USE OF CORTICAL AUDITORY EVOKED POTENTIALS IN ASSESSMENT OF HEARING AND EVALUATION OF HEARING AIDS

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1 USE OF CORTICAL AUDITORY EVOKED POTENTIALS IN ASSESSMENT OF HEARING AND EVALUATION OF HEARING AIDS Bram Van Dun 1,2, Fabrice Bardy 1,2, Harvey Dillon 1,2, Simone Punch 1,3, Alison King 1,3, Teresa Ching 1,2 1 The HEARing Cooperative Research Centre 2 The National Acoustic Laboratories 3 Australian Hearing BSA 2016, 26 April 2016

2 Disclosure The National Acoustic Laboratories is a division of Australian Hearing, a Statutory Authority of the Australian Government. NAL and the HEARing CRC have licenced some of the IP described in this presentation to Frye Electronics and it is or will be sold in the future as part of the HEARLab TM package. NAL, but not the authors, receives royalties from sale of HEARLab TM 1

3 Cortical Auditory Evoked Potentials: Theory 2

4 First 6 months of life Universal newborn hearing screening After detection of hearing loss Australian Hearing Approximately 400 infants per year Fitted with hearing aids Before 6 months of age Need to evaluate the hearing aid fitting Confirmation of fitting Fine-tuning needed Cochlear implant needed? 3

5 So baby, how does it sound? Objective hearing aid evaluation for: young infants difficult-to-test people 4

6 Why cortical responses to evaluate hearing aid fitting in infants? Dillon, Hear J (2005) 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. Increasing hearing aid gain increases CAEP amplitude Can be very frequency specific if needed Van Dun et al, Semin Hear (2016) The recording equipment doesn t have to be as sensitive 5

7 Drawbacks of CAEPs Influenced by the state of arousal Change dramatically when asleep Variable / unreliable morphology, especially in children Test awake and alert, or at least in a constant state Campbell and Colrain, Int J Psychophys (2002) Rather low sensitivity of CAEPs in infants and young children at low sensation levels (~75% in hearing impaired) Van Dun et al, Audiol Res (2012) Cone et al, Int J Ped ORL (2013) Variety of possible reasons including the cause mentioned above, cortical maturation and speech discrimination Absence of CAEPs across the board is a warning sign 6

8 CAEP origin Amplitude (µv) Infant Cortical Auditory Evoked Potential (CAEP) 10 P1 5 0 N Time (ms) 600 Sound presentation (about 50 ms long) 7

9 Presenting many stimuli and average responses Statistical testing for response detection: Hotelling s T 2 - P-value < 0.05 Response: Present Absent Inconclusive (due to high residual noise) Residual Noise Level for Infant testing: >3.2 uv <3.2 uv 8

10 Using CAEPs in a paediatric clinical environment 9

11 How do we measure CAEPs? Speech sounds (20-30 ms) 55, 65, 75 db SPL /m/ /g/ /t/ Free Field Speaker 3 electrodes are placed on the head (the same as for ABR) Forehead Vertex Baby sits on parent s lap or in a high-chair in front of the speaker Behind the ear 10

12 An example 11

13 Cortical testing & Australian Hearing Clinical protocol rolled out in Now downloadable from hearlab.nal.gov.au or Punch et al., Semin Hear (2016) Majority of hearing aid fittings is evaluated using CAEPs within 8 weeks after fitting. Currently 25 paediatric centres in Australian Hearing, and about 10 more outside AH 12

14 Clinical pathway at Australian Hearing 2 WEEKS 4-6 WEEKS SNHL ANSD Fit aids based upon ABR, ASSR. Fitting for ANSD based on behavioural tests, PEACH and unaided CAEPs. Match targets for all 3 input levels Follow up Aided CAEPs + adjust aid if required SNHL: sensorineural hearing loss ANSD: auditory neuropathy spectrum disorder ABR: auditory brainstem response ASSR: auditory steady-state response PEACH: Parents Evaluation Aural/Oral Performance of Children 13

15 Decision matrix 65 db SPL Resp. to 65dBSPL? Y Resp. to 55dBSPL? Y Aid settings appropriate. N Does speechogram predict audibility? Y Re-estimate audiogram (1SD) and retest if desired N Performance is as expected. 14

16 No 65 db SPL Resp. to 65dBSPL? N Resp. to 75dBSPL? Y Increase estimate of threshold by 1 SD & adjust aid if desired. N Increase estimate to 1.5 SD and adjust HA. Resp. to 75dBSPL? Y Y if desired. 15

17 No 75 db SPL Resp. to 75dBSPL? N Undertake PEACH or TEACH Indicates hearing responses? Y Don't adjust aid any further. Monitor closely N Discuss CI referral We re currently working on an update which requires less CAEP testing, and which is based on work described in Ching et al., Semin Hear (2016). 16

18 Case 1: HA fitting over multiple visits (1) Estimated Audiogram (db HL) at Visit Hz 1000 Hz 2000 Hz 4000 Hz Visit 1 (65 db) Right Left SD = 10 db Estimated Audiogram (db HL) at Visit Hz 1000 Hz 2000 Hz +1.5 SD = 15 db 4000 Hz Right Left

19 Case 1: HA fitting over multiple visits (2) Visit 1 (65 db SPL) Visit 2 (65 db SPL) 75 db SPL tested as all CAEPs present at 65 db SPL 55 db SPL not tested as not all CAEPs present at 65 db SPL 18

20 Case 2: Potential CI referral Visit 3, so far hearing aid has been adjusted twice Estimated Audiogram (db HL) at Visit Hz 1000 Hz 2000 Hz 4000 Hz Right Left

21 Case 3: ANSD FREQUENCY (Hz) m g t VRA 9 mo CAEP 3 mo ABR (CM only) ABR (CM only) ABR 1 mo - NR 20

22 Weeks after first hearing aid fitting 21

23 Using CAEPs with CI users Vicky Zhang Van Dun et al. (in prep) 22

24 Starting from the clinical end Single-channel clinical CAEP recording system Extending use towards cochlear implants Other methods like ECAPs (through e.g. NRT) Not so reliable Only evaluates early part of auditory system Current research varies in clinical applicability Gilley et al. (2006): use of 64 channel electrode cap + ICA Friesen et al. (2010): different interstimulus intervals Mc Laughlin et al. (2013): single channel high-sample Visram et al. (2015): 64 chan cap + direct stim + thresholds 23

25 Longterm clinical aim Using CAEPs Determine T- and C- levels for individual electrodes Evaluate and fine-tune CI fittings using broadband stimuli (e.g., speech) 24

26 Problem CI artefact grand average 1125 ms CI artefact Time ongoing EEG 25

27 CAEP presence (%) Prevalence of CAEPs M G T BRAND 1 BRAND 2 BRAND 3 Audible, ~65 db SPL, ~30-40 db SL False positive rate Stimuli Devices *** 26

28 Prevalence of CI artefacts CI artefact presence (%) M G T BRAND 1 BRAND 2 BRAND 3 Inaudible, ~65 db SPL, <0 db SL. Large artefacts only *** False positive rate Stimuli Devices 27

29 Julie Kosaner (Medel, Turkey) Recorded clinically using the HEARLab system (one channel, 3 electrodes) Kosaner et al. (in prep) CI = 45, 1-4 yrs NH = 20, 1-4 yrs 28

30 IDEAL Study Infant Discrimination and Early Acquisition of Language Fabrice Bardy Teresa Ching Vicky Zhang Cara Wong 29

31 Aims Objective and behavioural measures of early auditory speech discrimination predicting language skills at 3 years of age A validated clinical tool to assess early-life speech discrimination Why? Do we implant or not? < 60 db HL: no > 85 db HL: yes Between 60 and 85 db HL:? 30

32 Study design Study on 100 hearing-impaired children 3 12 months 36 ± 3 months ACC speech discrimination behavioural speech discrimination degree of hearing loss age of fitting communication mode maternal education socio-economic advantage gender presence of Auditory Neuropathy Spectrum Disorder predict Language score based on: PEACH PLS-4 Plural learning DEAP 31

33 Contrast 1: /u/ vs /i/ Vowel place discrimination silence (1.0 s) 1.5 s 1.5 s 0.5 s /u/ /i/ /u/ Presented at 20 sones (~ db SPL) silence (1.0 s) P1 P2 P1 P2 P1 P2 P1 P2 N1 response to onset N1 response to change (ACC) N1 N1 response to offset 32

34 Contrast 2: /s/ vs /z/ Voicing contrast discrimination P1 P2 P1 P2 P1 P2 response to onset N1 N1 response to change (ACC) N1 N1 response to offset 33

35 Contrast 3 & Current results Contrast 3: Spectral Ripple Noise Assesses spectral resolution ACC Number of HI babies tested Sensitivity (%) Specificity (%) /u/ vs /i/ / 11 = 96 % 9 / 11 = 82 % /s/ vs /z/ 11 8 / 11 = 73 % 11 / 11 = 100 % SRN 10 7 / 10 = 70 % 11 / 11 = 100 % 34

36 References Campbell, K. B., & Colrain, I. M. (2002). Event-related potential measures of the inhibition of information processing: II. The sleep onset period. International Journal of Psychophysiology, 46(3), Cone, B., & Whitaker, R. (2013). Dynamics of infant cortical auditory evoked potentials (CAEPs) for tone and speech tokens. International journal of pediatric otorhinolaryngology, 77(7), Ching, T., Zhang, V., Hou, S., and Van Buynder, P. (2016) Cortical auditory evoked potentials (CAEPs) reveal changes in audibility with nonlinear frequency compression in hearing aids for children: clinical implications. Seminars in Hearing, 37, Dillon, H. (2005). So, baby, how does it sound? Cortical assessment of infants with hearing aids. The Hearing Journal, 58(10), Friesen, L. M., & Picton, T. W. (2010). A method for removing cochlear implant artifact. Hearing research, 259(1), Gilley, P. M., Sharma, A., Dorman, M., Finley, C. C., Panch, A. S., & Martin, K. (2006). Minimization of cochlear implant stimulus artifact in cortical auditory evoked potentials. Clinical Neurophysiology, 117(8), Mc Laughlin, M., Valdes, A. L., Reilly, R. B., & Zeng, F. G. (2013). Cochlear implant artifact attenuation in late auditory evoked potentials: A single channel approach. Hearing research, 302, Punch, S., Van Dun, B., King, A., Carter, L. and Pearce, W. (2016). Clinical experience of using cortical auditory evoked potentials (CAEPs) in the treatment of infant hearing loss in Australia. Seminars in Hearing, 37, Van Dun, B., Carter, L., & Dillon, H. (2012). Sensitivity of cortical auditory evoked potential detection for hearing-impaired infants in response to short speech sounds. Audiology research, 2(1). Van Dun, B., Kania, A., and Dillon, H. (2016). Cortical auditory evoked potentials (CAEPs) in (un)aided normal-hearing and hearing-impaired adults. Seminars in Hearing, 37, Visram, A. S., Innes-Brown, H., El-Deredy, W., & McKay, C. M. (2015). Cortical auditory evoked potentials as an objective measure of behavioral thresholds in cochlear implant users. Hearing research, 327,

37 The HEARing CRC Member Organisations This research was financially supported by the HEARing CRC established and supported under the Australian Government s Cooperative Research Centres Program 36