What vocal change is most consistent with a superior laryngeal nerve injury?

A superior laryngeal nerve injury primarily affects the function of the cricothyroid muscle, which is responsible for adjusting the tension of the vocal cords, thereby playing a key role in modulating pitch. When this nerve is injured, individuals often experience a reduced ability to vary their pitch, resulting in a limited pitch range. This can manifest as a monotone voice and difficulty reaching higher pitches, which is why a reduced pitch range is the most consistent vocal change associated with such an injury.

The other options relate to different aspects of vocal function or other anatomical changes. For example, inspiratory stridor is typically related to airway obstruction rather than laryngeal nerve function. Hypernasal resonance is associated with velopharyngeal incompetence, which can be influenced by different nerves and structures. Complete aphonia, the inability to produce voice, may indicate more severe laryngeal damage beyond the scope of just the superior laryngeal nerve, affecting overall vocal fold function. Thus, reduced pitch range directly aligns with the specific impact of a superior laryngeal nerve injury.