The Audiogram

Measurement of Hearing and Audiogram Interpretation

Introduction

How we measure hearingHow those measurements can be recordedWhat the audiogram can tell us

Purposes of audiometric testing

Monitor the effectiveness of the hearing conservation programIdentify significant threshold shiftEstablish readiness and fitness for dutyEnsure proper referral and diagnosis

Vocabulary

Audiogram - A record of a persons pure-tone hearing threshold levels Threshold A level of sound that a person can detect 50% of the time or moreAudiometric Zero sensitivity of normal, young adults

Audiometric Zero (Ref ANSI S3.6 1996, TDH-39 earphones)

0 dB Hearing Level at 1000 Hz = 7 dB SPL

Audiometric ZeroSheet1Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013Sheet2Sheet3Audiometric Zero1252505007501000150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Sheet1Audiometric Zero1254525025.550011.575081000715006.52000930001040009.5600015.5800013Sheet2Sheet3

Does 0 dB HL mean the absence of sound?What is the intensity of a 0 dB HL pure-tone at 1000 Hz?

Output Limits of the DOEHRS-HC Audiometer

-10 to 100 dB HL

Serial Audiogram

Thresholds recorded to the nearest

5 dB

Used on DD Forms 2215 and 2216, entrance physicals and physical exam forms (SF 88 and DD 2808)

Serial Audiogram

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric Zero125250500750100150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Sheet4Serial AudiogramLeft Ear50010002000300040006000Baseline6/1/8351025203525Annual7/24/99101015201535Right Ear50010002000300040006000Baseline6/1/83101010252510Annual7/24/99101015201535Mild high-frequency hearing loss at 6000 Hz bilaterally.cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Graphic Audiograms

Provides a pictorial representation of hearing thresholds as a function of frequency and intensityUses symbols and/or colors to represent right ear, left ear, bone conduction hearing and masking levels

Graphic Audiograms

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric ZeroFrequency (Hz)Loudness (dB)cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Self-recording Audiogram

Degrees of Hearing Loss

Normal Hearing-10 - 25 dB HL Mild Hearing Loss 30 - 45 dB HLModerate Hearing Loss 50 - 65 dB HL Severe Hearing Loss 70 - 85 dB HLProfound Hearing Loss > 90 dB HL

Audiogram Configurations:
Progressive noise-induced hearing loss

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric ZeroFrequency (Hz)Loudness (dB)cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510202535252510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010252510cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe losscht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Hearing Loss Zones

9.unknown

dB

Hz

250 500 1000 2000 3000 4000 6000 8000

sh

f

th

s

ch

p h

k

Speech Sounds

Audiogram Configurations:
Gundecking

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric ZeroFrequency (Hz)Loudness (dB)cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510202535252510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010252510cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Audiogram Configurations:
Background Noise

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric Zero125250500750100150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Sheet4Serial AudiogramLeft Ear50010002000300040006000Baseline6/1/8351025203525Annual7/24/99101015201535Right Ear50010002000300040006000Baseline6/1/83101010252510Annual7/24/99101015201535Mild high-frequency hearing loss at 6000 Hz bilaterally.cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000background noiseLeft Ear500100020003000400060003050500Right Ear3005000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Cross-over

One ear hears much better than the otherThe sound presented to the test ear crosses through the skull and stimulates the hair cells of the cochlea of the non-test earThe non-test ear is the one actually responding to the toneDifferences of > 40 dB at the same frequency between ears are suspicious

Cross-over

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric Zero125250500750100150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Serial AudiogramLeft Ear50010002000300040006000Baseline6/1/8351025203525Annual7/24/99101015201535Right Ear50010002000300040006000Baseline6/1/83101010252510Annual7/24/99101015201535Mild high-frequency hearing loss at 6000 Hz bilaterally.cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000background noiseLeft Ear500100020003000400060003050500Right Ear3005000cht-cross-over5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level45545545570570107015cross-overLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)45454570707055551015cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375

Malingering

Pretending to have a hearing loss by waiting until the sound is quite loud before pressing the response buttonIAW Article 115, Paragraph 194, a person may be charged with malingering if he/she pretends to have a hearing loss that is later found to be non-existent

Automatic Rechecks

Sensorineural Hearing Loss

Determined by a complete audiological evaluationCompare air-conduction and bone-conduction pure-tone thresholdsLook at acoustic immittance test results

Sensorineural Hearing Loss

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric Zero125250500750100150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Sheet4Serial AudiogramLeft Ear50010002000300040006000Baseline6/1/8351025203525Annual7/24/99101015201535Right Ear50010002000300040006000Baseline6/1/83101010252510Annual7/24/99101015201535Mild high-frequency hearing loss at 6000 Hz bilaterally.cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375cht-sensorineural500500510001000520002000253000300040004000606000600080008000Left EarRight EarBC Left EarFrequency (Hz)dB Hearing Level1010101030355045705080559075sensorineuralLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear5001000200030004000600080005001000200030004000600080001000200030004000600050010002000300040006000Significant Threshold Shift (STS)10103050708090101035455055755525605

Conductive Hearing Loss

Audiometric Zero Audiometric Zero1254525025.550011.57508100715006.52000930001040009.5600015.5800013cht-Audiometric Zero125250500750100150020003000400060008000Frequency (Hz)Loudness (dB)4525.511.5876.59109.515.513Sheet4Serial AudiogramLeft Ear50010002000300040006000Baseline6/1/8351025203525Annual7/24/99101015201535Right Ear50010002000300040006000Baseline6/1/83101010252510Annual7/24/99101015201535Mild high-frequency hearing loss at 6000 Hz bilaterally.cht-Graphic Audiogram5005001000100020002000300030004000400060006000Left EarRight EarFrequency (Hz)dB Hearing Level51010102510201535202510Graphic AudiogramLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear50010002000300040006000500100020003000400060005001000200030004000600050010002000300040006000Significant Threshold Shift (STS)51025203525101010152010cht-nihl500500500100010001000200020002000300030003000400040004000600060006000Mild LossModerate LossSevere lossFrequency (Hz)dB HL101520152040204060305070406075305580nihl50010002000300040006000101520304030Mild Loss152040506055Moderate Loss204060707580Severe lossgundeckingRight Ear50010002000300040006000000000Left Ear50010002000300040006000000000Right Ear000000cht-pre&post audios5001000200030004000600050010002000300040006000Pretest10.93755.93757.187510.62513.437521.258.1255.31255.312510.93759.687519.375cht-sensorineural500500510001000520002000253000300040004000606000600080008000Left EarRight EarBC Left EarFrequency (Hz)dB Hearing Level1010101030355045705080559075sensorineuralLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear5001000200030004000600080005001000200030004000600080001000200030004000600050010002000300040006000Significant Threshold Shift (STS)10103050708090101035455055755525605cht-bone conduction5005005100010005200020005300030004000400056000600080008000Left EarRight EarBC Left EarFrequency (Hz)dB Hearing Level2510301555355545555055555575bone conductionLeft EarRight EarPost-Audio Left EarPost-Audio Right Ear5001000200030004000600080005001000200030004000600080001000200030004000600050010002000300040006000Significant Threshold Shift (STS)101535455055752530555555555555555

Counseling Patients

Explain the Test Results

Provide privacy for explanationBoth ears testedFrequencies testedThe lower the threshold, the better the hearingReview each ear in terms of intensity and frequency

Appropriate Explanations

Within normal limitsLoss in the high or low frequenciesLoss in one or both earsHearing has changed or remained the same

Making Diagnoses

Medical Legal Requirements Regardless of Type

Patients name, SSN, (MOS, SSI, Job Location, and Unit Identification Code)Examiners name, SSN, and certification numberDate of TestMake, model, and serial number of audiometerCalibration date of audiometer.

DOEHRS-HC supplies most of the necessary medical legal audiogram information

AUTOMATICALLY

DD Form 2215
Reference Audiogram

For all military and noise-exposed civiliansPerformed before noise-hazardous duties or as soon as possible thereafterNoise-free period of at least 14 hours before the testNo temporary ENT problems the day of testRefer for low-frequency or high-frequency hearing lossAfter a permanent STS, re-establish a new baseline

DD Form 2216
Hearing Conservation Data

Periodic audiogramAnnual90 - DayTerminationOther

Forms
General Information

Maintain audiograms for entire period of employment plus 5 yearsTest must be performed by audiologist, physician, persons certified by CAOHC, or one who has received equivalent military trainingEquivalent military training includes this course. The certification from this course and other Army courses is only 5 years

Audiogram Review

Trained personnel must review all audiograms for validity and proper patient disposition.

Who Reviews?

Initially any Hearing Conservation Technician Problem audiograms must be reviewed by an audiologist, otolaryngologist or other physician

Audiograms to Refer

DD 2215s

> 25 dB at 500, 1000, and 2000 Hz

> 55 dB at 3000, 4000, or 6000 Hz

DD 2216s

Significant Threshold Shift (STS) computed from the average of 2000, 3000, & 4000 Hz in either ear in comparison to the baseline or reference hearing test (DD2215)

Factors Affecting Validity

Poor test environment - audiometric test booth does not meet background noise criteriaCross-over hearingUncooperative patients

Review Questions

Does an audiometric booth need to be perfectly soundproof?Excessive noise in an audiometric test booth will probably effect which frequency?When hearing levels between ears at the same frequency differ by 50 to 70 dB, what should you suspect is going on?

Left Ear

50010002000300040006000

000000

Right Ear

000000

45

25.5

11.5

8

7

6.5

9

10

9.5

15.5

13

0

5

10

15

20

25

30

35

40

45

50

1252505007501000150020003000400060008000

Frequency (Hz)

Loudness (dB)

0

10

20

30

40

50

60

70

80

90

100

50010002000300040006000

Frequency (Hz)

dB Hearing Level

0

10

20

30

40

50

60

70

80

90

100

50010002000300040006000

Frequency (Hz)

dB Hearing Level

Left Ear

50010002000300040006000

Baseline1983/06/01

51025203525

Annual1999/07/24

101015201535

Right Ear

50010002000300040006000

Baseline1983/06/01

101010252510

Annual1999/07/24

101015201535

Mild high-frequency hearing loss at 6000 Hz bilaterally.

Left Ear

50010002000300040006000

3050500

Right Ear

3005000

0

10

20

30

40

50

60

70

80

90

100

50010002000300040006000

Frequency (Hz)

dB HL

Mild LossModerate LossSevere loss

0

10

20

30

40

50

60

70

80

90

100

500100020003000400060008000

Frequency (Hz)

dB Hearing Level

Left EarRight EarBC Left Ear

0

10

20

30

40

50

60

70

80

90

100

500100020003000400060008000

Frequency (Hz)

dB Hearing Level

Left EarRight EarBC Left Ear

Normal

0

10

20

30

40

50

60

70

80

90

100