Stages of dementia
Although each person's experience of dementia differs, in general the most common types of dementia progress through several stages, with the symptoms gradually getting worse. Understanding what to expect in the different stages of dementia can be helpful in preparing for what lies ahead.
Dementia – a progressive disorder
Alzheimer's disease, vascular dementia, dementia with Lewy bodies and frontotemporal dementia are the most prevalent types of dementia, but this isn't the only thing they have in common – they are all progressive disorders. This means that at first there may not be any symptoms, but as the condition progresses the chemistry and structure of the brain will be damaged, and over time symptoms will gradually appear and worsen. There will be a slow decline in the person's ability to remember, communicate, understand and reason, as well as in their mood and behaviour. The person will need increasingly more support with everyday living as dementia progresses.
The stages of progression
Each person's experience of dementia will be unique to them, and a wide range of factors can affect how quickly it progresses. For example, Alzheimer's disease, on average, progresses at a slower rate than other forms of dementia. People who are diagnosed with dementia before 65 years old usually have a faster progression, as do people who have other underlying health conditions such as diabetes, heart disease, stroke or repeated infections. Being more physically, mentally and socially active can help slow the progression. Health professionals use different scales to assess the changes in a person with dementia. They might measure a person's mental ability, everyday living skills such as getting dressed, behaviour and overall ability to function.
Once the symptoms of dementia appear, progression of the disorder can be categorised into three stages: mild (or early), moderate (or middle) and severe (or late), though there may be some overlap of the symptoms. These stages are based on Alzheimer's disease, the most studied and most common form of dementia. Other forms of dementia may have different symptoms in the early and moderate stages because different parts of the brain are affected, but the symptoms are similar in the late stage as the disorders affect more areas of the brain.
Before a diagnosis
Evidence suggests that before the symptoms of dementia appear, the underlying condition may have been damaging the brain for years, even decades. This is sometimes referred to as the pre-symptomatic period. Eventually the brain will be damaged enough to cause very mild symptoms, though these aren't considered severe enough to be considered dementia. There may be subtle changes in the person's ability to remember, plan, judge or reason, but not so much that it affects his or her daily life. This is referred to as mild cognitive impairment (MCI). A person with MCI may be forgetful, lose things and struggle in coming up with a particular word, for example, or may struggle in judging the amount of time a particular task requires. These changes aren't significant enough to affect the person's relationships or work. Only some people with MCI will develop dementia.