Can We Protect Our Brains From Cognitive Decline?
A unique combination of herbal extracts and mobile apps may point the way to improved cognition in older adults.
By Grace McPhee, Associate Professor Luke Downey & Professor Con Stough, Swinburne Centre for Human Psychopharmacology, Swinburne University
Over the last 50 years, the world has seen a steady increase in life expectancies and a subsequent rise in the world’s elderly population. Although we’re now living longer, an unfortunate side effect is that age-related brain disorders are becoming more prevalent. This places a growing burden on global and economic resources, particularly as an effective cure for dementia has yet to be developed. In addition to obvious clinical forms of cognitive deterioration (such as Alzheimer’s or Parkinson’s dementia), researchers have found that healthy adults will also experience some form of cognitive decline as they get older.
Evidence for age-associated decline in cognitive abilities was first shown in large scale longitudinal studies that aimed to map the trajectories of adult intelligence and health over the life-span. Since the 1950s, studies such as the Seattle Longitudinal Study and the Baltimore Longitudinal Study of Ageing have shown that decreases in cognitive ability can emerge from as early as 60 years, with more severe decline appearing from 80 years onward.
Initial cross-sectional investigations indicated that cognitive processes involved in rapidly solving and working on novel problems (eg. the ability to reason, process information quickly and remember verbal and spatial information) fell from mid-life onwards, while cognitive processes relying on previous knowledge or skills (eg. vocabulary and numeric knowledge) appeared relatively intact with age.
Although this suggests some aspects of cognitive ability are protected from age-associated cognitive decline, subsequent longitudinal analysis revealed that all cognitive measures, including vocabulary knowledge, deteriorate with increasing age. Evidently, decreases in overall cognitive ability appear to be part of the ageing process and can emerge from as early as mid-life.
Advances in brain imaging technology have allowed researchers to explore whether age-related reductions in cognitive ability are a result of changes in brain function and structure.
Evidence suggests that older adults experience degeneration of neural tissue in certain brain areas, which may be why cognitive processes become impaired with age. On a macro-level, these effects manifest themselves as an overall reduction in brain matter volume.
On a micro-level, evidence of this can be observed in the reduction of the connections among neurons, which impairs neural communication. The latter has important implications for cognitive function — we rely on efficient and rapid communication between neurons to successfully generate and transmit a signal between and within brain areas, and to allow us to effectively think, reason and communicate with the world around us.
Unsurprisingly then, researchers are increasingly trying to investigate interventions that effectively mitigate these adverse outcomes to brain health.
Controlled investigations into anecdotal reports or traditional remedies claiming to improve cognition are a good starting point for uncovering what type of interventions might protect older adults from cognitive decline.
For example, an intervention our research center is increasingly interested in is an herbal extract called Bacopa monnieri, or simply ‘Bacopa’. Bacopa is an extract from the water hyssop plant and has been used in traditional Ayurvidic medicine for the past 3,000 years. It’s often used to treat inflammation or as a memory tonic. In-vitro and animal studies have shown administering Bacopa increases certain proteins in neural tissue that are implicated in a process called synaptogenesis.
Synaptogenesis describes the increased formation and enhancement of connections between neurons. It is particularly important for older adults who experience neuro-deterioration and subsequent weakening of neural communication. Double-blind randomised placebo-controlled trials conducted in humans show daily ingestion of Bacopa for at least a 12-week period in middle-aged adults increases scores on tasks measuring memory ability and processing speed. As Bacopa also appears to enhance synaptogenesis in-vitro and in animals, improvements in these measures may be due to synaptogenic changes occurring in the brain.
One important aspect of the results from in-vitro studies, however, is that the synaptogenic effects of Bacopa appears largely attributable to the actions of post-synaptic signalling molecules. These are molecules that ‘tell’ the adjoining neuron to fire in response to activation already taking place in the preceding neuron. This is akin to Long Term Potentiation (LTP), which is the strengthening of neuron connections in response to repeated neural stimulation. Bacopa may therefore enhance or accelerate synaptogenic processes in response to LTP. This means the beneficial effects of Bacopa consumption might best be seen by encouraging more LTP.
In theory, stimulating LTP would mean promoting persistent neuron activation. In practice, this can be achieved by promoting regular brain activation through cognitive activities.
The benefits of persistent cognitive stimulation were first evidenced in the longitudinal studies mapping the trajectories of adult intelligence. Despite showing that overall cognitive ability declines with age, there were still some adults who seemed largely protected from severe cognitive decline. The researchers observed that mediating factors such as increased education attainment and participation in cognitively-stimulating activities (eg. reading, playing board games or playing musical instruments) appeared to reduce the risk of cognitive decline in their sample.
To test this idea, the Seattle Longitudinal Study asked a subset of the sample (subjects aged over 64 years) to complete regular reasoning-based cognitive exercises. They then determined if persistent challenges to cognition would imitate the apparent beneficial effects of education.
Results indicated that nearly two thirds of this sample demonstrated marked improvements in cognitive ability. Approximately 40% of the sample who had initially exhibited significant decline over 14 years had reverted to their pre-decline state. Studies employing additional types of cognitive exercises, such as the use of memory strategies and speed of processing, have also shown training-related improvements in older adults.
Recent neuroimaging studies further support these results, showing that cognitive training appears to beneficially alter the brains of older adults, and that these alterations are associated with improved scores on cognitive outcomes. For example, research has shown that when older adults complete cognitive training, even for a relatively short period of time of two to four weeks, scores on cognitive tests improve and the patterns of activation in their brains begin to resemble the brains of younger adults.
There is growing evidence that cognitive training not only produces positive outcomes for cognition, but also for brain function and for its ability to stimulate LTP.
Due to these positive outcomes and advancements in mobile technology, numerous commercial brain training apps and games have flooded the market. Many of these games remain untested, calling into question their utility as an option to prevent age-associated cognitive decline.
Despite this, the popularity and accessibility of brain training apps offer a promising pathway towards increasing our understanding of cognitive decline. They enable researchers to collect large amounts of information critical to improving research quality and determining their overall efficacy. Conducting cognitive training through a mobile app also allows researchers to send push notifications reminding participants of important study information, as well as gather data on the daily impacts of the intervention. These include incidences of cognitive complaints, overall well-being, and everyday function.
In addition, tech-based research helps determine the effectiveness of additional interventions (such as Bacopa) that may complement cognitive training. In doing so, it emulates how such interventions might reasonably be administered in everyday life to people concerned about their cognitive health.
There’s another advantage of incorporating mobile technology: Putting the intervention in the hands of older adults helps promote the possibility that cognitive decline is not an inevitable process; that in fact, there are ways to promote brain health and help an ever-growing elderly population live long, healthy and cognitively active lives.
Acknowledgements:
Grace McPhee is supported by a Swinburne University Postgraduate Research Scholarship. Associate Professor Luke Downey is supported by a National Health and Medical Research Council (NHMRC) Career Fellowship. Professor Con Stough is supported by grants from Soho Flordis International Research, an organization examining the effects of combined Bacopa (Keenmind: CDRI08) and cognitive training on cognition in older healthy Australians. The research study described in this article is also supported by generous donations from Swinburne Alumni. More information about this piece can be obtained by writing to Grace McPhee at gmcphee@swin.edu.au.
Further reading:
McPhee, G.M., Downey, L.A., Noble, A. and Stough, C., 2016. Cognitive training and Bacopa monnieri: Evidence for a combined intervention to alleviate age associated cognitive decline. Medical hypotheses, 95, pp.71–76.
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