In the early 1980s Dr Barry Reisberg developed a scale based on the amount of cognitive decline in a person which is most relevant for those with Alzheimer’s disease as some other types of dementia do not always include memory loss. It has since become widely used to outline the progression of the condition. 

Stage 1. There is no noticeable memory loss. 

Stage 2. Very mild cognitive decline. A person misplaces familiar objects and forgets names, but the symptoms of dementia are not evident to a doctor or loved ones. Dementia is not diagnosed at this point as the person may be suffering from age-related memory loss. 

Stage 3. Mild cognitive decline. There is an increase in forgetfulness and difficulty in finding the right words. Concentrating can also be a problem, and someone may read from a magazine or book but retain little of the information. At this point, loved ones start to notice that there is a change, and this stage can last between two and seven years. 

Stage 4. Moderate cognitive decline. Recent events tend to be forgotten, and personal finances become difficult or impossible to manage. A person is unable to travel to new places alone and struggles to complete tasks. At this stage, they may also be in denial about their symptoms and have difficulty socialising with friends and family. This stage, which can last for a couple of years, is also the first one where a doctor can detect cognitive problems. 

Stage 5. Moderately severe cognitive decline. Lasting between a year and a year and a half, a person forgets details such as their address or phone number as well as not knowing the date or time. They will also need some assistance with dressing and bathing. 

Stage 6. Severe cognitive decline. Names of family members are forgotten, and there can be personality as well as emotional changes and anxiety. Incontinence can be another problem, and they are unable to carry out dressing and bathing on their own. The average duration of this stage is two and a half years. 

Stage 7. Very severe cognitive decline.  Unable to speak or communicate, a person at the final stage will require help with most activities, lose motor skills and be unable to walk. Many sufferers pass away before reaching this stage. 

It is essential to seek medical help or advice if you believe that someone you love is showing some signs or symptoms of dementia.