The investigators plan to see what factors can influence the durability of Exelon patch treatment in Korean patients with Alzheimer's disease.

Based on these results, the investigators will find the ways to maximize the effect and durability of Exelon patch on Korean patients with Alzheimer's disease.

After finishing this study, the investigators are going to present the study results at the international and national academic meetings or conferences.

Also the investigators expect that they can publish the result in a journal of in the field of neurology or dementia till the winter of 2010.

A once-daily Exelon patch has recently been developed to reduce the GI side effect of rivastigmine and make application easier by once a day.

Thinking the patch as the first-line drug, it should be proven as safe for a long time. The safety and clinical effect of Exelon patch was tested in many studies.

However, most of studies have been conducted on Western countries and the study period was not more than a year.

There are only few data on Exelon patch related to other ethnic such as Asian patients with Alzheimer's disease.

Especially, there are many different environmental factors between Western and Asia countries, such as habitual or climate factors, skin type and behavioral styles which may be influenced on patch durability.

The aim of this study was to evaluate the durability of Exelon patch in Korean patients with Alzheimer's disease and what are the factors influencing the durability.

Also evaluating the significance of factors gives us the way to increase the patch durability.

Thirty patients per investigational center will be enrolled during 6 months.

Probable mild to moderate AD patients will be included whether they have depression or other neurological symptoms or diseases.

The period of this study will be 6 months, and we will start the treatment starting from Exelon patch 5cm2.

After 4 weeks, dose titration will be attempted to Exelon patch 10cm2.

If a patient is reporting too much discomfort to stick on high dose patch, investigators will assess the severity of the side effects followed by adjusting dose or considering discontinuation.

Cognitive, functional, and global outcome measures are obtained at baseline and at the end of month 6. Environmental factors including caregiver condition, participant's habitat type, and participant's skin type, etc. are also evaluated from the first visit, and they will be assessed at every visit.

Participants and their caregivers will be asked of any possible concerns or problems associated with patch use at every visit. And if there is any visible problem or adverse event, it will be taken as a picture and be uploaded to investigation web site for this study.

Finally, for the primary endpoint, participants who discontinue prematurely are evaluated during every visit.

Signs of skin irritation at the site of patch application are assessed at every visit by the investigator using skin irritation rating scale.

Caregivers evaluate patch adhesion throughout the study with ratings provided in accordance with a patch adhesion scoring system.

To assess factors to influence skin irritation or any other adverse events, we will classify skin type of each participant using "skin type measuring paper" at the first visit time.

We will search for any personal or family history of allergy, and characteristics of participant's habitat using questionnaire.

The information about the caregiver including his/her condition based on the annual income, living status, and education level.

To see if there is any specific allergic factor for discontinuation, we will investigate participant's allergy history more completely and thoroughly.

Inclusion Criteria:

• Probable AD by NINCDS-ADRDA and DSM-IV
• Male and female aged from 51 to 85 years old
• Magnetic resonance imaging or computed tomographic scan within 12 months consistent with a diagnosis of probable AD
• Patients who approved to release of personal information

Exclusion Criteria:

• Patient with any active pulmonary, gastrointestinal, renal, hepatic (severe hepatic function impaired patients), endocrine, or cardiovascular disease, clinically significant laboratory abnormalities, or any medical condition which would prohibit them from completing the study
• Any patients suspicious of drug addiction or alcohol addiction for the past 10 years
• Any other patients to be decided to be inappropriate for the study by the investigators

Patients with Alzheimer's disease