Written by Josh Horsman
Alzheimer’s Disease, like other forms of Dementia, is a progressive neurological condition. This means that the condition worsens over time and the severity of a person’s symptoms increases. The progression of Alzheimer’s Disease can be marked by seven distinct stages as defined by the widely-used Reisberg Scale (or Global Deterioration Scale).
A person living with Alzheimer’s typically lives for between 4 and 8 years with the condition, but some may live as long as 20 years, with their condition progressing through each of the seven stages at a slower rate.
The 7 stages of the Reisberg scale are based on the increasing severity of cognitive decline, mainly memory-loss and impaired judgement, which are the key symptoms of Alzheimer’s Disease. Here’s a detailed guide on what to expect at each stage:
Stage 1: No Cognitive Decline
People in stage 1 of Alzheimer's don’t actually display any sign of the disease at all. In fact, this stage classifies those who are mentally healthy and who do not have Dementia of any form.
Stage 2: Very Mild Cognitive Decline
The second stage in the Reisberg scale describes very subtle signs of cognitive decline such as occasionally forgetting names or where one has left everyday objects. These symptoms are usually typical of normal ageing and are not severe enough to be picked up by a doctor or even a person’s family and loved-ones.
Stage 3: Mild Cognitive Decline
The third stage on the Reisberg scale describes more obvious symptoms which begin to be noticed by the person’s friends and family. This could include more frequent memory-loss, getting lost or confused and trouble with speech. At this stage, lapses of cognitive function may sometimes make work or everyday tasks more difficult.
Stage 4: Moderate Cognitive Decline
Stage four comes with increasingly obvious symptoms that begin to get in the way of normal living. Memory-loss begins to become more pronounced, especially concerning more recent events and completing everyday tasks becomes more difficult as the person becomes more prone to errors. It will also be more difficult for them to absorb and learn new information.
The individual may react in different ways - some people begin to withdraw themselves socially, while others may strongly deny their symptoms. At this point cognitive decline is relatively straightforward for a doctor to detect through interview and examination.
Stage 5: Moderately Severe Cognitive Decline
The fifth stage is characterised by a loss of independence for the person as they begin to need help to complete everyday tasks such as dressing, bathing and cooking. By this stage, memory-loss has worsened to the point where they may struggle to recall some personal information like addresses and numbers.
Stage 6: Severe Cognitive Decline
By the time they reach stage six, people living with Alzheimer’s require almost round-the-clock care. They will be able to perform few, if any, of their normal daily activities independently as their judgement, organisational skills and memory have deteriorated significantly. The further impaired memory-loss means they are now likely to frequently forget names of even close family and loved-ones and occasionally have difficulty recognising them. Their long-term memory may remain in some form, but it is likely they only remember certain periods of their life or a few specific memories. Their short-term memory, however, is likely to be extremely limited. By this stage, the person may also have difficulty communicating effectively due to impaired speech and language skills.
Stage 7: Very Severe Cognitive Decline
People in the final stage of Alzheimer’s Disease, have lost most or all of their ability to communicate. They are reliant on the support of others for help with all daily tasks, including using the toilet, eating and washing. Many people in this stage will also find their mobility impaired and become unable to walk or move around easily. Their symptoms of memory-loss and impaired thinking-skills will continue to worsen along with their condition.
The Global Deterioration 'Reisberg' Scale (Reisberg, 1982)