Aminoglycosides can cause ototoxicity by affecting which cranial nerve?

• A. CN II
• B. CN X
• C. CN VII
• D. CN VIII

Answer: (D)

Aminoglycosides are ototoxic because they damage the inner ear’s sensory hair cells, which send signals for hearing and balance to the brain. Those signals travel via the vestibulocochlear nerve, CN VIII, so this nerve is the one affected. That's why ototoxicity presents with sensorineural hearing loss and sometimes vertigo or dizziness. The other nerves listed don’t handle hearing or balance—optic nerve for vision, vagus for autonomic functions, and facial nerve for facial movement and taste—so they aren’t the ones involved in this type of toxicity.