Can Someone Forget They Have Dementia?

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In our last article, we discussed why memories for habits, skills, and procedures are relatively preserved in dementia. In this week’s article, we will take a look at what happens to memory in the moderate to severe stage of dementia.

Memory may be variable over time

For reasons that we do not fully understand, in dementia the ability to create and store new memories as well as to retrieve old memories is often quite variable over weeks, days, and even hours. One commonly observed phenomenon is that people with dementia become more confused in the late afternoon or early evening, often called “sundowning.” Theories as to why this confusion occurs include that they are getting tired, their vision is impaired by the diminishing light, causing disorientation, or it is related to their circadian rhythm. During this time, it is more likely that they may not recognize their current home and think that they need to go “home,” which usually means to the house of their childhood.

Wandering is common when someone does not recognize where they are

We often use the term “wandering” to describe when someone with dementia leaves their home and begins walking somewhere. Wandering may occur for many reasons. The individual with dementia may be trying to get somewhere in the past, such as their childhood home. They get up and leave the house to go to work, forgetting that they haven’t worked for 20 years. Or perhaps they simply want to take a walk around the block and become lost along their route.

Shadowing is usually due to an inability to form new memories

Another phenomenon that often occurs is that your loved one doesn’t want to let you out of their sight. They will “shadow” you, following you from room to room. Have you heard of the phrase, “Out of sight, out of mind”? That is literally what is happening here. Because their hippocampus is damaged, and they cannot form new memories, if they cannot see you, they cannot remember where you are, when they have seen you last, or even if you are in the same house. They may think you have been gone for hours when you just used the bathroom for 10 minutes. Particularly if they are having trouble recognizing their home, they may feel anxious if they cannot see you, as you may be the only thing in their world that feels familiar to them. For these reasons they may tend to follow you around, becoming your shadow.

False memories and confabulations are common in the later stages of dementia

Although mixing up elements of memories occurs frequently in healthy individuals, it is even more common in those with dementia. Sometimes these false and distorted memories may be mundane—but still important—such as falsely believing that one has taken their medication or turned off the stove when one has only thought about these activities. Or, perhaps, one actually did them yesterday, but not today. Other times, false memories can be more unusual, such as one remembering that there was a party in their bedroom that was keeping them up all night, or recalling that they had a nice conversation with their parents who have been deceased for many years. These more extreme false memories are sometimes referred to as confabulations. However, whether mundane or extreme, the increase in false memories is simply another manifestation of the damage to the hippocampus and frontal lobes that occurs with dementia.

People often forget that they have dementia

One thing that is tricky about dementia is that people literally have trouble remembering all the times that they forget things. It is for this reason that they often underestimate how impaired their memory is—or they may not remember that they are impaired at all. Similarly, as their hippocampus deteriorates, they may completely forget that they have dementia, such that every time they are told they have the disorder, they experience the news as if they are hearing it for the first time.

© Andrew E. Budson, MD, 2019, all rights reserved.