Pressed voice is produced by which activation pattern according to Hirano?

• A. Significantly greater activation of TA than CT, making body stiff and cover slack during phonation
• B. Greater activation of CT than TA
• C. Low activation of CT and TA
• D. Slightly greater activation of TA than CT

Answer: (A)

Understanding how selective muscle activation shapes voice quality in Hirano's body-cover model helps explain this pattern. In this model, the vocal folds have a stiff inner body (the TA/vocalis) and a more pliable cover. Pressed voice arises when the body is strongly activated relative to the cover, increasing medial compression and making the voice sound tense and harsh.

When the thyroarytenoid (body) is activated far more than the cricothyroid (which would elongate and stiffen the folds), the body becomes stiff and pushes the folds together firmly. With relatively less activation of the cricothyroid, the cover isn’t pulled taut, so the mucosal cover remains comparatively slack. This combination produces the tight, loud, and pressed quality characterized by high medial constriction and reduced mucosal wave.

If the cricothyroid were more active than the thyroarytenoid, the folds would be lengthened and the balance of tension would shift, yielding a different voice quality rather than the pressed type. Very low activation of both or only a slight difference would result in a weak or breathy voice, not the pressed quality.