Finnish voice ergonomic studies

Finnish voice ergonomic studies Leena Rantala Eeva Sala

Surveys, Laboratory study, Field studies, Rehabilitation study (coming)

Surveys • Several studies • Aims e.g.

– Voice symptoms and voice related disorders – Working culture – Genetic vs. environmental origin

• Participants:

– teachers – nursery school teachers – teacher students

Laboratory study

Laboratory study: voice loading • Participants – 40 males and 40 females – Normal speakers

• Loading – 5 x 45 minutes + 2 rest periods – Different conditions: • Sound pressure levels: ’conversation’ level and loud • Postures: sitting and standing • Indoor air humidity: dry and humid

Field studies

Field study: loading changes • 2 studies for female teachers

• 33 and 79 participants • Voice symptoms and phoniatric examination • Voice production – Recordings » teaching speech (during lessons) » text reading, prolonged phonation (outside lessons)

• 1 study for male teachers • 22 participants

• 1 study for call centre advisers • 24 females, 8 males • 4 recordings during a workday

Voice ergonomics in workplaces

Study: Voice ergonomic assessment • 2 studies: nursery schools and schools • Voice risk factors assessed – (1) noise, (2) indoor air quality, (3) working postures, (4) working culture (included stress) and (5) a lack of using sound amplifier

• Voice symptoms • Voice use – during work – before and after a working day

Coming

Voice therapy: carrying voice ergonomics/good vocal habits into teaching culture • Female teachers – 30 voice therapy with special emphasis on carry over – Controls • 30 with ‘traditional voice therapy’ • 30 without therapy

• 2 year follow up

What do we know now?

Results

Voice symptoms • • • •

Environmental factors effect more than genetic ones Voice disorders have increased during last years Allergy is more typical in those with voice symptoms Occupational health care does not know how to treat voice disorders

• Teachers:

– 42 - 29 % symptoms frequently

• Nursery school teachers:

– 71 % symptoms frequently, 11 % organic changes in the larynx

• Teachers student

– 20 % voice symptoms, 19 % organic changes in the larynx

Voice loading • Voice symptoms arise • Voice rest – helps to recover (laboratory study) – the effects of voice risk factors are found in the morning (field study)

Voice loading effects • Voice production changes – Increase of • F0 (pitch) and SPL (loudness) • effort to produce voice (change of glottal pulse) • hyperfunctional voice quality (spectrum levels)

– Decrease of • Perturbation (jitter and shimmer) increases in vocal fold vibration

Voice ergonomics in work places • Nursery school – have high background noise levels – 17 % of the rooms in day care centre had adequate room acoustics (measured by RASTI)

• Nursery school teachers vs. nurses – talk longer (40 % of the working time) than nurses (28 %) – talk louder (78 dB) than nurses (72 dB)

• Many voice ergonomic risk factors in the classrooms

Voice ergonomics and voice health Teachers – The more voice ergonomic risk factors in the classroom • more voice symptoms • higher SPL (voice loudness) before and after a workday

– Poorer indoor air quality, more laryngitis

Carry over study: preliminary results • 8 teacher with carry over method/ 5 traditional – Both therapies affect • Voice quality towards more economical voice production (perceptual evaluation) • Subjective evaluation (VAS-scale): less voice tiredness

– ½ yr after therapy: more constant results with carry over method