Effects of Humidification of the Vocal Tract and Respiratory Muscle Training in Women With Voice Symptoms—A Pilot Study

  • Kerttu Huttunen
    Address correspondence and reprint requests to Kerttu Huttunen, Faculty of Humanities, Research Unit of Logopedics, University of Oulu, PO Box 1000, Oulu FI-90014, Finland.
    Faculty of Humanities, Research Unit of Logopedics, University of Oulu, Oulu, Finland

    PEDEGO Research Unit, University of Oulu, Oulu, Finland

    MRC Oulu, Oulu, Finland

    Department of Otorhinolaryngology, Head and Neck Surgery, Oulu University Hospital, Oulu, Finland
    Search for articles by this author
  • Leena Rantala
    Degree Programme in Logopedics, University of Tampere, Tampere, Finland
    Search for articles by this author



      The aim of this study was to determine the efficacy of a 4-week breathing exercise intervention in participants with voice symptoms.


      Six nonsmoking women (mean age 49) experiencing voice symptoms used a novel device WellO2 for respiratory exercises that provides counter pressure during both inspiration and expiration and warms and humidifies the breathing air. Speech samples were acoustically (Acoustic Voice Quality Index) and perceptually (grade, roughness, breathiness, asthenia, and strain scale) analyzed, and perceived voice symptoms and self-reported effort in breathing and phonation were obtained. Respiratory measurements included breathing frequency and pattern, peak expiratory flow, forced vital capacity, and forced expiratory volume in 1 minute.


      The total scores of Acoustic Voice Quality Index and some of its subcomponents (shimmer and harmonic-to-noise ratio), and the grade, roughness, and strain of the GRBAS scale indicated significantly improved voice quality. However, neither the nature or frequency of the experienced voice symptoms nor the perceived phonatory effort changed as the function of intervention. According to the participants, their breathing was significantly less effortful after the intervention, although no significant changes were observed in the objective respiratory measurements with a spirometer.


      Training with the WellO2 device has the potential to improve voice quality. The combination of inspiratory and expiratory training and warmed, humidified air is a multifaceted entity influencing several parts in the physiology of voice production. The effects of using WellO2 need to be confirmed by further studies with a larger number of participants.

      Key Words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic and Personal
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Voice
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Schneider SL
        • Sataloff RT
        Voice therapy for the professional voice.
        Otolaryngol Clin N Am. 2007; 40: 1133-1149
        • Boone D
        • McFarlane SC
        • von Berg SL
        • et al.
        The Voice and Voice Therapy.
        9th ed. Pearson, Boston, MA2014
        • Kostyk BE
        • Rochet AP
        Laryngeal airway resistance in teachers with vocal fatigue: a preliminary study.
        J Voice. 1998; 12: 287-299
        • Iwarsson J
        • Sundberg J
        Breathing behaviors during speech in healthy females and patients with vocal fold nodules.
        Logoped Phoniatr Vocol. 1999; 24: 154-169
        • Aronson AE
        • Bless DM
        Clinical Voice Disorders.
        4th ed. Thieme, New York2009
        • Lowell SY
        • Barkmeier-Kraemer JM
        • Hoit JD
        • et al.
        Respiratory and laryngeal function during spontaneous speaking in teachers with voice disorders.
        J Speech Lang Hear Res. 2008; 51: 333-349
        • Sperry EE
        • Hillman RE
        • Perkell JS
        The use of inductance plethysmography to assess respiratory function in a patient with vocal nodules.
        J Med Speech Lang Pathol. 1994; 2: 137-145
        • Stemple JC
        • Nelson R
        • Klaben B
        Clinical Voice Pathology: Theory and Management.
        5th ed. Plural Publishing, San Diego, CA2014
        • Sapienza CM
        • Stathopoulos ET
        • Brown Jr, WS
        Speech breathing during reading in women with vocal nodules.
        J Voice. 1997; 11: 195-201
        • Leydon C
        • Sivasankar M
        • Falciglia DL
        • et al.
        Vocal fold surface hydration: a review.
        J Voice. 2009; 23: 658-665
        • Smith S
        • Thyme K
        Die Akzentmethode.
        Spezial-Pädagogisher Verlag, Flensburg1980
        • Shiromoto O
        Management of non-organic voice disorders: physiological bases of Accent Method for non-organic voice disorders.
        Int Congr Ser. 2003; 1240: 1269-1276
        • Laukkanen A-M
        • Titze IR
        • Hoffman H
        • et al.
        Effects of a semioccluded vocal tract on laryngeal muscle activity and glottal adduction in a single female subject.
        Folia Phoniatr Logop. 2008; 60: 298-311
        • Titze IR
        Voice training and therapy with a semi-occluded vocal tract: rationale and theoretical underpinnings.
        J Speech Lang Hear Res. 2006; 49: 448-459
        • Seikel JA
        • King DW
        • Drumright DG
        Anatomy & Physiology for Speech, Language, and Hearing.
        4th ed. Delmar Cengage Learning, Clifton Park, NY2014
        • Sataloff RT
        Clinical anatomy and physiology of the voice.
        in: Sataloff RT Professional Voice. The Science and Art of Clinical Care. 3rd ed. Plural Publishing, San Diego, CA2005
        • Titze IR
        Principles of Voice Production.
        National Center for Voice and Speech, The University of Iowa, Salt Lake City, UT2000
        • Hunter EJ
        • Smith ME
        • Tanner K
        Gender differences affecting vocal health of women in vocally demanding careers.
        Logoped Phoniatr Vocol. 2011; 36: 128-136
        • Titze IR
        • Hunter EJ
        Comparison of vocal vibration-dose measures for potential-damage risk criteria.
        J Speech Lang Hear Res. 2015; 58: 1425-1439
        • Vintturi J
        • Alku P
        • Sala E
        • et al.
        Loading-related subjective symptoms during a vocal loading test with special reference to gender and some ergonomic factors.
        Folia Phoniatr Logop. 2003; 55: 55-69
        • Sivasankar M
        • Fisher K
        Oral breathing increases Pth and vocal effort by superficial drying of vocal fold mucosa.
        J Voice. 2002; 16: 172-181
        • Tanner K
        • Roy N
        • Merrill RM
        • et al.
        The effects of three nebulized osmotic agents in the dry larynx.
        J Speech Lang Hear Res. 2007; 50: 635-646
        • Hemler RJ
        • Wieneke GH
        • Lebacq J
        • et al.
        Laryngeal mucosa elasticity and viscosity in high and low relative air humidity.
        Eur Arch Otorhinolaryngol. 2001; 258: 125-129
        • Sivasankar M
        • Erickson E
        • Schneider S
        • et al.
        Phonatory effects of airway dehydration: preliminary evidence for impaired compensation to oral breathing in individuals with a history of vocal fatigue.
        J Speech Lang Hearing Res. 2008; 51: 1494-1506
        • Witt RE
        • Taylor LN
        • Regner MF
        • et al.
        Effects of surface dehydration on mucosal wave amplitude and frequency in excised canine larynges.
        Otolaryngol Head Neck Surg. 2011; 144: 108-113
        • Leydon C
        • Wroblewski M
        • Eichorn N
        • et al.
        A meta-analysis of outcomes of hydration intervention on phonation threshold pressure.
        J Voice. 2010; 24: 637-643
        • Roy N
        • Weinrich B
        • Gray SD
        • et al.
        Voice amplification versus vocal hygiene instruction for teachers with voice disorders: a treatment outcomes study.
        J Speech Lang Hear Res. 2002; 45: 625-638
        • Sivasankar M
        • Leydon C
        The role of hydration in vocal fold physiology.
        Curr Opin Otolaryngol Head Neck Surg. 2010; 18: 171-175
        • Alves M
        • Krüger E
        • Pillay B
        • et al.
        The effect of hydration on voice quality on adults: a systematic review.
        J Voice. 2019; 33 (125.e13–125.e28)
        • Verdolini-Marston K
        • Sandage M
        • Titze IR
        Effect of hydration treatments on laryngeal nodules and polyps and related voice measures.
        J Voice. 1994; 8: 30-47
        • Rocha Santana É.
        • Vaz Masson ML
        • Araújo TM
        The effect of surface hydration on teachers’ voice quality: an intervention study.
        J Voice. 2017; 31: 383c5-383c11https://doi.org/10.1016/j.jvoice.2016.08.019
        • Bless DM
        Measurement of vocal function.
        Otolaryngol Clin North Am. 1991; 24: 1023-1033
        • Iwarsson J
        • Thomasson M
        • Sundberg J
        Effects of lung volume on the glottal voice source.
        J Voice. 1998; 12: 424-433
        • Hammarberg B
        Voice research and clinical needs.
        Folia Phoniatr Logop. 2000; 52: 93-102
        • Milstein C
        • Watson PJ
        The effects of lung volume initiation on speech: a perceptual study.
        J Voice. 2004; 18: 38-45
        • Schaeffer N
        • Cavallo SA
        • Wall M
        • et al.
        Speech breathing behavior in normal and moderately to severely dysphonic subjects during connected sp`eech.
        J Med Speech Lang Pathol. 2002; 10: 1-18
        • Sapienza CM
        • Stathopoulos ET
        Respiratory and laryngeal measures of children and women with bilateral vocal fold nodules.
        J Speech Hear Res. 1994; 37: 1229-1243
        • Baker S
        • Davenport P
        • Sapienza S
        Examination of strength training and detraining effects in expiratory muscles.
        J Speech Lang Hear Res. 2005; 48: 1325-1333
        • Tsai YC
        • Huang S
        • Che WC
        • et al.
        The effects of expiratory muscle strength training on voice and associated factors in medical professionals with voice disorders.
        J Voice. 2016; 30 (759.e21–759.e27)
        • Roy N
        • Weinrich B
        • Gray SD
        • et al.
        Three treatments for teachers with voice disorders: a randomized clinical trial.
        J Speech Lang Hear Res. 2003; 46: 670-688
        • Wingate JM
        • Brown WS
        • Shrivastav R
        • et al.
        Treatment outcomes for professional voice users.
        J Voice. 2007; 21: 433-449
        • Simberg S
        • Sala E
        • Laine A
        • et al.
        A fast and easy method for voice disorders among teacher students.
        Logoped Phoniatr Vocol. 2001; 26: 10-16
        • Ohlsson A-C
        • Andersson EM
        • Södersten M
        • et al.
        Prevalence of voice symptoms and risk factors of teacher students.
        J Voice. 2012; 26: 629-634
        • Roy N
        • Merrill RM
        • Gray SD
        • et al.
        Voice disorders in the general population: prevalence, risk factors, and occupational impact.
        Laryngoscope. 2005; 115: 1988-1995
        • Sala E
        • Laine A
        • Simberg S
        • et al.
        The prevalence of voice disorders among day care center teachers compared with nurses: a questionnaire and clinical study.
        J Voice. 2001; 15: 413-423
        • Simberg S
        • Sala E
        • Tuomainen J
        • et al.
        Voice symptoms and allergy—a pilot study.
        J Voice. 2009; 23: 136-139
        • Spantideas N
        • Drosou E
        • Bougea A
        • et al.
        Inhaled corticosteroids and voice problems. What is new?.
        J Voice. 2017; 31 (384.e1–384.e7)
        • Tyrmi J
        • Laukkanen A-M
        How stressful is “deep bubbling”?.
        J Voice. 2017; 31 (262.e1–262.e6)
        • Laukkanen A-M
        • Ilomäki I
        • Leppänen K
        • et al.
        Acoustic measures and self-reports of vocal fatigue by female teachers.
        J Voice. 2008; 22: 283-289
        • Rantala L
        • Paavola L
        • Körkkö P
        • et al.
        Working-day effects on the spectral characteristics of teaching voice.
        Folia Phoniatr Logop. 1998; 50: 205-211
        • Maryn Y
        • Corthals P
        • Van Cauwenberge P
        • et al.
        Toward improved ecological validity in the acoustic measurement of overall voice quality: combining continuous speech and sustained vowels.
        J Voice. 2010; 24: 540-555
        • Barsties B
        • Maryn Y
        Test-retest-variabilität und interne Konsistenz des Acoustic Voice Quality Index.
        HNO. 2013; 61: 399-403
        • Maryn Y
        • De Bodt M
        • Roy N
        The Acoustic Voice Quality Index: toward improved treatment outcome assessment in voice disorders.
        J Comm Disord. 2010; 43: 161-174
        • Kankare E
        • Barsties V
        • Latoszek B
        • et al.
        The Acoustic Voice Quality Index version 02.02 in the Finnish speaking population.
        Logoped Phoniatr Vocol. 2019; 5 ([Epub ahead of print]): 1-8https://doi.org/10.1080/14015439.2018.1556332
        • Maryn Y
        • De Bodt M
        • Barsties B
        • et al.
        The value of the Acoustic Voice Quality Index as a measure of dysphonia severity in subjects speaking different languages.
        Eur Arch Otorhinolaryngol. 2014; 271: 1609-1619
        • Maryn Y
        • Weenink D
        Objective dysphonia measures in the program Praat: smoothed cepstral peak prominence and acoustic voice quality index.
        J Voice. 2015; 29: 35-43
      1. Boersma P, Weenink D. Praat: doing phonetics by computer [Computer program]. Version 6.0.30. Available at:http://www.praat.org. Accessed February 7, 2017

        • Hirano M
        Clinical Examination of Voice.
        Springer-Verlag, Wien1981
        • Karnell MP
        • Melton SD
        • Childes JM
        • et al.
        Reliability of clinician-based (GRBAS and CAPE-V) and patient-based (V-RQOL and IPVI) documentation of voice disorders.
        J Voice. 2007; 21: 576-590
        • Joshi A
        • Watts CR
        Measurement reliability of phonation quotient derived from three aerodynamic instruments.
        J Voice. 2016; 30 (773.e13–773.e19)
        • American Thoracic Society/European Respiratory Society
        ATS/ERS statement on respiratory muscle testing.
        Am J Respir Crit Care Med. 2002; 166: 518-524
        • Suomen Kliinisen Fysiologian yhdistys ja Suomen Keuhkolääkäriyhdistys
        Spirometria- ja PEF-mittausten suoritus ja tulkinta (execution and interpretation of spirometry and PEF measurements). Suomen kliinisen fysiologian yhdistyksen ja Suomen Keuhkolääkäriyhdistyksen suositus. ed 13.
        Moodi. 2015; 3b: 119-142
        • Cohen J
        A power primer.
        Psych Bull. 1992; 112: 155-159
        • Koo TK
        • Li MY
        A guide of selecting and reporting intraclass correlation coefficients for reliability research.
        J Chiropract Med. 2016; 15: 155-163
        • Chaitow L
        • Bradley D
        • Gilbert C
        What are breathing pattern disorders?.
        in: Chaitow L Bradley D Gilbert C Recognizing and Treating Breathing Disorders: A Multidisciplinary Approach. 2nd ed. Churchill Livingstone, London2013
        • Kainu A
        • Timonen KL
        • Toikka J
        • et al.
        Reference values of spirometry for Finnish adults.
        Clin Pysiol Funct Imaging. 2015; 36 (346–258)
        • Uloza V
        • Petrauskas T
        • Padervinskis E
        • et al.
        Validation of the Acoustic Voice Quality Index in the Lithuanian language.
        J Voice. 2017; 31 (257.e1–257.e11)
        • Laciuga H
        • Rosenbek JC
        • Davenport PW
        • et al.
        Functional outcomes associated with expiratory muscle training: narrative review.
        J Rehabil Res Dev. 2014; 51: 535-546
        • Mahalingam S
        • Boominathan P
        Effects of steam inhalation on voice quality‐related acoustic measures.
        Laryngoscope. 2016; 126: 2305-2309
        • Franca MC
        • Simpson KO
        Effects of systemic hydration on vocal acoustics of 18- to 35-year-old females.
        Commun Disord Q. 2012; 34: 29-37
        • Hemler RJ
        • Wieneke GH
        • Dejonckere PH
        The effect of relative humidity of inhaled air on acoustic parameters of voice in normal subjects.
        J Voice. 1997; 11: 295-300
        • Yiu EM
        • Chan RM
        Effect of hydration and vocal rest on the vocal fatigue in amateur karaoke singers.
        J Voice. 2003; 17: 216-227
        • Martin D
        • Fitch J
        • Wolfe V
        Pathologic voice type and the acoustic prediction of severity.
        J Speech Lang Hear Res. 1995; 38: 765-771
        • Samlan RA
        • Story B
        • Bunton K
        Relation of perceived breathiness to laryngeal kinematics and acoustic measures based on computational modeling.
        J Speech Lang Hear Res. 2013; 56: 1209-1223
        • Kitzing P
        LTAS criteria pertinent to the measurement of voice quality.
        J Phonetics. 1986; 14: 477-482
        • Leino T
        Long-term average spectrum in screening of voice quality in speech: untrained male university students.
        J Voice. 2009; 23: 671-676
        • Oates J
        Auditory-perceptual evaluation of disordered voice quality.
        Folia Phoniatr Logop. 2009; 61: 49-56
        • Bhuta T
        • Patrick L
        • Garnett JD
        Perceptual evaluation of voice quality and its correlation with acoustic measurements.
        J Voice. 2004; 18: 299-304
        • van Wyk L
        • Cloete M
        • Hattingh D
        • et al.
        The effect of hydration on the voice quality of future professional voice performers.
        J Voice. 2017; 31 (111.e29–111.e36)
        • Reinikainen LM
        • Jaakkola JJ
        • Heinonen OP
        The effect of air humidification on different symptoms in office workers—an epidemiologic study.
        Environ Int. 1991; 17: 243-250
        • Tanner K
        • Fujiki RB
        • Dromey C
        • et al.
        Laryngeal desiccation challenge and nebulized isotonic saline in healthy male singers and non-singers: effects on acoustics, aerodynamics and self-perceived effort and dryness measures.
        J Voice. 2015; 30: 670-776
        • Huttunen K
        • Rantala L
        • Järvinen K
        • et al.
        Effects of respiratory training and humidification of the vocal tract with WellO2 device on normal voiced participants. Preliminary findings.
        in: PEVOC 12 – Pan-European Voice Congress, August 30–September 1, Ghent, Belgium. 2017 (Available at:)
        • Suzuki S
        • Sato M
        • Obuko T
        Expiratory muscle training and sensation of respiratory effort during exercise in normal subjects.
        Thorax. 1995; 50: 366-370
        • Griffiths LA
        • McConnell AK
        The influence of inspiratory and expiratory muscle training upon rowing performance.
        Eur J Appl Physiol. 2007; 99: 457-466
        • Wang SZ
        • Li S
        • Xu XY
        • et al.
        Effect of slow abdominal breathing combined with biofeedback on blood pressure and heart rate variability in prehypertension.
        J Altern Complement Med. 2010; 16: 1039-1045
        • Wine JJ
        Parasympathetic control of airway submucosal glands: central reflexes and the airway intrinsic nervous system.
        Auton Neurosci. 2007; 133: 35-54
        • Laciuga H
        • Davenport PW
        • Sapienza C
        The acute effects of a single session of respiratory muscle strength training on blood pressure, heart rate, and oxygen saturation in healthy adults.
        Front Physiol. 2012; 3: 48
        • Ma X
        • Yue Z-Q
        • Gong Z-Q
        • et al.
        The effect of diaphragmatic breathing on attention, negative affect and stress in healthy adults.
        Front Psychol. 2017; 8: 874
        • Perciavalle V
        • Blandini M
        • Fecarotta M
        • et al.
        The role of deep breathing on stress.
        Neurol Sci. 2017; 38: 451-458
        • Mendoza E
        • Carballo G
        Acoustic analysis of induced vocal stress by mean of cognitive workload tasks.
        J Voice. 1998; 12: 263-273
        • Van Lierde K
        • van Heule S
        • De Le S
        • et al.
        Effect of psychological stress on female vocal quality.
        Folia Phoniatr Logop. 2009; 61: 105-111
        • Rantala LM
        • Hakala SJ
        • Holmqvist S
        • et al.
        Connections between voice ergonomic risk factors and voice symptoms, voice handicap, and respiratory tract diseases.
        J Voice. 2012; 26 (819.e13–819.e20)
        • Gassull C
        • Casanova C
        • Botey Q
        • et al.
        The impact of the reactivity to stress in teachers with voice problems.
        Folia Phoniatr Logop. 2010; 62: 35-39
        • Holmqvist-Jämsén S
        • Johansson A
        • Santtila P
        • et al.
        Investigating the role of salivary cortisol on vocal symptoms.
        J Speech Lang Hear Res. 2017; 60: 2781-2791
      2. Patovirta RL. Teachers’ health in moisture-damaged schools—a follow-up study [doctoral dissertation]. Publications of the National Public Health Institute A5/2005. Helsinki: National Public Health Institute, 2005. Available at: http://epublications.uef.fi/pub/urn_isbn_951-740-506-5/urn_isbn_951-740-506-5.pdf.

        • Mendell MJ
        • Mirer AG
        • Cheung K
        • et al.
        Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence.
        Environ Health Perspect. 2011; 119: 748-756
        • Ziegler A
        • Gillespie AI
        • Abbott KV
        Behavioral treatment of voice disorders in teachers.
        Folia Phoniatr Logop. 2010; 62: 9-23