What is sundowning and why does it happen to many people with dementia?

The term sundowning is sometimes used to describe a tendency for people with dementia to become more confused in the late afternoon and into the night.

At the outset, I should point out that the term sundowning is overly simplistic, as it is a shorthand term that can encompass a vast number of behaviors in many different contexts. When evaluating changed behaviors in dementia, it is always better to hear a complete and accurate description of what the person is actually doing at these times, rather than simply accepting that it is waning.

This set of behaviors commonly described as sundowning often includes (but is not limited to) confusion, anxiety, agitation, pacing, and stalking others. It can look different depending on the stage of the dementia, the person’s personality and past behavior patterns, and whether there are specific triggers.

Why then do such altered behaviors tend to happen at specific times of the day? And what should you do when it happens to your loved one?

Faded light

We all interpret the world through information that enters our brain through our five senses. Chief among these are sight and sound.

Imagine the difficulty you would have if you were asked to perform a complex task while in a dark room.

People living with dementia are equally dependent on sensory input to make sense of and correctly interpret their environment.

As light fades towards the end of the day, the amount of sensory input available to help a dementia patient interpret the world also decreases.

The impact of this on a brain struggling to integrate sensory information at best can be significant, resulting in increased confusion and unexpected behaviors.

Cognitive exhaustion

We’ve all heard that we use only a fraction of our brainpower, and it’s true that we all have far more brainpower than we normally require for most daily activities.

This cognitive reserve can be tapped when faced with complex or stressful tasks that require more mental effort. But what if you don’t have much cognitive reserve?

The changes that ultimately lead to the symptoms of Alzheimer’s disease can begin to develop up to 30 years before symptoms appear.

During that time, in simple terms, the condition erodes our cognitive reserve.

It is only when the damage done is so significant that our brains can no longer compensate for it that we develop the first symptoms of Alzheimer’s disease and other dementias.

So when someone first presents with very early dementia symptoms, a lot of the damage has already been done. Cognitive reserve has been lost and finally the symptoms of memory loss become apparent.

As a result, people with dementia have to exert much more mental effort over the course of a routine day than most of us.

We’ve all felt cognitively exhausted, run down, and perhaps a little cranky after a long, difficult day at work that consumed an extreme amount of mental effort and focus.

Those living with dementia are required to exert a similar amount of mental effort just to get through their daytime routine.

So is it any surprise that after several hours of concerted mental effort just to get by (often in an unfamiliar location), people tend to become cognitively exhausted?

What should I do if it happens to my loved one?

The homes of people with dementia should be well lit in the late afternoon and evening as the sun is setting to help the person with dementia integrate and interpret sensory input.

A short nap after lunch can help ease cognitive fatigue towards the end of the day. It gives the brain, and with it a person’s resilience, an opportunity to recharge.

However, there is no substitute for a more comprehensive evaluation of other causes that may be contributing to the impaired behavior.

Unmet needs such as hunger or thirst, the presence of pain, depression, boredom or loneliness can all contribute, as can stimulants such as caffeine or sugar given too late in the day.

The behaviors too often described by the overly simplistic term sunset are complex, and their causes are often highly individual and interrelated. As is often the case in medicine, a particular set of symptoms is often best managed by better understanding the root causes.

Steve Macfarlane, Head of Clinical Services, Dementia Support Australia, and Associate Professor of Psychiatry, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.