M Sdersten, Karolinska Institutet, Oct 13, 2012, Rekjavik Voice - - PDF document

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 1

Voice ergonomics work in Sweden. What we have done and what is the need ?

Södersten Maria

Speech therapist, PhD, Associate prpfessor

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

Reykjavik October 13 2012

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

KTH

Södersten M, ELS 2012 2

Content

What has been done in Sweden and what is needed 1 In occupational voice research 2 In clinical work

• 1. Background

Prof Björn Fritzell

Fritzell had a deep interest in the field of voice problems and occupations. 1970’s supervised many theses, e.g., prevalence of voice disorders in different

• ccupational groups.

National study to obtain statistics among patients at the phoniatric departments in Sweden. Based on research he claimed the importance

• f preventive voice care for teachers.

Fritzell B. (1996) Voice disorders and

• ccupations. Log Phon Vocol 2:7-12.

Investigated occupation, age and gender in 1200 patients at their first visit to voice clinics Results Teachers were the largest group of patients. 76 % were women Most common diagnoses:

Phonastenia 72 % women Vocal fold oedema 89 % ” Vocal fold polyp 59 % ” Vocal nodules 97 % ” This study ”repeated” 2011 – same results

Gender differences in voice

Women have

Shorter vocal fold - higher frequency, more vocal fold collisions Shorter vocal tract (the resonance tupe from the vocal folds to the lips) – ”lighter” voice quality and weaker voice Less degree of hyaluronic acid in the vocal folds – less dampening of the vibrations

Work in vocally demanding occupations More vulnerable to voice problems (?)

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 2

Ohlsson A-C. (1988) Voice and work environment: Towards an ecology of vocal behaviour. Doctoral thesis, Gothenburgh University

New: Voice Accumulator

to measure vocal behavior during work for telephone operators, nurses, speech pathologists, welders

• 1. Background

Current research areas

• Long-term measurement of voice with

focus on voice production in high background/actitivity noise (Research group in Stockholm)

• Teachers voice and room acoustics in

schools (Research group in Lund and Denmark)

• Preventive voice care in teachers

(Research group in Gothenburgh) Voice Accumulator – to measure voice use in

• ccupational and non-occupational settings

Ohlsson 1988, Buekers et al 1995; Szabo Leroy 2004; Szabo Portela (submitted)

Subjects 12 vocally healthy pre- school teachers Variables

• Fundamental frequency (Hz)
• Phonation time (s and %)

Diary - activities

Fundamental frequency during and after work

Szabo Portela et al (submitted)

Average fundamental frequency during and after work for healthy pre-school teachers (n=12)

160 180 200 220 240 260 280 300 320 1 2 3 4 5 6 7 8 9 10 11 12 F0 (Hz) At Work After Work

Szabo Portela et al (submitted)

Phonation time in % during and after work for healthy pre-school teachers (n=12)

2 4 6 8 10 12 14 16 18 20 1 2 3 4 5 6 7 8 9 10 11 12 Fonationstid (%) At Work After Work

Szabo Portela et al (submitted)

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 3

Similar results when measuring 56 teachers voice use during work and leasure

Hunter EJ, Titze IR. (2010) Variations in intensity, fundamental frequency, and voicing for teachers in occupational versus nonoccupational settings. Journal of Speech, Language, and Hearing Research. 53, 862–875.

Important information in discussions if a voice disorder should be classified as a work disease

Project: Female voice in pre-school settings

( Background: 1970s: many new large day care centers were built with and were followed by architects and acousticians 1980s: To high noise levels – interventions – decrease the background/activity noise by 10 dB 1990s: Larger groups of children, increase of noise levels Noise increased to 70-80 dB common

• Binaural DAT recording

DAT

MICROPHONES

Granqvist 2003, Södersten et al 2002, Ternström et al 1994

• Also used for measuring

childrens’ voices in pre- school settings (McAllister et al

2009)

Södersten et al 2002

Noise levels at 10 pre-schools

Södersten et al 2002

76 dBA (73-79)

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Background/Activity noise

Noise level Consequences for the speaker 40 dBA starts increasing the voice intensity 55 dBA* normal and audible (1 m) voice intensity 70 dBA high intensity to be heard at 1 m. 85 dBA has to shout to be heard * Good for speech communication

AFS 2008, 2005 Sala et al 2005

Voice intensity in habitual reading and during work

Leq dB (at microphones)

Mean (SD)

p<.001

60 65 70 75 80 85 90

Baseline reading During Work Södersten et al 2002

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 4

Fundamental frequency in habitual voice and during work

100 120 140 160 180 200 220 240 260 280 300

Baseline reading During work

Mean (SD)

p<.001

Södersten et al 2002

Conclusions Preschool teachers very vocally demanding work Background/Activity noise – found to be a risk factor Importance of field studies Time-consuming and problematic method

Szabo Leroy 2004, Södersten et al 2002

J Voice

Noise level measure at the ears of the children at three preschools

McAllister et al 2009 McAllister et al 2009

Vocal loading in background noise at different work environments – laboratory studies

Sten Ternström, Mikael Bohman

Dept of Speech, Music, Hearing, Royal Institute of Technology, Stockholm

Maria Södersten, Carina Aronsson

Dept of Logopedics and Phoniatrics Karolinska Institutet Supported by The Swedish Council for Working Life and Social Research

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 5

Working environments with high background

• r activity noise levels

Daycare centres 76 dB Industries 85 dB Pubs 80-90 dB

mic A mic B subject SOUND-TREATED BOOTH PC with DSP rod PC running slide show Acquisition Operator Prompting Operator window spoken commands

LCD projector DAT

sub-woofer movie screen

• Ternström et al 2006

Subjects

Vocally healthy adults 12 women, 30 to 54 years (mean age 44) 11 men, 20 to 53 years (mean age 34)

Södersten et al 2005; Ternström et al 2006

Recording conditions

Background Leq Situation

• 1. Quiet

< 30 Quiet classroom

• 2. Soft

70 Outside a ventilation room

• 3. Day-care

76 Noisy day-care

• 4. Disco

87 A rowdy night

• 5. Loud

85 Inside a ventilation room

Questionnaire

Did you make yourself heard? Was your speech/voice effortful? Did you feel vocal fatigue or strain in you voice/throat during the reading? Answers on a 100 mm visual analogue scale

(not at all – extremely)

• 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

(Bohman et al 2002, Ternström et al 2002)

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 6

Acoustic analyses Methods:

Phonetogram Phog, Swell (Saven Hitech AB)

Variables

voice sound pressure level fundamental frequency phonetogram area total reading time phonation ratio (phonation time expressed in percent

• f the reading time)

acoustic spectrum

Results - male/female differences

• Males were 3-5 dB louder throughout.
• Females 50% higher pitch (in Hz)
• Females felt more strain during reading
• Females felt they had to exert their voices more
• Males were more confident of having been heard

The results support the notion that females are more vulnerable to vocal overload in noisy environments

Södersten et al, 2005 Ternström et al, 2006 Lunds Universitet Viveka Lyberg Åhlander

Current projekt:

To identify risk factors for voice disorders

KTH Stockholm Sten Ternström Göteborgs Universitet Kerstin Waye Persson Linköpings Universitet Anita McAllister Karolinska Universitetssjukhuset/KI Maria Södersten Umeå universitet Fredric Lindström

Support: Forskningsrådet för arbetsliv och socialvetenskap (FAS)

Voxlog – portabel voice accumulator

Accelerometer and microphone Fundamental frequency (Hz) Phonation time (s and %) Vocie Intensity (dB) Level of noise (dB)

Lindström et al (2011) Sonvox (2012) Thorsdotter 2011

Questions

Is vocal behavior affected by the level of the background/activity noise? Does vocal loading measured with ”accumulated cycle dose” correlated with subjective symtoms of vocal fatigue Are there differences in voice use in occupational and non-occupational settings? In patients with voice disorders and healthy controls?

Subjects:

30 patients with work-related voice disorders 30 vocally healthy controls matched as regards gender and work place)

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 7

Voice assessments prior field registration Interview Voice recording in a sound-treated booth

Speech range profile (text reading and narrating and reading in background noise) Voice range profile

Laryngostroboscopy. Subjective evaluations

VHI, VHI-T (Ohlsson & Dotewall, 2009, Lyberg-Åhlander et al 2010). VAPP (Ma & Yiu, 2001; Elofsson & Lind, 2005),

PSS Perceived Stress Scale (Cohen et al 1989)

Voice ergonomic assessment

Voice ergonomic protocol (Sala et al 2009: 2011, Thorsdotter 2011)

Long term field registration

1-2 weeks registration using Voxlog from morning to night during work and leisure Subjects have to write a diary – activities Ratings of voice symptoms (100 mm VAS)

vocal fatigue and hoarseness

39 40

Analyses

Data collection ongoing Pilot study (in Swedish)

Thorsdotter M (2011). Long term registration of voice use, using the portable voice accumulator VoxLog and subjective evaluations; A pilot study to quantify risk factors for voice disorders. Master thesis, Karolinska Institutet.

Teachers’ voice and room acoustics in schools (Research group in Lund and Denmark)

1 Speech language pathologist + 1 acoustician

Prevalence of voice problems in teachers 13 % n= 467

Teachers with voice problems 1) had been absent from work, 2) used hearing aid, 3) were sensitive to strong smells, and 4) used asthma medication more often than the teachers without voice problems

Lyberg Åhlander V. (2011) Voice use in teaching environments. Speakers comfort.Doktorsavhandling, Lunds universitet. Lund, Sverige Lyberg Åhlander, V., Rydell, R. & Löfqvist, A. (2010). Speaker’s comfort in teaching

• environments. Voice problems in Swedish teaching staff. Journal of Voice. [Epub ahead of

print] doi:10.1016/j.jvoice.2009.12.006).

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 8

Different room acoustics were tested in a laboratory setting simulating different classrooms (room size, short vs long RT) The speakers voice use changed with the size of the room, RT, and ”room gain” that is how the room supports the voice Results: The better the room ”supported” the voice the more comfortable for the speaker, not too short RT They also measured RT, ”room gain” and activity noise level in 30 real class-rooms. Results: The teachers voice intensity were mostly affected by the activity noise BUT teachers with weak voices and voice problems were more dependent on the room acoustics

Pelegrín-García, D., Lyberg-Åhlander, V., Rydell, R., Löfqvist, A. & Brunskog, J. (2010). Influence of classroom acoustics on the voice levels of teachers with and without voice problems: a field study. Proc of the 2nd Pan-American/Iberian Meeting

• n Acoustics, Mexico.

Pelegrín-García, D., Smits, B., Brunskog, J. & Jeong, C.-H. (2011). Vocal effort with changing talker-to-listener distance in different acoustic environments. JASA

Preventive voice care in teachers (Research

group in Gothenburgh

Of 1636 teacher students 1250 (76%) answered two questionnaires about voice symptoms and one questionnaire about potential risk factors. A majority were women, mean age 23 (range 18-52) years. Results: 208 out of 1250 students (17%) had voice problems, defined as at least two symptoms weekly or more often. The proportion of women was larger in the group with voice problems than in the group without voice problems. Significant risk factors for voice problems were: voice problems in childhood and adulthood, frequent throat infections, air- born allergy, smoking, hearing problems, previous work as teacher or leader, voice demanding hobbies, and previous speech therapy or voice training. Ohlsson, Andersson, Sodersten, Simberg, Barregard. (2012). Prevalence

• f voice symptoms in teacher students. J Voice

Preventive voice training is given during the students education with systematic follow up

Supported by Forskningsrådet för Arbetsliv och Socialvetenskap (FAS 2008-1365). BULLER

AFS 2005:16

• BULLER

AFS 2005:16

• AFS 2005:16 Buller

”Om bakgrundsbullret har sådan nivå att röststyrkan ofta behöver höjas för att talet ska kunna uppfattas tillräckligt bra finns även risk för röstproblem. Detta är speciellt angeläget att beakta i miljöer där talkommunikation är viktig, t.ex. i skolor och förskolor. För att höras i buller höjer talaren såväl röststyrkan som röstläget och pressar

• fta rösten. Detta kan innebära slitage

på stämbandsslemhinnan och påfrestning på struphuvudets

• muskulatur. Kvinnor löper större risk än

män att få problem med rösten vid arbete i miljöer där röststyrkan behöver höjas.”

SWEA – campaine 2005

BORT MED BULLRET GET RID OF THE NOISE – A GOOD NOISE ENVIRONMENT IS EFFECTIVE INSPECTIONS OF > 700 PRESCHOOLS

48

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 9

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Commissioned by the Swedish Work Environment Authority (SWEA)

www.av.se Mandate from government to ensure that occupational safety and working time laws are followed. Goal to reduce risks of illness and accidents at work and to improve working environment in terms of physical, mental, social and work-organization. Is responsible for statistics on occupational and work- related injuries in Sweden.

50

Background

2006 The Nordic Voice Ergonomics Group

• The first meeting on Iceland.
• Goal to reach the Authorities - high background and activity noise in

schools. 2004 Contact with SWEA regarding revisions AFS 2001: Noise AFS 2005: A paragraph about effects of noise on the voice 2007 Advanced Course: Occupational voice disorders and voice ergonomics, Karolinska Institutet. Invited specialists from SWEA 2008 Contact SWEA – voice ergonomics information on web site 2009 Invited to give a presentation about Voice ergonomics for health and safety inspectors from all over Sweden

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2009 SWEA commissioned the Research survey from Karolinska Institutet 2010 WORK A reference group with specialists: Eeva Sala (phoniatricians and ass. prof) Stellan Hertegård (phoniatricians and ass. prof) Susanna Simberg (SLP and prof) and Sten Ternström (engineer and prof) 2011 Publication and a seminar May 30th 2011.

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Target groups

Employers Politicians Occupational health service Inspectors at SWEA Authorities General public

53

Teachers, callcenter personnel, artists

Well known as patients in voice clinics Work environment hazards – risk groups Poor voice education for students and employees Seek medical advice seldom or late

54

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 Life habits General health Vocal demands Medication Psychosocial sit. After Sala et al 2005; Simberg et al., 2009; Vilkman 1996; 2004

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 10

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Epidemiological studies Clinical studies Field studies Laboratory studies Intervention studies Occupational Voice disorders

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Goal

Spread knowledge Improve work environment and vocal health Provide basis for intervention and education Prevent occupational voice disorders

Used as a text book in Swedish Part 2:

What has been done in Sweden and what is needed as regards clinical work Challenge to incorporate new knowledge in clinical practice Education

Different target groups:

Colleagues - SLP Students – SLP Chiefs Other professions

Colleagues

Specialized courses in occupational voice disorders and voice ergonomics. Arranged by

Karolinska Institute 2007, 2011, 5 weeks full-time course Lund University 2012 Theory – Updated research, Risk factors in work environment (stress, noise, air quality, acoustics), Voice ergonomics, Ergonomics, Voice rest, Voice dosimetry, Prevention, Intervention. Practice: Laboratory activities, amplification equipments, test to speak in background noise, Voice ergonomics assessments (checklist), Voxlog .

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 11

Visit a voice patient at work Use the checklist to judge voice ergonomic factors at work (Sala and coworkers, 2011) and propose intervention ”Eye-opener” – very positive experience Written case reports about voice ergonomics assessment (arbetsplatsbesök)

Södersten, Hammarberg 2008

Colleagues

Colleagues

Short course, 1-day, arranged by the Union for speech pathologistst in Sweden (Svenska Logopedförbundet). National Network for Voice Ergonomics Meeting once a year

Students

Lectures about occupational voice and voice ergonomics at all 6 SLP university programmes

Stockholm Lund Gothenburgh Umeå Linköping Uppsala The students are encouraged to visit patients at their working place

Chief Speech Pathologists

Important group! So that they can support their staff to do e.g., work visits and voice ergonomics assessments (more time- consuming than seeing the patient in the clinic). Lectures about Occupational voice and voice ergonomics – but needs to be done regularly.

Other professions

Employers Emplyees Unions Physical therapists - ergonomics Occupational health services - Very few patients are referred from them Company health services Inspectors (from SWEA) Architects In Sweden we need to do this much more, HOW ?

Measurements of voice at work:

There are now 2 availabe equipments:

Ambulatory Phonation Monitor (APM)

(Cheyne et al 2006)

Voxlog

(Lindström et al 2010)

M Södersten, Karolinska Institutet, Oct 13, 2012, Rekjavik 12

Conclusions

There is evidence that environmental factors can cause voice disorders The Work Environment law shall be used much more Employers need to be involved

Södersten, Lindhe 2011

Conclusions (cont.)

Voice ergonomics assessment should be part of the Systematic Work Environment screening at work places where a functioning voice is necessary for the work outcome Development of methods and routines are needed Checklist is a start.

Södersten, Lindhe 2011

Conclusions (cont)

Statistics is missing in Sweden about costs for society for Occupational voice disorders. This information should be gathered. Critera and norms for how much a voice can be loaded are needed to avoid voice disorders. Research is needed. Criteria for decisions about voice disorders as work disease needs to be developed.

Södersten, Lindhe 2011

Conclusions (cont)

Need for education is large Preventive voice education is needed in programs educating persons to vocally demanding occupations.

Södersten, Lindhe 2011

What does the law say ?

Working conditions shall be adapted to people’s different physical and mental aptitudes Work shall be planned and arranged in such a way as to provide a suitable working environment The emplyee shall be given the opportunity of participating in design of his own working situation Working premises shall be arranged and equipped in such a way as to provide a suitable working environment Personal protective equipment shall be used when adequate security from ill-health and accidents cannot be achieved by other means. This equipment should be provided by the employer.

The Swedish Work Environment Act