Electromyography of the larynx muscles (larynx EMG), which measures the electrical activity of the larynx muscles via thin needle electrodes, allows better differentiation between a neural lesion and other causes of impaired mobility of the vocal fold and localization of the lesion along the nerve. The larynx EMG can, within limits, provide a prognosis of the development of a recurrent laryngeal nerve paralysis. Patients with a poor chance of healing can be identified at an early stage. Unfortunately, this advanced examination technique is not available in all treatment centers. The treating physician must view all examination results combined and establish an individual diagnosis and treatment plan for each patient. Classification
Vocal fold paresis refers to a partial loss of input to the nerve of the vocal folds. This loss of neural input leads to reduced vocal fold mobility. It is a condition with a variable profile, as the severity of the paresis can range on a wide continuum from minor to major loss of vocal fold mobility. Vocal fold paralysis, distinguished from vocal paresis, is the total loss of vocal fold mobility due to a lack of neural input to the vocal folds. These conditions result from continuous damage to the laryngeal nerves and often lead to vocal disability. Recurrent laryngeal nerve damage is the most common cause of vocal fold paresis. The RLN is responsible for motor input to the vocal folds. Physicians may also use the term recurrent laryngeal nerve paralysis. Additionally, superior laryngeal nerve damage (SLN) can also lead to vocal fold paresis.
It is often difficult for the speaker to project their voice and speak loud enough to be heard in noisy environments, over background noise, or when speaking to someone from a distance. It is possible for symptoms to surface only in situations where the environmental acoustics are poor, such as outdoors. Patients may report feeling pain in the throat or experiencing bouts of choking. A patient presenting with diplophonia is of major concern as this typically means that the mass and tension of their vocal folds are asymmetrical which may also indicate vocal fold paresis.Swallowing difficulties (dysphagia) are not commonly seen in vocal fold paresis that results from RLN damage. Dysphagia may however, suggest SLN damage. Symptoms of sensory nerve damage include: chronic coughing, the feeling of having a lump in the throat (globus sensation), hypersensitivity or abnormal sensation, spasms of the vocal folds (laryngospasms), dysphagia, pain from vocal use, and voice loss in high pitch ranges. It is possible for both the RLN and the SLN to be damaged simultaneously, so the symptoms of RLN and SLN damage may be seen independently or alongside one another.If maladaptive compensatory strategies are used more and more to try to offset the voice difficulties, the vocal mechanisms will fatigue and the above symptoms will worsen. Causes
There are a wide variety of possible causes of vocal fold (VF) paresis, including congenital (i.e. present at birth) causes, infectious causes, tumors, traumatic causes, endocrinologic diseases (i.e. thyroid disease), and systemic neurologic diseases.