Voice is vibration. Hoarseness is a disruption of that vibration — either air leaking through an unclosed gap, or two vocal cords vibrating at different pitches. Every diagnosis in laryngology traces back to one or both of these two mechanisms.
The sound we know as voice is created by vibration, and voice can only be produced by vibrating structures. In the larynx, the source of vibration is almost always the true vocal cords. Hoarseness is produced in two different ways: by air leak or by asymmetric vibrations. Air leak causes husky hoarseness. Asymmetric vibrations cause rough hoarseness. Numerous disorders have both air leak and asymmetric vibrations, and perhaps even more than one type of asymmetry.
Air may leak from the front, middle, or back of the vocal cords. The vocal cords may be asymmetric in several different ways: mass, tension, length, stiffness, or timing.
The most important part of the question “Why am I hoarse?” is the why. Mere presence of a finding on the larynx is not sufficient justification for cause.
Two personality traits strongly influence vocal cord disorders. Talkativeness is an innate personality trait that puts a person at risk for mucosal lesions — more vibrations means an increasing risk of calluses and swellings, typically leading to a mixed rough and husky hoarseness. A lack of talkativeness puts a person at risk for muscle atrophy, and typically husky hoarseness and discomfort from muscle compensation.
There is an implicit assumption often made that since voice comes from the larynx, all the examiner has to do is look in the vicinity of the vocal cords and whatever appears is likely causing the hoarseness. But mere presence is not sufficient justification for cause. The examiner must identify specifically what about the vocal cords is causing air leak and what is causing asymmetry.
What You Learned
- Hoarseness has exactly two mechanisms — husky (air leak through a gap) and rough (diplophonia from asymmetric vibration).
- Gaps occur in five locations — posterior, anterior, central, split, and timing; all create husky hoarseness.
- Asymmetries occur in four dimensions — tension, mass, length, and stiffness; all cause rough hoarseness.
- Most disorders combine both — pure huskiness or pure roughness is less common than a mixture.
- Personality predicts pathology — high talkativeness predicts mucosal swellings; low talkativeness predicts atrophy.
- The examiner must find the mechanism, not just the lesion — ask specifically what is causing air leak and what is causing asymmetry.