Spasmodic Dysphonia is a neurogenic voice disorder caused by involuntary laryngeal muscle contractions. The cause is unknown, and there is no cure. Symptoms can be reduced by using Botulinum toxin or surgery to weaken laryngeal muscles.

A functional voice disorder is the result of vocal misuse or abuse of an anatomically and physiological intact vocal apparatus. When the voice is disproportionately poor compared to laryngeal findings, then a functional voice disorder should be suspected. Six different types of functional voice disorders are described in the literature: Type 1, hysterical aphonia/dysphonia; type 2, habituated hoarseness; type 3, falsetto voice, type 4, vocal abuse; type 5, postoperative dysphonia; and type 6 relapsing aphonia.

Vocal fold paralysis etiology can be divided into three main groups, idiopathic, iatrogenic and compression due to a mass. It can lead to frustrating symptoms for the patient, with a weak and breathy voice, vocal fatigue and loss of projection. For professional voice users this may determine the timing of intervention. Risk of aspiration needs to be assessed, especially for older patients and patients with high vagal injuries, such as carotid endarterectomy. Imaging is of outmost importance, as compression due to a mass is not uncommon and can lead to diagnosis of cancer.

Nodules, Polyps, Cysts and Sulci generally occur within the phonatory epithelium or lamina propria of the true vocal fold.  An impaired vocal fold edge compromises apposition of the vocal fold edges and may impair the vibratory surface of the vocal folds.   These benign lesions yield an inefficient glottis manifesting as dysphonia.  Diagnosis is heavily dependent on history and exam findings, namely stroboscopy.  Treatment is individualized with consideration of the subjective patient’s voice handicap and the practitioner’s perceptual rating, the patient’s voice demand and the potential for

Vocal nodules are callouses that form on the vocal folds in response to chronic vocal trauma. Treatment requires reduction or elimination of vocally abusive behavior, and voice therapy is the mainstay of treatment. Surgery may be required for recalcitrant nodules, and in this case care must be taken through careful operative technique to preserve vocal fold vibration.

Benign laryngeal lesions are related to vocal trauma (that may or may not be due to vocally abusive behaviors), inflammatory processes, and neoplastic changes. Though hoarseness is the most common complaint with these lesions, other symptoms such as vocal fatigue, increased vocal effort, loss of range, dyspnea, frequent throat clearing, should also alert the clinician to the possibility of a benign laryngeal lesion.

Laryngopharyngeal reflux results from laryngeal exposure to gastric contents leading to various symptoms including but not limited to globus, throat clearing, cough, and dysphonia. Patients should undergo a full head and neck examination including flexible laryngoscopy.

Vocal function tests are useful adjuncts to the evaluation and treatment of voice disorders. They allow for the objective measurement of the voice and of the functional impact of the voice disorder on the patient’s life. They also allow the ability to follow changes in the voice through time. No one test is sufficient to provide a global view of vocal function, and the use of vocal function testing is best used as a battery of cognitive, behavioral, physical, acoustic, aerodynamic, and electromyographic evaluation.

Fiber optic laryngoscopy and rigid per-oral endoscopy are methods for imaging the upper aero-digestive tract. Imaging with video is now standardized with defined protocols for both anatomical and pathological changes to the vocal tract as well as observation of airway physiology and vibratory function. The imaging modalities today include the use of stroboscopy light, narrow band imaging, and high speed camera. Using stroboscopy, the clinician can observe vocal vibratory function in patients presenting with dysphonia that otherwise could not be diagnosed.

The physiology of the voice, breathing, and swallowing are inextricably intertwined with each other and dependent upon the complex anatomy of the upper aerodigestive tract. The larynx has evolved to manage the critical tasks of breathing, phonation, and protection of the lower airways during swallowing. Evaluation of structure and function are achieved through direct or indirect examination, imaging, and other specific tests. Test results are combined to determine overall function of the larynx and associated structures.