What Is Vocal Cord Paresis (Paralysis)? What Causes Vocal Cord Paresis?
Vocal cord paresis, also known as vocal cord paralysis is the inability of one or both vocal cords (vocal folds) to move. It can greatly impact on the daily life of the sufferer, including employment, choice of job, social interactions and leisure time activities. The damage is caused by damage to nerves going to the vocal cord - the nerve impulses in the larynx (voice box) are interrupted, resulting in paralysis of the vocal cord muscles. It can also be caused by brain damage.
Patients with vocal paresis typically experience hoarseness, vocal fatigue, mild to severe reduction in speech volume, a pain in the throat when speaking, and swallowing things down the wrong way and choking. The vocal cords, as well as allowing us to produce utterances (speak, etc.) also protect the airway, preventing food, drink and saliva from entering the trachea (windpipe). In extreme cases the resultant choking can lead to death.
Individuals with vocal cord paresis may find the effectiveness of coughing, swallowing or sneezing in removing laryngeal area waste is undermined reduced vocal cord mobility. This may result in accumulations in the area, allowing for bacterial and viral colonization, and subsequent infections and throat discomfort.
What are the signs and symptoms of vocal cord paresis (paralysis)?A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.
The vocal cords consist of two bands of muscle, located at the trachea (entrance to the windpipe). When we make an utterance (produce sound from the mouth) the two bands of muscle tissue touch each other and vibrate. When we are not uttering sounds the vocal cords are in an open, relaxed position, allowing air to flow freely into our windpipe - allowing us to breathe.
Most cases of vocal cord paresis involve just one cord being paralyzed. However, sometimes both are affected, and the patient is likely to experience swallowing as well as breathing difficulties.
The following signs and symptoms are possible:
- The voice may change, and become more "breathy", like a loud whisper
- Hoarseness, huskiness
- The patients breathing may be noisier
- Vocal pitch may be affected
- When swallowing solids or liquids the patient might choke (including saliva sometimes)
- While speaking the sufferer may have to catch his/her breathe more often than usual
- Voice volume may be affected. The patient may not be able to raise their voice.
- Pharyngeal reflex (gag reflex) may be lost - the pharyngeal reflex is a reflex contraction of the back of the throat, evoked by touching the soft palate. It prevents something from entering the throat except as part of normal swallowing and helps prevent choking.
- Coughs that do not clear the throat properly
What are the risk factors and causes for vocal cord paresis (paralysis)?A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2. The following factors may raise the chances of developing vocal cord paresis:
- Gender - females have a slightly higher risk than males.
- Some types of surgery - especially chest or throat surgery. Breathing tubes used in surgery may damage vocal cord nerved. Cardiac surgery represents a risk to normal voice function as the nerves serving the larynx are routed near the heart - damage to this nerve during open heart surgery is not uncommon. The recurrent laryngeal nerve also runs close to the thyroid gland making, hoarseness of voice due to partial paralysis an important side effect of thyroid surgery.
- Certain neurological conditions - people with multiple sclerosis (MS), Parkinson's disease, or myasthenia gravis have a higher risk of developing vocal cord paresis, compared to other individuals. The risk of vocal cord weakness is greater than paralysis.
- Injury to the chest or neck - a trauma may damage the nerves that serve the vocal cords or the larynx.
- Stroke - the part of the brain that sends messages to the larynx (voice box) may be damaged from a stroke.
- Tumors - these may develop around or in the cartilages, nerves or muscles of the voice box. The tumors may be benign or malignant (cancerous).
- Inflammation or scarring of the vocal cord joints, as well as the space between the two vocal cord cartilages may prevent the larynx from working properly. Although the cord nerves are usually working correctly, the inflammation can give vocal cord paresis-like signs and symptoms. Some infections may also cause inflammation.
Diagnosing vocal cord paresis (paralysis)Initially, the patient will probable see a GP (general practitioner, primary care physician) who will ask about symptoms and check out for some signs, such as listening to their voice and asking how long there have been problems.
The following diagnostic tests may also be ordered:
- Endoscopy - a long, thin, flexible tube (endoscope) is used to look at the vocal cords. A special device with a small camera at the end (videostrobolaryngoscopy) may be used. The doctor can get a good look at the vocal cords on a monitor.
- Laryngeal electromyography (LEMG) - electric currents in the larynx muscles are measured. Small needles are inserted into the vocal cord muscles through the skin of the neck. The test measures the strength of the neuromuscular signal from the brain to the muscles controlling the vocal folds (cords). During an LEMG the doctor will ask the patient to perform a number of tasks that would normally activate the muscles.
- Other tests - the doctor may order blood tests and imaging scans, such as x-rays, CT scans, MRI scans to help determine the cause of the paralysis.
What are the treatment options for vocal cord paresis (paralysis)?Vocal cord paresis treatment depends on several factors, including what caused it, how severe symptoms are, and how long they have been present. The patient may be advised to have voice therapy, surgery, or both.
Voice therapy - the equivalent of physical therapy for large muscle paralysis. The therapist asks the patient to do special exercise and some other activities to strengthen their vocal cords, improve their breath and control while speaking, prevent unusual tensions in other muscles near the affected vocal cord(s), and protect the airway from liquids and solids.
Surgery - if the patient does not recover completely with voice therapy, the doctor may recommend surgical intervention:
- Bulk injection - the vocal cord muscle will most likely be weak due to paralysis of the nerve. The otolaryngologist (ear, nose and throat specialist doctor) may inject fat, collagen or some filler into the vocal cord. The extra bulk brings the vocal cord nearer to the middle of the larynx (voice box), making it easier for the opposite cord muscle to move effectively when the patient coughs, swallows or speaks.
- Phonosurgery (vocal cord repositioning) - this operation repositions and/or reshapes the vocal fold (cord) to improve voice functions.
- Tracheotomy - if both vocal folds (cords) are affected and very close to each other, breathing will be more difficult because of decreased air flow. The doctor makes an incision (cut) in front of the neck and an opening is created into the trachea (windpipe). A breathing tube is inserted so that the patient can breathe with air bypassing the paralyzed vocal cords. Put simply, the patient breathes through a hole in the neck because the opening in the larynx is too small for proper breathing.
ComplicationsBreathing - if symptoms are severe enough the patient can have serious, life-threatening breathing problems.
Aspiration - because there is paralysis in the area where food or liquid may go down the wrong way (aspiration), there is a risk of choking. Aspiration can lead to severe pneumonia.