Opportunities for enhancing brain health across the lifespan
Published online by Cambridge University Press: 22 March 2021
As we age, there are characteristic changes in our thinking, reasoning and memory skills (referred to as cognitive ageing). However, variation between people in the timing and degree of change experienced suggests that a range of factors determine individual cognitive ageing trajectories. This narrative review considers some of the lifestyle factors that might promote (or harm) cognitive health. The focus on lifestyle factors is because these are potentially modifiable by individuals or may be the targets of behavioural or societal interventions. To support that, the review briefly considers people’s beliefs and attitudes about cognitive ageing; the nature and timing of cognitive changes across the lifespan; and the genetic contributions to cognitive ability level and change. In introducing potentially modifiable determinants, a framing that draws evidence derived from epidemiological studies of dementia is provided, before an overview of lifestyle and behavioural predictors of cognitive health, including education and occupation, diet and activity.
‘Journal of Neurology, Neurosurgery & Psychiatry” (July 10, 2020):
We tested the hypothesis that apathy, but not depression, is associated with dementia in patients with SVD. We found that higher baseline apathy, as well as increasing apathy over time, were associated with an increased dementia risk. In contrast, neither baseline depression or change in depression was associated with dementia. The relationship between apathy and dementia remained after controlling for other well-established risk factors including age, education and cognition. Finally, adding apathy to models predicting dementia improved model fit. These results suggest that apathy may be a prodromal symptom of dementia in patients with SVD.
Cerebral small vessel disease (SVD) is the leading vascular cause of dementia and plays a major role in cognitive decline and mortality.1 2 SVD affects the small vessels of the brain, leading to damage in the subcortical grey and white matter.1 The resulting clinical presentation includes cognitive and neuropsychiatric symptoms.1
Apathy is a reduction in goal-directed behaviour, which is a common neuropsychiatric symptom in SVD.3 Importantly, apathy is dissociable from depression,3 4 another symptom in SVD for which low mood is a predominant manifestation.5 Although there is some symptomatic overlap between the two,6 research using diffusion imaging reported that apathy, but not depression, was associated with white matter network damage in SVD.3 Many of the white matter pathways underlying apathy overlap with those related to cognitive impairment, and accordingly apathy, rather than depression, has been associated with cognitive deficits in SVD.7 These results suggest that apathy and cognitive impairment are symptomatic of prodromal dementia in SVD.
We observed that increased adherence to the MedDiet modulates specific components of the gut microbiota that were associated with a reduction in risk of frailty, improved cognitive function and reduced inflammatory status.
Dr Philip Smith, Digital and Education Editor of Gut and Consultant Gastroenterologist at the Royal Liverpool Hospital interviews Professor Paul O’Toole; who is Professor of Microbial Genomics, Head of School of Microbiology and Principal Investigator in APC Microbiome Ireland, an SFI funded centre at University College Cork, Ireland, on “Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across 5 European countries” published in paper copy in Gut in July 2020.
Even limited hearing loss might be associated with cognitive decline. If true, early intervention with hearing aids might help people have better cognitive performance.
Michael Johns III, MD, online editor for JAMA Otolaryngology, speaks with Justin Golub, MD, MS, assistant professor of otolaryngology at Columbia University, whose research has shown that very mild hearing loss can be associated with cognitive disability.
Can you imagine if each word had its own colour, or you could ‘see’ different types of music?
Synesthetes can experience the ordinary world in some pretty extraordinary ways. In this video Jamie Ward explains the variety of different ways in synesthesia can manifest itself, and what is happening in the brains of those who experience it.
Jamie Ward is Professor of Cognitive Neuroscience at the University of Sussex. He has written books a number of books about neuroscience and synesthesia.
Synesthesia is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes. Awareness of synesthetic perceptions varies from person to person. In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored. In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (for example, 1980 may be “farther away” than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). Synesthetic associations can occur in any combination and any number of senses or cognitive pathways.
From a MedPage Today online article (April 2, 2020):
This relationship between higher glucose levels and poorer cognitive functioning extended beyond just CASI z-score, as well, Cukierman-Yaffe noted. Higher HbA1c levels were also tied to significantly poorer performance in other psychological tests, including the clock making test of executive functioning, test of discriminative ability, and for the test of verbal fluency.
Poorer glycemic control was tied to cognitive decline following a lacunar stroke in a prospective cohort study.
Among 942 individuals with type 2 diabetes who had a lacunar stroke, every 1% higher HbA1c was tied to a 0.06 drop in cognitive function at baseline measured by Cognitive Assessment Screening Instrument (CASI) z-score (95% CI -0.101 to -0.018), reported Tali Cukierman-Yaffe, MD, MSc, of Sheba Medical Center and the Sackler School of Medicine of Tel Aviv University in Israel.
From a JAMA Network Open online release (February 21, 2020):
Across the 6 studies of 8699 participants, mean age ranged between 70 and 74 years and mean gait speed ranged between 1.05 and 1.26 m/s. Incident dementia ranged from 5 to 21 per 1000 person-years. Compared with usual agers, participants with only memory decline had 2.2 to 4.6 times higher risk for developing dementia…
Those with only gait decline had 2.1 to 3.6 times higher risk. Those with dual decline had 5.2 to 11.7 times the risk…
Impaired mobility, such as slow gait, is associated with an increased risk of dementia, but the effect size of this association is generally modest.1–6 Identifying persons who experience both mobility decline and memory decline, a main symptom in the early stage of dementia, may have a greater prognostic value in assessing risk of dementia because the combination could identify a group in whom gait speed decline is at least in part caused by neurodegenerative pathologic conditions of the central nervous system rather than local musculoskeletal problems, such as sarcopenia or osteoarthritis.7–9 A recent study of 154 participants with mild cognitive impairment reported that those who declined in both cognition and gait speed had the highest risk of dementia.