Dementia can cause dizziness, particularly if it is vascular dementia, but I do not see dizziness caused by Alzheimer's very often. Dizziness is more commonly associated with vascular dementia because
blood flow to the brain is restricted.
With Alzheimer's, your loved one's balance may be affected. Balance issues are common with dementia, which may give an observer the impression that the person is suffering from dizziness. Dementia causes a person to perceive the world differently, and the person does not always know how to react. So it is possible that what your loved one is experiencing is caused by one of these dementia symptoms.
If your loved one is taking medication for dementia, read the possible side effects. Many drugs for dementia can cause dizziness. If this is what is causing your loved one's difficulty, talk with his or her doctor about trying a different medication.
Also, keep in mind that aging itself can sometimes cause people to feel dizzy more frequently, especially if they make sudden movements. Encourage your loved one to take his or her time when moving around. Railings and grab bars in stairwells, bathrooms and throughout the home can help your loved one get around more easily and reduce the risk of falling.
Learn more about dementia and its effects in Caring.com's Dementia Resource Center.