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HEARLab training Harvey Dillon, Bram Van Dun, Lyndal Carter, Kirsty Gardner-Berry HEARing CRC National Acoustic Labora

INTRODUCTION. NAL: Dillon, Van Dun, Carter, Gardner-Berry. The need for a new measurement tool. NAL: Dillon, Van Dun, Carter, Gardner-Berry. Evaluation of aided functioning in infants. Universal new born screening. . Early fitting of hearing aids. . Need for an evaluation method. NAL: Dillon, Van Dun, Carter, Gardner-Berry.

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HEARLab training Harvey Dillon, Bram Van Dun, Lyndal Carter, Kirsty Gardner-Berry HEARing CRC National Acoustic Labora

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    2. INTRODUCTION

    3. The need for a new measurement tool

    4. Evaluation of aided functioning in infants Universal new born screening

    5. So baby, how does it sound? Objective hearing aid evaluation for: young infants difficult-to-test people

    6. Why the rush? Language ability 6 months after implantation

    7. Early intervention leads to better language development at 6 months after fitting (n=90)

    8. Why use cortical responses?

    9. Why cortical responses to evaluate hearing aid fitting in infants? Reliably present in awake young infants More likely to correlate well with perception Can be elicited by a range of speech phonemes – close to desired outcomes Stimuli handled reasonably by hearing aids Can be very frequency specific if needed

    10. FUNDAMENTALS OF CORTICAL RESPONSES

    12. The end of the road

    13. Auditory cortex orientation

    14. Auditory cortex orientation

    15. Auditory cortex orientation

    17. Cortical responses in adults with normal hearing

    18. Adult

    19. Adult grand mean waveforms at Cz

    20. Cortical responses in infants with normal hearing

    21. Infants

    24. P1 amplitude

    25. Latency versus age

    26. HEARLAB: TECHNICAL OVERVIEW

    27. Practical implementation of cortical testing: HEARLab Disclosure: NAL will get a royalty for each unit sold. Thank you: The HEARLab development team – Teck Loi, Barry Clinch, Isabella Tan, Ben Rudzyn, Lyndal Carter, Dan Zhou, Scott Brewer

    40. Automatic detection of cortical responses

    41. Why automated method? variable shape across ages variable shape with auditory experience variable shape from person to person variable shape from time to time (state of person, especially sleepiness) variable shape with stimulus Variable shape with inter-stimulus interval

    42. Desirable characteristics No reliance on a template Able to use information from contributing portions of waveform Able to discount non-contributing portions of waveform

    43. Each response* is divided into 50 ms time bins (50 – 500 ms) The data points are averaged within each time bin to form 9 variables

    45. Effect of sensation level, hearing loss, and unrelated EEG or muscle noise

    46. Residual noise levels (for 100 epochs)

    47. Growth of amplitude with SL

    48. Conclusions: Detecting cortical response presence Large responses are more easily detected Response amplitude grows with sensation level Response amplitude at low SL is larger for people with sensorineural hearing loss that for people with normal hearing Responses are more easily detected when residual noise is low (<3.4 µV for infants; < 1.5 µV for adults)

    49. CLINICAL USE OF HEARLAB

    50. Equipment configuration and test environment

    51. Equipment configuration

    52. Equipment configuration

    53. CAEP room set-up at the National Acoustic Laboratories

    54. Calibration

    55. Ambient noise measurement

    57. Before the appointment

    59. Preparation for testing

    61. Electrode equipment

    62. Keeping electrodes on the baby using a headband

    64. Conducting a measurement

    81. Keeping the baby awake!

    82. Tools for keeping baby quiet, alert, awake

    83. (More) tools for keeping baby quiet, alert, awake

    84. (Yet more) tools for keeping baby quiet, alert, awake

    87. Finishing up

    89. INTERPRETATION OF THE RESULTS & CLINICAL APPLICATIONS

    90. Estimating hearing thresholds in non-responsive adults Elderly infirm – stroke, dementia Workers’ compensation

    91. Good agreement between CAEP and audiometric thresholds in awake adults

    92. Cortical threshold vs behavioural threshold - adults

    94. Conclusions: Estimating behavioural thresholds in hearing-impaired adults Cortical thresholds overestimate behavioural thresholds by 2.4 dB, on average Standard deviation of cortical – behavioural threshold differences is 6.3 dB About 7% overestimates hearing thresholds severely (by 20 dB or more). Applications: hearing compensation, clients unable to respond

    95. Cortical potentials to assess speech audibility for infants

    96. Clinical implications of corticals Significant response is obtained to speech at 65 dB SPL No significant response is obtained to speech at 65 dB SPL or to speech at 75 dB SPL

    97. Noisy results - chewing

    98. Clinical implications of corticals (cont)

    99. Hearing loss at birth ….. for parents

    101. CASE STUDIES

    102. Case 1 Age at aided cortical testing Visit 1 6 weeks old (Initial hearing aid fitting day) Visit 2 3 months old Subject BR; DOB = 23/02/2009Subject BR; DOB = 23/02/2009

    104. Visit 1

    105. Visit 2

    106. The infant received bilateral cochlear implants at 5 months of age. Email from the baby’s parents ~ “Thank you so much for the information you gave us on the previous testing as it helped us with our decision to proceed with the implants.”

    107. Case 2 Age at aided cortical testing Visit 1 13 weeks old Visit 2 17 weeks old Visit 3 21 weeks old Hearing aid fitting at 8 weeks of age Subject CB; DOB = 28/04/2009Subject CB; DOB = 28/04/2009

    109. Visit 1

    110. Visit 2

    111. Visit 3

    112. The parents still believe that their baby boy can be oral by using hearing aids. They are hoping to see that their baby can benefit from more powerful hearing aids. The baby’s hearing aids were changed from Siemens Explorer 500 P to Phonak Una SP after Visit 3.

    113. Case 3 Age at aided cortical testing Visit 1 4.5 months old Visit 2 5.5 months old Hearing aid fitting at 5 weeks of age Subject XH; DOB = 27/02/2009Subject XH; DOB = 27/02/2009

    115. Visit 1

    116. Visit 2

    118. Case 4 Age at aided cortical testing Visit 1 8 months old Visit 2 9 months old Hearing aids have been increased in gain two weeks before the second visit. Hearing aid fitting at 9 weeks of age Subject WM; DOB = 1/12/2008Subject WM; DOB = 1/12/2008

    120. Visit 1

    121. Case 5 Age at testing: 4.5 years Multiple disabilities A reliable behavioural audiogram has not yet been obtained. Subject MT; DOB = 16/11/2004Subject MT; DOB = 16/11/2004

    122. She was moving all the time.

    123. At her quietest state, but this only lasted for a few seconds.

    124. Cortical testing at 8 months of age, nine days after the initial hearing aid fitting Case 6 Subject WM; DOB = 27/10/2008 Subject WM; DOB = 27/10/2008

    128. Auditory neuropathy

    129. WP ASA 2004 CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided

    130. WP ASA 2004 CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided

    131. WP ASA 2004 CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided

    132. WP ASA 2004 CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided CAEP results different from all other electrophysiological results. Parental report is of seeing responses aided and unaided

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