Voice production Larynx and the vocal folds ARTICULATION PHONATION - - PDF document

M Södersten, Karolinska Institutet, Rekjavik, Oct 12, 2012 1

Voice production and teachers’ voice disorders How does the voice work and what makes it to fail?

Södersten Maria

Speech therapist, PhD, Associate prpfessor

1Speech Language Pathology, Karolinska university Hospital 2Division of Speech Pathology, Clintec, Karolinska Institutet

Reykjavik October 12 2012

Speech language pathologists ENT/phoniatricians Engineer ”Voice team” Karolinska University Hospital and Karolinska Institute

KTH

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Voice production

ARTICULATION PHONATION BREATHING

Sundberg, 2001

Larynx and the vocal folds

(Lena Lyons efter CIBA, The larynx)

Structure of a vocal fold

Hirano et al, 1983

Epithelium Superficial layer Intermediate layer Deep layer Muscle Vocalis Lamina propria GOOD FOR VIBRATIONS Demonstration

M Södersten, Karolinska Institutet, Rekjavik, Oct 12, 2012 2

How fast do the vocal folds vibrate ? Women Men

Vocal fold vibrations/sec (Hz) 200 100 Total amount of vibrations 1 minute 12 000 6000 Teachers vocal fold vibrate ca 20-30 % during work 1-2 miljon vibrations / working day

Hunter, Titze 2009; 2010; Lyberg Åhlander, 2011; Morrow, Connor 2010; Rantala, Vilkman 1999; Titze m fl 2007)

Too much voice use may cause:

• Damage to the

lamina propria due to mechanical forces

• Fatigue in the Vocalis

muscle

e.g., Chang Karnell 2004; Titze 1994;

Voice activity and voice rest

Hypothesis: The more loading the longer recovery is needed. Important with voice rest and pauses for teachers

(Titze 1999)

Teachers and pre-school teachers

Quality Vocal loading Occupation

High High Actors and classical singers High Average Radio- and TV journalists Average High Teachers, pre-school teachers, telemarketers, priests Average Average Bank-, lawers, doctors, nurses Low High Industrial workers

(After Vilkman 2000)

Demands on voice quality and vocal loading in different occupations

Questionnaires Prevalence: 11% n=1234 (Roy et al, 2004; 2005) 13 % n= 467 (Lyberg Åhlander et al 2010) 29 % n= 241 (Simberg et al 2001)

(e g., Gotaas, & Starr 1993; Ohlsson, 1988; Pekkarinen, m. fl., 1992; Russell, m. fl., 1998; Sapir, m. fl., 1993; Smith, m. fl., 1997; 1998)

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Voice problems in teachers ?

M Södersten, Karolinska Institutet, Rekjavik, Oct 12, 2012 3

Prevalence of voice disorders seems to increase

Year Percent teachers with voice problems 1988 12 % 2001 29 %

More pupils in the classes, increased noise levels, increased stress

(Simberg m fl 2005)

Pre-school teachers

High background noise levels, poor room acoustics

(Sala et al 2001; 2002)

High background levels (Södersten et al 2002) Use of a loud voice and extensive voice use (Buekers,

1998; Szabo Leroy, 2004

Teachers in

• music
• sport
• chemistry

higher prevalence of voice symptoms than teachers working in smaller groups (children with special needs)

(Smith m fl 1998, Thibeault m fl 2004)

Voice disorder

When the elaborate function of breathing- phonation-articulation has failed which affects communication (Hammarberg,2008) When the voice does not function according to the needs (Sala et al 2005; Vilkman 2000) Medical diagnosis

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Number of patients in relationship to the number in the population

Occupation % Pat (n=1200) % in Sweden (4.5 milj) All teachers 16.3 5.9 Pre-school teachers 3.1 1.4 Music teachers 1.3 0.2

(Fritzell, 1996)

The most common diagnosis in teachers Acute Laryngitis Functional voice disorder Vocal nodules ♀ ♀ ♀ ♀ > ♂ ♂ ♂ ♂

M Södersten, Karolinska Institutet, Rekjavik, Oct 12, 2012 4

Voice disorders

Symtoms

hoarseness

strain vocal fatigue lump in the throat throat clearing voice is not stable the voice is weak cannot be heard in noisy environments Increase during voice use and decrease in voice rest Consequencies

avoid to speak

avoid working tasks decreased working ability sick leaves avoid social contacts at work and privately cannot work change of occupation

(after Sala et al 2005)

Complex etiology behind voice disorders

(Sala et al 2005; Simberg et al 2009; Södersten, Lindhe 2011; Vilkman 2000; 2004)

Voice disorder

Individual Environmental work related factors

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WORK ENVIRONMENT INDIVIDUAL

Voice rest Background noise Room acoustics Air quality Posture Stress Technical aid

Factors that affect our voice

Genetics Gender Personality Voice training Medication Health, Diseases Vocal demands Life habits Psychosocial sit.

After Sala et al 2005; Simberg et al., 2009; Vilkman 1996; 2004

Physical environmental problems in schools in Sweden

Ventilation % Out doors Cleaning dust Noise, acoustics Inapropriate rooms Traffic Lack of maintenance Temperature Sunprotectio n % Out doors Traffic Lack of maintenance Temperature Sunprotectio n

SWEA, 2006

Teachers who because of noise can’t speak in normal voice intensity >25% of working time

10 20 30 40 50 60 Practical esthetic Primary school Special needs High shool University All % SWEA 2003

Background noise masks speech consequences:

45 dB – speaker starts to raise voice intensity 55 dB – ok for speech communication (1m) 70 dB – loud voice to be heard (1m) 85 dB – have to shout to be heard

Arlinger, 1999

M Södersten, Karolinska Institutet, Rekjavik, Oct 12, 2012 5

Noise Noise + voice Voice? +

Sound-treated booth

• 30
• 20
• 10

10 2000 4000 6000 8000 10000 Hz dB

Booth acoustics

a filter which is exactly like the channel above Voice!

Acquisition

Ternström m fl 2002; 2006; FAS-projekt (2001-0341, 2002-0416)

What happens when one talk in high background/acitivity noise? Speak louder Higher voice pitch

More hyperfunctional and pressed voice

May be hazardous to the voice Summary

Teachers are at risk to develop voice disorders They have extremely high demands on the voice related to their profession Many employers and teachers do not seem to be aware of that To improve vocal health among teachers the knowledge has to increase about voice production, risk factors for voice disorders, and voice ergonomics Prevention (for students during education and courses for working teachers)

Some voice ergonomic recommendations

• Plan the schedule with pauses for voice rest
• Decrease noise levels at the source, try not to be

heard over noise, go closer to the listener

• Drink water, air humidity (elastic vocal folds)
• When you have a cold and are hoarse stay at home

and rest the voice.

• Take early signs of symtoms seriousty
• If you are hoarse more than 2 weeks see a doctor –

important with a medical assessment (laryngologist/phoniatrician)