Which clinical finding may indicate involvement of cranial nerve VI?

The correct answer is double vision. Cranial nerve VI, also known as the abducens nerve, is primarily responsible for controlling lateral eye movement by innervating the lateral rectus muscle. When there is involvement of this nerve, patients may experience diplopia or double vision, particularly when attempting to look to the side of the affected eye. This condition arises because the affected eye cannot move laterally, leading to misalignment of the eyes and resulting in the perception of two images.

While other clinical findings such as facial asymmetry, inadequate blinking, and drooping eyelid may indicate issues with various cranial nerves, they do not specifically relate to cranial nerve VI. Facial asymmetry could suggest problems with the facial nerve (cranial nerve VII), inadequate blinking may indicate issues with either the same nerve or others involved in the blink reflex, and drooping eyelid is associated with the function of cranial nerve III, which controls eyelid elevation. Thus, the presence of double vision is a definitive sign of cranial nerve VI involvement, making it the correct choice.