Most people associate memory loss as one of the main features of dementia. Whilst this is true for some types of dementia, such as Alzheimer’s disease, memory loss isn’t always one of the earlier symptoms. As each type of dementia affects a different part of the brain, the earlier symptoms a person experiences, will depend on the type of dementia they have (although the symptoms of each type of dementia become more similar as the disease progress and more of the brain becomes damaged).
There are different types of memory and each type of memory is processed and stored in different parts of the brain. Below is a quick summary.
Types of Memory
Dementia and Memory Loss
Knowing about the different types of memory and how they are processed and stored in the brain helps to understand how memory is affected in the earlier stages of the different types of dementia. Below is a summary of the main types of dementia and how memory is affected in the earlier stages of the disease
In Alzheimer’s disease, one of the first areas to be affected is the hippocampus, which makes it harder for someone to form new memories or learn new information. Although the hippocampus is required to retrieve newer memories, it isn’t relied on so heavily to retrieve memories from longer ago. The amygdala, responsible for emotional memories, is also less affected in the earlier stages. This means that someone with Alzheimer’s will struggle to remember what happened earlier that day but will be able to remember things that happened in their childhood and will be able to remember the emotional aspects of certain memories.
As vascular dementia is caused by different diseases disrupting blood supply to the brain, the earlier symptoms can be more variable depending on the part of the brain affected. So memory loss may be an earlier symptom, if for example, the hippocampus is damaged by a mini stroke.
Memory usually remains fairly intact in the earlier stages of dementia with Lewy bodies. Instead people tend to have more trouble retrieving information already stored, leading to problems with performing day to day tasks.
In all forms of frontotemporal dementia the early symptoms impact a person’s behaviour and language. In semantic dementia, the semantic memory is damaged first, so while they may have fluent speech they may struggle to remember the correct words or ask the meaning of a word that they have previously known i.e. plate.
So while for some types of dementia, short term memory loss is one of the key earlier symptoms, it isn’t always the case and is perhaps one of the most misunderstood facts about dementia.