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Dysphonia is the medical term for disorders of the voice: an impairment in the ability to produce voice sounds using the vocal organs (it is distinct from dysarthria which signifies dysfunction in the muscles needed to produce speech). Thus, dysphonia is a phonation disorder. The dysphonic voice can be hoarse or excessively breathy, harsh, or rough, but some kind of phonation is still possible (contrasted with the more severe aphonia where phonation is impossible). Dysphonia has either organic or functional causes due to impairment of any one of the vocal organs. However, typically it is caused by some kind of interruption of the ability of the vocal folds to vibrate normally during exhalation. Thus, it is most often observed in the production of vowel sounds. For example, during typical normal phonation, the vocal folds come together to vibrate in a simple open/closed cycle modulating the airflow from the lungs. Weakness (paresis) of one side of the larynx can prevent simple cyclic vibration and lead to irregular movement in one or both sides of the glottis. This irregular motion is heard as roughness. This is quite common in vocal fold paresis.〔Little, M.A. et al. (2009). (Objective dysphonia quantification in vocal fold paralysis: comparing nonlinear with classical measures. ) ''Journal of Voice'' (in press).〕 ==Common types of dysphonia== * Organic dysphonia * * Laryngitis (Acute: viral, bacterial) - (Chronic: smoking, GERD, LPR) * * Neoplasm (Premalignant: dysplasia) - (Malignant: Squamous cell carcinoma) * * Trauma (Iatrogenic: surgery, intubation) - (Accidental: blunt, penetrating, thermal) * * Endocrine (Hypothyroidism, hypogonadism) * * Haematological (Amyloidosis) * * Iatrogenic (inhaled corticosteroids) * Functional dysphonia * * Psychogenic * * Vocal misuse * * Idiopathic 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dysphonia」の詳細全文を読む スポンサード リンク
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