Vocal cord paresis

Typically, patients with vocal fold paresis or paralysis are able to identify the onset of their symptoms. The most commonly reported symptom patients with either vocal fold paresis or paralysis make is having a rough voice quality. It is important to note that the symptoms of vocal fold paresis are not specific to the condition and tend to be common symptoms of other voice disorders as well. Vocal fold bowing, decreased vocal fold mobility, especially decreased mobility of the arytenoid cartilage, are often observed in vocal fold paresis. Glottal insufficiency is another common symptom observed in vocal fold paresis. In this case, the vocal folds do not come together properly. Glottal insufficiency may be hard to identify, especially when the area above the vocal folds is hyperfunctional. Hyperfunction may also make it difficult to detect the presence of vocal fold paresis. Hyperfunction of the area above the vocal folds may be considered a sign of glottal insufficiency and potentially, vocal fold paresis. In some cases, glottal closure may appear to be normal, however, asymmetries in the vocal folds may still be present. Though voice qualities may appear normal in some cases of vocal fold paresis or paralysis, mild differences in tension between the two vocal folds of the larynx can result in changes of voice pitch, intensity and reduced vocal stamina. Patients with either vocal fold paresis or paralysis may exhibit a breathy voice quality. This voice quality results from the increased activity of the vocal folds to compensate for the immobility of the PCA muscle(s). Patients may need to use more effort than normal when speaking and may find that their voice quiets or grows tired after speaking for a long time. This is known as vocal fatigue. Patients may also complain about having a limited pitch range and trouble varying their pitch at quick rate. 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. 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. • Radiation as a treatment for malignant head and neck tumors can reduce the number of blood vessels in the treatment area and lead to scarring. In some cases, this can paralyze the vagus nerve, of which the RLNs are branches. • Charcot-Marie-Tooth (CMT), a neurological heredity disease that affects both motor and sensory functions. CMT affects the nerve cells and interrupts the transmission of nerve impulses as it concerns the axons and the myelination of the nerve cells. • Multiple Sclerosis (MS), which is an autoimmune disease that damages the myelin sheet surrounding the axons of the cranial nerves and the spinal nerves. There are several types of MS depending on the course of the disease. 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 patient's 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 patient's 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). This allows the S-LP to make a judgment about the overall severity of the voice quality. The CAPE-V is used in a similar manner, rating of the dimensions of voice quality on a subjective scale from 0–100, and using this to determine an overall severity score. In the presence of neural lesions with unknown cause, a thorough ENT endoscopy In incompletely or only partially healed paralyses, stroboscopic larynx examinations yield a type of slow motion picture to assess tension and fine mobility of the vocal folds during vocalization. Stroboscopy 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 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. Additionally, superior laryngeal nerve damage (SLN) can also lead to vocal fold paresis. The posterior cricoarytenoid (PCA) is a muscle of the larynx that is responsible for pulling the vocal folds apart from one another. Unilateral vocal fold paresis is the term used when there is damage to the RLN on one side of the body. In unilateral vocal fold paresis, there is a lack of nerve supply to one side of the vocal fold's PCA muscle. This lack of nerve supply renders the arytenoid cartilage immobile. The RLN may be damaged during surgical procedures. The right RLN in particular, has a greater chance of being damaged during surgery due to its position in the neck. When both of the vocal folds' PCA muscles lack a nerve supply, the term bilateral vocal fold paresis is used. With bilateral vocal fold paresis, a person's airway may become blocked as the muscles are unable to pull the vocal folds apart fully. == Treatment ==

The treatment of vocal fold paralysis varies depending on its cause and main symptoms. For example, if laryngeal nerve paralysis is caused by a tumor, suitable therapy should be initiated. In the absence of any additional pathology, the first step of clinical management should be observation to determine whether spontaneous nerve recovery will occur. Voice therapy with a speech-language pathologist is suitable at this time, to help manage compensatory vocal behaviours which may manifest in response to the paralysis. Hard glottal attacks Hard glottal attacks involve building up subglottal pressure (air pressure below the vocal folds) before letting out a vowel sound. Often, this method is beneficial for clients who compensate by use of a falsetto register. In this procedure, a variety of materials can be injected into the body of the vocal fold in order to bring it closer to the midline of the glottis. The choice of substance is dependent on several factors, taking into consideration the specific condition and preference of the patient as well as the clinical practice of the surgeon. The materials serve the purpose of filling up the vocal folds and increasing their volume. As a result, the paralyzed vocal fold is supported in a position closer to the midline of the glottis, and retains its ability to vibrate and phonate efficiently. This procedure restores nerve supply to the larynx and can be accomplished according to different techniques. Depending on the specific condition (i.e. bilateral versus unilateral vocal fold paralysis), these techniques include reconnecting parts of the RLN, supplying the laryngeal muscles with a donor nerve like the ansa cervicalis, or connecting the RLN to a donor nerve. However, none of these surgical interventions has been shown to be significantly better than the others. Voice therapy after surgery It is generally recommended that voice therapy start 1 to 2 months after surgery, when swelling has subsided. Post-surgical intervention is warranted to restore laryngeal muscle strength, agility and coordination. == Epidemiology ==

Due to the complex and controversial nature of this condition, epidemiological (incidence) reports vary significantly and more research in this area is needed. Instead of reporting the incidence of this condition within the general population, most studies are conducted within specialized voice disorder clinics. In such a setting, one study found that approximately 26% of patients are diagnosed with paralysis or paresis of the vocal folds. Yet, incidence rates as high as 80% for vocal fold paresis have been reported elsewhere. Yet another source reported only 71 cases of vocal fold paresis over 7 years. Incidence rates of vocal fold paresis after undergoing thyroid surgery have been reported between 0.3% and 13.2%, whereas these incidence rates are between 2% and 21.6% after undergoing spinal surgery. == See also ==