Vocal cord nodule

Vocal cord nodules are bilaterally symmetrical benign white masses (nodules) that form at the midpoint of the vocal folds. 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.

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. Due to these changes, the quality of the voice may be affected. As such, the major perceptual signs of vocal fold nodules include vocal hoarseness and breathiness. Other common symptoms include vocal fatigue, soreness or pain lateral to the larynx, and reduced frequency and intensity range. Airflow levels during speech may also be increased. 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. Predisposing factors include profession, gender, dehydration, respiratory infection, and other inflammatory factors.

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. 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. About 10% of nodules resolve on their own, which is more likely if they are smaller and the onset more recent. 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. In children, vocal fold nodules are more common in males; in adults, they are more common in females.

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

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, and it may be especially difficult to produce pitches in the higher range. The intensity of the voice, an acoustic measure of amplitude or loudness, may also be normal. However, the individual's amplitude range may be reduced as well. Perturbations or variations in frequency, known as jitter, and in amplitude, known as shimmer, may be increased.

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. 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.

Vocal fold nodules are thought to be the result of vocal fold tissue trauma caused by excessive mechanical stress. 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. 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. 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 and subsequent wound formation. Repeated or chronic mechanical stress is thought to lead to the remodeling of the superficial layer of the lamina propria. It is this process of tissue remodeling that results in the formation of benign lesions of the vocal folds such as nodules.

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. Gender may be another predisposing factor, as vocal fold nodules occur more frequently in females. 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.