A 72-year-old man complains of memory difficulties. He is worried that he has Alzheimer disease. He has trouble recalling the names of friends, and last month forgot his son's birthday, which had never happened before. On two occasions he became lost driving to a familiar department store. He is now afraid to make trips away from home. His children tell him that he has forgotten things they have discussed even 1 day previously. He lives independently and has not had any difficulty preparing meals, paying bills, using the telephone, or taking his medications. He takes lisinopril and hydrochlorothiazide for hypertension. He does not use alcohol. Folstein MMSE score is 27/30 and Montreal Cognitive Assessment (MoCA) score is 26/30. Neurologic examination is normal. Which of the following is most appropriate?