musicians and the prevention of hearing loss dr. marshall chasin, aud, m.sc., reg. caslpo, aud(c),...
TRANSCRIPT
Musicians and the Prevention Musicians and the Prevention of Hearing Lossof Hearing Loss
Dr. Marshall Chasin, AuD, M.Sc.,
Reg. CASLPO, Aud(C), Audiologist
Musicians’ Clinics of Canada,
October 2006
Musicians’ Clinics of CanadaMusicians’ Clinics of Canada
Powerpoints available on …Powerpoints available on …
www.randomizedtimer.net/music
Special issue on musiciansSpecial issue on musicians
Hearing Review, March 2006– (guest edited by Marshall Chasin)– www.hearingreview.com
www.musiciansclinics.comwww.musiciansclinics.com
Sections on:
Hearing loss FAQs
Hearing loss prevention articles
Summary fact sheets (instruments)
Performing arts injuries
Links section
Fligor (2003, 2006)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.
Fligor (2006)Fligor (2006)
CD player with Panasonic Supra CD player with Panasonic Supra aural headphones (Fligor, 2004)aural headphones (Fligor, 2004)
Jazz Rap/
R&B
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
The 60/120 ipod RuleThe 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.
The 60/60 CD RuleThe 60/60 CD Rule
This is appropriate for CD playersThese are about 3 dB more intense than
ipods.“60% volume setting for 60 minutes”
Portable music is portable…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.
Portable music is portable…Portable music is portable…
The “best” headphone is one that isolates you from the environment…
You won’t need to turn up the volume control in a noisy place.
BUT, you also lose warning cues!
BEWARE!!!
Zogby International (March ’06)Zogby International (March ’06)
69% would turn down the volume
42% would listen less often
36% would use special (isolator) earphones
So …So …
60/60 rule for CD players
60/120 rule for ipods
Use isolator earphones
BUT watch out for traffic!
… … and another thing…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.
Noisy Toys ….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.
Jansson and Karlsson (1983)Jansson and Karlsson (1983)
Maximum limits for symphony orchestras are achieved at anywhere between 10 and 25 hours per week of playing.
Chasin and Chong (1991)Chasin and Chong (1991)
Levels in excess of 85 dBA were measured even during a relatively quiet etude at Canada’s National Ballet with a peak level of 126 dBA.
Maximum Levels for InstrumentsMaximum Levels for Instruments(Wagner Ring Cycle: Camp and Horstman, 1992)(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 >120
(Amplified Guitar >115)
Chasin (2006)Chasin (2006)
With musicians, hearing loss With musicians, hearing loss is not as significant as …is not as significant as …
Tinnitus
Pitch perception problems
Two Factors Affecting Hearing LossTwo Factors Affecting Hearing Loss
Intensity (dBA)
Duration (hours)
……. 3 dB exchange rate
BUT ……….BUT ……….
Lindgren and Axelsson (1983)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.
HHöörmann et al. (1970)rmann et al. (1970)
Studied the emotional effects on TTS at 4kHz.
“reward”group had TTS of 12.8 dB“punishment” group had TTS of 18.1 dB
Swanson et al. (1987)Swanson et al. (1987)
Studied the effects of liking music on TTSGroup 1: Liked pop musicGroup 2: Disliked pop music
TTS (Group 1) < TTS (Group 2)
Liking The MusicLiking 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
Three Factors Affecting Hearing LossThree Factors Affecting Hearing Loss
Intensity
Duration
“Liking the music”
Stapedial ReflexStapedial Reflex
Zakrisson et al. (1980) studied unilateral Bell’s 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.
Stapedial Reflex and MusicStapedial 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.
Four Factors Affecting Hearing LossFour Factors Affecting Hearing Loss
Intensity
Duration
“Liking the music”
Stapedial reflex
Individual FactorsIndividual 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
Effects of Physical Fitness at 4kHz Effects of Physical Fitness at 4kHz (Alessio et al., (Alessio et al.,
2002)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
Five Factors Affecting Hearing Five Factors Affecting Hearing LossLoss
Intensity
Duration
“Liking the music”
Stapedial reflex
(Individual factors)
… … Musicians are “slightly” less prone Musicians are “slightly” less prone to hearing loss than workers …to hearing loss than workers …
Limited duration each week
Liking the music
Stapedial reflex
Intermittent nature of the music
Effective quiet (critical levels)
Estimates of Effective Quiet (E.Quiet)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
Effective QuietEffective Quiet(note similarity to music spectrum vs. noise!)(note similarity to music spectrum vs. noise!)
74
75
76
77
78
79
80
81
82
0 1000 2000 3000 4000 5000
Frequency (Hz)
Max
imu
m L
evel
s P
rio
r to
T
TS
(d
B S
PL
)
Rockers less prone to hearing loss!!!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?)
How I Assess a MusicianHow 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
Audiometric AsymmetriesAudiometric 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
Otoacoustic EmissionsOtoacoustic Emissions(Drummer - symmetrical “hearing”)(Drummer - symmetrical “hearing”)
Disortion Product OAEs for Mr. WJ.
-20
-10
0
10
20
30
0 2000 4000 6000 8000
Frequency (Hz)
dB
SP
L
Left ear
Right ear
Otoacoustic EmissionsOtoacoustic Emissions(Lead singer moved away (Lead singer moved away
from drummer)from drummer)Mr. GJ initially and after 6 month
recheck
-20
-10
0
10
20
0 5000 10000
Frequency (Hz)
dB
SP
LLeft ear -initially
Right ear -initially
Left ear - after6 monthrecheck
OAE “notch” at 5000 Hz and OAE “notch” at 5000 Hz and not measured on audiometry...not measured on audiometry...
OAE Loss at a Non-Audiometric Frequency
-20
-15
-10
-5
0
5
10
15
0 1000 2000 3000 4000 5000 6000 7000
Frequency (Hz)
dB
SP
L 4 weeks after "TTS"
2 weeks after "TTS"
Day after "loud gig"
AAA poster session on OAEsAAA poster session on OAEs
Lisa Battani, “Effects of cigarette smoking on DPOAE”– Greater effect (reduction) seen in higher
frequencies. Vascular? Ototoxicity?
Real Ear MeasurementReal 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.
Real Ear MeasurementReal 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).
What to do with the information?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?)
Hearing Protection AlternativesHearing 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.
Hearing Protection AlternativesHearing 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.
Hearing Protection AlternativesHearing 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….
Other Hearing Protection Other Hearing Protection AlternativesAlternatives
Other alternatives exist:
– Bilsom “Natural Sound Technology” (NST)
– (Digital) signal processing approaches
– Other vented/tuned approaches Variable venting schemes Variable (acoustic) filtering schemes
Earplugs and Auditory DangerEarplugs 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
Verifying AttenuationVerifying 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
14 Year Follow-up for ER-Earplugs14 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
Follow-up for ER-EarplugsFollow-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)
Vented/tuned earplugsVented/tuned earplugs
Resonant Frequency α area
LoVe
Improved vocal awareness as frequency of the vent resonance is decreased. (decrease area and increase L)
Vented/tuned earplugsVented/tuned earplugs
-20
-15
-10
-5
0
5
10
0 2000 4000 6000 8000 10000
Frequency (Hz)
Rel
ativ
e d
B
The wrong hearing protection can be The wrong hearing protection can be worse than none at all…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.
The wrong hearing protection can The wrong hearing protection can be worse than none at all…be worse than none at all…
No hearing protection 103 dB SPL
“Industrial” protection 113 dB SPL
ER-25
(proper protection)
104 dB SPL
The wrong hearing protection can be The wrong hearing protection can be worse than none at all…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
A Study of Conventional Earplugs A Study of Conventional Earplugs with Brass Musicians with Brass Musicians (Smith and Thelin, 2003)(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.
Acoustic MonitorAcoustic 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!)
Acoustic MonitorAcoustic Monitor
0
5
10
15
20
25
0 500 1000 1500 2000 2500
Frequency (Hz)
Rel
ativ
e d
B
Bass ShakersBass Shakers
BafflesBaffles
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)
Attenuation from BafflesAttenuation from Baffles
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
0 2000 4000 6000 8000 10000
Frequency (Hz)
Rel
ativ
e d
B
In-The-Ear MonitorsIn-The-Ear Monitors
These are either:
Custom (Futuresonics, Sensaphonics, Westone, Ultimate Ear …)
Or
Non-custom (ER-4, ER-6, Shure, Sennheiser …)
In-The-Ear Monitors (in situ)In-The-Ear Monitors (in situ)
In-The-Ear Monitors In-The-Ear Monitors (transceiver)(transceiver)
Transceivers:– Sennheiser– Shure
Intensity vs. LoudnessIntensity 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.
The Zen Of Hearing Loss PreventionThe Zen Of Hearing Loss Prevention
“Maintenance of loudness with reduction of intensity”
The Mantra….The Mantra….
Improved monitoring
- Bass increase
- Shakers (ultra-low frequency woofers)
- In-the-ear monitors
- Acoustic monitors
The Big Four …The Big Four …
Moderation
Humming
Improved monitoring
Environmental strategies
Four Expedient Environmental Four Expedient Environmental
Techniques to Reduce Noise/Music Techniques to Reduce Noise/Music
ExposureExposure
1. Speaker/amplifier combinations 1. Speaker/amplifier combinations should be elevated from the floor.should be elevated from the floor.
Energy Loss with Loudspeaker in Energy Loss with Loudspeaker in Contact with FloorContact with Floor
-7
-6
-5
-4
-3
-2
-1
0
1
2
0 500 1000 1500 2000 2500
Frequency (Hz)
Rel
ativ
e d
B
2. Strings should always have at 2. Strings should always have at least two meters of unobstructed least two meters of unobstructed space above them.space above them.
High Frequency Loss with a Poorly High Frequency Loss with a Poorly Constructed Pit OverhangConstructed Pit Overhang
0
20
40
60
80
100
120
0 1000 2000 3000 4000 5000
Frequency (Hz)
dB
SP
L
3. Two meters of unobstructed floor 3. Two meters of unobstructed floor space in front of the orchestra.space in front of the orchestra.
Two Meters of Unobstructed Floor Two Meters of Unobstructed Floor Space in Front of OrchestraSpace in Front of Orchestra
-2
-1
0
1
2
3
4
5
6
7
0 1000 2000 3000 4000 5000
Frequency (Hz)
Rel
ativ
e d
B
4. Treble brass instruments should be 4. Treble brass instruments should be on risers.on risers.
Loss of Energy for Higher Loss of Energy for Higher Frequencies at –45 Degrees Frequencies at –45 Degrees
(low [red], mid [yellow] and high [green] frequency)(low [red], mid [yellow] and high [green] frequency)
-10
-8
-6
-4
-2
0
2
0 2000 4000 6000 8000 10000
Frequency (Hz)
Rel
ativ
e d
B
Why do you instantly dislike Why do you instantly dislike trumpet players?trumpet players?
Because it saves time…Because it saves time…
