Apathy (reduced goal-directed behaviour) is common in persons with dementia and is associated with lower quality of life, increased dependence and faster decline. Two treatments were recently shown to be modestly effective: the first is an oral medication called methylphenidate; the second is brain stimulation. Looking at the way brain stimulation works, methylphenidate may improve the response to it and help improvements last longer. Our 10-week study will assess a method of brain stimulation, intermittent theta burst stimulation (iTBS), in treating apathy in 6 persons with Alzheimer disease who are taking methylphenidate for apathy and 6 persons with Alzheimer disease who are not taking methylphenidate for apathy. The study will determine if the combined treatments of methylphenidate plus iTBS work more effectively than iTBS alone in treating apathy in persons with dementia.