Voice production. M Södersten, Karolinska Institutet, Rekjavik, Oct 12, Larynx and the vocal folds. Structure of a vocal fold

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1 Voice team Karolinska University Hospital and Karolinska Institute Voice production and teachers voice disorders How does the voice work and what makes it to fail? Södersten Maria Speech therapist, PhD, Associate prpfessor 1 Speech Language Pathology, Karolinska university Hospital Division of Speech Pathology, Clintec, Karolinska Institutet Reykjavik October 1 01 Speech language pathologists ENT/phoniatricians Engineer KTH Voice production Larynx and the vocal folds ARTICULATION PHONATION BREATHING Sundberg, 001 (Lena Lyons efter CIBA, The larynx) Structure of a vocal fold Demonstration Epithelium Superficial layer Intermediate layer Deep layer Muscle Vocalis Lamina propria GOOD FOR VIBRATIONS Hirano et al,

2 How fast do the vocal folds vibrate? Women Men Vocal fold vibrations/sec (Hz) Total amount of vibrations 1 minute Teachers vocal fold vibrate ca 0-30 % during work 1- miljon vibrations / working day Too much voice use may cause: Damage to the lamina propria due to mechanical forces Fatigue in the Vocalis muscle Hunter, Titze 009; 010; Lyberg Åhlander, 011; Morrow, Connor 010; Rantala, Vilkman 1999; Titze m fl 007) e.g., Chang Karnell 004; Titze 1994; Voice activity and voice rest Teachers and pre-school teachers Hypothesis: The more loading the longer recovery is needed. Important with voice rest and pauses for teachers (Titze 1999) Demands on voice quality and vocal loading in different occupations Voice problems in 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 000) Questionnaires Prevalence: 11% n=134 (Roy et al, 004; 005) 13 % n= 467 (Lyberg Åhlander et al 010) 9 % n= 41 (Simberg et al 001) (e g., Gotaas, & Starr 1993; Ohlsson, 1988; Pekkarinen, m. fl., 199; Russell, m. fl., 1998; Sapir, m. fl., 1993; Smith, m. fl., 1997; 1998) 1

3 Prevalence of voice disorders seems to increase Year Percent teachers with voice problems % % Pre-school teachers High background noise levels, poor room acoustics (Sala et al 001; 00) High background levels (Södersten et al 00) Use of a loud voice and extensive voice use (Buekers, 1998; Szabo Leroy, 004 More pupils in the classes, increased noise levels, increased stress (Simberg m fl 005) Teachers in music sport chemistry higher prevalence of voice symptoms than teachers working in smaller groups (children with special needs) Voice disorder When the elaborate function of breathingphonation-articulation has failed which affects communication (Hammarberg,008) When the voice does not function according to the needs (Sala et al 005; Vilkman 000) Medical diagnosis (Smith m fl 1998, Thibeault m fl 004) Number of patients in relationship to the number in the population The most common diagnosis in teachers Acute Laryngitis Occupation % Pat (n=100) % in Sweden (4.5 milj) All teachers Functional voice disorder Vocal nodules > Pre-school teachers Music teachers (Fritzell, 1996) 17 3

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 005) Complex etiology behind voice disorders Individual Voice disorder Environmental work related factors (Sala et al 005; Simberg et al 009; Södersten, Lindhe 011; Vilkman 000; 004) Factors that affect our voice WORK ENVIRONMENT INDIVIDUAL Vocal demands Health, Diseases Voice rest Medication Background noise Life habits Room acoustics Personality Air quality Psychosocial sit. Posture Voice training Stress Gender Technical aid Genetics After Sala et al 005; Simberg et al., 009; Vilkman 1996; Physical environmental problems in schools in Sweden Ventilation Temperature Out doors Cleaning dust Noise, acoustics Inapropriate rooms Traffic Lack of maintenance Sunprotectio n SWEA, 006 % Teachers who because of noise can t speak in normal voice intensity >5% of working time Background noise masks speech consequences: All University High shool Special needs Primary school 45 db speaker starts to raise voice intensity 55 db ok for speech communication (1m) 70 db loud voice to be heard (1m) Practical esthetic % SWEA db have to shout to be heard Arlinger,

5 Basic idea Noise Booth acoustics 10 db Sound-treated booth a filter which is exactly like the channel above Noise + voice + Voice? Voice! What happens when one talk in high background/acitivity noise? Speak louder Higher voice pitch More hyperfunctional and pressed voice -30 Acquisition 0 Hz Ternström m fl 00; 006; FAS-projekt ( , ) 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 weeks see a doctor important with a medical assessment (laryngologist/phoniatrician) 5