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Standards for NHS Equipment aka What Are We Measuring in NHS Programs? Barbara L. Kurman, Au.D., FAAA Vice-President, Northeastern Technologies Group,

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Presentation on theme: "Standards for NHS Equipment aka What Are We Measuring in NHS Programs? Barbara L. Kurman, Au.D., FAAA Vice-President, Northeastern Technologies Group,"— Presentation transcript:

1 Standards for NHS Equipment aka What Are We Measuring in NHS Programs? Barbara L. Kurman, Au.D., FAAA Vice-President, Northeastern Technologies Group, Inc., NY Managing Member, Midlantic Technologies Group, LLC., PA Judy Gravel, Ph.D. Director, Center for Childhood Communication The Childrens Hospital of Philadelphia, PA

2 Faculty Disclosure Information As a Special Instrument Distributor (SID), Barbara Kurman has contractual relationships with most manufacturers whose products will be referred to in this presentation. In the past 12 months, Judith Gravel has not had a significant financial interest or other relationship with the manufacturer(s) of the product(s) or provider(s) of the service(s) that will be discussed in this presentation. This presentation will not include discussion of pharmaceuticals or devices that have not been approved by the FDA. There will be no discussion or unapproved or "off-label" uses of pharmaceuticals or devices.

3 Agenda Background: review of newborn hearing screening programs – who are we missing? Technologies and current devices – what is commercially available? Should We Have Standards for NHS? Other NHS product considerations

4 NIH 1993 Consensus Conference 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.

5 What hearing losses are we missing with newborn screening? The best screening tests are not 100% accurate Evidence suggests that at best, our screening tests are identifying about 80% - 90% of infants who have hearing loss in the newborn period (e.g., Norton et al., 2000; Davis et al., 1997; Lutman et al., 1997)

6 What hearing losses are we missing with newborn screening? Mild hearing loss < dB HL Some unusual configurations of hearing loss –Isolated low-frequency hearing loss (both OAE and ABR technologies) –Oddly-shaped hearing loss Steeply sloping high-frequency hearing loss Mid-frequency hearing loss Delayed onset and progressive hearing losses AN and genetic IHC loss where OHCs are intact (if only use OAE screening technology)

7 What hearing losses are we missing with newborn screening? Missing deaf ears –Estimates of false-negative (false pass) rate: 1-2% of deaf ears will pass ABR screening (Roger Marsh, CHOP 2006 Repeated screening of a failed ear to achieve a pass will increase the likelihood of a pass response in a deaf ear

8 Centers for Disease Control and Prevention (CDC) Request for Proposals - January 2000 Concerns have been raised about infants who fail OAE but pass ABR and are then dismissed from follow-up. These infants may have a mild loss that was missed by ABR

9 A Multi-Center Evaluation of How Many Infants with Permanent Hearing Loss Pass a Two-Stage OAE/A-ABR Newborn Hearing Screening Protocol Johnson, White, Widen, Gravel, James, Kennalley, Maxon, Spivak, Sullivan-Mahoney, Vohr, Weirather, and Holstrum Pediatrics 116(3) Sept 2005;

10 Prospective, cohort study 7 geographically-dispersed birthing centers in U.S. Ethnic & socio-economic characteristics representative of U.S. population Johnson et al. (Pediatrics 2005 )

11 2-technology screening protocol: – TEOAE (Otodynamics) or DPOAE (Biologic) – A-ABR (ALGO: 35 dB nHL click) Some used protocol in both well-baby and NICU Johnson et al. 2005

12 86,634 infants: screened in 7 Centers 704 (0.8%) failed OAE/failed A-ABR screening –Comparison Group: 604 (85.8%) returned for diagnostic tests 3, 362 (4%) failed OAE/passed A-ABR in at least one ear –Study Group: 1,524 (44%) infants were enrolled for follow-up Johnson et al. 2005

13 Study Group 973 infants (64%) returned for audiologic follow-up Audiologic tests completed at mean age 9.7 months –VRA (AC & BC); –tympanometry; –OAE Johnson et al. 2005

14 21 infants (30 ears) who failed OAE & passed A-ABR in newborn period had permanent bilateral or unilateral HL at ~9 months of age

15 Degree (poorer ear) of PHL (VRA) in Study & Comparison Groups (Johnson et al. 2005) Mild (25-40 dB) Mod (41-70 dB) Sev/Prof (>71 dB) Total with PHL Study Grp 15 (71.4%) 5 (23.8%) 1 (4.8%) 21 (100%) Comp Grp 31 (19.6%) 64 (40.5%) 63 (39.9%) 158 (100%) Total46 (25.7%) 69 (38.5%) 64 (35.8%) 179 (100%)

16 Examples of PHL (VRA) in Infants who fail OAE/pass A-ABR (Johnson et al. 2005) ID #.5 kHz1 kHz2 kHz4 kHz

17 Examples of PHL (VRA) in Infants who fail OAE/pass A-ABR (Johnson et al. 2005) ID #.5 kHz1 kHz2 kHz4 kHz

18 Identifying Mild PHL in Infants: Challenges Norton et al. (2000) Three measures (ABR, TEOAE, DPOAE) - able to identify majority of ears with moderate hearing loss or greater. –more difficult for any tool to distinguish between normal hearing and mild hearing loss (p.533) –some ears with mild hearing loss will be missed, regardless of which test is used (p.534)

19 Cone-Wesson et al. (2000); n = 2995 infants Ears with mild PHL (n=22 [30.2%] of 86 ears with PHL) confirmed at 8-12 months (VRA) Outcomes (neonatal ABR and OAE [DPOAE and TEOAE]) –10 ears failed both OAE and A-ABR tests, –4 ears passed both OAE and A-ABR tests, –4 passed ABR and failed both OAE measures –2 failed ABR and passed OAE tests. –2 ears that failed ABR passed DPOAE but failed TEOAE. Identifying Mild PHL in Infants: Challenges

20 Issues Impacting NHS Data No ANSI standards for use in calibration of OAE or ABR devices Variability among screening devices test parameters Individual variability of SPL at TM – issue most significant for ABR

21 Muff Flat plate Ear coupler base Microphone B&K type 4144 Method of measuring stimulus output of AABR muffs From: John Stevens 2004

22 Variability Based on the estimate of the RETSPL value, the results indicate that the stimulus levels in current equipment [automated ABR] are considerably above the stated stimulus level of 35 dB HL. Estimated: 38.5 to 44.9 dB HL Stevens 2004

23 Eight Manufacturers of Hearing Screening Devices Commercially Available in U.S. Bio-logic GN Otometrics – Madsen GSI – Grason Stadler: VIASYS Otodynamics, Ltd Maico Diagnostics Natus Interacoustics USA Intelligent Hearing Systems SonaMed Corp

24 Devices: Types available currently: TEOAE only (1 manufacturer only) DPOAE only (1 manufacturer only) TEOAE and/or DPOAE (5 manufacturers) Screening OAE and/or screening ABR in one device (6 manufacturers) Screening ABR only (5 manufacturers offer ABR as stand-alone device)

25 Commercially-Available Screening Products Single technology: –TEOAE, DPOAE, ABR Combined technologies – can be configured in multiple ways –TEOAE, DPOAE, ABR

26 What the Products Have in Common Designed for ease of use - automation Parameters cannot be changed by screening personnel All provide only pass or refer outcome Probe tips or couplers (circumaural cushions) are disposable (single use) All identify some violation of proper test conditions: low stimulus level, too noisy.

27 TEOAE: Examples Product Variability ManufStimulus Stim Level (dB SPL) Pass Criteria 1 6 freq bands: 1.5 – 4 kHz 83 4 dB S/N 2 Primary resp. band: 1.6 – 3.2 kHz 84 6 dB S/N 3 Primary resp. band: 1.2 – 3.5 kHz 80 6 dB S/N

28 DPOAE: Examples Product Variability ManufStimulus f1-f2 Levels L1- L2 Pass Criteria 1 4 tonal pairs (f1-f2) (2 – 5 kHz) 65/55 6 dB SNR in 3 frequencies = pass (not consecutive) 2 5 tonal pairs: 2-6 kHz 65/55 3 out of 5 frequencies = pass which meet: Min -5 dB SPL amplitude & min 8 dB SNR, or min noise floor amplitude -17 dB SPL

29 Automated ABR: Examples Product Variability ManufChange levels? Ear Canal Calibration? Transducer Choice? 1yes 2 No – probe only 3yes**? No – circumaural only

30 Calibration Manufacture Recommends: –Some recommend a yearly calibration: (e.g., on site by a NASED –certified audiometric technician or ship device back to factory) –Some recommend no annual calibration is needed NASED (National Association of Special Equipment Distributors) – examining calibration standards for OAE devices where no current national standards exist

31 Lack of National Standards for NHS

32 Problems Associated with the Lack of National Standards for NHS Programs Prevalence data may not be comparable across programs –Impacts our understanding of differences in prevalence among populations and geographic regions –Impacts public health, education, fiscal policy planning

33 Comparing Within & Among NHS Data Sets NYS Demonstration Project – same protocol and pass/fail criteria English Screening program – same protocol and pass/fail criteria Ontario screening program – same protocol and pass/fail criteria U.S. screening program - variability of screening protocols & pass/fail criteria among hospitals & states and across the nation

34 Problems Associated with the Lack of National Standards for NHS Programs Manufacturer algorithms designed to provide best performance (low fail rates) along with high sensitivity (most hearing losses identified) Pass-fail criteria differ among devices Few data from manufacturers on the statistical false-negative (false-pass) rate

35 Screening outcome by ABR compared to Four Different DPOAE Pass Criteria (Barker, Lesperance & Kileny, 2000) 1184 ears examined: all ears passed ABR screening (35 dB nHL) DPOAE screening Depending on four different pass-refer criterion applied, between 64% and 89% of ears passed screening

36 Solutions: Refer to accepted Position Statements and Guidelines or State Regulations and Guidelines

37 Newborn Hearing Screening Objective measure must be used –Auditory Brainstem Response (ABR) –Otoacoustic Emissions (OAE) –pass-refer criteria preferred –automated response detection preferred –non-professional: pass-refer outcome required JCIH 2000

38 In-hospital screening –variety of protocols useful –one technology and two technology protocols Well-baby nursery (WBN) versus Neonatal Intensive Care Unit (NICU) Re-screen (out-patient) –within 1 month of discharge –minimizes number of referrals audiologic assessment: reduces over-referral rate (false-positive outcomes)

39 Physiologic screen of hearing only Screening Equipment (OAE – ABR) not specified required to be fully automated (only providing pass-refer outcome) when used by technical personnel The Law: NY State UNHS Regulations

40 Solutions: Use published parameters from clinical trials that provided data about accuracy of screening tests (sensitivity & specificity) Only one study available: Norton et al NIH-NIDCD

41 Multi-center Investigation Sponsored by NIH-NIDCD Investigators: Norton, Gorga, Widen, Folsom, Sininger, Cone-Wesson, Vohr et al., 2000 To determine the accuracy of three measures of peripheral auditory system status (TEOAE, DPOAE and ABR) applied in the perinatal period for predicting behavioral hearing status at 8-12 months corrected age.

42 NIH Multi-Center Study (Norton et al. Ear & Hearing: 5; 2000) 7 institutions 7,179 infants evaluated –2,348 = WBN babies –4,478 = NICU babies – 355 = well babies with high risk indicators Targeted for 8-12 months : NICU, WBN with HRI, and 80 WBN (no HRI) infants who failed one or more neonatal testing 3,134 (64%) returned for VRA

43 Screening Test Accuracy for detecting HL > 30 dB HL using VRA MRL, SAT and PTA2 (2 + 4 kHz) and PTA3 (1, 2, 4 kHz) at 8-12mos as gold standard Progressive HL and ME pathology excluded (Norton et al., 2000)

44 Conclusions: Screening Tests (Norton et al., 2000) Screening test failure rate increased as degree of hearing loss increased DP 65/50, TEOAE and ABR similar in identifying HL of moderate degree and greater (PTA2: kHz) Overall poorer performance of DPOAE 75/75 condition

45 Could We Do It With Current Commercially Available Devices?

46 Automated ABR Test Parameters Norton et al Custom-designed system; not available commercially 30 dB nHL clicks –Automated Pass Criterion: Fsp > 3.1 –Visual confirmation of wave V (Observer Based Criteria: OBC) in addition Stimuli calibrated using OAE system & probe –Tester could adjust level with resultant voltage setting for click –Click transduced via OAE probe

47 Commercially-Available Automated ABR Screening Products 5 of 6 manufacturers allow probe/ear canal transducer option –Verify level within tolerance parameters in order to run the test 2 of 6 manufacturers allow either probe/ear canal transducer or circumaural cushion option –Verify level within tolerance parameters in order to run the test

48 Commercially-Available Automated ABR Screening Products 1 manufacturer uses circumaural cushion only –? Verify level 6 of 6 manufactures allow user (administrator) to set stimulus level 3 manufacturers employ some version of Fsp stopping criteria to determine pass/fail 3 manufacturers can meet Norton et al. 2000

49 Distortion Product OAE Test Parameters Norton et al Commercially available product (not screening device) Evoking stimuli: 65/50 dB SPL –Stimulus level (SPL) measured in ear canal prior to test Pass criteria: 3 dB S/N +2 SD (equivalent to 8-10 dB S/N) at 2, 3, & 4 kHz (f2)

50 Commercially-Available DPOAE Screening Products 6 of 9 manufactures allow either the user or administrator to set stimulus levels and/or pass-fail criteria 3 manufacturers ship to purchaser without a way to change levels or pass- fail criteria 6 manufacturers can meet Norton et al criteria

51 Transient OAE Test Parameters Norton et al Commercially available product (not screening device) Evoking stimulus: 80 dB pSPL click –Stimulus level (SPL) measured in ear canal prior to test Pass criteria: S/N = 3 dB at 1.5 kHz; 6 dB at 2, 3, & 4 kHz bandwidths

52 Commercially-Available TEOAE Screening Products 5 manufactures have available screening products Products cannot be changed re: stimulus level or pass/fail criteria 5 manufacturers can meet Norton et al criteria

53 Lacking A National or Agreed-Upon Standard – What Else Should You Look for in Selecting Screening Devices?

54 Considerations for Product Purchase Stand alone device: 1 technology –With true database management –Without true database managment Combination device: OAE/ABR –With database management –Without database management Ease of use Cost of instrument & disposables Flexibility Durability Maintenance Service, support & training

55 Suggestions for How Screening Programs Can select an Appropriate Device Decide what you want to screen for (sensory, neural, mild HL, etc.) Consider the screening environment and screening personnel Require manufacturers specifications to reflect all stimulus parameters and pass/fail criteria Have a evidence-base for selection of screening parameters and pass/fail criteria

56 Your Questions and Comments


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