Congenital
Congenital conditions that are implicated in VFP include neurological disorders like hydrocephalus and Arnold-Chiari malformation, dysmorphic neurological disorders such as Moebius syndrome or Goldenhar Syndrome, anatomical abnormalities such as a tracheoesophageal fistula, vascular anomalies (e.g. vascular ring) affecting the vocal mechanism, syndromes affecting brainstem function or atrophic diseases such as Charcot-Marie-Tooth.In the absence of imaging, either invasive (e.g. laryngoscopy) or non-invasive (e.g. computed tomography scan), congenital VFP can be detected in infants through the presence of stridor (i.e. a high-pitched wheezing resulting from a blockage in the larynx or trachea), difficulties feeding, an abnormal sounding cry or excessive hoarseness.Recovery from congenital VFP varies and is reliant on the severity of the condition. Some cases of VFP recover spontaneously, often within the first year. If the paresis is persistent, surgical options such as vocal fold injections or tracheotomy can be taken into consideration. Infection
Many viral infections have been reported as a cause for VF paresis, including herpes simplex virus, Epstein-Barr virus, Varicella-Zoster, cytomegalovirus, HIV, West Nile virus, and upper respiratory infection. Bacterial infections have also been reported to cause VF paresis, such as syphilis and Lyme disease. Tumors
When abnormal cells group together in the body, they are said to form a tumor. Tumors can be either malignant (cancerous) or benign (non-cancerous). Tumors may lead to paralysis of the vocal folds when they affect the recurrent laryngeal nerves (RLNs) either directly or indirectly:

RLN paralysis can be caused by tumors of the thyroid, lung, esophagus, and mediastinum.
Spinocerebellar Degeneration is usually an inherited progressive disease; however, toxicity and vitamin deficiency can result in the acquired type of cerebellar degeneration disease.Additionally, there are pieces of evidence that some Systemic Rheumatological Diseases such as sarcoidosis, rheumatoid, scleroderma can result in having VF paresis. Cardiovascular
A rare cause of vocal cord paresis that often presents itself as unexplained hoarseness is cardiovocal syndrome or Ortners syndrome. Although it was originally identified in patients with left atrial enlargement, the definition has expanded to include aneurysms of the aortic arch, pulmonary hypertension due to mixed connective tissue disease, or aberrant subclavian artery syndrome among other causes of left recurrent laryngeal nerve palsy with cardiovascular origin. Diagnosis
There are a variety of ways to diagnose vocal fold paralysis. Important indications of possible causes can be revealed in the patients medical history, which may inform which diagnostic approach is taken. Voice diagnostics are used to assess voice quality and vocal performance. Voice assessment is necessary to plan and estimate the success of a possible speech therapy. [12]An auditory-perceptual evaluation is conducted by a Speech-Language Pathologist (S-LP), and allows changes in voice quality to be monitored over time. There are two scales which can be used to subjectively measure voice quality: the GRBAS (grade, roughness, breathiness, asthenia, strain) and the CAPE-V (Consensus Auditory Perceptual Evaluation of Voice). The GRBAS is used to rate the patients voice quality on 5 dimensions: grade (overall severity), roughness, breathiness, asthenia (weakness) and strain. Each dimension will receive a severity rating from 0 (not present) to 3 (severe).