THE EFFICACY OF AN OAE/AABR PROTOCOL FOR IDENTIFYING HEARING LOSS IN NEWBORNS:

Are Infants with Hearing Loss Not Being Identified?

presented at

NHS 2004The International Conference on Newborn Hearing

Screening, Diagnosis and Intervention

Cernobbio, ItalyMay 29, 2004

Research Team

Principal Investigator: Jean Johnson, DrPH Research Coordinator: Karl R. White, PhDDiagnostic Evaluation Coordinator: Judith E. Widen, PhD

Site Co-Principal Investigators:Judith Gravel, PhD: Jacobi Medical Center (Bronx, New York)Michele James-Trychel, MEd: Arnold Palmer Hospital (Florida)Teresa Kennalley, MA: Via Christi Regional Medical Center (Kansas)Antonia B. Maxon, PhD: Lawrence & Memorial (Connecticut)Lynn Spivak, PhD: Long Island Jewish Health System (New York)Maureen Sullivan-Mahoney, MA: Good Samaritan Hospital (Ohio)Betty Vohr, MD: Women & Infants Hospital (Rhode Island)Yusnita Weirather, MA: Kapi`olani Medical Center (Hawai`i)

Funded by the Centers for Disease Control and Prevention

CDC Consultants:June Holstrum, PhDBrandt Culpepper, PhDKrista Biernath, MD Lee Ann Ramsey, BBA, GCPH

under a Cooperative Agreement with:The Association of Teachers of Preventive Medicine

with a sub-agreement to:The University of Hawai`i

Background National Institutes of Health (NIH) Consensus Panel

recommended in March 1993 that:“the preferred model for screening should begin with an evoked otoacoustic emissions test and should be followed by an auditory brainstem response test for all infants who fail the evoked otoacousticemissions test.”

Continuing improvement of ABR technology led to a number of hospitals in the US implementing a variation of the NIH recommendation that was based on automated ABR (AABR)

Anecdotal reports to the Centers for Disease Control and Prevention (CDC) in the mid to late 1990’s that the two-stage OAE/AABR protocol was not identifying infants with mild hearing loss.

The CDC issued a competitive Request for Proposals in late 2000 to investigate whether the OAE/AABR screening protocol was not identifying babies with hearing loss

AABRScreening

Comprehensive HearingEvaluation Before 6 Months

of AgeFail Fail

Pass Pass

Discharge Discharge

OAE Screening Prior toHospital Discharge

RESEARCH QUESTION

Are infants with permanent hearing loss not being identified when newborn hearing screening is done with a two-stage OAE/AABR protocol in which infants who fail OAE and pass AABR are not followed?

Study SampleComprehensive Audiological Assessment at 8-12 months of age

Comparison Group

CRITERIA for SELECTING SITES• 2,000 or more births per year

• Established newborn hearing screening program with at least six month history of success

• Historical refer rates of less than 10% for OAE and 4% for ABR

• Success in obtaining follow-up on 90% or more of referrals

• Ethnic and socio-economic distribution similar to US population

Participating Sites

Name of Hospital Location

Arnold Palmer Hospital Tampa, Florida

Good Samaritan Hospital Columbus, Ohio Jacobi Medical Center and North Central Bronx Hospital New York, New York

Kapi`olani Medical Center Honolulu, Hawaii

Long Island Jewish Medical System New York, New York (included North Shore University, Hunter

and Long Island Jewish Hospitals)

Via Christi Regional Medical Center Kansas City, Kansas

Women & Infants Hospital Providence, Rhode Island

Data Collection Process• Eligible infants (Failed OAE and Passed AABR) identified

following newborn hearing screening.

• Parents contacted and research study explained.

• Consent obtained from families.

• Enrollment data collected.

• Contact maintained with family at 2, 4, & 6 months of age via post cards.

• Infants seen for audiological diagnostic evaluation at 8-12 months of adjusted age.

Data Collected for Each Participating Infant

Birthdate Bronchio-pulmonary Dysplasia

Gender Mechanical Ventilation >7 Days

Birth Weight ECMO

Gestational Age Number of Children in Home

APGAR Scores Number of Adults in Home

Days in NICU Total Household Income

Malformations of the Head and Neck Child’s Race/Ethnicity

Syndrome Associated with Hearing Loss Health Insurance

In-utero Infections Family History of Hearing Loss

Study Sample

1,524 Infants Enrolled

973 (63.8%) Returned for Evaluation

1,432 Ears Evaluated

Enrollment Period

Births During Enrollment

OAE AABR Recruitment from

May 1, 2001 to 16,608 6.3% 0.8%Dec 31, 2002

June 1, 2001 to 9,393 4.5% 0.9%Jan 31, 2003

Sep 20, 2001 to 4,509 8.0% 1.0%Jan, 2003

May 15, 2001 to 9,252 3.1% 0.8%Jan 31, 2003

May 1, 2001 to 24,032 2.4% 0.8%Jan 31, 2003

May 1, 2001 to 16,623 5.3% 1.2%Jan 31, 2003

May 1, 2001 to 6,217 9.6% 2.8%Jan 31, 2003

Total 86,634 4.8% 1.0%

Site # 7 WB/NICU

Site # 5 WB/NICU

Site # 6 WB/NICU

Site # 3 WB

Site # 4 WB

Referral Rate

Site # 1 WB/NICU

Site # 2 WB/NICU

Enrollment of Study Participants

 

    Number of Infants:

 Births During

EnrollmentEligible for Enrollment

Total Enrolled Not Recruited # of Refusals

Site # 116,608 1,044 191 418 435

  6.3% 18.3% 40.0% 41.7%

Site # 29,393 421 370 18 33

  4.5% 87.9% 4.3% 7.8%

Site # 34,509 285 84 186 15

  6.3% 29.5% 65.3% 5.3%

Site # 49,252 209 147 30 32

  2.3% 70.3% 14.4% 15.3%

Site # 524,032 456 170 11 275

  1.9% 37.3% 2.4% 60.3%

Site # 6 16,623 614 296 71 247

  3.7% 48.2% 11.6% 40.2%

Site # 76,217 433 266 50 117

  7.0% 61.4% 11.5% 27.0%

Total 86,634 3,462 1,524 784 1,154

4.0% 44.0% 22.6% 33.3%

Enrollment of Study Participants (continued)

AUDIOLOGICAL DIAGNOSTIC EVALUATION

» Visual reinforcement

audiometry

» Tympanometry

» Either TEOAE or

DPOAE

VRA PROTOCOL

• Protocol based on University of Washington (2000) study

• Responses at 500, 1K, 2K, 4K Hz

– Order of testing 2K, .5K, 4K, 1K

– Aiming for minimal response level of 15 dB HL

• Multiple visits often necessary to complete testing

– 68% completed in 1 visit

– 24 % required 2 visits

– 8% required 3 or more visits

Category Description

Not Permanent Hearing Loss Using the ”best” results from all assessments, MRL thresholds of < 20dB at 1K, 2K, and 4K.

Probable Not Permanent Hearing Loss

MRL data not available at 1K, 2K, and 4K, BUT* All frequencies had MRLs < 20dB OR OAEs within normal limits* OR Tone burst ABR

data < 25dB.

Permanent Hearing Loss (PHL)Sensorineural

MRLs > 25dB at 1K, 2K, or 4K (tested with good confidence) OR ABR threshold > 30dB; AND if tested, OAEs below normal limits at the frequencies with elevated MRLs; AND normal middle ear functioning based on tympanometry or bone conduction.

Permanent Conductive MRLs > 25dB at 1K, 2K, or 4K (tested with good confidence); AND if tested, OAEs below normal limits; AND bone conduction thresholds < 20dB with an Air/Bone gap > 15dB at frequencies with MRLs > 25dB.

Increased Suspicion of PHLHigh Suspicion

MRLs > 25dB at 1K, 2K, or 4K, BUT OAEs within normal limits for those frequencies OR only fair confidence in VRA testing.

Some Suspicion * MRLs > 30dB at 1 frequency or > 25dB at more than one frequency, BUT abnormal tympanometry AND no bone conduction.

* Sound field thresholds > 25dB (with fair confidence) AND normal tympanometry AND OAEs below normal limits.

Not Sufficient Data to Rule Out PHL

* No MRLs or OAEs within normal limits for 1K, 2K, or 4K and none of the above criteria for permanent hearing loss are met.

* OAEs within normal limits were defined as > 3-6dB at 1K and > 6dB at 2K and 4K.

Criteria for Categorizing Hearing Loss

Category Tymp Tymp Tymp Assigned .5K 1K 2K 4K Qual rslt 1K 2K 4K .5K 1K 2K 4K Qual rslt 1K 2K 4K .5K 1K 2K 4K Qual rslt 1k 2k 4k

Not PHL D D D D n/a 3 D 6 6 15 15 15 15 1 1 6 6 6 . . . . . . . .

probably NOT PHL 15 C 15 20 1 1 6 6 6 . . . . . . . . . . . . . . . .

PHL: SN 30 30 30 45 1 1 2 2 2 30 45 30 50 1.5 1 6 6 2 . . . . . . . .

High Suspicion D 35 25 25 1 2 2 6 2 D 30 35 35 1.5 1 2 2 2 25 D D 30 2 3 6 6 6

Some Suspicion 55 50 45 65 1 3 2 2 2 . . . . . . . . . . . . . . . .

Insufficient Data C C 20 C 1 1 D 6 6 4 D 6 6

MRL's MRL's

Assessment #2

OAEs

Assessment # 1

OAEs OAEs

Assessment #3

MRL's

Examples of How Hearing Status was Categorized

For Tymp Results"1" means normal tympanograms (all variables with normal limits),"2" means abnormal tympanograms (at least one variable in abnormal range), "3" means questionable (at least one variable within normal limits, others are -8, nopeak; -9, missing; or -1, not available) "4" means missing data (all four variables were coded as missing).

Qual means quality of the VRA result and is an average of the frequencies rated with 1=good and 2=fairOAE data are coded as 2=<3 dB; 4=3-6 dB; 6=>6 dB"." in the results column or for indiviudal variables means the data form was blank for variable(s)

# of Infants with Dx Data

Percent of Infants

Total Ears Not PHL

Probable Not PHL

w/ Dx Data SNHL PC high some

81 42.4% 148 131 0 0 0 0 6 11

299 80.8% 478 432 7 0 0 0 35 4

42 50.0% 59 40 0 0 0 2 6 11

109 74.1% 165 82 10 5 17 12 24 15

86 50.6% 111 58 2 0 0 5 16 30

184 69.2% 241 202 4 0 2 8 8 17

172 58.1% 230 195 2 0 0 1 5 27

973 63.8% 1432 1140 25 5 19 28 100 115100% 79.6% 1.7% 0.3% 1.3% 2.0% 7.0% 8.0%

Total

Site # 5

Hearing Status of Study Infants from All HospitalsIncreased Suspicion of

PHL:

Site # 3

Site # 4

Not Sufficient

Data

Permanent Hearing Loss

(PHL)

Site # 1

Site # 2

Site # 6

Site # 7

Is It Important that 21 Infants (30 ears) with Permanent Hearing Loss Were Found?

• How many does it add to what would have been identified otherwise?

• How many ears with hearing loss were found among those that passed the initial screen?

• How many infants would you have to follow to find 21 infants with PHL?

• Is this congenital or late-onset hearing loss?

SN PC Total SN PC Total

16,608 17 1 18 24 2 26 1.08 1.2% 82.4%

199 164

9,393 18 1 19 31 2 33 2.02 1.5% 95.7%

140 134

4,509 4 0 4 6 0 6 0.89 0.2% 88.9%

9 8

9,252 16 0 16 27 0 27 1.73 0.3% 96.4%

28 27

24,032 39 3 42 60 3 63 1.75 0.8% 87.6%

193 169

6,217 16 1 17 25 2 27 2.73 0.7% 65.9%

41 27

16,623 36 6 42 55 6 61 2.53 0.6% 79.8%

94 75

86,634 146 12 158 228 15 243 1.82 0.8% 85.8%704 604

Prevalence of PHL (per

1000)

All Comparison Group Sites

Births during enrollment

Infants w/ PHL Ears w/ PHLReferred for Dx Completed Dx

Site # 1

Site # 2

Site # 3

Site # 4

Site # 5

Site # 7

Site # 6

Total

PHL in Comparison Group Sites(Fail OAE/Fail AABR)

# of Infants with Dx Data

Percent of Infants

Total Ears Not PHL

Probable Not PHL

w/ Dx Data SNHL PC high some

81 42.4% 148 131 0 0 0 0 6 11

299 80.8% 478 432 7 0 0 0 35 4

42 50.0% 59 40 0 0 0 2 6 11

109 74.1% 165 82 10 5 17 12 24 15

86 50.6% 111 58 2 0 0 5 16 30

184 69.2% 241 202 4 0 2 8 8 17

172 58.1% 230 195 2 0 0 1 5 27

973 63.8% 1432 1140 25 5 19 28 100 115100% 79.6% 1.7% 0.3% 1.3% 2.0% 7.0% 8.0%

Total

Site # 5

Hearing Status of Study Infants from All HospitalsIncreased Suspicion of

PHL:

Site # 3

Site # 4

Not Sufficient

Data

Permanent Hearing Loss

(PHL)

Site # 1

Site # 2

Site # 6

Site # 7

How Many Additional Infants with Permanent Hearing Loss were Identified?

Comparison Group(Fail OAE/ Fail AABR)

Study Group(Fail OAE/ Pass AABR)

Total

Number of Infants 158 21 179Prevalence per 1,000 1.82 0.24 2.06

Represents 11.7% of all infants with PHL in

birth cohort

Degree of Hearing Loss* in Study and Comparison Group Infants

Mild ModerateMod-

Severe Severe Profound(20-40 dB) (41-55 dB) (56-70 dB) (71-90 dB) (≥ 91dB)

15 4 1 0 1

71.4% 19.0% 4.8% 0.0% 4.8%31 38 26 30 29

20.1% 24.7% 16.9% 19.5% 18.8%

46 42 27 30 30

26.3% 24.0% 15.4% 17.1% 17.1%*As measured in the worse ear

Total

Study Group

Comparison Group

79.9%

28.6%

Total Ears Not PHL

Probable Not PHL

SNHL PC High Some

13 11 0 0 0 0 0 2

112 107 0 0 1 0 3 1

25 3 0 0 1 0 15 6

53 19 0 0 2 6 15 11

53 30 0 0 1 2 5 15

127 60 0 0 3 1 38 25

113 30 0 0 0 0 22 61

496 260 0 0 8 9 98 121100% 52.4% 0.0% 0.0% 1.6% 1.8% 19.8% 24.4%

Ears of Study Infants that Passed Initial OAE

Increased Suspicion of PHL:

Site # 1

Not Sufficient

Data

Permanent Hearing Loss

(PHL)

Site # 2

Site # 3

Site # 4

Site # 5

Site # 6

Site # 7

Total

PHL in Ears of Study Infants that Passed Initial OAE

How Many Infants Must Be Screened to Find 21 with PHL?

• The obvious answer is 973, but….– This ignores that most screening programs

that use OAE also do second stage OAE screen (usually following hospital discharge)

– Such outpatient screening is less expensive than the diagnostic protocol used in this study

– Difficulty of getting infants to return for outpatient screening must be considered

Were any of these earslate-onset losses?

This study was not designed to answer that question.

We do know that IF all of the ears with risk factors had been followed and identified, 10 of 21 babies would still not have been identified

Little is know about the incidence or what predicts Late-onset hearing loss

Most of the hearing losses not identified were mild which is what we would expect if ears are being missed

What’s the Best Estimate of the Number of Infants Not Identified by the

OAE/AABR Screening Protocol?

• Depends on the criteria used for determining PHL

• Variation among sites

• Adjustments for Differences Between Study and Comparison Groups

# of Infants with Dx Data

Percent of Infants w/

Dx DataTotal Ears Not PHL

Probable Not PHL

SNHL PC high some

81 42.4% 148 131 0 0 0 0 6 11

299 80.8% 478 432 7 0 0 0 35 4

42 50.0% 59 40 0 0 0 2 6 11

109 74.1% 165 82 10 5 17 12 24 15

86 50.6% 111 58 2 0 0 5 16 30

184 69.2% 241 202 4 0 2 8 8 17

172 58.1% 230 195 2 0 0 1 5 27

973 63.8% 1432 1140 25 5 19 28 100 115100% 79.6% 1.7% 0.3% 1.3% 2.0% 7.0% 8.0%

Site # 6

Site # 7

Site # 3

Site # 4

Not Sufficient

Data

Permanent Hearing Loss

(PHL)

Site # 1

Site # 2

Total

Site # 5

Hearing Status of Study Infants from All HospitalsIncreased Suspicion of

PHL:

Different Criteria for Determining Permanent Hearing Loss

Comparison Group

Study Group

Total

Based only on those meeting criteria for PHL

1.82 .24(21 babies)

2.06

Including those categorized as high suspicion of PHL

1.82 .43(37 babies)

2.25X XX X

Variation Among Sites

The study design assumed that sites are all equally well implemented

To the degree that this isn’t true, data from some sites may be a better estimate of the number of infants not being identified

Indicators of Implementation QualityBirths During Enrollment

% of Eligible Infants Enrolled

Refusals During Recruitment

% Returning for Diagnositic

% "Not Sufficient Data"

16,608 191 435

18.3% 41.7% 42.4% 7.4%

9,393 370 33

87.9% 7.8% 80.8% 0.8%

4,509 84 15

29.5% 5.3% 50.0% 18.6%

9,252 147 32

70.3% 15.3% 74.1% 9.1%

24,032 170 275

37.3% 60.3% 50.6% 27.0%

16,623 296 247

48.2% 40.2% 69.2% 7.1%

6,217 266 117

61.4% 27.0% 58.1% 11.7%Total 86,634 44% 33% 63.8% 8.0%

Site # 5

Site # 6

Site # 7

Site # 1

Site # 2

Site # 3

Site # 4

First BestSecondThirdFourth Good

Total InfantsPercent of

Infants Total Ears Not PHL

Probable Not PHL

w/ Dx Data SNHL PC high some

299 80.8% 478 432 7 0 0 0 35 4

109 74.1% 165 82 10 5 17 12 24 15

184 69.2% 241 202 4 0 2 8 8 17

172 58.1% 230 195 2 0 0 1 5 27

764 70.8% 1114 911 23 5 19 21 72 63100% 81.8% 2.1% 0.4% 1.7% 1.9% 6.5% 5.7%

Permanent Hearing Loss

(PHL)Increased Suspicion of

PHL:

Not Sufficient

Data

Study Infants with PHL from Sites with Best Implementation

Site # 2

Site # 4

Site # 6

Site # 7

Total

Total InfantsPercent of

Infants Total Ears Not PHL

Probable Not PHL

w/ Dx Data SNHL PC high some

81 42.4% 148 131 0 0 0 0 6 11

42 50.0% 59 40 0 0 0 2 6 11

86 50.6% 111 58 2 0 0 5 16 30

Total 209 47.0% 318 229 2 0 0 7 28 52100% 72.0% 0.6% 0.0% 0.0% 2.2% 8.8% 16.4%

Increased Suspicion of PHL:

Permanent Hearing Loss

(PHL)

Study Infants with PHL from Sites with Fair Implementation

Site # 1

Site # 3

Site # 5

Not Sufficient

Data

Comparability of Study and Comparison Groups

What Percent of “Referred” Infants Did Sites Try to

Follow?

What Percent of “Followed” Infants Were Diagnosed?

Study Group

(Fail OAE/ Pass AABR44% 63.8%

Comparison Group

(Fail OAE/ Fail AABR)100% 85.8%

Reasonable to adjust prevalence rates for those who were not recruited

Adjusting prevalence rates for differences in the percent of diagnostics completed is problematic

Families who think their infant has a hearing loss are more likely to return

Families that are poor, single heads of household, transient , etc. are less likely to return and these variables may be correlated with the incidence of hearing loss

Prevalence of PHL per 1,000

Best Estimate of Amount of PHL not Identified by OAE/AABR protocol

Infants Who Failed OAE / Failed AABR

Adding Infants who failed OAE / Passed AABR

Based on 44% that participated

Adjusted for those who did not participate

All Sites 1.82 2.06(0.24 increase)

2.37(0.55 increase)

Sites with Best Implementation

2.27 2.73(0.46 Increase)

2.99(0.72 increase)

11.7% of infants with PHL in birth cohort

24% of infants with PHL in birth cohort

23% of infants with PHL in birth cohort

16.8% of infants with PHL in birth cohort

Conclusions

The OAE/AABR protocol implemented in this study does not identify a substantial number of infants with permanent hearing loss

Best estimate is .55 per thousand or 23% of all infants with permanent hearing loss

Mostly mild sensorineural hearing loss

Impossible to determine whether this is congenital or late-onset

About 45% would be identified if all infants with risk factors or contralateral refer ears were followed, but this may not be practical

Screening for permanent hearing loss should extend into early childhood (e.g. physician’s offices, early childhood programs)

Emphasize to families and physicians that passing hospital-based hearing screening does not eliminate the need to vigilantly monitor language development.

Screening program administrators should ensure that the stimulus levels of equipment used are consistent with the degree of hearing loss they want to identify

The relative advantages and disadvantages of the two-stage (OAE/AABR) protocol need to be carefully considered for individual circumstances

Recommendations

Prevalence and methods of identifying late-onset hearing loss

Ongoing investigation of sensitivity of various screening protocols and equipment (including what level of hearing loss is targeted)

Practicality and cost-efficiency of alternative “continuous” screening and surveillance techniques

Recommendations for Further Research