Doctors are trying to figure out who should get a new treatment for Alzheimer's disease.
The drug's recent approval by the Food and Drug Administration sparked both excitement and skepticism.
It's the first drug that U.S. regulators say might help slow the disease. Other Alzheimer's drugs only treat its symptoms.
The new drug is expensive and is given through monthly IVs. And insurers including Medicare haven't determined how they are going to cover the drug. While some clinics have already started giving the drug, many providers say it will take weeks or months before they are ready to offer it.