Cognitive impairment is not exactly the same as dementia. Dementia is a more severe stage of cognitive impairment, which usually has a serious impact on the patient’s work and life in general, resulting in impaired social functioning and a reduced quality of life. Alzheimer’s disease can be caused by Alzheimer’s disease, cerebrovascular disease, trauma, hydrocephalus, brain tumours and many other diseases, and is often accompanied by mental behavioural abnormalities on top of the cognitive impairment.