Review Question - QID 213386

A 67-year-old woman presents to her primary care physician for memory difficulty. She states that for the past couple months she has had trouble with her memory including forgetting simple things like bills she needs to pay or locking doors. She was previously fully functional and did not make these types of mistakes. The patient has not been ill lately but came in because her daughter was concerned about her memory. She makes her own food and eats a varied diet. Review of systems is notable for a decrease in the patient’s mood for the past 2 months since her husband died and a sensation that her limbs are heavy making it difficult for her to do anything. Her temperature is 99.3°F (37.4°C), blood pressure is 112/68 mmHg, pulse is 71/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam is notable for an elderly woman. Her neurological exam is unremarkable; however, the patient struggles to recall 3 objects after a short period of time and can only recall 2 of them. The patient’s weight is unchanged from her previous visit and cardiac, pulmonary, and dermatologic exams are within normal limits. Which of the following is the most likely diagnosis?