Vocal cord nodule

Vocal cord nodules are bilaterally symmetrical benign white masses (nodules) that form at the midpoint of the vocal folds.<ref name="Verdolini et al 2014 Vocal Fold Nodules">Template:Cite book</ref> Although diagnosis involves a physical examination of the head and neck, as well as perceptual voice measures, visualization of the vocal nodules via laryngeal endoscopy remains the primary diagnostic method.<ref name=pmid14631179>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Vocal fold nodules interfere with the vibratory characteristics of the vocal folds by increasing the mass of the vocal folds and changing the configuration of the vocal fold closure pattern.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /><ref name="Colton et al 2006 Nodules">Template:Cite book</ref> Due to these changes, the quality of the voice may be affected.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> As such, the major perceptual signs of vocal fold nodules include vocal hoarseness and breathiness.<ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347">Template:Cite journal</ref> Other common symptoms include vocal fatigue, soreness or pain lateral to the larynx, and reduced frequency and intensity range.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> Airflow levels during speech may also be increased.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> Vocal fold nodules are thought to be the result of vocal fold tissue trauma caused by excessive mechanical stress, including repeated or chronic vocal overuse, abuse, or misuse.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /><ref name="pmid19779347" /> Predisposing factors include profession, gender, dehydration, respiratory infection, and other inflammatory factors.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" />

For professional voice users as well as individuals who frequently experience hoarseness, vocal hygiene practices are recommended for the prevention of vocal fold nodules and other voice disorders.<ref name=pmid19741535>Template:Cite journal</ref> Vocal hygiene practices include three components: regulating the quantity and quality of voice use, improving vocal fold hydration, and reducing behaviours that jeopardize vocal health.<ref name=pmid19741535/> About 10% of nodules resolve on their own, which is more likely if they are smaller and the onset more recent.<ref name="Simpson & Rosen 2008 Vocal Fold Nodules">Template:Cite book</ref> Treatment of vocal fold nodules usually involves behavioural intervention therapy administered by a speech–language pathologist. In severe cases, surgery to remove the lesions is recommended for best prognosis.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> In children, vocal fold nodules are more common in males; in adults, they are more common in females.<ref name=pmid2199731>Template:Cite journal</ref><ref name="pmid19779347" />

Signs and symptoms

One of the major perceptual signs of vocal fold nodules is a change in the quality of the voice.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> The voice may be perceived as hoarse,<ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> due to aperiodic vibrations of the vocal folds,<ref name="pmid19779347" /> and may also be perceived as breathy,<ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> due to an incomplete closure of the vocal folds upon phonation.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> The degree of hoarseness and breathiness perceived may vary in severity. This variability may be due to the size and firmness of the nodules.<ref name="Colton et al 2006 Nodules" /> Other common symptoms include difficulty producing vocal pitches in the higher range,<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> increased phonatory effort,<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> and vocal fatigue.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid19779347" /> There may be a sensation of soreness or pain in the neck, lateral to the larynx,<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> which generally occurs because of the increased effort needed to produce the voice.<ref name="Verdolini et al 2014 Vocal Fold Nodules" />

Acoustic signs

Major acoustic signs of vocal fold nodules involve changes in the frequency and the intensity of the voice. The fundamental frequency, an acoustic measure of voice pitch, may be normal. However, the range of pitches the individual is capable of producing may be reduced,<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> and it may be especially difficult to produce pitches in the higher range.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> The intensity of the voice, an acoustic measure of amplitude or loudness, may also be normal.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> However, the individual's amplitude range may be reduced as well.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> Perturbations or variations in frequency, known as jitter, and in amplitude, known as shimmer, may be increased.<ref name="Colton et al 2006 Nodules" />

Aerodynamic signs

If the nodules affect the closure of the vocal folds, airflow levels during speech may be increased in comparison to the speaker's habitual levels. However, airflow levels may still fall within the upper limits of the normal range.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> The degree to which an individual's airflow levels increase seems to depend on the severity of the injury. Subglottal pressure, the air pressure that is available below the glottis and in the trachea to produce speech, may be increased as well.<ref name="Colton et al 2006 Nodules" />

Causes

Vocal fold nodules are thought to be the result of vocal fold tissue trauma caused by excessive mechanical stress.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /><ref name="pmid19779347" /> During phonation, the vocal folds undergo many forms of mechanical stress. One example of such stress is the impact stress caused by the collision between the left and right vocal fold surfaces during vibration.<ref name="pmid14631179" /> This stress is thought to reach its maximum in the mid-membranous region of the vocal folds, at the junction of the anterior 1/3rd and posterior 2/3rd, the most common site of nodule formation.<ref name="pmid14631179" /><ref name="pmid19779347" /> Vocal overuse (speaking for long periods), abuse (yelling), or misuse (hyperfunction) may produce excessive amounts of mechanical stress by increasing the rate and/or force with which the vocal folds collide. This may lead to trauma that is focalized to the mid-membranous vocal fold<ref name="pmid19779347" /> and subsequent wound formation.<ref name="pmid14631179" /> Repeated or chronic mechanical stress is thought to lead to the remodeling of the superficial layer of the lamina propria.<ref name="pmid19779347" /> It is this process of tissue remodeling that results in the formation of benign lesions of the vocal folds such as nodules.<ref name="pmid14631179" /><ref name="pmid19779347" />

There are several factors that may predispose an individual to vocal fold nodules. Activities or professions that may contribute to phonotraumatic behaviors include cheerleading, untrained singing, speaking above noise, and teaching without voice amplification, as these increase mechanical stress and subsequent vocal fold trauma.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> Gender may be another predisposing factor, as vocal fold nodules occur more frequently in females.<ref name="pmid19779347" /> The presence of dehydration, respiratory infection, and inflammatory factors may also act as predisposing or aggravating factors. Inflammatory factors may include allergies, tobacco and alcohol use, laryngopharyngeal reflux, and other environmental influences.<ref name="Verdolini et al 2014 Vocal Fold Nodules" />

Pathophysiology

Vocal fold nodules often alter the mechanical properties of the vocal folds, which can interfere with their vibratory characteristics.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> Nodules may increase the mass of the vocal folds, especially along the medial edge where they are typically found. This increased mass may result in aperiodic or irregular vibration, the perception of greater pitch and loudness perturbations, and of increased hoarseness.<ref name="Colton et al 2006 Nodules" /> Nodules may also affect the mucosal wave of the vocal folds by changing the configuration of the vocal fold closure pattern. They often cause incomplete closure of the vocal folds, resulting in an hourglass configuration.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /><ref name="Colton et al 2006 Nodules" /> The incomplete closure allows more air to escape through the vocal folds, which often results in the perception of breathiness.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /> The degree to which nodules will affect the mucosal wave and vibratory characteristics of the vocal folds depends highly on the size of the nodule.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="pmid14631179" /> Smaller nodules may still allow the vocal folds to achieve complete closure.<ref name="Verdolini et al 2014 Vocal Fold Nodules" />

Diagnosis

Diagnosing vocal fold nodules typically includes a comprehensive analysis of medical and voice history, a physical examination of the head and neck, perceptual evaluation of voice, and visualization of the vocal folds.<ref name="Johns, M. M">Johns, M. M. (January 01, 2003). Update on the etiology, diagnosis, and treatment of vocal fold nodules, polyps, and cysts. Current Opinion in Otolaryngology & Head and Neck Surgery, 11, 6, 456-61.</ref> Visualization is considered to be the main method of diagnosis as perceptual evaluation, which includes acoustic and aerodynamic measures, alone is insufficient.<ref name="Pedersen">Pedersen M, McGlashan J. Surgical versus non-surgical interventions for vocal cord nodules. Cochrane Database of Systematic Reviews 2012, Issue 6. Art. No.: CD001934. DOI: 10.1002/14651858.CD001934.pub2</ref> Laryngeal videostroboscopy, an imaging technique, is commonly used to view the vocal folds: this procedure can be performed nasally or orally.<ref name="Johns, M. M"/> Vocal fold nodules are most often characterized as bilaterally symmetrical whitish masses,<ref name="Johns, M. M"/> and tend to form at the midpoint of the vocal folds.<ref name="Pedersen"/>

Nodules may prevent complete closure of the glottis, also known as glottal closure, and their presence may lead to an hourglass-shaped glottal closure.<ref name="Johns, M. M"/> Voice problems may result from the presence of vocal fold nodules.<ref name="Verdolini">Verdolini, K., Rosen, C.A., & Branski, R.C. (2014). Classification Manual for Voice Disorders-I. New York, New York: Psychology Press.</ref> They are diagnosed based on the presence of perceptual features not explicable by other causes.<ref name="Verdolini"/> Such symptoms include: vocal fatigue, breathiness, loss of high pitch notes, lack of vocal control, or increased phonatory effort (i.e. increased effort to produce speech).<ref name="Verdolini"/>

Prevention

Regulating voice use

For individuals who work with their voice (e.g., singers, actors, teachers, stock brokers), voice training that includes vocal function exercises (VFEs) may help reduce undue vocal strain.<ref name=pmid19342952>Template:Cite journal</ref> Furthermore, recommendations for voice professionals include warm-up and cool-down exercises for the voice to reduce strain.<ref name=pmid19342952/> Additionally, using amplification devices, such as speakers or microphones, is recommended for individuals who speak to large, and even small groups or in the presence of background noise.<ref name=pmid19741535/>

Hydration

Staying hydrated decreases the pressure that the vocal folds exert on one another by ensuring sufficient lubrication by mucosa, increasing the efficiency of vocal fold oscillation during speech, and promoting a healthy voice quality.<ref>Template:Cite journal</ref> Consumption of caffeine in large quantities is dehydrating and is therefore implicated in an increased risk of vocal fold nodules.<ref name=pmid19342952/>

Lifestyle changes

Behaviours such as frequent throat clearing, shouting, speaking over background noise, and hard crying are associated with an increased risk of developing nodules and other vocal pathologies.<ref name=pmid19342952/> Furthermore, unconventional voice practices such as speaking in the falsetto register, cause excessive strain and may result in nodules.<ref>Template:Cite bookTemplate:Page needed</ref> The avoidance of damaging vocal behaviours may prevent the formation of nodules. Tobacco, alcohol, certain medications, and recreational drugs have also been implicated in pathologies of the vocal folds.<ref name=pmid19342952/> Reducing exposure to these substances has been shown to reduce one's risk of nodules. Other behaviours that are implicated in vocal fold nodules include poor sleeping habits and poor nutrition.<ref name=pmid19342952/>

Treatment

The two main methods of treating vocal fold nodules are voice therapy (a behavioural treatment) and laryngeal microsurgery (a surgical treatment).<ref name=":0">Template:Cite journal</ref> Because of general risks of surgery (e.g. scar formation, or those posed by general anesthesia<ref name=":0" />), behavioural treatment is usually recommended first.<ref name=":0" />

Behavioural treatment

Behavioural voice therapy is typically carried out by speech–language pathologists.<ref>Template:Cite journal</ref> While behavioural treatments methods vary greatly, they are generally effective at improving vocal quality and decreasing size of vocal fold nodules.<ref name=":0" /><ref name="pmid19741535" /> Complete resolution of nodules through behavioural treatment is possible<ref name=":0" /> but unlikely.<ref name="pmid19741535" />

Behavioural techniques can be indirect or direct.<ref name=":0" /> Indirect approaches focus on improving vocal hygiene, introducing and/or maintaining safe voice practices (thereby reducing opportunities for phonotrauma) and, occasionally, implementing vocal rest.<ref name="pmid19779347" /> Direct approaches involve reducing the physiological strain on the vocal system while the voice is being used (e.g. during speaking or singing), such as by reducing collision forces between the vocal folds, ensuring sufficient pulmonary support while speaking (e.g. by changing the individual's breathing pattern), and optimizing resonance of the larynx and other structures of the vocal apparatus.<ref name="pmid19741535" />

Behavioural treatments also vary in delivery model.<ref name=":0" /> Traditional therapy distribution (e.g. eight sessions within eight weeks), more intensive approaches (e.g. eight session within three weeks) and remote therapy (i.e. telehealth) have all shown effectiveness in treating vocal fold nodules.<ref name=":0" />

Assessment of outcomes of behavioural treatments also varies greatly.<ref name=":0" /> Effects can be measured visually<ref name=":0" /> (e.g. by the same methods typically used to confirm the presence of vocal fold nodules: video endoscopy and video stroboscopy<ref name=":0" />), aerodynamically<ref name=":0" /> (e.g. by measuring parameters such as transglottal pressure and the glottal airflow waveform<ref>Template:Cite journal</ref>), perceptually<ref name=":0" /> (e.g. by rating the voice in terms of dimensions such as roughness, breathiness, asthenia and strain<ref name=":0" />), in terms of effect on quality of life measures,<ref name=":0" /> or using any combination of the above.<ref name=":0" />

Finally, recurrence of vocal fold nodules after behavioural treatment is always a possibility, particularly if nodules were not completely resolved or if skills gained during treatment were not carried-over outside of therapy sessions or maintained after therapy blocks.<ref name=":0" />

Surgery

When behavioural treatments have been deemed ineffective for a voice user, surgical intervention is often considered.<ref name=":0" /> Surgical treatments are considered in cases of unresolved dysphonia which negatively impacts the patient's quality of life.<ref name="Simpson & Rosen 2008 Vocal Fold Nodules"/> Removal of vocal fold nodules is a relatively safe and minor surgeryTemplate:Citation needed. However, those who sing professionally or otherwise should take serious consideration before having surgery as it can affect the ability to sustain phonation, as well as alter the vocal range.<ref name=pmid8903451>Template:Cite journal</ref> While the patient is subdued under general anesthesia, long thin scissors and scalpels or CO₂ surgical lasers might be used to remove the nodules.<ref name=pmid8903451/> Microsutures are sometimes used to close the incision.<ref name=pmid8903451/> Vocal rest for a period of 4 to 14 days is recommended post surgery to facilitate healing.<ref name=pmid14631179/>

Prognosis

Vocal fold nodules typically respond well to non-surgical/behavioural treatment techniques such as those described in the "Treatment" section. Therefore, if the patient is able to engage in such behaviour modification techniques the prognosis is good (although exact data is not available).<ref name="Verdolini et al 2014 Vocal Fold Nodules"/> If lesions are still present after non-surgical treatment methods, it is likely they are another form of benign vocal fold lesion (polyp, fibrous mass, cyst, or pseudocyst). The prognosis of requiring surgery would only occur after an exhaustive attempt at non-surgical therapy techniques has been applied.<ref name="Simpson & Rosen 2008 Vocal Fold Nodules"/>

Epidemiology

Research on the epidemiology of vocal fold nodules in children has suggested that nodules are more common in boys (2:1), in particular boys who are active and scream more frequently.<ref name=pmid2199731/><ref>Template:Cite bookTemplate:Page needed</ref> However, in adulthood, women are more likely to have nodules, and are especially likely if they have an outgoing personality or sing frequently.<ref name=pmid19342952/> The exact prevalence of vocal fold nodules is not known, but it has been reported that 23.4% of children who attended an ENT clinic for voice hoarseness, 6% of phoniatric clinic attendees, and 43% of teachers with dysphonia had nodules.<ref name="Verdolini et al 2014 Vocal Fold Nodules"/>

External links

• How an untreated vocal cord nodule affected one person at The Guardian

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