DOES OAE/A-ABR HEARING SCREENING MISS HEARING LOSS?

2005 EDHI Conference

Jean L. Johnson, DrPHJean L. Johnson, DrPHCenter for Disability StudiesCenter for Disability Studies

Director (Interim)Director (Interim)

March 3, 2005March 3, 2005

Atlanta, GA

International Conference on Newborn Hearing Screening, Diagnosis and Intervention

Cernobbio, Italy - May 2004

Second Annual Conference of the CDC Centers on Birth Defects and Developmental Disabilities

Washington, DC – July 2004

Asia Region Neonatal Screening ConferenceShanghai, China - September 2004

UH College of Education Research SymposiumHonolulu, HI - October 2004

American Speech-Language and Hearing AssociationPhiladelphia, PA – November 2004

CDC Ad Hoc Group – TeleconferenceJanuary 11, 2005

Research Team

Principal Investigator - Jean Johnson, DrPH Research Coordinator - Karl R. White, PhD

Diagnostic Evaluation Coordinator - Judith E. Widen, PhD

Site Co-Principal Investigators

Judith Gravel, PhDMichele James, AuD

Teresa Kennalley, MAAntonia B. Maxon, PhD

Lynn Spivak, PhDMaureen Sullivan-Mahoney, MA

Betty Vohr, MDYusnita Weirather, MA

Funded by the Centers for Disease Control and Prevention

CDC Consultants:June Holstrum, PhDRoy Ing, MD, MPHBrandt 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

Why is early identification of hearing loss so important?

• Hearing loss occurs more frequently than any other birth defect.

• Undetected hearing loss has serious negative consequences.

• Dramatic benefits are associated with early identification of hearing loss.

It is true for severe to profound loss.Is it also true for milder hearing loss?

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 otoacoustic emissions 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 some infants with permanent hearing loss.

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

Oto-Acoustic Emissions (OAE) Screening

Auditory Brain Stem (ABR)Screening

AABRScreening

Comprehensive HearingEvaluation Before 3 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/A-ABR 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 85% or more of referrals

• Ethnic and socio-economic distribution similar to US population

Participating Sites

Name of Hospital Location

Arnold Palmer Hospital Orlando, Florida

Good Samaritan Hospital Columbus, Ohio Jacobi Medical Center New York, New York

Kapi`olani Medical Center Honolulu, Hawaii

Long Island Jewish Medical System New York, New York

Via Christi Regional Medical Center Kansas City, Kansas

Women & Infants Hospital Providence, Rhode Island

Enrollment Process• Eligible babies (Failed OAE and Passed A-ABR) were

identified following newborn hearing screening.

• Parents were contacted and research study explained.

• Consent was obtained from families.

• Enrollment data was collected.

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

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

Date Collected for Each Participating Baby

Birthdate Bronchio-pulmonary Dsplasia

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 of Study Participants

Enrollment Period

Births During

Enrollment

Referral

OAE

Rate

ABR

Recruitment From

Site #1 May 1, 2001 to Dec 31, 2002

16,608 6.3% 0.8% WB/NICU

Site #2 June 1, 2001 to Jan 31, 2003

9,393 4.5% 0.9% WB/NICU

Site #3 May 1, 2001 to Jan 31, 2003

24,032 2.4% 0.8% WB/NICU

Site #4 Sep 20, 2001 to Jan, 2003

4,509 8.0% 1.0% WB

Site #5 May 15, 2001 to Jan 31, 2003

9,252 3.1% 0.8% WB

Site #6 May 1, 2001 to Jan 31, 2003

16,623 5.3% 1.2% WB/NICU

Site #7 May 1, 2001 to Jan 31, 2003

6,217 9.6% 2.8% WB/NICU

Total 86,634 4.8% 1.0%

 

    Number of Babies:

 Births During

EnrollmentEligible for Enrollment

Total Enrolled Number Not Recruited

Number 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 # 324,032 456 170 11 275

  1.9% 37.3% 2.4% 60.3%

Site # 44,509 285 84 186 15

  6.3% 29.5% 65.3% 5.3%

Site # 59,252 209 147 30 32

  2.3% 70.3% 14.4% 15.3%

Site # 6 6,217 433 266 50 117

  7.0% 61.4% 11.5% 27.0%

Site # 716,623 614 296 71 247

  3.7% 48.2% 11.6% 40.2%

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 (VRA)

• Tympanometry

• OAE - Either TOAE or DPOAE

VRA Protocol

• Protocol patterned after National institutes of Health Study (Norton, Univ. of Washington)

• 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 Criteria

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

Complete 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 Hearing Loss (PHL) 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

# of Infants with Dx Data

Percent of Infants

w/ Dx Data

Total Ears

Not PHL Permanent Loss

Hearing

(PHL)

Increased

of

Suspicion

PHL:

Probable Not PHL

Not Sufficient

Data

SNHL PC High Some

Site #1

81 42.4% 148 131 0 0 0 0 6 11

Site #2

299 80.8% 478 432 7 0 0 0 35 4

Site #3

42 50.0% 59 40 0 0 0 2 6 11

Site #4

109 74.1% 165 82 10 5 17 12 24 15

Site #5

86 50.6% 111 58 2 0 0 5 16 30

Site #6

184 69.2% 241 202 4 0 2 8 8 17

Site #7

172 58.1% 230 195 2 0 0 1 5 27

Total 973 63.8% 1432100%

114079.6%

25

1.7%

5

0.3%

19

1.3%

28

2.0%

100

7.0%

115

8.0%

Hearing Status of Study Ears from All Hospitals

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

Site # 5

Site # 7

Site # 6

Total

Site # 1

Site # 2

Site # 3

Site # 4

All Comparison Group Sites

Births during

enrollment

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

Prevalence of PHL (per

1000)

PHL in Comparison Group Sites(Fail OAE/Fail A-ABR)

PHL in Ears of Study Infants that Passed Initial OAE

Ears of Study Infants that Passed Initial OAETotal Ears Not PHL Permanent

Loss

Hearing

(PHL)

Increased

of

Suspicion

PHL:

Probable Not PHL

Not Sufficient

Data

SNHL PC High Some

Site #1 13 11 0 0 0 0 0 2

Site #2 112 107 0 0 1 0 3 1

Site #3 25 3 0 0 1 0 15 6

Site #4 53 19 0 0 2 6 15 11

Site #5 53 30 0 0 1 2 5 15

Site #6 127 60 0 0 3 1 38 25

Site #7 113 30 0 0 0 0 22 61

Total 496

100%

260

52.4%

0

0.0%

0

0.0%

8

1.6%

9

1.8%

98

19.8%

121

24.4%

Mild

(25-40 dB)

Moderate

(41-70 dB)

Severe through

Profound

(>70 dB)

Total Infants

Study Group 15

71.4%

5

23.8%

1

4.8%

21

100.0%

Comparison Group

31

19.6%

64

40.5%

63

39.6%

158

100.0%

Total 46

25.7%

69

38.5%

64

35./%

179

100.0%

Degree of Hearing Loss in Study and Comparison Group Babies

80.3%

28.6%

As measured in the worse ear

Comparability of Study and Comparison Groups

What Percent of “Referred” Babies Did Sites Try to

Follow?

What Percent of “Followed” Babies Were Diagnosed?

Study Group

(Fail OAE/ Pass A-ABR)44% 64%

Comparison Group

(Fail OAE/ Fail A-ABR)100% 87%

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 child 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

How Many Additional Babies with Permanent Hearing Loss (PHL) were Identified?

Comparison Group(Fail OAE/ Fail A-ABR)

Study Group(Fail OAE/ Pass A-ABR)

Total

Number of Babies 158 21 179Prevalence per 1,000 1.82 .24 2.06

*Adjusted for proportion of OAE fails that enrolled

Represents 12% of all babies with PHL in birth cohort

Is it important that 21 Babies (30 ears) with PHL 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 babies would you have to follow to find 21 babies PHL?

• Is this congenital or late-onset hearing loss?

How many babies 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 babies to return for outpatient screening must be considered

Screening Failures

PassedScreening

FailedScreening

False Positives

True Positives

Cost of Screening

• Direct cost

• Indirect cost

• Follow-up cost

Cost-Benefit of Screening

Benefit COST Good follow-up

Benefit COST Mediocre follow-up

Benefit COST Poor follow-up

Were any of these ears late-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, 9 of 21 babies would still have been missed

• Little is known about the incidence or what predicts late-onset hearing loss

• Most (>3/4ths) of the hearing losses “missed” were mild as was expected

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(33 babies)

2.49

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(33 babies)

2.49X 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 babies being missed

# of Study Group

Infants with PHL

Average “Rank” for Implementation Quality

of Site

Births During

Enrollment Period

% and N of Eligible Infants

Enrolled

% and N of Refusals During

Recruitment

% Returning

for Diagnostic Evaluations

% with “Not Sufficient

Data”

Site # 1 0 5.8 16,608 18.3%191

41.7%435

42.4% 7.4%

Site # 2 5 1.3 9,393 87.9%370

7.8%33

80.8% 0.8%

Site # 3 0 4.8 4,509 29.5%84

5.3%15

50.0% 18.6%

Site # 4 10 2.8 9,252 70.3%147

15.3%32

74.1% 9.1%

Site # 5 2 6.0 24,032 37.3%170

60.3%275

50.6% 27.0%

Site # 6 3 3.0 6,217 61.4%266

27.0%117

69.2% 7.1%

Site # 7 2 4.5 16,623 48.2%296

40.2%247

58.1% 11.7%

Indicators of Implementation Quality at Each Site

PHL=permanent hearing loss

Presumed Curve of Health Care

Bell-Shaped Curve of Health Care

Best Estimate of Amount of PHL Missed by OAE/AABR protocol

12% of children with PHL in birth cohort

23% of children with PHL in birth cohort

Babies Who Failed OAE / Failed AABR

Babies who failed OAE/ Passed AABR

Based on 44% that participated

Adjusted for those who did not participate

All Sites 1.82 2.06(.24 increase)

2.37(.55 increase)

Sites with Best Implementation

2.27 2.75(.48 Increase)

2.95(.68 increase)

23% of children with PHL in birth cohort

17% of children with PHL in birth cohort

What’s the Best Estimate of the Number of Babies Missed 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

Conclusions

The OAE/AABR protocol, as implemented at these sites, failed to identify a substantial number of infants with PHL.

Best estimate is .55 per thousand or 24% of all infants with PHL.

Most were mild sensorineural hearing loss

Impossible from this study to determine how many are late-onset losses

About 41% might be identified if all infants with risk factors or opposite refer ears were followed, but this is not likely.

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/A-ABR) protocol need to be carefully considered for individual programs.

Recommendations

Prevalence and methods of identifying late-onset hearing loss

Identification and monitoring of progressive 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 or additional “continuous” screening and surveillance techniques, especially in early childhood

Further Research Recommendations

Questions to Ponder

• What degree of hearing loss do you want to identify?

• What cost will be required for that identification?

• Can you assure that follow-up will occur?• What interventions can you provide?• How can you provide continuing surveillance

of late onset or progressive loss?• How comfortable are you with the quality of

services being provided?

Key Large-Scale Newborn Hearing Screening Studies in the United StatesLocation/Dates Cohort Size Nurseries Screening

Techniques Refer Rates

Follow Up Rate Prevalence Per 1000 of Hearing

Loss

RIHAP 3

(8/90 – 2/91)

1,850 NICU & WBN OAE / ABR

26.9% 73%

5.95

Colorado

(1/92-12/96

27,938 NICU & WBN AABR 2.56

Rhode Island

(1/93 – 12/95)

53,121 NICU & WBN OAE / ABR

14.7%

74--88%a 2.00

New Jersey

(1/93 – 12/95)

15,749 NICU & WBN ABR

3%

3.3 overall

2.00 – WBN

13.0 NICU

Hawai‘i

(1/94 – 12/95)

9,605 WBN OAE 89% 4.15

Texas

(1/94 – 6/97)

54,228 NICU & WBN OAE & AABR

3.5%

82.3% 3.14

NIDCD

(1994-1997)

4,478

2,701

NICU & WBN ABR-

TOAE-

DPOAE-

64.4%

(Research)

56.0

New York

(1/96 – 12/96)

69,761 NICU & WBN OAE & AABR 72% 8.00 (NICU)

0.9 (WBN)

Washington, DC

(2/97 – 12/02)

39,437 NICU & WBR TOAE

1.6%

82.7 2.3 overall

1.9 WBN

6.8 - NICU

ATPM/CDC

(5/2001 – 1/2003)

86,634 NICU & WBN OAE: 4.8

AABR: 1.0

63.8(Research)

85.8

2.05

Other Dissemination

• Article has been selected for publication in Pediatrics

• Five articles prepared for publication in American Journal of Audiology

• Presentation at Council on Exceptional Children Conference in Baltimore in April 2005.

Additional Information on Newborn Hearing Screening

www.infanthearing.org

www.babyhearing.org

jeanj@hawaii.edu

Deafness separates people from people.--- Helen Keller