Vocal fold weakness (technically called paresis) is a surprisingly common problem, and it can go untreated because it can be difficult to diagnose.
What is vocal fold paresis?
Paresis is on the same continuum as paralysis, but paralysis means a complete lack of movement while paresis is just a weakness. It comes from damage to one of the nerves that feeds energy to the vocal cords. Because the muscle isn’t getting enough juice, it is weak.
Where does paresis come from?
While some people are born with this type of vocal cord weakness, it more commonly comes from either a virus or something damaging the nerve.
The viral version (probably the most common) is the one most likely to go undiagnosed, because it typically happens during a cold when people are already hoarse. But then the voice just never fully recovers.
Surgery in the torso or neck can damage the nerve and cause paresis (or full paralysis). This nerve gets around the body! Sometimes the nerve gets stretched when moved out of the way during surgery, or effectively bruised. If the nerve is fully severed, then the result is total paralysis, not partial.
While a tumor pressing on the nerve somewhere can cause paralysis, it is less likely to be a culprit here (though certainly still possible).
What are the symptoms of paresis?
Because the vocal folds typically meet and close relatively completely during voicing, a weakness like this tends to prevent them from fully meeting because the weakened cord can’t get all the way to midline.
As a result, people might experience hoarseness, loss of loudness/power, decreased vocal stamina, effort or strain when speaking or singing, decreased vocal range, or other changes to voice quality.
How is it diagnosed?
Visualization of the vocal cords is done using an exam called videostroboscopy. The weakness is often apparent there because one fold isn’t moving as well as the other, or isn’t making it to midline, or is losing muscle mass, or isn’t vibrating as exoected.
The trick is that sometimes these things are so subtle that they can be missed. And sometimes normal vocal cords might look that way so it’s hard to know if there is an issue. Clinical wisdom and symptom tracking is essential here.
Some doctors use EMG (electromyography) to assess the nerve/muscle strength. This is a more invasive exam and not all docs find it useful.
How is it treated?
Sometimes vocal cord paresis recovers on its own as the nerve regains function – think of it as being stunned and then waking back up. If this doesn’t happen, the next course of action is voice therapy.
Voice therapy has a couple purposes here. One is to help promote as much vocal fold closure as possible. It can feel like we are nudging the nerve back to life (though probably not really). The second purpose is to help reduce the tension that inevitably shows up as a result of the weakness. It’s a natural byproduct of people unwittingly working extra hard to try to get their folds closed. But it ventually becomes a part of the problem instead of a coping strategy.
If therapy is insufficient (or if the paresis is interfering with swallowing), surgical options exist. These are referred to as medialization. One way to get the vocal folds to touch is to literally move the weak one over, inserting a little block of material to keep it in place. Another is to inject the weak vocal folds with something to beef it up, thereby allowing for better closure.
If you had a cold and your voice never quite recovered, keep this in mind as a possible reason. If you’d like to disuccss your voice issues further, reach out to schedule a session!
