Musicians and the Prevention of Hearing Loss

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Musicians and the Prevention of Hearing Loss

• Dr. Marshall Chasin, AuD, M.Sc.,
• Reg. CASLPO, Aud(C), Audiologist
• Musicians Clinics of Canada,
• Marshall.Chasin_at_rogers.com
• October 2006

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Musicians Clinics of Canada
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Powerpoints available on

• www.randomizedtimer.net/music

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Special issue on musicians

• Hearing Review, March 2006
• (guest edited by Marshall Chasin)
• www.hearingreview.com

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www.musiciansclinics.com

• Sections on
• Hearing loss FAQs
• Hearing loss prevention articles
• Summary fact sheets (instruments)
• Performing arts injuries
• Links section

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Fligor (2003, 2006)

• Auditory risk assessment of portable compact disc
  players
• On most CD disc players (depending on the type of
  music and the earphone used), caution should be
  exercised above volume 5 or 6.
• One disc player he used (using a vertically
  oriented earphone) yielded excessive outputs even
  when as low as volume 3-4.

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Fligor (2006)
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CD player with Panasonic Supra aural headphones
(Fligor, 2004)
Jazz Rap/ RB Classical Country Pop Adult Dance
Peak SPL 110.8 116.9 96.7 120.7 118.9 121 111.6
Avg dBA 88.5 98.6 79.2 102.8 97.9 105.7 95
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The 60/120 ipod Rule

• The Fligor Rule (2006)
• Maximum settings to obtain 50 maximum dosage
• ipod volume at 60 for 120 minutes
• Depends on earphone used
• Some earphones isolate the ear.
• Some earphones have different electro-acoustic
  characteristics.

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The 60/60 CD Rule

• This is appropriate for CD players
• These are about 3 dB more intense than ipods.
• 60 volume setting for 60 minutes

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Portable music is portable

• The volume control is turned up in the presence
  of background noise
• 50 volume control may be comfortable in quiet,
  but this same comfortable listening level may be
  80 volume in noise.

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Portable music is portable

• The best headphone is one that isolates you
  from the environment
• You wont need to turn up the volume control in a
  noisy place.
• BUT, you also lose warning cues!
• BEWARE!!!

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Zogby International (March 06)

• 69 would turn down the volume
• 42 would listen less often
• 36 would use special (isolator) earphones

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So

• 60/60 rule for CD players
• 60/120 rule for ipods
• Use isolator earphones
• BUT watch out for traffic!

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and another thing

• Use the MP3 players in both ears.
• Some kids use one earphone for them and the other
  for their friend.
• Because of LACK of binaural summation, the volume
  needs to be 6 dB more intense this is equivalent
  to four times the damage.

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Noisy Toys .

• - Can potentially cause hearing loss
• - Acoustic trauma can occur
• Occurs at or near the peak frequency of the
  acoustic signal
• May or may not be at an audiometric frequency so
  can easily miss the loss.

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Jansson and Karlsson (1983)

• Maximum limits for symphony orchestras are
  achieved at anywhere between 10 and 25 hours per
  week of playing.

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Chasin and Chong (1991)

• Levels in excess of 85 dBA were measured even
  during a relatively quiet etude at Canadas
  National Ballet with a peak level of 126 dBA.

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Maximum Levels for Instruments(Wagner Ring
Cycle Camp and Horstman, 1992)
Instrument Peak Level (dB SPL)
French Horn 107
Bassoon 102
Trombone 108
Tuba 110
Trumpet 111
Violin 109
Clarinet 108
Percussion gt120
(Amplified Guitar gt115)
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Chasin (2006)
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With musicians, hearing loss is not as
significant as

• Tinnitus
• Pitch perception problems

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Two Factors Affecting Hearing Loss

• Intensity (dBA)
• Duration (hours)
• . 3 dB exchange rate

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BUT .
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Lindgren and Axelsson (1983)

• Temporary threshold shift was equal in 4 out of
  10 subjects who were exposed to noise and music
  of equal energy, but greater for the noise
  exposure in the other 6 subjects.

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Hörmann et al. (1970)

• Studied the emotional effects on TTS at
  4kHz. rewardgroup had TTS of 12.8
  dB punishment group had TTS of 18.1 dB

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Swanson et al. (1987)

• Studied the effects of liking music on
  TTS Group 1 Liked pop music Group 2
  Disliked pop music TTS (Group 1) lt TTS (Group 2)

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Liking The Music

• Role of efferent pathways
• Musicians have greater efferent suppression than
  non-musicians (Mecheyl et al., 1995, Perrot et
  al., 1999, Brashears et al., 2003)
• Stress resulting in chemical changes in cochlea

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Three Factors Affecting Hearing Loss

• Intensity
• Duration
• Liking the music

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Stapedial Reflex

• Zakrisson et al. (1980) studied unilateral Bells
  Palsy in humans.
• TTS was 10 dB greater in de-innervated ear than
  normally functioning ear.
• Borg et al. (1983) surgically cut stapedius
  muscle unilaterally in rabbits.
• PTS was 30 dB greater in operated ear.

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Stapedial Reflex and Music

• Music is intermittent allows reflex to reset.
• Industrial noise tends to more steady state and
  reflex is only useful for first 10-15 seconds.

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Four Factors Affecting Hearing Loss

• Intensity
• Duration
• Liking the music
• Stapedial reflex

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Individual Factors

• Efferent neurological effects (eg.
  Lonsbury-Martin)
• Musicians have greater efferent suppression than
  non-musicians (Mecheyl et al., 1995, Perrot et
  al., 1999, Brashears et al., 2003)
• Inaccurate patient noise exposure history
• Genetic predisposition (eg. Kujawa)
• Differing bio-chemical cochlear content
• Individual factors
• Environmental contributions (eg. Ototoxicity)
• Availability of oxygen to cochlea

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Effects of Physical Fitness at 4kHz
(Alessio et al., 2002)
Age/Fitness Low Medium High
Teens 2.0 2.2 0.75
50-60 13.5 11.3 13.0
60-80 34.5 21.2 14.2
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Five Factors Affecting Hearing Loss

• Intensity
• Duration
• Liking the music
• Stapedial reflex
• (Individual factors)

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Musicians are slightly less prone to hearing
loss than workers

• Limited duration each week
• Liking the music
• Stapedial reflex
• Intermittent nature of the music
• Effective quiet (critical levels)

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Estimates of Effective Quiet (E.Quiet)
Freq. (Hz) E.Quiet (dBA) Clarinet (dBA) Violin (dBA) Trumpet (dBA)
250 77 72-82 75-84 75-98
500 75-85 73-84 75-87 76-98
1000 81-82 69-81 71-78 70-87
2000 77-78 66-74 70-74 66-77
4000 74-76 56-62 59-65 60-67
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Effective Quiet(note similarity to music
spectrum vs. noise!)
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Rockers less prone to hearing loss!!!

• Hart et al. (1987). Only 30 of rockers had
  hearing loss.
• vs.
• Royster et al. (1991) . 52 for classical music.
• 1. Rockers only are subjected to loud music for
  several hours per week.
• 2. Enjoyment of music
• 3. Stapedial reflex (sings along?)

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How I Assess a Musician

• Routine audiometry (pure tones, speech testing
  and impedance).
• If asymmetries, then ABR/MRI
• - explained (eg. Violins, drummers)
• - unexplained (eg. unrecalled acoustic traumas,
  neuromas)
• Otoacoustic emission testing
• Real Ear Measurement of their instrument

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Audiometric Asymmetries

• Industrial exposure is (usually) symmetrical
• Highly reverberant locations
• Predominantly low-frequency noise
• Music exposure can be asymmetrical
• Low reverberant locations
• Significant mid- and high-frequency music energy
• Head and body shadow effects

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Otoacoustic Emissions(Drummer - symmetrical
hearing)
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Otoacoustic Emissions(Lead singer moved away
from drummer)
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OAE notch at 5000 Hz and not measured on
audiometry...
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AAA poster session on OAEs

• Lisa Battani, Effects of cigarette smoking on
  DPOAE
• Greater effect (reduction) seen in higher
  frequencies.
• Vascular? Ototoxicity?

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Real Ear Measurement

• REM is modified to assess external stimuli
• Disable the reference microphone and disable the
  speaker
• eg. Audioscan stimulus level 0 dB
• Frye stimulus off
• Perform a sweep with a low-frequency, a
  mid-frequency, and a high-frequency sound at
  quiet, medium, and loud levels.

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Real Ear Measurement

• RECALL Unlike noise, music has significant mid-
  and high-frequency energy.
• REM can (should) be performed at TM to take
  advantage of ear canal resonances.
• Music enhanced by 17 dB at 3kHz over sound field.
• Industrial noise is not enhanced in this region
  (except impulse noise).

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What to do with the information?

• The REM data will provide information on the
  relative contribution of noise exposure from that
  instrument.
• Draw a picture of the noise environment, to see
  who else can be the culprit (eg. Drummer to the
  rear?)

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Hearing Protection Alternatives

• ER-15 (1988, Etymotic Research)
• Custom made uniform attenuator provides 15 dB of
  attenuation up to 8000 Hz. It uses an element
  that interacts with an inductance to provide a
  3000 Hz resonance, thus off-setting the loss of
  the ear canal resonance.
• ER-25 (1992)
• Custom made uniform attenuator provides 25 dB of
  attenuation up to 6000 Hz.

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Hearing Protection Alternatives

• ER-15 SP
• Similar to ER-15 but LESS attenuation above 4000
  Hz.
• ER-9
• Custom made uniform attenuator provides 9 dB of
  attenuation.
• ER-20 ( HI-FI)
• Non-custom earplug with a slight high-frequency
  roll-off. Costs about 10-12.

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Hearing Protection Alternatives

• Vented/tuned earplugs
• Similar to filtered earplugs, except uses a SAV
  down the main sound bore. In its most open
  position is acoustically transparent below 1500
  Hz. almost.

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Other Hearing Protection Alternatives

• Other alternatives exist
• Bilsom Natural Sound Technology (NST)
• (Digital) signal processing approaches
• Other vented/tuned approaches
• Variable venting schemes
• Variable (acoustic) filtering schemes

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Earplugs and Auditory Danger
Instrument Danger Earplug
Violin/Viola Violin/Viola ER-15
Woodwinds Percussion ER-15/ vented-tuned
Brass Brass/Percussion ER-15
Percussion Percussion ER-25
Amplified Instruments Loudspeakers/ Drums ER-15
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Verifying Attenuation

• Real Ear Measurement
• REUR - REOR (unaided aided)
• Perform at 70 dB or greater
• Functional attenuation
• Threshold with hearing protector in place
  unaided
• 2 dB steps (standard error 2.8 dB)
• Covering the opening of the hearing protector
• subjective

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14 Year Follow-up for ER-Earplugs

• Survey of 850 earplug recommendations
• 1990 32 decided to get them
• 1995 64 decided to get them
• 1997 72 decided to get them
• 2005 94 decided to get them

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Follow-up for ER-Earplugs

• Survey of 425 users
• 83 still wearing them
• 14 changed to a different type (usually less)
• 3 did not like them (usually French Horn
  players)

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Vented/tuned earplugs

• Resonant Frequency a area
• LoVe
• Improved vocal awareness as frequency of the
  vent resonance is decreased. (decrease area and
  increase L)

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Vented/tuned earplugs
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The wrong hearing protection can be worse than
none at all

• A 25 year old drummer read that he needed to use
  earplugs.
• He started using industrial strength earplugs and
  6 months later noted wrist and arm problems.

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The wrong hearing protection can be worse than
none at all
No hearing protection 103 dB SPL
Industrial protection 113 dB SPL
ER-25 (proper protection) 104 dB SPL
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The wrong hearing protection can be worse than
none at all

• With the ER-25, wrist and arm strain was reduced
• EMG activity returned to normal
• Improved monitoring was the key

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A Study of Conventional Earplugs with Brass
Musicians (Smith and Thelin, 2003)

• With conventional foam earplugs, the playing
  level of brass players increased by 2.2 dB.
• Decreased monitoring ability
• Decreased sound quality because of high-frequency
  loss.

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Acoustic Monitor

• Useful for bass string instruments such as the
  cello and acoustic bass.
• Four feet of 13 hearing aid tubing with an
  adaptor. One end plugs in to the left
  Vented/tuned earplug and the other is inserted in
  the ƒ-hole of the cello or bass.
• Similar to an acoustic stethoscope
• (only less than 10 in parts!)

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Acoustic Monitor
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Bass Shakers
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Baffles

• Baffles have limited usefulness unless they are
  within 7 inches of the ear with optimal
  attenuations being 15-17 dB in the higher
  frequencies.
• (Camp and Horstman, 1992)

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Attenuation from Baffles
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In-The-Ear Monitors

• These are either
• Custom (Futuresonics, Sensaphonics, Westone,
  Ultimate Ear )
• Or
• Non-custom (ER-4, ER-6, Shure, Sennheiser )

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In-The-Ear Monitors (in situ)
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In-The-Ear Monitors (transceiver)

• Transceivers
• Sennheiser
• Shure

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Intensity vs. Loudness

• Our role as hearing health care professionals is
  to delude the musician into thinking that the
  music is sufficiently loud, but at a lower
  intensity level.

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The Zen Of Hearing Loss Prevention

• Maintenance of loudness with reduction of
  intensity

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The Mantra.

• Improved monitoring
• - Bass increase
• - Shakers (ultra-low frequency woofers)
• - In-the-ear monitors
• - Acoustic monitors

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The Big Four

• Moderation
• Humming
• Improved monitoring
• Environmental strategies

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Four Expedient Environmental Techniques to
Reduce Noise/Music Exposure
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1. Speaker/amplifier combinations should be
elevated from the floor.
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Energy Loss with Loudspeaker in Contact with Floor
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2. Strings should always have at least two
meters of unobstructed space above them.
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High Frequency Loss with a Poorly Constructed Pit
Overhang
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3. Two meters of unobstructed floor space in
front of the orchestra.
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Two Meters of Unobstructed Floor Space in Front
of Orchestra
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4. Treble brass instruments should be on risers.
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Loss of Energy for Higher Frequencies at 45
Degrees (low red, mid yellow and high
green frequency)
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Why do you instantly dislike trumpet players?
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Because it saves time
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Marshall.Chasin_at_rogers.comwww.musiciansclinics.c
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