Acetylcholinesterase inhibitors (AChEIs) increase the amount acetylcholine at ACh receptors within the brain, and are the primary medications used to treat AD. Alzheimer's disease patients are frequently associated with mild or moderate white matter changes on MR imaging. The impact of whiter matter changes on the efficacy of cognition, functional abilities, behavioral and psychiatric symptoms and caregiver burden for probable Alzheimer's disease is not well known. There are very few studies for the efficacy of rivastigmine between the patients with mild to moderate Alzheimer's disease associated with or without vascular risk factors.