Symptoms
A typical symptom of vocal fold paralysis on one side is hoarseness. Due to the loss of one side of the laryngeal muscles, the phonation in the larynx can no longer run properly and a permanent hoarseness develops. Vibrations and tone formation are disturbed, depending on how pronounced the paralysis of the laryngeal muscles is.
As a result, normal speech requires more air consumption. If both sides are affected by vocal fold paralysis, the glottis can no longer open by itself, resulting in acute shortness of breath. The air can no longer escape through the closed vocal folds and therefore the patient must be ventilated by intensive care if the paralysis is complete.
The anatomy of the recurrent nerves is different on both sides. Just like the large arterial vessels that branch off from the aorta in the direction of the neck, the laryngeal nerves differ on both sides. On the right side, the fine recurrent nerve branches off the main nerve and wraps around the main artery of the neck and arm at the level of the collarbone.
On the left side, however, the nerve pulls much deeper into the chest and winds around the aorta itself just above the heart. Its course is significantly longer than on the right side and therefore the nerve is more susceptible to damage in its long course.As a result, the left side is affected by vocal fold paralysis almost twice as often as the right side. Single-sided vocal fold paralysis is significantly more common than bilateral paralysis.
A hoarseness is the typical consequence, by one-sided missing oscillations of the glottis. There is no shortness of breath, but more air is needed for normal speech. A bilateral vocal fold paralysis is rare.
If it occurs, it leads to serious symptoms and the need for intensive medical care. In a normal relaxed state, the glottis is closed. Especially the muscles that open the glottis wide are affected by vocal fold paralysis.
As a result, the larynx cannot be opened and breathing difficulties, severe hoarseness and a hissing sound when trying to breathe occur. In severe, acute respiratory distress, the patient must be supported by artificial respiration if necessary. If there is no improvement or prospect of recovery, surgery can help to widen the glottis permanently.
In some cases, the patient must continue to be ventilated permanently via the artificial access. Infections of the lungs and respiratory tract are a particularly frequent consequence, as mucus and germs can no longer be reliably coughed up. An important part of the diagnosis of vocal fold paralysis is based on the patient’s medical history and speech formation.
A typical persistent hoarseness is already groundbreaking for the diagnosis. The larynx can then be examined by the ENT physician either with the help of a laryngeal mirror, which the physician holds in the patient’s throat, or by endoscopy of the larynx. In this so-called “laryngoscopy”, a camera with light is inserted into the larynx and the glottis is viewed on a display.
Especially when comparing the left and right sides, pareses of one side quickly become apparent. In order to secure the diagnosis an “electromyography“, i.e. a control of the muscle ability by electrical stimulation, can be performed. If no thyroid gland operation has been performed before, the cause of vocal fold paralysis should be determined.
A CT or MRI examination of the neck and chest can show any abnormalities well. The treatment depends on the extent of the damage. If the nerve has been completely severed, for example during thyroid surgery, there is no prospect of improvement through exercise.
Surgical intervention can help to align the vocal fold so that symptoms are minimized. In the case of bilateral vocal fold paralysis, surgery can also widen the vocal fold to prevent acute shortness of breath. If the nerve of the larynx is only irritated and limited in its function, its function can be restored by exercise.
Certain speech exercises can help to regain the ability to move. If the muscles of the larynx are irritated and partially fail, there is a good chance of regaining their original functions. The exercises aim to produce as many different sounds as possible.
Just like normal muscle training to build up muscles, the muscles of the larynx must be exercised evenly. To ensure successful rehabilitation, a speech therapist should be consulted. By constantly practicing different vowels with increased emphasis, a large part of the speech ability can often be regained over time.
Nowadays, electrostimulation techniques are also used. The contraction can be triggered by targeted stimulation of certain muscles. Electrostimulation to strengthen the muscles has the same effect as deliberate tensing through phonation exercises.
