What assessment should be performed to evaluate a patient's sensory function related to CN V?

To evaluate a patient's sensory function related to cranial nerve V (trigeminal nerve), lightly touching the patient's face with a cotton swab is the most appropriate assessment. The trigeminal nerve is primarily responsible for sensation in the face, including the forehead, cheeks, and jaw. By using a cotton swab to lightly touch different areas of the face, the healthcare provider can assess the patient's ability to perceive light touch in these regions.

This assessment effectively tests the sensory branches of the trigeminal nerve, including the ophthalmic, maxillary, and mandibular divisions. Normal response to this touch indicates that the sensory pathways from the face to the brain are functioning correctly.

Other options focus on different cranial nerves or functions. Testing the gag reflex evaluates cranial nerves IX and X, while asking the patient to smile primarily assesses facial nerve function. Evaluating the shoulder shrug checks cranial nerve XI, which is unrelated to sensory function of the face.