How a Mass Might Reduce the Persons Ability to Speak Loudly - Essay Example

Vocal nodules are primarily benign growth on the vocal folds which arises due to vocal misuse and abuse. However to fully appreciate the mechanism involved in this process an understanding of speech mechanism concerning the role of vocal fold nodules is required. This is discussed below;

The larynx or the voice box has a twin infolding of mucous membranes (vocal folds) stretched across the larynx. During speech or phonation, the airflow (originating from the lungs) is modulated by these membrane vibrations. Increased air flow/air pressure in the lungs causes the folds to open and once the pressure recedes after the air flows out the fold close again. These folds vibrate when closed due to internal air pressure. (Cumming 2005) In effect, the loudness of speech, or what is best termed as the pitch of the voice is determined by the resonance frequency of the vocal folds and is measured in hertz. The fundamental frequency of vocal fold vibration correlates with changes in vocal fold tension and subglottal pressure and hence vocal fold mass, stiffness, and viscosity is the main predictor of the pitch of the voice (Hirano 1987).

Vibrations of the vocal folds that are too forceful or prolonged result in vascular congestion. If persistent they will eventually result in the hyalinization of superficial lamina propria and eventually, this is likely to lead to the formation of nodules. Nodules are commonly bilateral in occurrence with a classic location at the junction of the anterior and middle third of the vocal fold (Dikkers 1995). Phonotrauma or vocal cord insults are indeed intricately linked with the formation of nodules. Most importantly clinical and phenotypic expression/appearance of benign vocal fold lesions is most commonly associated with a voice change.

A plausible explanation for this could be that nodules if found on the glottal margin interfere with the vibratory patterns of the vocal fold by increasing the mass and reducing the pliability of the overlying cover (ie, cover/body theory of vocal fold vibration). In addition, they restrict adequate closure of the membranous folds throughout the glottic cycle. The fundamental frequency of vocal fold vibration is also altered since the nodules affect the frequency at the mechanical level and hydration of the vocal folds. Overall voice quality and ease of voice production and hence the pitch of the voice is severely affected or significantly lowered.

Given the importance of voice in everyday life, it is only natural that voice disorders receive much attention. In addition, we need to ensure that we do not knowingly cause phonological trauma. Knowing the mechanism of voice insults is a step ahead in this direction! Read More