Paralysis/Paresis of the Vocal Folds

Overview:

Paralysis of the vocal folds means that one cannot move either one, or both of the vocal folds. Paresis means either one or both of the folds is weak. Usually there is a gap between the folds due to inadequate closure causing excess air to flow through them.


Figure 1A (left): The vocal fold on the right of this photo is paralyzed after a thyroid operation.
Figure 1B (right): An effort to make voice moves the other fold to the midline, but a substantial 
gap remains between the two. This makes for a soft, breathy voice.


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Cause:

Damage to the Vagus Nerve (Cranial Nerve 10) causes paralysis or paresis. The Vagus nerve has three branches: the Recurrent Laryngeal nerve, Pharyngeal branch and the Superior Laryngeal nerve.  These nerves travel from the brain to the pharynx, larynx and along the carotid artery. Vocal fold paralysis or paresis can result from surgeries in the brainstem, head, or neck. Thyroid, pulmonary, cardiac or spinal surgeries can affect the vocal folds. Specifically, the Recurrent Laryngeal Nerve is most often damaged, since it hooks under the aortic arch of the heart.

Symptoms:

The voice may be characterized differently depending on the severity of the paralysis/paresis of the vocal folds and nerves in the laryngeal/pharyngeal area.

Vocal Quality:

• weak
• breathy
• rough
• hoarse
• diplophonic (sounds like two pitches occurring at the same time) inability to sustain voiced sounds

People with paralysis or paresis often complain of the following symptoms:

• Lack of volume
• Breathy voice
• Inability to speak loudly
• Choking or coughing while eating
• Inability to sustain or support phonation for a long time (“ahhhh”)
• Food or liquid could be aspirated into the lungs causing pneumonia since the vocal folds don’t close properly

Diagnosis:

An endoscope is used to examine this vocal folds and throat area. This tiny scope with a camera and a light on the end of it is inserted through the nose or mouth. It is used to look inside at the structure and function of the area at rest and during phonation (sound production). It helps determine if paresis or paralysis exists.

 Treatment:

Voice Therapy:

 It is administered by a speech pathologist and they work on breath support, phonation and loudness.  The SLP focuses on proper placement of the vocal mechanism for optimal voicing. For example, turning the head either to the right or the left should bring the vocal folds together and the client as well as the SLP can determine which side the voice sounds better on. Manipulating or performing Circumlaryngeal massage helps to relax the musculature in the neck and upper chest area. This assists in improving voice quality and output.

Surgery:

The goal of having surgery is to move the paralyzed vocal fold closer to mid line so it can interact with the working vocal fold to help produce vibration.

Injections:

Injections can also be used to treat weakness or paralysis of the vocal folds, the immovable vocal fold is injected with a substance to plump it up and move it toward the center.

Permanent Injection materials include:

Teflon – this tends to be controversial because it is known to migrate to other parts of the body and it can produce a granuloma (benign tumor). Fat is also thought to be another permanent injection substance, though it does get reabsorbed by the body, so more research needs to be done.

Temporary Injection materials include:

Gelfoam, collagen, Calciumhydroxylapatite (CaHA), various gels and fat get reabsorbed by the body over time 2- 12 months. Collagen, hyaluronic acid & CaHA are other materials, they are more liquid –like and therefore more easily administered right through the skin. One has the downside of being a bovine (cow) product so has some risk of an allergic reaction.

Implants:

Another procedure for a weak or paralyzed vocal fold is called a thyroplasty, this is when a small hole or “window” is cut into the cartilage of the larynx and a solid piece of material is passed through it and placed in the damaged vocal fold to assist in bringing it more midline. The person is awake during this procedure so the voice can be tested and the implant adjusted as need. Different materials are used such as Silastic, hydroxadhesive and goretex.

Reinnervation:

Another option for unilateral vocal fold immobility due to nerve dysfunction is reinnervation. A nerve is “borrowed” from one of the neck muscles and attached to the recurrent laryngeal nerve. It often takes 6-12 months for the nerve to start functioning to provide voice improvement. Often a vocal fold injection is used to bulk it up temporarily and move it toward the middle, the vocal fold often will not move, but it will have excellent tone, bulk and muscle.

Recovery from Injections:

At the end of the injection ones voice may seem tight and stiff. It stays swollen for about a week and therefore the voice is worse, until the swelling subsides. Recovery from injection therapy depends on whether the substance was permanent or temporary.  Permanent materials should reach a stable state in 1 month, whereas temporary injections only last 3-6 months and the voice deteriorates over time.

Instructions during healing

Limit talking for a few days, but over time your symptoms should improve. If you develop swelling or redness of the skin at the injection site or if you feel like you are getting short of breath, you should call your physician immediately.

References:

Bastian RW; Delsupehe KG. Indirect larynx and pharynx surgery: a replacement for direct laryngoscopy. Laryngoscope 1996 Oct;106(10):1280-6

Boone, D., McFarlane, S., Von Berg S. (2005). The voice and voice therapy (7th ed.). New York: Allyn & Bacon

Colton, R, Casper J., Leonard, R. (2006). Understanding voice problems: A physiological perspective for diagnosis and treatment (3rd ed.). New York: Lippincott Williams and Wilkins

Roth, F.P and Worthington, C.K. (2001). Intervention for voice and alaryngeal speech. In Treatment resource manual for speech-language pathology, 2^nd ed. Albany, NY; Singular Thomson Learning.

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