When someone develops dementia, what changes are happening in the brain?
NATHAN WALLIS: Basically, the brain starts to rewind. When we’re learning, we’re creating neural pathways. When we’re consolidating our knowledge, we’re laying down myelin on those neural pathways (like insulation covering electric wire). During that ‘aha!’ moment in learning to tie your shoes (for example), you put myelin on that pathway, and for the rest of your life, you know how to tie your shoes!
When you get dementia, the myelin starts coming off those pathways – so you start going backwards. That’s why people might still be able to remember their 40th birthday decades ago but can’t remember the people they saw yesterday. The more recent memories get wiped from the brain. Dementia is taking away the neural pathways and undoing the learning.
Is all cognitive decline dementia?
NATHAN: No – some cognitive decline is caused by brain injury, neglect, or other trauma. If someone’s been traumatised, the frontal cortex (logic and reasoning centre) can be shut off. Brain scans of people who’ve gone through emotional trauma ‘shut down’ and don’t ‘glow’ in the same way. With dementia, the scans glow, but the pathways are being undone, so the messages can’t get across. Also, with dementia, the function is shutting off permanently – whereas, with cognitive decline from trauma, it’ll come back online if you deal with the trauma.
Is there a timeframe where recovering the damage caused by trauma becomes irreversible?
NATHAN: Emotional trauma can (technically speaking) always be healed, so there’s not really a deadline there – but lots of factors affect the extent and rate of recovery. In terms of brain injury, most of the physical damage to the brain occurs in the first 24-48 hours after the injury itself… It’s not just when someone falls off the ladder that determines the extent of the damage; it’s what happens afterwards. When you’re rushed into the A&E, they’ll put one of those caps on your head to keep your brain at exactly the right temperature to stop more cells from dying.
So the delay between the injury itself and the treatment is a huge factor in determining the extent of the damage – which means that the key time for intervention is when the accident first happens.
There’s very little science exploring how long it takes for recovery because there are too many variables. A hundred people can have the same severity of stroke, affecting the same parts of the brain, and they’ll all go back to completely different environments. Those who return to houses that are anti-social – with lots of negative language, swearing, and aggression – are going to have much more limited recovery than those in pro-social environments that are nurturing, helpful, and positive.
It also depends on what they do when they get home. People who consume higher amounts of sugar, alcohol, and caffeine impede their learning (or re-learning) process – and that slows down their ability to heal. Your beliefs also impact your healing and recovery. If you think, “Well, I’ve had a stroke, so I’ve got one foot in the grave, and it’s all downhill from here”, you’re not going to have as successful a recovery as someone who believes, with the right effort and mindset, they can get well. It’s really about the principles of neuroplasticity; if you encourage people to accept their brains are capable of improvement and healing, they’re going to do much better than if they have a fixed mindset about it.
And the more stress you can reduce from the environment, the better. This is why daily meditation can help accelerate healing – it’s about calming that stress response.
How can age-related cognitive decline be prevented?
NATHAN: The number one cause of cognitive decline in ageing is isolation. So you can help prevent it with interaction. Think of the older person whose family has grown and moved away … they might go for days without actually speaking to anybody. That lack of interaction means you’re not releasing all the peptides and endorphins you get when simply chatting with someone. Your brain needs the stimulation – the electrical activity – provided by interaction to stay healthy. Even just having a pet makes a huge difference.
Another thing that’s important for keeping your mind active is movement (physical exercise). Yoga’s brilliant for anti-ageing because it engages both body and mind. And coffee helps! Caffeine can inhibit the creation of myelin when you’re learning and growing, but likewise, it can also prevent the decline of that myelin along the neural pathways as you age. So the recommendation is to have at least three cups of coffee a day for people over 65 – because it has a huge impact on reducing cognitive decline. Coffee drinkers have something like an 80% reduced chance of developing dementia!
The other thing that slows cognitive decline is exercising your brain. A neuroscientist friend has a significant family history of cognitive decline kicking in at about age 70. So she planned to start learning an instrument when she turned 60. She already had strengths with languages (so she’d already developed plenty of those neural pathways) – but she didn’t have any musical experience. This meant that learning an instrument would be a bigger and better challenge for her brain. She stuck with it, and she played for us at her retirement party five years later. By going through that process, she’s ensured that her brain’s much ‘younger’ and more agile – she’s significantly reduced her chances of developing cognitive decline.
So, learn something new – and learn something that’s not comfortable for you to learn. If you’re already musical and know a bunch of languages – take an accountancy course. Do something you wouldn’t normally do.
The interesting thing about cognitive decline is that most people don’t die of brain issues … the vast majority die of heart issues. Biologically speaking, the brain is still in its infancy when we’re reaching the end of our lifespan – it doesn’t get old and die like just about every one of our other organs. The tissues around the heart look like they’re designed to last about 100 years, but if you didn’t know the human lifespan and you looked at the brain, it’d look like it was designed to last about 900 years!
So the brain doesn’t age in the same way as our other organs, but of course, there are genetic, environmental, and lifestyle factors that all contribute to the decline of its function.
NATHAN WALLIS HAS DEVELOPED A REPUTATION AS A LIVELY AND ENGAGING SPEAKER. HIS HUMOUR AND PLAIN LANGUAGE MAKE THE COMPLEX TOPIC OF NEUROSCIENCE BURST INTO LIFE! FIND HIM ON FACEBOOK AND LOOK FOR AN EVENT NEAR YOU …
