The most common type of dementia is Alzheimer's disease, which accounts for about 60% to 70% of all cases according to the WHO. This article will explain how Alzheimer's disease progresses. Although Alzheimer's is irreversible, understanding how it may progress allows you to be aware of how it might impact you or your loved ones.
The progression of dementia in Alzheimer’s disease (AD) must be considered in the context of the disorder’s clinical presentation, course and biology. Historically, it has been defined as a memory disorder, with the disease progression being described largely in terms of memory loss and cognitive impairment. In addition, the clinical diagnosis of AD requires multiple cognitive impairments that are sufficiently severe to interfere significantly with occupational or social function. Nonetheless, AD as a form of dementia is specifically characterised by memory loss, changes in personality and language.
The progression of AD follows a gradual but ultimately unstoppable decline in memory and thinking skills. At the same time, the person’s physical condition declines as well. For example, AD causes "motor symptoms" such as problems with balance and coordination. A person's emotional state may change too; they may become confused or disoriented. These symptoms are part of the general condition of dementia. The person, however, is still capable of independent living and is able to care for themselves. However, as symptoms worsen, a person needs more help with everyday activities such as bathing or dressing. This is called "dependency" in which the disease progresses to such a stage that the person requires assistance with bathing, dressing, and/or various other daily activities. The person may no longer recognize his or her new surroundings and needs help from someone else in daily living.
AD is understood to be a progressive disease and it is thought that the underlying mechanism of neurodegeneration leading to AD starts 20 years before the patients show specific symptoms of the disease. Nonetheless, the normal progression of AD follows three stages:
- starting with the asymptomatic stage, called preclinical AD
- a symptomatic stage before dementia, which is normally called Mild Cognitive Impairments (MCI)
- ultimately progresses to dementia, with varying symptoms which can be mild to severe
The progression of dementia in AD has been described more specifically to follow seven stages. This progression is of specific interest because symptoms of AD often start with subtle signs. Families may often mistake early AD signs as forms of normal ageing and consequently put off going to a doctor when such action could delay the progression of the disease. The stages of dementia in AD are as follows:
Stages of dementia in Alzheimer’s Disease
Stage I - No cognitive decline
The first stage is the preclinical stage. Changes in the brain seen in imaging technologies are due to the normal ageing process that do not lead to cognitive signs and symptoms.
Stage II - Very mild cognitive decline (also called MCI)
This is the earliest stage of dementia when the symptoms are still relatively minor, or in other words, you would not necessarily be able to tell that someone has dementia. However, the person may begin to experience subtle memory problems and notice some personality changes. These symptoms will vary from person to person, and patients may start to forget names of close friends or family members.
Stage III - Mild cognitive decline
The patient may start to show some more symptoms of dementia, such as short-term memory loss (forgetting what they just read or what someone said to them) or long-term memory loss (frequently misplacing and losing objects). Personality changes also become more noticeable with time - patients beginning to forget what was previously known and/or why things are happening as well as more noticeable difficulties to make plans.
Stage IV - Moderate cognitive decline
This is the beginning of the middle stage of dementia. Signs and symptoms of cognitive decline become more objective. Patients may act more like they are senile, having clear difficulties with previously simple things like calculations. The patient's interest in what used to bring them joy wanes. This stage is most likely to be the one where a clear clinical diagnostic is made.
Stage V - Moderately severe cognitive decline
The patient starts to experience major memory disturbances with clear effects on simple daily behaviours such as choosing which clothes to wear. They sometimes may get lost in their own thoughts and need help retracing what they have done in the past.
stage VI - Severe cognitive decline
The patient shows major cognitive impairment with significant functional deterioration. The patient may suffer from severe confusion associated with hallucinations, delusions, or have trouble distinguishing reality from fantasy.
Stage VII - Very severe cognitive decline
This is the final stage or end-stage of dementia where a patient becomes completely dependent to carry out basic activities. At this stage, their ability to communicate falls drastically, sometimes impairing their ability to speak with words completely.
Finally, it should be noted that as dementia progresses through the stages of Alzheimer’s disease, not all patients will experience the same changes or the same type of cognitive decline at each stage, some of which may be experienced sooner or later, or even overlap.
