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Voice Disorders

See the Voice Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.

The scope of this page focuses on voice disorders of organic (i.e., structural and neurogenic) and functional origin. Psychogenic voice disorders are also discussed.

Portal pages on head and neck cancer, resonance disorders, aerodigestive disorders affecting voice, and transgender voice will be developed in the future.

A voice disorder occurs when voice quality, pitch, and loudness differ or are inappropriate for an individual's age, gender, cultural background, or geographic location (Aronson & Bless, 2009; Boone, McFarlane, Von Berg, & Zraik, 2010; Lee, Stemple, Glaze, & Kelchner, 2004). A voice disorder is present when an individual expresses concern about having an abnormal voice that does not meet daily needs—even if others do not perceive it as different or deviant (American Speech-Language-Hearing Association [ASHA], 1993; Colton & Casper, 1996; Stemple, Glaze, & Klaben, 2010; Verdolini & Ramig, 2001).

A number of different systems are used for classifying voice disorders. For the purposes of this document, voice disorders are categorized as follows:

  • Organic — voice disorders that are physiological in nature and result from alterations in respiratory, laryngeal, or vocal tract mechanisms
    • Structural — organic voice disorders that result from physical changes in the voice mechanism (e.g., alterations in vocal fold tissues such as edema or vocal nodules; structural changes in the larynx due to aging)
    • Neurogenic — organic voice disorders that result from problems with the central or peripheral nervous system innervation to the larynx that affect functioning of the vocal mechanism (e.g., vocal tremor, spasmodic dysphonia, or paralysis of vocal folds)
  • Functional — voice disorders that result from improper or inefficient use of the vocal mechanism when the physical structure is normal (e.g., vocal fatigue; muscle tension dysphonia or aphonia; diplophonia; ventricular phonation)

Voice quality can also be affected when psychological stressors lead to habitual, maladaptive aphonia or dysphonia. The resulting voice disorders are referred to as psychogenic voice disorders or psychogenic conversion aphonia/dysphonia (Stemple, Glaze, & Klaben, 2010). These voice disorders are rare. SLPs refer individuals suspected of having a psychogenic voice disorder to other appropriate professionals (e.g., psychologist or psychiatrist) for diagnosis and may collaborate in subsequent treatment.

Voice disorders are not mutually exclusive, and overlap is common. For example, the etiology of nodules is functional, as they result from behavioral voice misuse. The voice misuse results in repeated trauma to the vocal folds, which may then lead to structural (organic) changes to the vocal fold tissue.

Speech-language pathologists (SLPs) may also be involved in the assessment and treatment of disorders that affect the voice mechanism (i.e., the aerodigestive tract) but are not classified as voice disorders. An example is paradoxical vocal fold movement (PVFM), a condition in which there is intermittent adduction of the vocal folds that interferes with breathing. When PVFM is suspected, SLPs are often consulted to help identify abnormal laryngeal and respiratory function and to teach various techniques (e.g., vocal exercises, relaxation techniques, quick-release breathing techniques, and proper breath management) to improve laryngeal and respiratory control (Mathers-Schmidt, 2001; Patel, Venediktov, Schooling, & Wang, 2015; Traister, Fajt, & Petrov, 2016). An ASHA Practice Portal page on aerodigestive disorders affecting voice will be developed in the future.

Voice disorders have been estimated to be present in between 3% and 9% of the U.S. population (Ramig & Verdolini, 1998; Roy, Merrill, Gray, & Smith, 2005). However, information from a large U.S. claims database (Cohen, Kim, Roy, Asche, & Courey, 2012) indicates the point prevalence (i.e., the number of individuals with the condition in the database at the time that data were retrieved) of voice disorders is 0.98% in a treatment-seeking population. This likely suggests that a large number of those individuals with voice disorders do not seek treatment.

The prevalence of voice disorders among treatment-seeking individuals has been shown to be affected by gender, age, and occupation (Cohen et al., 2012; Van Houtte, Van Lierde, D'Haeseleer, & Claeys, 2009).


  • Prevalence is higher in adult females than in adult males, with a reported ratio of 1.5:1.0 (Martins et al., 2015; Roy et al., 2005).
  • In children, voice disorders are significantly more prevalent in males than in females (Carding, Roulstone, Northstone, & the ALSPAC Study Team, 2006; Martins et al., 2015).


  • Prevalence has been reported to be higher in elderly adults (Cohen et al., 2012; Roy, Stemple, Merrill, & Thomas, 2007), with estimates ranging from 4.8% to 29.1% in population-based studies (de Araújo Pernambuco, Espelt, Balata, & de Lima, 2014).
  • In the pediatric population, the reported prevalence of a voice disorder has ranged from 1.4% to 6.0% (Black, Vahratian, & Hoffman, 2015; Carding et al., 2006; Duff, Proctor, & Yairi, 2004).


  • Occupational groups that appear to be most at risk for developing a voice disorder include teachers, manufacturing/factory workers, salespersons, and singers (Cohen et al., 2012; Fritzell, 1996; Miller & Verdolini, 1995; Thibeault, Merrill, Roy, Gray & Smith, 2004; Williams, 2003).
    • The estimated prevalence of reporting a current voice problem was higher in teachers (11.0%) than in nonteachers (6.2%; Roy et al., 2004).
    • Reported prevalence for teachers at a single point in time ranged from 9% to 37% (Cantor Cutiva, Vogel, & Burdorf, 2013. Reported lifetime prevalence (i.e., the percentage of teachers who experienced a voice disorder at some point in their lifetime) was between 50% and 80% (Cantor Cutiva et al., 2013; Martins et al., 2015).

Prevalence of Voice Disorder Etiologies

A wide range of etiologies may be associated with voice disorders. The relative proportion of these etiologies is also affected by gender, age, and occupation (Cohen et al., 2012; Martins et al., 2015).


  • Although adult females more frequently received diagnoses of dysphonia with no specific cause noted, adult males were more frequently diagnosed with chronic laryngitis (Cohen et al., 2012). Also, after the age of 40 years, males had higher prevalence rates of laryngeal cancer than did females (Cohen et al., 2012).


  • Among adults (aged between 19 and 60 years) with a voice disorder, the most frequent diagnoses included functional dysphonia (20.5%), acid laryngitis (12.5%), and vocal polyps (12%; Martins et al., 2015).
  • Of individuals over the age of 60 years who had been evaluated for vocal problems, voice disorders were most commonly associated with presbyphonia (changes associated with aging voice), reflux/inflammation, functional dysphonia, vocal fold paralysis/paresis, Reinke's edema, or laryngeal cancer (Hagen & Lyons, 1996; Martins et al., 2015).
  • Vocal fold nodules were the most frequently diagnosed voice disorder in the pediatric population (Martins, Hidalgo Ribeiro, Fernandes de Mello, Branco, & Tavares, 2012, Martins et al., 2015). The prevalence of vocal fold nodules may be as high as 16.9% in school-age children and is approximately twice as high for males than for females (Dobres, Lee, Stemple, Klummer, & Kretschmer, 1990; Kiliҫ, Okur, Yildirim, & Güzelsoy, 2004).


  • In a Flemish treatment-seeking population, the three main pathologies associated with professional voice users (i.e., teachers, performers, telemarketers, broadcasters, salesmen, and tour guides) included functional voice disorders (41%), vocal fold nodules/hypertrophy (15%), and reflux/laryngitis/inflammation (11%; Van Houtte et al., 2009).

The generic term dysphonia encompasses the auditory-perceptual symptoms of voice disorders. Dysphonia is characterized by altered vocal quality, pitch, loudness, or vocal effort.

Signs and symptoms of dysphonia include

  • roughness (perception of aberrant vocal fold vibration);
  • breathiness (perception of audible air escape in the sound signal or bursts of breathiness);
  • strained quality (perception of increased effort; tense or harsh as if talking and lifting at the same time);
  • strangled quality (as if talking with breath held);
  • abnormal pitch (too high, too low, pitch breaks, decreased pitch range);
  • abnormal loudness/volume (too high, too low, decreased range, unsteady volume);
  • abnormal resonance (hypernasal, hyponasal, cul de sac resonance);
  • aphonia (loss of voice);
  • phonation breaks;
  • asthenia (weak voice);
  • gurgly/wet sounding voice;
  • hoarse voice (raspy, audible aperiodicity in sound);
  • pulsed voice (fry register, audible creaks or pulses in sound);
  • shrill voice (high, piercing sound, as if stifling a scream); and
  • tremulous voice (shaky voice; rhythmic pitch and loudness undulations).

Other signs and symptoms include

  • increased vocal effort associated with speaking;
  • decreased vocal endurance or onset of fatigue with prolonged voice use;
  • variable vocal quality throughout the day or during speaking;
  • running out of breath quickly;
  • frequent coughing or throat clearing (may worsen with increased voice use); and
  • excessive throat or laryngeal tension/pain/tenderness.

Signs and symptoms can occur in isolation or in combination. As treatment progresses, some may dissipate, and others may emerge as compensatory strategies are eliminated.

Auditory-perceptual quality of voice in individuals with voice disorders can vary depending on the type and severity of disorder, the size and site of lesion (if present), and the individual's compensatory responses. The severity of the voice disorder cannot always be determined by auditory-perceptual voice quality alone.

Normal voice production depends on power and airflow supplied by the respiratory system; laryngeal muscle strength, balance, coordination, and stamina; and coordination among these and the supraglottic resonatory structures (pharynx, oral cavity, nasal cavity).

A disturbance in one of the three subsystems of voice production (i.e., respiratory, laryngeal, and subglottal vocal tract) or in the physiological balance among the systems may lead to a voice disturbance. Disruptions can be due to organic, functional, and/or psychogenic causes.

Organic causes include the following:

  • Structural
    • Vocal fold abnormalities (e.g., vocal nodules, edema, glottal stenosis, recurrent respiratory papilloma, sarcopenia [muscle atrophy associated with aging])
    • Inflammation of the larynx (e.g., arthritis of the cricoarytenoid or cricothyroid, laryngitis, laryngopharyngeal reflux)
    • Trauma to the larynx (e.g., from intubation, chemical exposure, or external trauma)
  • Neurologic
    • Recurrent laryngeal nerve paralysis
    • Adductor/abductor spasmodic dysphonia
    • Parkinson's disease
    • Multiple sclerosis

Functional causes include the following:

  • Phonotrauma (e.g., yelling, screaming, excessive throat-clearing)
  • Muscle tension dysphonia
  • Ventricular phonation
  • Vocal fatigue (e.g., due to effort or overuse)

Psychogenic causes include the following:

  • Chronic stress disorders
  • Anxiety
  • Depression
  • Conversion reaction (e.g., conversion aphonia and dysphonia)

The complementary relationships among these organic, functional, and psychogenic influences ensure that many voice disorders will have contributions from more than one etiologic factor (Stemple, Roy, & Klaben, 2014; Verdolini, Rosen, & Branski, 2006).

Recognizing associations among these factors, along with patient history, may help in identifying the possible causes of the voice disorder. Even when an obvious cause is identified and treated, the voice problem may persist. For example, an upper respiratory infection could be the cause of the dysphonia, but poor or inefficient compensatory techniques may cause dysphonia to persist, even when the infection has been successfully treated.

SLPs play a central role in the assessment, diagnosis, and treatment of voice disorders. The professional roles and activities in speech-language pathology include clinical services (diagnosis, assessment, planning, and treatment), prevention and advocacy, education, administration, and research.

SLPs are trained to evaluate voice use and vocal function to determine the cause of reported symptoms and to determine optimal treatment methods for improving voice production.

Appropriate roles for SLPs include the following:

  • Provide prevention information to individuals and groups known to be at risk for voice disorders, as well as to individuals working with those at risk.
  • Conduct a culturally and linguistically appropriate comprehensive voice assessment, including clinical and instrumental evaluation.
  • Identify normal and abnormal vocal function, describe perceptual qualities of voice, and assess vocal habits.
  • Diagnose a voice disorder.
  • Refer individuals to other professionals as needed to obtain a medical diagnosis (e.g., unilateral vocal fold immobility as the cause of dysphonia).
  • Refer individuals to other health care professionals when medical/surgical or psychological evaluation and treatment are indicated and facilitate patient access to comprehensive services.
  • Make decisions about management of voice disorders and develop culturally and linguistically appropriate treatment plans.
  • Provide treatment, document progress, and determine appropriate dismissal criteria.
  • Counsel patients and provide education aimed at preventing further complications from voice disorders.
  • Serve as an integral member of a collaborative team that includes the otolaryngologists and other professionals (e.g., pulmonologists, allergy and asthma physicians, gastroenterologists, neurologists, endocrinologists, mental health professionals, and vocal coaches or voice teachers), as appropriate. (See the ASHA resources on collaboration and teaming and interprofessional education/interprofessional practice [IPE/IPP].)
  • Consult with other professionals, family members, and caregivers to facilitate program development and to provide supervision, evaluation, and/or expert testimony, as appropriate.
  • Remain informed of research in the area of voice disorders, and help advance the knowledge base related to the nature and treatment of voice disorders.
  • Advocate for individuals with voice disorders at the local, state, and national levels.

As indicated in the Code of Ethics (ASHA, 2016a), SLPs who serve this population should be specifically educated and appropriately trained to do so.

See the Assessment section of the Voice Disorders evidence map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.


Screening may be conducted if a voice disorder is suspected. It may be triggered by concerns from individuals, parents, teachers, or health care providers. When deviations from normal voice are detected during screening, further evaluation is warranted.

Screening includes evaluation of vocal characteristics related to respiration, phonation, and resonance, as well as vocal range and flexibility (e.g., pitch, loudness, pitch range, and endurance). Clinicians may use a formal screening tool (Lee et al., 2004) or obtain data using informal tasks. Standardized self-report questionnaires can be included for a more thorough screening (e.g., Deary, Wilson, Carding, & MacKenzie, 2003; Hogikyan & Sethuraman, 1999; Jacobson et al., 1997).

Comprehensive Assessment

Assessment and treatment of voice disorders may require use of appropriate personal protective equipment.

All patients/clients with voice disorders are examined by a physician, preferably in a discipline appropriate to the presenting complaint. The physician's examination may occur before or after the voice evaluation by the speech-language pathologist.

A comprehensive assessment is conducted for individuals suspected of having a voice disorder, using both standardized and nonstandardized measures (see ASHA resource on assessment tools, techniques, and data sources). Norms are based on age, gender, type of instrumentation used, cultural background, and dialect. For a review of clinical voice assessments, see Roy et al. (2013).

Diagnostic therapy may be performed as part of the comprehensive assessment to help in making a diagnosis and to determine if the individual is stimulable to voice therapy efforts.

Consistent with the World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF) framework (ASHA, 2016b; WHO, 2001), comprehensive assessment is conducted to identify and describe

  • impairments in body structure and function, including underlying strengths and weaknesses in speech sound production and verbal/nonverbal communication;
  • co-morbid deficits such as other health conditions and medications that can affect voice;
  • the individual's limitations in activity and participation, including functional status in communication and interpersonal interactions;
  • contextual (environmental and personal) factors that serve as barriers to, or facilitators of, successful communication and life participation; and
  • the impact of communication impairments on quality of life and functional limitations relative to premorbid social roles and abilities for the individual and the impact on his or her community.

See the ASHA resource titled Person-Centered Focus on Function: Voice [PDF] for an example of assessment data consistent with ICF.

Comprehensive Assessment for Voice Disorders: Typical Components

Case History
  • Individual's description of voice problem, including onset and variability of symptoms
  • Medical status and history, including surgeries, chronic disorders, and medications
  • Previous voice treatment
  • Daily habits related to vocal hygiene
  • Individual's assessment of how voice problem affects
    • emotions and self-image; and
    • ability to communicate effectively in everyday activities and in social and work settings (e.g., Hogikyan & Sethuraman, 1999; Jacobson et al., 1997; Ma & Yiu, 2001).
Oral-Peripheral Examination
  • Assessment of structural or motor-based deficits that may affect communication and voice, including strength, speed, and range of motion of oral musculature
  • Assessment of symmetry and movement of structures of the face, oral cavity, head, neck, and respiratory system during rest and purposeful speech tasks
  • Testing of mechano-sensation of face and oral cavity
  • Testing of chemo-sensation (i.e., taste and smell)
  • Assessment of laryngeal sensations (dryness, tickling, burning, pain, etc.) and palpation of extrinsic laryngeal musculature, as indicated
Assessment of Respiration
  • Respiratory pattern (abdominal, thoracic, clavicular)
  • Coordination of respiration with phonation (breath-holding patterns, habitual use of residual air, length of breath groups)
  • Maximum phonation time (MPT; Dejonckere, 2010; Speyer et al., 2010)
  • s/z ratio to assess for glottal insufficiency, which may be indicative of laryngeal pathology (Eckel & Boone, 1981; Stemple et al., 2010)

Auditory-Perceptual Assessment

Subjective Assessment Based on Clinical Impressions of the SLP

Voice Quality

  • Consensus features assessed during production of sustained vowels, sentences, and running speech
    • Roughness—perceived irregularity in voicing source
    • Breathiness—audible air escape in voice
    • Strain—perception of excessive vocal effort
    • Pitch (perceptual correlate of fundamental frequency)—deviations from normal relative to age, gender, and referent culture
    • Loudness (perceptual correlate of sound intensity)—deviations from normal relative to age, gender, and referent culture
    • Overall severity—global, integrated impression of voice deviance
  • Additional perceptual features
    • Diplophonia, aphonia, pitch instability, tremor, vocal fry, falsetto, wet/gurgly

(Kemper, Gerratt, Abbott, Barkmeier-Kraemer, & Hillman, 2009; ASHA, 2002; ASHA , n.d.)


  • Assess resonance quality (normal, hyponasal, hypernasal, cul-de-sac).
  • If abnormal, assess stimulability for normal resonance.
  • If normal, evaluate the focus of resonance (oral, pharyngeal/laryngeal, nasal).

See ASHA's Practice Portal page on Resonance Disorders.


  • Voice onset/offset (e.g., delayed voice onset; quality of voice at onset)
  • Ability to sustain the voice to achieve appropriate phrasing during speaking
  • Ability to demonstrate strong and consistent rate of vocal fold valving during diadochokinesis


Deviations from normal relative to age, gender, and referent culture

Instrumental Assessment

Adapted from Recommended Protocols for Instrumental Assessment of Voice (ASHA, 2015)

Laryngeal Imaging

  • Measures of structure and gross function (using videoendoscopy) and measures of vocal fold vibration during phonation (using videostroboscopy)
    • Videolaryngoendoscopy
      • Vocal fold edges—appearance of superior vocal fold edges during abduction
      • Vocal fold mobility—movement of vocal folds toward and away from midline at level of cricoarytenoid joint during laryngeal diadochokinetic task
      • Supraglottic activity—degree of compression of supraglottic structures during sustained phonation
    • Videolaryngostroboscopy
      • Regularity—consistency of successive glottic cycles
      • Amplitude—lateral movement of the vocal fold medial plane
      • Mucosal wave—independent lateral movement of mucosa over vocal fold
      • Left/right phase symmetry—symmetry of vocal folds (opening, closing, maximum lateral–medial excursion) during glottic cycle
      • Vertical level—level difference in vertical plane between vocal folds during maximum closed phase of glottic cycle
      • Glottal closure pattern—glottal configuration during maximum closure
      • Glottal closure duration—relative proportion of glottal cycle in which glottis is closed

Acoustic Assessment

  • Objective measures of vocal function related to vocal loudness, pitch, and quality
    • Vocal amplitude
      • Habitual sound pressure level (SPL) in decibels (dB)—typical sound level of voice during connected speech (standard reading passage)
      • Minimum and maximum vocal SPL (dB)—softest and loudest sustainable phonation
    • Vocal frequency
      • Mean vocal f0 (Hz)—average of the estimates of the f0 for acoustic signal recorded during connected speech (standard reading passage)
      • Vocal f0 standard deviation (SD; Hz)—SD of the estimates of the f0 for acoustic signal recorded during connected speech
      • Minimum and maximum vocal f0 (Hz)—f0 values for the lowest and highest pitched sustainable phonations
    • Vocal signal quality
      • Vocal cepstral peak prominence (CPP; dB)—relative amplitude of the peak in the cepstrum that represents the dominant rahmonic of the vocal acoustic signal (sustained vowels and connected speech samples)

Aerodynamic Assessment

  • Measures (using noninvasive procedures) of glottal aerodynamic parameters required for phonation
    • Glottal airflow
      • Average glottal airflow rate (L/sec or mL/sec)—estimated from oral airflow rate during vowel production
    • Subglottal air pressure
      • Average subglottal air pressure (cm of water [cmH2O] or kilopascals [kPa])—estimated for intraoral air pressure produced during repetition of stop consonants in syllable strings
    • Mean vocal SPL and f0—extracted from simultaneously recorded acoustic signal; facilitates interpretation of airflow and air pressure measurements

Assessment may result in

  • diagnosis of a voice disorder;
  • clinical description of the characteristics and severity of the disorder;
  • statement of prognosis and recommendations for intervention;
  • identification of appropriate treatment or management options; and
  • referral to other professionals, as needed.

See the Treatment section of the Voice Disorders evidence map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.

Intervention is conducted to achieve improved voice production and coordination of respiration and laryngeal valving. The ASHA Practice Portal page on head and neck cancer will address intervention aimed at acquisition of alaryngeal speech sufficient to allow for functional oral communication.

Consistent with the WHO (2001) framework, intervention is designed to

  • capitalize on strengths and address weaknesses related to underlying structures and functions that affect voice production;
  • facilitate the individual's activities and participation by assisting the person in acquiring new communication skills and strategies; and
  • modify contextual factors to reduce barriers and enhance facilitators of successful communication and participation, and to provide appropriate accommodations and other supports, as well as training in how to use them.

See the ASHA resource titled Person-Centered Focus on Function: Voice [PDF] for an example of functional goals consistent with ICF.

Collaborating With Other Professionals

In the case of medically related voice disorders (e.g., vocal polyps, vocal cysts, spasmodic dysphonia), SLPs often team with otolaryngologists and other medical professionals (e.g., pulmonologists, gastroenterologists, neurologists, allergists, endocrinologists, and occupational medicine physicians) and, if appropriate, develop treatment plans to support the medical plan and to optimize outcomes.

Some individuals develop voice disorders in the absence of structural pathology (e.g., functional aphonia, muscle tension dysphonia, and mutational/functional falsetto) and may benefit from support in addition to what can be provided by the SLP. Counseling, direct manipulation of the voice, and use of interview questions can be used to probe possible factors contributing to the voice problem. SLPs refer the individual to appropriate health care professionals (e.g., psychologists) to address issues outside the SLP's scope of practice (ASHA, 2016b). SLPs often engage in collaborative approaches throughout the course of assessment and subsequent treatment.

See the ASHA resources on collaboration and teaming and interprofessional education/interprofessional practice (IPE/IPP).

Treatment Approaches

Norms within different settings are considered when determining vocal needs and establishing goals. For example, vocal norms and needs within the workplace may be different from those within the community (e.g., home and social settings).

SLPs often incorporate aspects of more than one therapeutic approach in developing a treatment plan.

Approaches can be direct or indirect.

  • Direct approaches focus on manipulating the voice-producing mechanisms (e.g., phonation, respiration, and musculoskeletal function) in order to modify vocal behaviors and establishing healthy voice production (Colton & Casper, 1996; Stemple, 2000).
  • Indirect approaches modify the cognitive, behavioral, psychological, and physical environments in which voicing occurs (Roy, et al., 2001; Thomas & Stemple, 2007). Indirect approaches include the following two components:
    • Patient education—discussing normal physiology of voice production and the impact of voice disorders on function; providing information about the impact of vocal misuse and strategies for maintaining vocal health (vocal hygiene)
    • Counseling—identifying and implementing strategies such as stress management to modify psychosocial factors that negatively affect vocal health (Van Stan, Roy, Awan, Stemple, & Hillman, 2015)

A therapeutic plan typically involves the use of at least one of the direct approaches and one or more of the indirect approaches based on the patient's condition and goals. Some clinicians concentrate on directly modifying the specific symptoms of the inappropriate voice, whereas others take a more holistic approach, with the goal of balancing the physiologic subsystems of voice production—respiration, phonation, and resonance.

Many clinicians begin by

  • identifying behaviors that are contributing to the voice problems, including unhealthy vocal hygiene practices (e.g., shouting, talking loudly over noise, coughing, throat clearing, and poor hydration) and
  • implementing healthy vocal hygiene practices (e.g., drinking plenty of water and talking at a moderate volume) and practices to reduce vocally traumatic behaviors (e.g., voice conservation).

Treatment Options

The following subsections offer brief descriptions of general and specific treatments for individuals with voice disorders. They are organized under two broad categories: physiologic voice therapy (i.e., those treatments that directly modify the physiology of the vocal mechanism) and symptomatic voice therapy (i.e., those treatments aimed at modifying deviant vocal symptoms or perceptual voice components using a variety of facilitating techniques). This list of treatment options is not exhaustive, and the inclusion of any specific treatment approach does not imply endorsement by ASHA. For more information about treatment approaches and their use with various voice disorders, see Stemple et al. (2010).

Treatment selection depends on the type and severity of the disorder and the communication needs of the individual. Clinicians are sensitive to cultural, linguistic, and individual variables when selecting appropriate treatment approaches. As indicated in the Code of Ethics (ASHA, 2016a), SLPs who serve this population should be specifically educated and appropriately trained to do so.

Physiologic Voice Therapy

Physiologic voice therapy is inherently a holistic approach to treatment. Physiologic voice therapy programs strive to balance the three subsystems of voice production (respiration, phonation, and resonance) as opposed to working directly on isolated voice symptoms. Most physiologic approaches may be used with a variety of disorders that result in hyper- and hypofunctional vocal patterns. Below are some of the physiologic voice therapy programs, arranged in alphabetical order.

Accent Method

The accent method is designed to increase pulmonary output, improve glottic efficiency, reduce excessive muscular tension, and normalize the vibratory pattern during phonation. During therapy, the clinician may do one or more of the following tasks:

  • Facilitate abdominal breathing by initially placing the patient in a recumbent position.
  • Use rhythmic vocal play with models of accented phonation patterns, which the patient then imitates.
  • Transfer rhythms to articulated speech, initially being given a model and eventually progressing through reading, monologues, and conversational speech.

(See, e.g., Kotby, Shiromoto, & Hirano, 1993; Malki, Nasser, Hassan, & Farahat, 2008.)

Conversation Training Therapy (CTT)

Conversation Training Therapy (CTT) focuses exclusively on voice awareness and production in patient-driven conversational narrative, without the use of a traditional therapeutic hierarchy. Grounded in the tenets of motor learning, CTT strives to guide patients in achieving balanced phonation through clinician reinforcement, imitation and modeling in conversational speech. CTT incorporates six interchangeable components: 1) clear speech, 2) auditory and kinesthetic awareness, 3) negative practice/labeling, 4) embedding basic training gestures into speech, 5) prosody, projection and pauses, and 6) rapport building (Gartner-Schmidt et al, 2016; Gillespie et al, 2019).

Cup Bubble/Lax Vox

Cup bubble, also known as Lax Vox, is an aerodynamic building task aimed at improving ability to sustain phonation while speaking. It is done by having a patient blow air initially into a cup of water without voice. Voicing can be added for subsequent trials, and in time, pitch can be altered across and within trials. Eventually, the cup is removed during voicing, and the phonation continues. These exercises are thought to widen the vocal tract during phonation and reduce tension in the vocal folds. Biofeedback increases the individual's awareness of his or her healthy voice production (e.g., Denizoglu & Sihvo, 2010; Simberg & Laine, 2007).

Expiratory Muscle Strength Training (EMST)

Expiratory muscle strength training (EMST) improves respiratory strength during phonation. Increase in maximum expiratory pressure (MEP) can be trained with specific calibrated exercises over time, thus improving the relationship between respiration, phonation, and resonance. EMST uses an external device to mechanically overload the expiratory muscles. The device has a one-way, spring-loaded valve that blocks the flow of air until the targeted expiratory pressure is produced. The device can be calibrated to increase or decrease physiologic load on the targeted muscles (Pitts et al., 2009).

Lee Silverman Voice Treatment (LSVT®)

Lee Silverman Voice Treatment (LSVT®; Ramig, Bonitati, Lemke, & Horii, 1994) was initially developed for patients with Parkinson disease but can also be used with other populations. It is designed to help maximize phonatory and respiratory function using a set of simple tasks. Individuals are instructed to produce a loud voice with maximum effort and to monitor the loudness of their voices while speaking. The effort that is involved generates improved respiratory support, laryngeal muscle activity, articulation, and even facial expression and animation. Using a sound-level meter, visual biofeedback is provided to demonstrate the effort necessary to increase loudness. LSVT is provided by clinicians who are specifically trained and certified in the administration of this technique.

Five basic principles are followed in LSVT:

  • Individuals should "think loud/think shout."
  • Speech effort must be high.
  • Treatment must be intensive.
  • Patients must recalibrate their loudness level.
  • Improvements are quantified over time.
Manual Circumlaryngeal Techniques

Manual circumlaryngeal techniques are intended to reduce musculoskeletal tension and hyperfunction by re-posturing the larynx during phonation. There are three main manual laryngeal re-posturing techniques:

  • Push-back maneuver—place forefinger on thyroid cartilage and push back to change shape of glottis.
  • Pull-down maneuver—place thumb and forefinger in the thyrohyoid space and pull the larynx downward.
  • Medial compression and downward traction—place thumb and forefinger in the thyrohyoid space, and apply medial compression.

Applying these maneuvers during vocalization allows the individual to hear resulting changes in voice quality (Andrews, 2006; Roy, Bless, Heisey, & Ford, 1997). Care is taken when employing these techniques, as some patients report discomfort.

Phonation Resistance Training Exercise (PhoRTE)

Phonation Resistance Training Exercise (PhoRTE; Ziegler & Hapner, 2013) was adapted from LSVT and consists of four exercises:

  • Producing /a/ with loud maximum sustained phonation
  • Producing /a/ with loud ascending and descending pitch glides over the entire pitch range
  • Producing functional phrases using a loud and high (pitched) voice
  • Producing the same functional phrases using loud and low (pitched) voice

Individuals are reminded to maintain a "strong" voice throughout these treatment exercises. PhoRTE has a less intensive intervention schedule than LSVT. PhoRTE also differs in that it combines both loudness and pitch when producing phrases (i.e., loud and low pitch; loud and high pitch). Use of PhoRTE has been studied in adults with presbyphonia (aging voice) as a way to improve vocal outcomes (e.g., decrease phonatory effort) and increase voice-related quality of life (Ziegler, Verdolini Abbott, Johns, Klein, & Hapner, 2014).

Resonant Voice Therapy

Resonant voice is defined as voice production involving oral vibratory sensations, usually on the anterior alveolar ridge or lips or higher in the face in the context of easy phonation. Resonant voice therapy uses a continuum of oral sensations and easy phonation, building from basic speech gestures through conversational speech. The goal is to achieve the strongest, "cleanest" possible voice with the least effort and impact between the vocal folds to minimize the likelihood of injury and maximize the likelihood of vocal health (Stemple et al., 2010). The program incorporates humming and both voiced and voiceless productions that are shaped into phrase and conversational productions (Verdolini, 1998, 2000).

Stretch and Flow Phonation

Stretch and flow phonation —also known as Casper-Stone Flow Phonation—is a physiological technique used to treat functional dysphonia or aphonia (Stone & Casteel, 1982). It focuses on airflow management and is used for individuals with breath-holding tendencies. Individuals are instructed to focus on a steady outflow of air during exhalation. Various biofeedback methods are used, including placing a piece of tissue in front of the mouth or holding one's hand in front of the mouth to monitor airflow. Voicing is introduced once the individual masters continuous airflow during exhalation. As such, this technique produces a breathy voice quality. Eventually, this voice quality is carried into trials with spoken words and phrases, and the breathiness is gradually reduced.

Flow Phonation (Gartner-Schmidt, 2008, 2010) is a hierarchical therapy program to designed to facilitate increased airflow, ease of phonation, and forward oral resonance. It was modified from Stretch and Flow Phonation by eliminating the “stretch” component which reduced the rate of speech in the original therapy.

Vocal Function Exercises (VFEs)

Vocal function exercises (VFEs) are a series of systematic voice manipulations designed to facilitate return to healthy voice function by strengthening and coordinating laryngeal musculature and improving efficiency of the relationship among airflow, vocal fold vibration, and supraglottic treatment of phonation (Stemple, 1984). Sounds used in training are specific, and correct production is encouraged. VFEs consist of four exercises—warm-up, stretching, contracting, and power exercises. Exercises are completed twice a day (morning and evening) in sets of two. Maximum phonation time goals are set on the basis of individual lung capacity and an airflow rate of 80 ml/sec. Individuals are advised to use a soft, engaged tone and are trained to use a semi-occluded vocal tract (lip buzz) without tension during voice productions.

Symptomatic Voice Therapy

The focus of symptomatic voice therapy is on the modification of the deviant vocal symptoms or perceptual voice components. Deviant symptoms may include pitch that is too high or low, voice that is too soft or loud, breathy phonation, or the use of hard glottal attacks or glottal fry. Symptomatic voice therapy assumes voice improvement through direct symptom modification using a variety of voice facilitating techniques (Boone et al., 2010) that are either direct or indirect.


Amplification devices such as microphones can be used to amplify the voice in any situation that requires increased volume (e.g., when speaking to large groups, or during conversation when the individual's voice is weak). As such, voice amplification can function as a supportive tool or as a means of augmentative communication. It can help prevent vocal hyperfunction as a result of talking at increased volume or for extended periods of time.

Auditory Masking

Auditory masking is used in cases of functional aphonia/dysphonia and often results in changed or normal phonation. Individuals are instructed to talk or read passages aloud while wearing headphones with masking noise input. Using a loud noise background, the individual often produces voice at increased volume (Lombard effect) that can be recorded and used later in treatment as a comparison (e.g., Brumm & Zollinger, 2011; Adams & Lang, 1992).


The basis of biofeedback is that self-control of physiologic functions is possible with continuous, immediate information about internal bodily state. Biofeedback provides clear and reliable feedback in response to alterations in voice production, thus facilitating improvements in pitch, loudness, quality, and effort. It can be kinesthetic, auditory, or visual. Using biofeedback, individuals are trained to become aware of physical sensations with respect to respiration, body position, and vibratory sensation. Awareness helps the individual understand his or her physiological processes when generating voice. Auditory feedback, such as real-time amplification auditory modeling is an effective way to achieve voice improvement.

Chant Speech

Chant speech is characterized by a rhythmic, prosodic pattern that serves as a template for spoken utterances. It is used in therapy to help reduce phonatory effort that results in vocal fatigue and decrease in phonatory capabilities. Chant speech requires pitch fluctuations and coordination among respiratory, phonatory, and resonance subsystems. Speakers habituate to these more efficient vocal patterns. The increased lung pressure required for these tasks may also decrease reliance on laryngeal resistance and reduce fatigue (e.g., McCabe & Titze, 2002).

Confidential Voice

Confidential voice is designed to reduce laryngeal tension/hyperfunction and increase air flow (Casper, 2000). The individual begins with an easy and breathy vocal quality and builds to normal voicing without decreasing airflow. This technique is intended to address excessive vocal tension and to facilitate relaxation in the muscles of the larynx.

Glottal Fry

Glottal fry is useful for patients with vocal nodules and other problems associated with hyperfunction (e.g., polyps, functional dysphonia, spasmodic dysphonia, vocal fold thickening, and ventricular phonation). Because the vocal folds must be relaxed in order to produce glottal fry, this technique can be a useful index of vocal fold relaxation (Boone et al., 2010). Although glottal fry is a powerful facilitative technique to offload tension in the larynx, it is not a long-term speech quality target.

Inhalation Phonation

Inhalation phonation is a technique used to facilitate true vocal vibration in the presence of habitual ventricular fold phonation, functional aphonia, and muscle tension dysphonia. Individuals produce a high-pitched voice on inhalation. Upon inhalation voicing, the true vocal folds are in a stretched position, suddenly adducted and in vibration. Upon exhalation, patients try to achieve a nearly matched voice. This approach eases the way to gaining true vocal fold vibration.

Semi-Occluded Vocal Tract (SOVT) Exercises

Semi-occluded vocal tract (SOVT) exercises in voice therapy involve narrowing at any supraglottic point along the vocal tract in order to maximize interaction between vocal fold vibration (sound production) and the vocal tract (the sound filter) and to produce resonant voice.

Straw Phonation

Straw phonation is one of the most frequently used methods to create semi-occlusion in the vocal tract (Titze, 2006). Narrowing the vocal tract increases air pressure above the vocal folds, keeping them slightly separated during phonation and reducing the impact collision force. To accomplish this, the individual semi-occludes the vocal tract by phonating through a straw or tube. Resistance can be manipulated by varying the length and diameter of the straw. Individuals practice sustaining vowels, performing pitch glides, humming songs, and transitioning to the intonation and stress patterns of speech. Eventually, use of the straw is reduced and eliminated.

Lip Trill

Semi-occlusion at the level of the lips is accomplished via lip trills. This technique involves a smooth movement of air through the oral cavity and over the lips, causing a vibration (lip buzz), similar to blowing bubbles underwater. Often, the trills are paired with phonation and pitch changes. The focus is to improve breath support and produce voicing without tension.


The patient is instructed in the technique of sitting with upright posture and with the shoulders in a low, relaxed position to facilitate voice production with less effort. Collaboration with a physical therapist or occupational therapist may be necessary with some patients.


In cases of vocal hyperfunction, a variety of relaxation techniques may be useful as a tool to reduce both whole-body and laryngeal area tension. The goal of these techniques is to reduce effortful phonation. Frequently used techniques include progressive muscle relaxation (slowly tensing and then relaxing successive muscle groups), visualization (forming mental images of a peaceful, calming place or situation), and deep breathing exercises.

Twang Therapy

Twang therapy is used for individuals with hypophonic voice. It involves the narrowing of the aryepiglottic sphincter using a "twang" voice to create a high-intensity voice quality while maintaining low vocal effort (Lombard & Steinhauer, 2007). The desired outcome is decreasing phonatory effort and increasing vocal efficiency.


This facilitating technique uses the natural functions of yawning and sighing to overcome symptoms of vocal hyperfunction (e.g., elevated larynx and vocal constriction). The technique is intended to lower the position of the larynx and subsequently widen the supraglottal space in order to produce a more relaxed voice and encourage a more natural pitch.

Service Delivery

Refer to the Service Delivery section of the Voice Disorders evidence map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.

In addition to determining the type of speech and language treatment that is optimal for individuals with voice disorders, SLPs consider other service delivery variables—including format, provider, dosage, and timing—that may affect treatment outcomes.

  • Format — the structure of the treatment session (e.g., group vs. individual; direct and/or consultative).
  • Provider — the person offering the treatment (e.g., SLP, trained volunteer, caregiver).
  • Dosage — the frequency, intensity, and duration of service. Clinicians consider the unique needs of each patient and the nature of the voice disorder in determining appropriate dosage for therapy. Some voice therapy programs will have specific dosage parameters. See De Bodt, Patteeuw, & Versele (2015) for a summary of international practices regarding temporal variables (dosage and frequency) in voice therapy.
  • Timing — when intervention is conducted relative to the diagnosis.
  • Setting — location of treatment (e.g., home, community based, work).

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Content for ASHA's Practice Portal is developed through a comprehensive process that includes multiple rounds of subject matter expert input and review. ASHA extends its gratitude to the following subject matter experts who were involved in the development of the Voice Disorders page:

  • Julie M. Barkmeier-Kraemer, PhD, CCC-SLP
  • Jennifer N. Craig, MS, CCC-SLP
  • Archie B. Harmon, PhD, CCC-SLP
  • Robert E. Hillman, PhD, CCC-SLP
  • Rita R. Patel, PhD, CCC-SLP
  • Bari Hoffman Ruddy, PhD, CCC-SLP
  • Joseph C. Stemple, PhD, CCC-SLP
  • Yumi A. Sumida, MS, MFA, CCC-SLP
  • Kristine Tanner, PhD, CCC-SLP
  • Miriam R. van Mersbergen, PhD, CCC-SLP
  • Laura Purcell Verdun, MA, CCC-SLP

In addition, ASHA thanks the American Academy of Otolaryngology-HNS Speech, Voice and Swallowing Committee members and ASHA Special Interest Division 3, Voice and Voice Disorders Steering Committee members whose work was foundational to the development of this content.

The members of the AAO-HNS Speech, Voice and Swallowing Committee included Robert Sataloff, Jonathan Aviv, Mary Beaver, Alison Behrman (ASHA representative), Mark Courey, Glendon Gardner, Norman Hogikyan, Christy Ludlow (ASHA representative), Roger Nuss, Clark Rosen, Mark Shikowitz, Robert Stachler, Lee Akst, and Susan Sedory Holzer (staff liaison).

The members of the ASHA Special Interest Division 3, Voice and Voice Disorders Steering Committee included Leslie Glaze (coordinator), Bernice Klaben, Lori Lombard, Mary Sandage (associate coordinator), Susan Thibeault, and Michelle Ferketic (ex officio). Celia Hooper, vice president for professional practices (2003–2005), served as monitoring vice president for ASHA.

Citing Practice Portal Pages

The recommended citation for this Practice Portal page is:

American Speech-Language-Hearing Association. (n.d.). Voice Disorders.  (Practice Portal). Retrieved month, day, year, from

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