A 76-year-old woman is brought to the office by her daughter due to progressively worsening memory and language difficulties. The patient first started having memory problems and word-findinq difficulties 5 years ago. She then began having difficulty balancing her checkbook and buying groceries. The patient became lost while driving to church last year and no longer drives. She is now dependent on her daughter for cooking and cleaning. Over the past 6 months, the patient's personality has changed from seeming apathetic to becoming more paranoid and agitated; she frequently claims to have seen her niece stealing from her purse. The patient recently developed urinary incontinence. She has a history of hyperlipidemia and osteoarthritis of the left hip and both knees. Blood pressure is 130/80 mm Hg and pulse is 90/min. Deep tendon reflexes are 2+ throughout, and she has preserved motor strength. The patient recalls none of 3 objects on memory testing and cannot draw a clock. Laboratory studies show normal electrolytes, lipid panel, TSH, vitamin 812, and complete blood count