There are some symptoms of dementia that are more commonly known, such as memory loss. Seizures are a less common symptom of dementia that are not as understood. Hear from one of our dementia researchers who has been studying seizures in people with the condition.
How common are epileptic seizures in dementia? Who is most at risk of having them? What do these seizures look like? What effect do they have on how someone’s memory changes over time?
These are the questions that I have been researching since starting my PhD in 2016. I'm a student funded by Alzheimer’s Society as part of the University of Exeter doctoral training centre.
What do we know about seizures and dementia?
People with dementia are at risk of having epileptic seizures. We’ve known this for a long time – it was described by Alzheimer himself in 1911.
However, how common they are remains unclear. This is because epileptic seizures can often be subtle.
There are two common types of epileptic seizures:
Generalised tonic-clonic seizures
Most of us are familiar with the kind of epileptic seizures we see on TV or in films. People become unresponsive, they fall to the ground, become stiff and their whole-body shakes in a convulsion.
Generalised tonic-clonic seizures are hard to miss. But this is not what most epileptic seizures look like.
Focal onset seizures
Most epileptic seizures in people with dementia are known as focal onset seizures. These can involve brief periods of increased amnesia or unresponsiveness. We see involuntary repeating movements, often of the hands and arms, or of the face (chewing, lip-smacking or swallowing).
Understandably, the latter are more easily missed, especially as the person affected will often quickly be back to normal afterwards..
Who might be affected by seizures?
For a long time, researchers believed epileptic seizures occurred only in people who had long been diagnosed with dementia. It was thought they were a reflection of how much the brain had changed and shrunk because of it.
However, more recent research has suggested that seizures can occur early-on in Alzheimer’s disease. In some people, seizures may happen even before memory problems become apparent.
As part of my research, I recruited people from the local memory clinic here in Exeter. We asked them questions about epilepsy.
It quickly became clear that most people don’t know that having dementia, particularly Alzheimer’s disease, can increase your risk of seizures.
In our group, around 1 in 8 patients with dementia described episodes which we believe could have been epileptic seizures.
We interviewed our participants one year later and found that those who had described having had epileptic seizures previously performed less well on memory tests than those who showed no evidence of epilepsy.
Why do people with dementia develop seizures?
Ultimately, anything that changes the structure of the brain can cause seizures.
This happens for some people after a stroke, a head injury, or with a brain infection like meningitis. A similar problem is happening in the brain in dementia. As cells in the brain die and the brain shrinks this can lead to epilepsy.
In addition, we know that two proteins that build up in the brain of people with Alzheimer’s disease – amyloid and tau – affect how the brain’s nerve cells communicate with each other.
Sometimes these nerve cells can become 'hyper-excitable', meaning they can behave uncontrollably, causing epileptic seizures.
Can seizures be managed in people with dementia?
There is good news. There are medications that are effective at reducing, and hopefully stopping, epileptic seizures.
If you think that you, or someone you know with dementia may be having epileptic seizures you should tell a doctor. They might want to perform some extra tests, and may want to start some extra medications to treat this problem.
What we don’t know yet is whether starting treatment for epilepsy might help to slow down dementia and whether it might help keep people’s memory function better for longer.
We have learned so much about the brain – but there is still so much to discover.
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