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|Classification and external resources|
Dysphonia, also known as a hoarse voice, 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. Dysphonia can be characterized by hoarse, breathy, harsh, or rough vocal qualities, 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, it is typically caused an 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.
The prevalence rate is higher in elderly adults and in females.
- 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 (Hyperthyroidism, hypogonadism)
- Haematological (Amyloidosis)
- Iatrogenic (inhaled corticosteroids)
- Functional dysphonia
- Vocal misuse
Associated conditions (incomplete list)
- Voice disorders
- Gastroesophageal reflux disease: When there is a clinical suspicion for GERD as the cause of the dysphonia, an Esophageal pH Monitoring is required to confirm the diagnosis and establish the relationship between GERD and dysphonia.
- Laryngeal cancer
- Myasthenia gravis
- Lung cancer
- Juvenile dermatomyositis
- Parkinson's disease
- Botulinum toxin
- Down Syndrome
Dysphonia is measured using a variety of examination tools that allow the clinician to see the pattern of vibration of the vocal folds, principally laryngeal videostroboscopy. Acoustic examination is also common, which is obtained by recording the sounds made during sustained phonation or whilst speaking. Another useful tool is electroglottography.
Subjective measurement of the severity of dysphonia is carried out by trained clinical staff. The GRBAS (Grade, Roughness, Breathiness, Asthenia, Strain) scale, the CAPE-V (Consensus Auditory Perceptual Evaluation—Voice) and the Oates Perceptual Profile are widely used for this purpose. These subjective, auditory-perceptual measures are a more commonly used assessment tool than objective, instrumental measures. Objective measurement of the severity of dysphonia typically requires signal processing algorithms applied to acoustic or electroglottographic recordings. These include algorithms such as jitter, shimmer and noise-to-harmonics ratios, but these have been shown to have some critical limitations, particularly for severe dysphonia. Recent advances in signal processing theory have led to more robust algorithms.
- National Center for Voice and Speech
- Human voice
- Lists of language disorders
- Little, M.A. et al. (2009). Objective dysphonia quantification in vocal fold paralysis: comparing nonlinear with classical measures. Journal of Voice (in press).
- Cohen, Seth M.; Kim, Jaewhan; Roy, Nelson; Asche, Carl; Courey, Mark (2012-02-01). "Prevalence and causes of dysphonia in a large treatment-seeking population". The Laryngoscope. 122 (2): 343–348. doi:10.1002/lary.22426. ISSN 1531-4995.
- Mehta, Daryush D.; Hillman, Robert E. "Current role of stroboscopy in laryngeal imaging". Current Opinion in Otolaryngology & Head and Neck Surgery. 20 (6): 429–436. doi:10.1097/moo.0b013e3283585f04.
- Oates, J (2009). "Auditory-perceptual evaluation of disordered voice quality: pros, cons and future directions.". Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP). 61 (1): 49–56. PMID 19204393.
- Little, M.A. et al. (2007). Exploiting nonlinear recurrence and fractal scaling properties for voice disorder detection. Biomed Eng Online, 6:23.
- Vocal Dysphonia and Vocal Disorder Online Support Network
- Pediatric ENT
- Objective measurement of dysphonia for clinical purposes.
- Singing Voice
- National Center for Voice and Speech's official website
- The Department of Speech Pathology and Audiology at the University of Iowa's official website
- The Voice Academy's official website
- National Spasmodic Dysphonia Association
- Synthesis of disordered voices