Compensation

Compensation is your natural tendency to maintain smooth sound production despite injury or weakness. An examiner understanding how to remove compensation is essential for diagnosing voice disorders accurately.

Compensation

Surprisingly, when someone with hoarseness comes in seeking a diagnosis, they try to avoid sounding hoarse during the examination. Naturally and fairly immediately they try to compensate for any hoarseness. As soon as their voice breaks or cracks, they stop the vocal task and apologize. Then they try the vocal task again, trying not to sound “bad.” Internally they compensate and produce the sound again.

A robust redundancy in the vocal system allows compensation, often maintaining sound production even when there is a problem. However, for the examiner, compensation tends to hide a voice disorder, both audibly as well as visually. Some common instances hidden by compensation include mucosal disorders on the edge of the vocal cord where the vocal cords can be held apart to avoid touching the bump or weakness from neurologic and muscular disorders where the opposite side’s muscle works harder. Yet the astute examiner attempts to eliminate compensation, exposing a problem.

When an examiner removes compensation — typically by initiating a change in pitch or volume — asymmetries and gaps become more audible and more visible.

For example, the TA muscle and the CT muscle both have the effect of raising pitch. If there is decreased neurologic input to one of these muscles, the other compensates at least partially. In the case where the TA muscle is not working on one side, a patient automatically compensates by pulling the CT muscle tighter. This has a net effect of raising the comfortable speaking pitch when the patient tries to speak with the same volume as before the injury.

When performing an endoscopic exam on a patient speaking at an unnaturally high pitch, progressively lower pitches should be requested. At each lower note, compensatory tightness from the CT muscle is progressively removed. As the CT muscle’s contraction is removed, if there is a weak TA muscle, the vocal cord would begin to bow and then flutter while a healthy TA muscle on the other side would remain tight. Removing compensation amplifies this difference between each side of the larynx and allows improved visualization of the neurologic impairment.

Mucosal disorders also involve natural compensation. At higher pitches, the vocal cord is pulled tighter. A mucosal swelling on the edge of a vocal cord would stand out farther with the increasing tension of higher pitch. The further the swelling sticks out, the more likely it is to touch the other vocal cord and stop vibrations. The patient compensates for this “stopping effect” by increasing airflow to blow the touching swellings apart — in effect increasing volume to compensate for the swelling. As an examiner, removing this compensation means asking the patient to make only soft sounds while going up in pitch. At low lung pressure, the slightest touch of a swelling on one vocal cord stops or alters the vibrations on both.

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