What is the difference between Alzheimer's and dementia?

Dementia is a general term for a variety of symptoms that most often afflict the elderly and includes memory loss, an inability to reason and incredible difficulty with communicating. Dementia occurs when brain cells have been damaged. The most common form of dementia is Alzheimer's disease, which affects 60 to 80 percent of dementia patients, followed by vascular dementia, which is caused by poor blood flow to the brain. However, certain types of dementia can be reversible, such as dementia caused by vitamin deficiencies, excessive alcohol use, medication, or thyroid problems. 

Alzheimer's disease is a form of dementia where the patient gets progressively worse and eventually is unable to perform basic daily activities, speak, respond, or walk. Unfortunately, there is no cure or successful treatment for Alzheimer's, and patients will continue to get progressively worse.