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Dysphonia, also commonly referred to as hoarse voice, is a broad clinical term meaning dysfunction in the ability to produce phonation (or voice). Dysphonia is not a disorder, but rather a collection of signs and symptoms resulting from abnormalities in one or more parameters of voice: pitch, loudness, quality, or variability. It can be perceptually characterized by hoarse, breathy, harsh, or rough vocal qualities, but some kind of phonation remains.

Current prevalence rates suggest that dysphonia is higher in females and elderly adults, however, it can be present in both sexes and across age groups. Furthermore, it is suggested that certain occupational groups, such as teachers and singers, are at increased risk for developing voice problems.

Definition
Dysphonia is a broad clinical term which refers to abnormal functioning of the voice. More specifically, a voice can be classified as “dysphonic” when there are abnormalities or impairments in one or more of the following parameters of voice: pitch, loudness, quality, and variability. For example, abnormal pitch can be characterized by a voice that is too high or low whereas abnormal loudness can be characterized by a voice that is too weak or loud. Similarly, a voice that is "unpleasant" or has frequent, inappropriate breaks characterizes abnormal quality while a voice that is monotone (i.e., very flat) or has excessive fluctuations characterizes abnormal variability.

While hoarseness is used interchangeably with the term dysphonia, it is important to note that the two are not synonymous. Hoarseness is merely a subjective term to explain the perceptual quality of a dysphonic voice. While hoarseness is a common symptom (or complaint) of dysphonia, there are several other signs and symptoms that can be present such as: breathiness, roughness, and dryness. Furthermore, a voice can be classified as dysphonic when it poses problems in the functional or occupational needs of the individual or is inappropriate for their age or sex. .

Mechanism
Located in the anterior portion of the neck is the larynx (also known as the voice box), a structure made up of several supporting cartilages and ligaments, which houses the vocal folds. In normal voice production, exhaled air moves out of the lungs and passes upward through the vocal tract. At the level of the larynx, the exhaled air causes the vocal folds to move toward the midline of the tract (called adduction). The adducted vocal folds do not close completely but instead remain partially open. The narrow opening between the folds is referred to as the glottis. As air moves through the glottis, it causes a distortion of the air particles which sets the vocal folds into vibratory motion. It is this vibratory motion that produces phonation or voice.

In dysphonia, there is an impairment in the ability to produce an appropriate level of phonation. More specifically, it results from an impairment in vocal fold vibration or the nerve supply of the larynx.

Prevalence
Up to now, prevalence studies investigating rates of dysphonia on a large-scale level have been limited. According to a large sample of 55 million patients seeking health-care treatment in the United States, dysphonia can be found in approximately 1% of the population. Higher rates are reported in females and elderly adults, however, dysphonia can be found in both sexes and across age groups. It is proposed that higher rates in the females are due to anatomical differences.

Certain occupational groups may be more prone to developing voice disorders, namely dysphonia. Occupations that require extensive use of voice are more at risk such as teachers and singers. However, the evidence is highly variable and must be interpreted carefully.