Partial paralysis; partial loss of nerve input to a muscle, resulting in muscle weakness
Complete loss of nerve input to a muscle resulting in complete loss of muscle function
Laryngeal Electromyography (LEMG)
Test that measures electrical signals of nerve inputs to muscles
Recurrent Laryngeal Nerve (RLN)
Branch of vagus nerve to voice box muscles that open and close vocal folds
Superior Laryngeal Nerve (SLN)
Branch of vagus nerve to cricothyroid muscle involved in control of pitch
Partial (paresis) or complete loss (paralysis) of nerve function to voice box muscles results in abnormal vocal fold function, affects the ability to speak and sing and, in some cases, also breathe and swallow. Attempts to compensate for loss of muscle function, often leads to voice tiring after prolonged use (vocal fatigue).
Interruption of the nerve input to voice box muscles may be temporary or permanent, partial or complete, and may affect one or more voice box muscles.
Vocal fold paresis and paralysis comprise a range – from mild to severe – of abnormal voice box muscle functions due to varying degrees of abnormal nerve input.
A Frequently Missed Cause of Voice Disorders
Paresis of voice box muscles is often missed as the cause of a voice disorder because patient complaints can be very mild. For example, a patient with vocal fold paresis may only notice voice tiring after use, often at the end of the day (vocal fatigue).
Identification of Paresis and Paralysis Needs to Be Carefully Done
Absence of vocal fold movement (vocal fold immobility) is highly suggestive of vocal fold paralysis but may also be due to other causes – hence thorough medical evaluation is necessary.
Likewise, if the vocal folds do move, it does not eliminate nerve impairment as a cause of the voice disorder since vocal fold paresis may be present.
Two Key Tests Used to Identify Paresis and Paralysis
Magnified viewing of vocal movement and position through a special scope (laryngoscopy) can identify vocal fold abnormalities suggestive of vocal fold paralysis. (For more information, see Laryngoscopy/Stroboscopy.)
Identification of Cause
Cause Is Key to Treatment Plan
Since there are many causes of vocal fold paresis and paralysis, the cause for each patient needs to be evaluated systematically. As with all disorders, finding out the cause helps map out a treatment plan.
Even when nothing can be done about the nerve damage causing vocal fold paresis or paralysis, improving the function of the vocal fold and voice can be addressed by the voice box surgeon-specialist (laryngologist).
Any and all airway problems require immediate attention.
Patient education material presented here does not substitute for medical consultation or examination, nor is this material intended to provide advice on the medical treatment appropriate to any specific circumstances.
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