Ask any singer what vocal disaster she dreads the most, and the answer likely will be either laryngeal hemorrhage or vocal-fold paralysis. Certainly, the visual image of bleeding is frightening, and “paralysis” conjures up images of permanent loss of function, somewhat like a stroke.
Well, if you have been a faithful reader of these columns, you know by now that hemorrhage in most cases is a temporary impairment that with early recognition and proper management usually resolves completely. But surely, you say, paralysis is more serious? The answer is, yes and no.
The function of the larynx depends on the movement of its muscles: they open and close the glottis, tighten and bulk up the vocal folds, or stretch them out flat and thin. Muscle movement is triggered by electrical impulses from the laryngeal nerves, which connect these muscles to various parts of the brain. For our discussion here (which is limited to motor function only), two nerves are important: the recurrent laryngeal nerve, which activates the muscles inside the larynx, and the superior laryngeal nerve, which activates the cricothyroid muscles on the outer surface of the laryngeal cartilage.
The recurrent laryngeal nerve is most important, since it comes into play in both the chest and head voices. The superior laryngeal nerve, on the other hand, is activated as the cricothyroid muscles tilt the thyroid cartilage forward in head voice.
Since most untrained voices speak in chest voice, a paralysis of the recurrent nerve is immediately obvious, while a superior nerve paralysis may be subtle, and missed. Either or both of these nerves may lose some or all of their function, resulting in some degree of paralysis and ensuing hoarseness.
The most common reason laryngeal nerves stop working is a viral infection. These viruses, believed to be in the herpes family, can have a variety of effects, depending on which cranial nerve is involved. Bell’s palsy of the face is the best known such viral paralysis, but any cranial nerve can be affected, and sometimes several are (polycranial neuropathy).
Less common causes of laryngeal paralysis may include trauma, either accidental or surgical. Blunt trauma to the neck (such as in a car accident) can leave the voice hoarse. Surgery—such as thyroid operations, cervical vertebral fusion, or carotid artery surgery—can cause stretching of the nerve and (usually temporary) hoarseness.
Viral injury is most prevalent, however. We don’t really know the true frequency of viral injury to the laryngeal nerves, simply because many are mild and transient. Over time, most of these cases resolve themselves completely, with no treatment. From the patient’s point of view, the voice becomes suddenly hoarse, and then, over several weeks, recovers. Many patients never see a doctor, so the true cause of their hoarseness goes undiagnosed. Of course, the duration of this recovery—and indeed, whether it takes place at all—depends on the degree of nerve injury. With severe viral damage, (or if the nerve has been physically interrupted), recovery may never occur. Fortunately, this is rare.
If the recurrent nerve is not functioning, the voice becomes breathy, and loses power and its tonal center. If the affected vocal fold is completely flaccid, the voice sounds wet and rattly, reminiscent of a flag flapping in the wind (which is in fact the case: the floppy vocal fold flaps with attempted phonation).
Isolated paralysis of the superior laryngeal nerve causes problems primarily in the head voice. If, for no apparent reason, you have suddenly lost your head voice, this may be the cause.
What about recovery?
With recurrent laryngeal nerve paralysis, over time one of three outcomes occurs. Optimally, the nerve recovers completely, with normal muscle movement, and the voice is fully restored. Less optimally, the nerve may recover to a degree where tone, but not movement, is restored to the vocal fold. This is also a good thing, since the partially recovered fold presents a surface against which the unaffected opposite vocal fold can learn to approximate. Vocally, the result may not be perfect, but at times it can. I have seen several such singers, who perform and function well with only one mobile vocal fold (a clinical finding that was completely unknown and surprising to both patient and doctor!).
In the worst cases, fortunately rare, the affected vocal fold regains neither movement nor tone. It remains flaccid, and the voice poor. These are the cases where surgery (laryngoplasty) might be used to strengthen the voice.
As a singer, you need to know several facts about laryngeal paralysis:
• It is relatively uncommon and often missed, since it is mild and temporary.
• Even more serious cases often recover, but this recovery takes time.
• If you have been diagnosed with a paralyzed vocal fold, don’t rush to surgery—recovery may take months. During this time, use your voice, don’t rest it. Your larynx needs this physical therapy to recover more effectively. This is true for both recurrent and superior laryngeal nerve weakness.
Have the vocal folds examined regularly, by all means, but do it to monitor any progress, and for psychological reinforcement during a difficult time. An early sign of recovery is your ability to produce a clean, hard cough sound.
If things look discouraging and surgery is recommended, get several opinions. A laryngoplasty is not an emergency procedure, and the outcome, while usually good, is not guaranteed, especially for the singing voice.
