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Hearing Test

By Triangle Occupational Healthcare Alliance

 

Most hearing test are done using the Standard Threshold Shift (STS) method. The standard threshold shift is the average shift of 10 dB or more at 2000, 3000, and 4000 Hz relative to the base line audiogram. Below is an example of how the test is preformed.

Left Ear Right Ear

   

500

1k

2k

3k

4k

6k

8k

   

500

1k

2k

3k

4k

6k

8k

B

1987

5

5

5

10

15

10

5

 

B

5

5

5

5

10

10

5

 

1988

5

5

5

10

20

15

5

   

5

5

5

10

10

15

5

RB

1989

5

5

10

20

30

20

15

 

RB

5

5

10

15

25

30

10

 

1990

10

5

15

25

30

25

15

   

5

10

15

25

40

30

20

 

Baselin Audiogram: 1987

Left ear average: 5 + 10 + 15 = 30/3 = 10 dB

Right ear average: 5 + 5 + 10 = 20/3 = 6.67 (7 dB)

Annual Audiogram: 1988

Left ear average = 11.67 (12 dB) NO SHIFT

Right ear average = 8.33 (9 dB) NO SHIFT

Annual Audiogram: 1989

Left ear average = 20 dB 10 dB SHIFT - REVISED BASELINE

Right ear average = 16.67 (17 dB) 10 dB SHIFT - REVISED BASELINE

OSHA requires that the employer inform the employee in writing that he has sustained an STS within 21 working days of the determination. The employer has the option of retesting the employee within 30 days to see if the STS persists. If it does not, the retest audiogram may be used for the annual audiogram. If it does persist, it becomes the REVISED BASELINE.

 

 

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