Rivastigmine, an acetylcholinesterase inhibitor which has been approved by FDA & HSA, is authorized for use in the treatment of mild to moderate dementia of the Alzheimer's type.

In this trial, the investigators will be studying the effectiveness of Rivastigmine in subjects with AD and cerebrovascular disease.

Inclusion Criteria:

• Age between 50-85 years
• Diagnosis of dementia of the Alzheimer's type according to the National Institute of Ageing-Alzheimer's Association Criteriah
• MRI brain (with T2 or FLAIR sequences) performed within a 12 month period from time of recruitment demonstrating the presence of WMH of ≥2 on the Fazekas scale (Score range of 0-3 wherein a score of 1 indicates mild WMH, 2 indicates moderate WMH and 3 indicates severe WMH).i
• Clinical Dementia Rating score of 1-2j
• Mini-Mental State Examination (MMSE) scores of 12-26 inclusivek
• English or Mandarin speaking, literate participants

Exclusion Criteria:

• Severe neurological, psychiatric or systemic disease which in the opinion of the clinician could interfere with trial assessments
• The use of any investigational drugs, new psychotropic or dopaminergic agents, cholinesterase inhibitors or anti-cholinergic agents during the 4 weeks prior to recruitment
• Known skin allergy or previous allergic reaction to Rivastigmine patch