000 Hz, equals or exceeds 10 (ten) dB (HL);
b) The worsening in an isolated frequency equals or exceeds 15 (fifteen) dB (HL).
5.5 For the purposes of this Annex, the reference audiometric exam must remain the reference until a sequential audiometric exam shows NIHL onset or worsening.
5.5.1 The sequential audiometric exam demonstrating NIHL onset or worsening will then become the new reference audiometric exam.
6. The conclusive diagnosis, differential diagnosis, and determination of fitness for the function or activity in suspected NIHL cases are the responsibilities of the occupational physician in charge of the PCMSO.
7. Special attention should be given to employees exposed to ototoxic substances and/or vibration, either isolated or simultaneous to exposure to potentially harmful noise levels.
8. NIHL alone is not indicative of unfitness for work; the following factors must be considered in each case analysis, in addition to the audiometric tracing or sequential evolution of audiometric exams:
a) The employee’s clinical and occupational history;
b) The results of otoscopy and other complementary audiological tests;
c) The employee’s age;
d) The previous and current exposure times to high sound pressure levels;
e) The sound pressure levels to which the employee is, has been, or will be exposed in the workplace;
f) The auditory demand of the work or function;
g) Non-occupational exposure to high sound pressure levels;
h) Occupational exposure to other risk agents to the auditory system;
i) Non-occupational exposure to other risk agents to the auditory system;
j) The examined employee’s professional training;
k) The hearing conservation programs available to the employee.
9. In cases of NIHL onset or worsening according to the criteria of this Annex, the occupational physician in charge of the PCMSO must:
a) Determine the employee’s fitness for the function;
b) Include the case in the Analytical Report of the PCMSO;
c) Participate in the implementation, improvement, and control of programs aimed at hearing conservation and preventing the progression of the employee’s hearing loss, considering exposure to vibration and occupational ototoxic agents;
d) Provide copies of audiometric exams to the employees.
10. If the reference audiometric exam shows changes whose evolution does not align with the NIHL patterns defined in this Annex, the occupational physician in charge of the PCMSO must:
a) Verify the possibility of concurrent exposure to more than one type of aggression to the auditory system;
b) Guide and refer the employee for specialized evaluation;
c) Determine the employee’s fitness for the function;
d) Participate in the implementation and improvement of programs aimed at hearing conservation and preventing the progression of the employee’s hearing loss, considering exposure to vibration and occupational ototoxic agents;
e) Provide copies of audiometric exams to the employees.
MODEL FORM FOR RECORDING AUDIOMETRIC TRACING
RIGHT EAR
Frequency in kHz
LEFT EAR
Frequency in kHz
Notes: The distance between each octave of frequency should correspond to a variation of 20 dB on the hearing level axis (D).
SYMBOLS FOR AUDIOMETRY RECORDS
| RIGHT EAR | LEFT EAR | |
| PRESENT RESPONSES Air Conduction Pathway Bone Conduction Pathway |  |  |
| PRESENT RESPONSES Air Conduction Pathway Bone Conduction Pathway |  |  |
Notes:
a) Symbols for air conduction must be connected by continuous lines for the right ear and dashed lines for the left ear.
b) Bone conduction symbols must not be interconnected.
c) If colors are used: red should be used for symbols related to the right ear, and blue should be used for symbols related to the left ear.