If your loved one needs medical care outside of his or her usual group of care providers, you can help make the experience a smoother, more respectful one by providing a little "crash training" to healthcare providers on how to interact with someone who has dementia.
Whether the provider is a specialist doctor, a physical therapist, a rehab specialist, a nursing aide, or any other kind of medical staffer, politely go over these three things:
Let care providers know at the outset that there are memory issues. You can't say this often enough, even if the information is right there in the chart.
Tell the staff how the person likes to be addressed (Mrs. Smith, Dr. Smith, Carol). Call them on it when they revert to a name your loved one dislikes or a patronizing "dearie" (if you know your loved one would be offended).
Ask that they include the person in the conversation, rather than talking as if he or she weren't in the room. Often doctors talk to the caregiver instead of the patient because it's more efficient. But the person with dementia should not be ignored entirely, which can be unnerving to both of you.