Alzheimer’s disease is caused by the progressive destruction of neurons in the brain. However, physicians may refer to “stages” of Alzheimer's disease when diagnosing or monitoring the progress of the disease in a patient. These stages are commonly accepted patterns of progression that physicians have witnessed in people with the disease. However, it is important to remember that the stages are used as a rough approximation of the progress of the disease and that different staging frameworks may be used by different physicians. An example of a staging framework may be:

• Early-stage Alzheimer's disease. At this stage, the symptoms of Alzheimer's disease are mild and may include problems remembering recent events and a tendency to be more withdrawn than usual. These symptoms may be noticeable by friends and family. At this stage, patients are usually able to live independently and compensate for many of the symptoms they may be experiencing.
  
  
• Mid-stage Alzheimer's disease. By this stage, the symptoms of Alzheimer's disease may become more pronounced and the patient may require assistance with some activities of daily living, such as dressing, eating and using the bathroom. Patients may be unable to remember essential information about themselves such as their current address or telephone number. They may also be confused about where they are and what day, month or year it is. At this stage, patients may or may not have a problem remembering their own name or the names of their family members. The patient may begin to experience signs of personality and behavioral changes.
  
  
• Late-stage Alzheimer's disease. At this stage of the disease, symptoms become severe and the patient usually requires constant assistance for the majority of daily functions. Patients may have lost the ability to use or understand language. They may also be unable to recognize members of their family or remember their own name. They may have lost many aspects of motor function, requiring assistance to sit, walk and support their head. Swallowing may become impaired, increasing the risk of choking or developing pneumonia.