A 65-year-old man with emphysema and bronchitis has come to the clinic for a follow-up appointment.
On assessment the nurse might expect to see which finding?

Choice A rationale

The optic nerve (CN II) is responsible for vision. It transmits visual information from the retina to the brain. Dysfunction in this nerve typically results in visual disturbances such as loss of vision, visual field defects, or difficulty in distinguishing colors. It does not control the movement or strength of the tongue.

Choice B rationale

The abducens nerve (CN VI) innervates the lateral rectus muscle of the eye, which is responsible for abducting the eye (moving it outward). Dysfunction in this nerve can lead to strabismus (misalignment of the eyes), double vision, or inability to move the eye outward. It does not affect tongue movement or strength.

Choice C rationale

The hypoglossal nerve (CN XII) innervates the muscles of the tongue, controlling its movement and strength. Dysfunction in this nerve can result in difficulty protruding the tongue, poor strength against resistance, and impaired speech or swallowing. Therefore, the symptoms described in the question indicate a dysfunction of the hypoglossal nerve.

Choice D rationale

The vestibulocochlear nerve (CN VIII) is responsible for hearing and balance. It transmits sound and equilibrium information from the inner ear to the brain. Dysfunction in this nerve can lead to hearing loss, tinnitus, vertigo, or balance problems. It does not control tongue movement or strength.

Choice A rationale

The Cover/Uncover test is used to assess the presence of strabismus or eye muscle weakness. During this test, one eye is covered while the other eye is observed for movement. The uncovered eye is then observed when the cover is removed. If there is a misalignment or weakness, the uncovered eye will move to re-establish focus, indicating a problem with eye muscle control.

Choice B rationale

Testing peripheral vision involves assessing the range of vision around the central focus point and is not specifically used to detect eye muscle weakness. It evaluates the function of the retina and optic nerve rather than the eye muscles. This test helps identify issues such as glaucoma or retinal detachment.

Choice C rationale

The Snellen chart test measures visual acuity, specifically how well a person can see at various distances. It is not designed to assess eye muscle strength or alignment. The test involves reading letters of different sizes from a chart placed at a standard distance.

Choice D rationale

The Weber test is an auditory test used to assess hearing loss by placing a vibrating tuning fork on the forehead or middle of the head. It helps determine whether hearing loss is conductive or sensorineural in nature. This test does not provide information about eye muscle function or alignment.