linical & Experimental Audiology 1 Otoacoustic Emissions in Monitoring NIHL for Professional Musicians: A 2-Year Follow-up Study Annual NHCA Conference, 20 February 2016 Hilde Eising, MSc. Hiske W. Helleman, MSc. Prof. Wouter A. Dreschler Academic Medical Centre, Amsterdam, The Netherlands

linical & Experimental Audiology 2 Content  Professional musicians from 3 symphonic orchestras  2 years of (music) noise exposure  Audiometry  Otoacoustic emissions (OAEs)

linical & Experimental Audiology 3 Content  Background Otoacoustic emissions (OAEs) Noise exposure in a symphonic orchestra  What do we know from literature? OAEs versus audiometry  OAEs in monitoring NIHL for professional musicians: Research questions Preliminary results  Discussion

linical & Experimental Audiology 4 Background - Noise induced hearing loss  Noise effects outer hair cells first  ‘Noise notch’ around 4-6 kHz visible in the audiogram  Often accompanied by tinnitus

linical & Experimental Audiology 5 Background - Otoacoustic emissions (OAE)  Gives information about functioning of outer hair cells  Neonatal hearing screening (PASS / REFER)  Requires ‘clear’ signal above noise floor speaker microphone

linical & Experimental Audiology 6 Background - Otoacoustic emissions (OAE)  Now: audiometry is gold standard  OAEs in occupational hearing programs?  Why OAEs? Objective Fast Easy to operate ? Detect pre-clinical damage? ? Predict individual susceptibility to NIHL?

linical & Experimental Audiology 7 Background – Noise exposure of musicians Average daily noise exposure:  Depends on factors like repertoire, arrangement, acoustical circumstances, conductor  Exceeds the European guidelines for exposure to sound in a professional environment ~80 dB(A) ~88 dB(A) ~85 dB(A) Source: ‘Onderzoek schadelijk geluid orkesten’, Peutz & Associés, 2003.

linical & Experimental Audiology 8 Background – Noise exposure of musicians  Audiograms show notches Corrected for age and gender (ISO 7029) Jansen E.J. et al Noise induced hearing loss and other hearing complaints among musicians of symphony orchestras. Int Arch Occup Environ Health, 82, 2, 153–164.

linical & Experimental Audiology 9 Background – Noise exposure of musicians  Audiograms show notches  Complaints about tinnitus (51%) and hyperacusis (79%) More than could be expected in the general population Jansen E.J. et al Noise induced hearing loss and other hearing complaints among musicians of symphony orchestras. Int Arch Occup Environ Health, 82, 2, 153–164.

linical & Experimental Audiology 10 Background – Noise exposure of musicians  Audiograms show notches  Complaints about tinnitus (51%) and hyperacusis (79%)  Regular use of (mostly disposable) hearing protection during: Orchestra repetitions: 52% Concerts: 29% Jansen E.J. et al Noise induced hearing loss and other hearing complaints among musicians of symphony orchestras. Int Arch Occup Environ Health, 82, 2, 153–164.

linical & Experimental Audiology 11 OAEs: What do we know from literature?  Longitudinal studies No clear relation between changes in audiometry and OAE  e.g. Moukos et al. 2014, Helleman et al. 2012, Marshall et al. 2009, Lapsley-Miller et al Low-level, absent or abnormal OAEs might indicate an increased risk of future NIHL  Lapsley-Miller et al. 2006, Shupak et al. 2007, Duvdevany et al. 2007, Job et al. 2009, Marshall et al. 2009

linical & Experimental Audiology 12 In progress: systematic literature review  Why? Limited amount of longitudinal studies  Published literature is inconsistent Study duration OAE stimulus parameters Study population …  However, OAEs are promoted in occupational health programs..  ‘Otoacoustic emissions: a new gold standard for early detection of hearing loss’

linical & Experimental Audiology 13 In progress: systematic literature review  Inclusion criteria Subjects exposed to noise OAE and audiometry measured at baseline and at least 1 follow-up  ‘long term effects’ (permanent threshold shifts, PTS)  ‘short term effects’ (temporary threshold shifts, TTS) Prospero registration nr.: CRD abstracts screened 114 full text screened 63 excluded 51 included In review Duplicates removed 37 ‘short-term’ effects 14 ‘long-term’ effects 525 excluded

linical & Experimental Audiology 14 Otoacoustic Emissions in Monitoring NIHL for Professional Musicians: A 2-Year Follow-up Study Work in progress

linical & Experimental Audiology 15 Method  60 professional musicians from 3 symphonic orchestras 34 Male, 26 Female Median age: 42, range  2 measurements, ~2 years apart Baseline Follow-up  Audiometry (250 Hz - 8 kHz), air conduction  TEOAE (5 frequency bands: 1-4 kHz)  DPOAE (27 frequencies: kHz, 1 / 8 oct)  Tympanometry / otoscopic inspection  All tests performed at audiological department of AMC

linical & Experimental Audiology 16 Research questions 1.Is the effect of approximately two years of noise (music) exposure measurable using audiometry, TEOAE and DPOAE 2.Are individual cases of noise induced audiometric threshold shift associated with emission shift? 3.Are we able to predict which persons have increased risk of future hearing loss based on initial OAEs?

linical & Experimental Audiology 17 Research questions 1.Is the effect of approximately two years of noise (music) exposure measurable using audiometry, TEOAE and DPOAE 2.Are individual cases of noise induced audiometric threshold shift associated with emission shift? 3.Are we able to predict which persons have increased risk of future hearing loss based on initial OAEs?

linical & Experimental Audiology 18 Preliminary remark How you usually look at an audiogram

linical & Experimental Audiology 19 Preliminary remark How you usually look at an audiogram

linical & Experimental Audiology 20 Preliminary remark How I will show you this audiogram today

linical & Experimental Audiology 21 Mean results at baseline – right versus left Right Left At baseline: Audiometry: the left ear is slightly worse than right at high frequencies

linical & Experimental Audiology 22 Mean results at baseline – right versus left Right Left At baseline: Audiometry: the left ear is slightly worse than right at high frequencies OAEs: left ear has lower amplitudes in mid frequencies

linical & Experimental Audiology 23 Mean results at baseline and follow-up Baseline Follow-up Group results show changes in audiometry, TEOAE and DPOAE

linical & Experimental Audiology 24 Mean change – group Change AudiometryTEOAEDPOAE -Overall trend decrease -Deterioration mostly at 4-8 kHz -Deterioration at mid frequencies (~2 kHz) -Deterioration mid frequencies (~2-4 kHz) -Improvement low/high Audiometry compared to OAE: different frequency area Deterioration

linical & Experimental Audiology 25 Research questions 1.Is the effect of approximately two years of noise (music) exposure measurable using audiometry, TEOAE and DPOAE 2.Are individual cases of noise induced audiometric threshold shift associated with emission shift? 3.Are we able to predict which persons have increased risk of future hearing loss based on initial OAEs?

linical & Experimental Audiology 26 Threshold shift versus emission shift Shift  Audiometry: 4-6 kHz  TEOAE: overall  Relation between threshold shift and emission shift? Audiometry TEOAE

linical & Experimental Audiology 27 Threshold shift versus emission shift

linical & Experimental Audiology 28 Threshold shift versus emission shift TS- No TS-

linical & Experimental Audiology 29 Threshold shift versus emission shift ES-No ES- TS- No TS-

linical & Experimental Audiology 30 Threshold shift versus emission shift ES-No ES- TS- No TS- No ES- TS- & ES-

linical & Experimental Audiology 31 Threshold shift versus emission shift ES-No ES- TS- No TS- No ES- Enhanced sensitivity of OAE’s? TS- & ES-

linical & Experimental Audiology 32 Threshold shift versus emission shift ES-No ES- TS- No TS- No ES- Enhanced sensitivity of OAE’s? Were OAEs already decreased? TS- & ES-

linical & Experimental Audiology 33 Threshold shift versus emission shift Overall observations:  Small number of threshold or emission shifts  No clear relation between changes in audiometry and OAE

linical & Experimental Audiology 34 Threshold shift versus emission shift ES-No ES- TS- No TS- Predict?

linical & Experimental Audiology 35 Research questions 1.Is the effect of approximately two years of noise (music) exposure measurable using audiometry, TEOAE and DPOAE 2.Are individual cases of noise induced audiometric threshold shift associated with emission shift? 3.Are we able to predict which persons have increased risk of future hearing loss based on initial OAEs?

linical & Experimental Audiology 36 Individual threshold shifts  How to define individual threshold shift?

linical & Experimental Audiology 37 Individual threshold shifts Two groups:  ‘Change’. Mean age: 42 (range 24-64). N=17 RightLeftTotal ChangeN=10N=7N=17

linical & Experimental Audiology 38 Individual threshold shifts Two groups:  ‘Change’. Mean age: 42 (range 24-64). N=17  ‘No change’. Mean age: 46 (range 32-64). N=103 RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103

linical & Experimental Audiology 39 ‘No change’ – shift RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103

linical & Experimental Audiology 40 ‘Change’ versus ‘No Change’ – shift RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103 Audiometry: Clear difference between groups TEOAE  Largest shift ~2 kHz DPOAE  Largest shift kHz.  Very low and high frequencies less reliable

linical & Experimental Audiology 41 ‘Change’ versus ‘No Change’ – at baseline RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103 Did these groups differ at baseline?

linical & Experimental Audiology 42 ‘Change’ versus ‘No Change’ – at baseline RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103 Audiometry: No difference between groups

linical & Experimental Audiology 43 ‘Change’ versus ‘No Change’ – at baseline Audiometry: No difference between groups OAEs ‘Change group’ shows higher amplitudes ~ kHz and lower amplitudes in high frequency range. Different ‘shape’ of OAE amplitude spectra RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103

linical & Experimental Audiology 44 Take home messages 1.Group results Small but consistent differences between baseline and follow-up OAEs show changes in other frequency area than PTA 2.Individual results Small number of ears with emission shift or threshold shift No clear relation between emission shift and threshold shift 3.Predictive value We observe intriguing differences in baseline OAEs when comparing groups of ears with and without threshold shift Future (statistical) analysis will clarify whether OAEs have a predictive value in individual cases of NIHL

linical & Experimental Audiology 45 Acknowledgements  The participants from 5 Dutch symphonic orchestras Koninklijk Concertgebouworkest Nederlands Philharmonisch Orkest Holland Symfonia Het Gelders Orkest Residentie Orkest  Colleagues at AMC

linical & Experimental Audiology 46 Thank you for you attention! Questions? Hilde Eising, MSc.

linical & Experimental Audiology 47 Method  Audiometry Interacoustics AC40 audiometer with TDH39 headphones Calibrated according to ISO 389 Sound–isolated booth  TEOAE (Otodynamics ILO 292) 80 dB SPL click Non-linear Half-octave frequency band (1, 1.5, 2, 4 and 4 kHz)  DPOAE (Otodynamics ILO 292) L1=75 dB SPL, L2=70 dB SPL  at follow-up also L1=65 dB SPL and L2=55 dB SPL f2/f1=1.22 Measured at 27 f2 frequencies (815 to 8000 Hz) (8 points per octave)

linical & Experimental Audiology 48 Statistical analysis  Goal: to describe the observed effects in a correct way  Linear mixed effects model Controlling for ear, age, gender, hearing threshold at baseline

linical & Experimental Audiology 49 OAEs: What do we know from literature?  Cross-sectional studies Lower OAE levels associated with poorer audiometric thresholds  e.g. Attias et al. 2001, Mansfield et al Noise exposed people have lower OAE amplitudes than non-exposed people with similar audiometric thresholds  e.g. Murray et al. 1993, Attias et al. 2001, Desai et al  What are ‘similar thresholds’?

linical & Experimental Audiology 50 ‘Change’ versus ‘No Change’ – at follow-up RightLeftTotal ChangeN=10N=7N=17 No changeN=50N=53N=103

linical & Experimental Audiology 51 Mean results baseline – male versus female Male Female Male: better thresholds <3 kHz. Female: generally higher OAE amplitudes

linical & Experimental Audiology 52 Only NH ears - baseline No changeChangeTotal NHN=62N=20N=82 RestN=28N=10N=38 TotalN=90N=30N=120

linical & Experimental Audiology 53 Only NH ears - change

linical & Experimental Audiology 54 Case study – patient nr