THEY were considered flukes. Older people found upon their deaths to have brains full of the plaques and tangles associated with Alzheimer’s disease, yet who had shown no signs of cognitive decline while alive. But then more cases appeared, and yet more. Something was protecting these people whose mental faculties remained bright, despite them facing the same destruction in their brain as others with memory loss, confusion and other symptoms of dementia.
As more brains were analysed, it was discovered that these cases aren’t rare. Up to 30 per cent of older people have enough plaques and tangles to be…
IF I never thought about dementia before, I thought of little else after the condition manifested in my mother. The odd thing was that dementia – Alzheimer’s disease, in her case – didn’t occur to me until she asked, out of the blue, when we had first met.
My failure to recognise the extent of her cognitive decline was born partly of denial, but also because she was doubtless compensating for her galloping brain damage, taking cerebral detours around the potholes dug by her condition. After all, she had done this before. Following a stroke four years previously, she had lost the ability to read; after much hard work, she learned the skill again.
So how come this ability to adapt, which seemed to sustain her after her stroke, was unable to withstand the pathology of dementia? This also made me think about my own resilience to cognitive decline and what, if anything, I could do about it.
We have known for almost three decades that some peoples’ brains can function normally even when riddled with the plaques and other damage associated with dementia, due to an enigmatic capacity called cognitive reserve. Yet despite growing evidence of its importance, it has been challenging to pin down how this quality operates in the brain. Now, we are finally beginning to understand the mechanisms that underlie cognitive reserve, opening up possible new dementia treatments and fresh ideas about how we can protect our thinking abilities into old age. And it turns out that obsessing about learning another language or doing a daily crossword might be missing the bigger picture.
IMAGINE a medical device that could treat an enormous range of our ills, both big and small. A gadget that showed promise for destroying cancerous tumours or obliterating the body fat associated with obesity. Or that was potentially effective against the likes of back pain and glaucoma – and that was even versatile enough to be considered as a tool for tackling depression or anxiety. Surprisingly, such technology exists. Even more surprisingly, it works simply by generating sound waves.
While perhaps most familiar to us for its use in medical imaging, ultrasound has emerged in recent decades as an extraordinarily flexible medical tool. Using the heat that intense ultrasound waves generate, we can destroy tumours or other problematic tissue deep within the body without making any incisions. Dial down the intensity, meanwhile, and we can gain unprecedented access to the brain, shaking cells to change their behaviour in ways that seem to improve mental health. For good measure, ultrasound may even reverse signs of physical ageing and reduce the learning and memory problems associated with older age.
“Ultrasound is already a ubiquitous tool in medicine,” says Nir Lipsman at Sunnybrook Research Institute in Toronto, Canada. “But there’s tremendous focus on it right now because of the different ways we could use it to treat different medical problems.”
The potential applications are coming so thick and fast that they are outpacing our ability to understand why it is so effective. The question now is: can we figure out how ultrasound affects our cells, so the technology can reach its full potential?
Protein plaques in the brain may be caused by failing mitochondria
Sebastian Kaulitzki/Alamy
IF YOU own a car, you will have noticed the engine getting less efficient with time. The further you drive it, the more fuel it takes to make the same journey – until, eventually, it becomes so underpowered that it needs a physical push to climb even a gentle hill.
Now, it is emerging that much the same is true of the human brain. Microscopic structures called mitochondria, found in every brain cell, are quite literally the engines of our thoughts and feelings. As we age, they find it harder and harder to produce sufficient energy to power our mental activities. Worse, in a similar way to an old car leaving clouds of smoke in its wake, the cell’s powerhouses start generating unwanted waste products that slowly poison our brains. This means that malfunctioning mitochondria may underlie many of the most devastating brain conditions, including Alzheimer’s, Parkinson’s, Huntington’s and motor neuron disease.
According to this “grand unified theory” of neurodegeneration, we could prolong our brain’s healthy functioning by recharging our neurons through restoration of their powerhouses. The idea is already inspiring some exciting new therapies for age-related brain conditions, with multiple drug candidates under investigation. Some researchers are even exploring the possibility of transplanting healthy mitochondria into damaged, ageing brains to re-energise them. “If you keep changing the parts of a car, it can last forever,” says Claudio Soto, a neurologist at the University of Texas Health Science Center at Houston. “So what happens if we try to do the…
COURTNEY SHUKIS was looking forward to lunch: she had just recovered from covid-19 and was glad to be meeting her friends again. Before leaving her home in Plano, Texas, she checked the calendar, making a mental note of the restaurant and when to meet. “But instead of going there, I got in my car and drove to a completely different place,” she recalls. “I sat at the table for half an hour, looking at my phone, wondering where everyone was. My brain fog was really bad.”
That wasn’t a one-off. After having covid-19, Shukis had frequent episodes of memory loss. She would forget to make dinner, had trouble finding the words to describe things and got confused about school pick-up times. “I had never had any difficulties with these kinds of things before. It just felt like my brain wasn’t working right.”
Shukis is one of millions of people worldwide reporting a severe dent in cognitive functioning following a covid-19 infection, and as a result, the issue of brain fog has been thrust into the limelight. For many, this is long overdue. “It’s something that patients with a wide variety of different medical problems have said has interfered with their ability to function for a long time,” says Sabina Brennan, a neuroscientist at Trinity College Dublin, Ireland, and author of Beating Brain Fog. The hope is that this interest could improve care for those experiencing it. “If there’s anything positive to come out of the covid-19 pandemic, it’s that the spotlight is now on brain fog and the scientific community is paying much more attention to it,” says Brennan.…
YOU know that person. The one who uses a delayed train as an excuse to get stuck into a good book. The one who can make a joke 10 seconds after breaking their ankle. The one who loves giving presentations and never falters under pressure. They seem to float through life unfazed by the stress that can overwhelm the rest of us. What’s their secret?
Are they blessed with stress-resistant genes? Did their upbringing make them exceptionally resilient? Have they learned specific ways of coping with life’s challenges? Or do they just know how to avoid stress altogether? To answer these questions, researchers have been examining how humans and animals react and adapt to adversity, identifying those who are particularly resilient to stress and teasing apart the factors that contribute to this ability. It is a journey that has taken them from orphanages in Romania and interrogation chambers in North Carolina to fire stations in Indianapolis and humour classes in Austria.
This work is helping the military recruit candidates for high-stress jobs. It has also led to the first human trial of a “stress vaccine”, with the potential to inoculate us against its devastating effects, from post-traumatic stress disorder (PTSD) to depression. But there is a bigger pay-off to understanding the secret of stress-free living. Knowing why some people handle stress better than others, and the things we might all do to improve our resilience, won’t just help all of us manage life’s daily struggles better, it might also teach us how to use stress to our advantage.
One thing is for certain: whether you are running late for…
Article amended on 27 February 2020
We clarified when people suffered negative effects of stress.
