An 80-year-old patient is placed in isolation when infected with methicillin-resistant Staphylococcus aureus. The patient was alert and oriented on admission, but is now having visual hallucinations and can follow only simple directions. The medical-surgical nurse recognizes that the changes in the patient's mental status are related to:
a fluid and electrolyte imbalance.
a stimulating environment.
sensory deprivation.
sundowning.