Aging

Air pollution substantially reduces cognitive ability in older adults

  • A very large study shows that greater exposure to air pollution was linked to poorer cognitive performance in older adults, especially men and the less educated.

A large Chinese study involving 20,000 people has found that the longer people were exposed to air pollution, the worse their cognitive performance in verbal and math tests. The effect of air pollution on verbal tests became more pronounced with age, especially for men and the less educated.

The study followed the participants from 2010 to 2014, meaning that the same individuals could be assessed as air pollution varied from one year to the next.

The findings add to previous research showing the harmful effects of air pollution on cognitive performance in children.

https://www.theguardian.com/environment/2018/aug/27/air-pollution-causes-huge-reduction-in-intelligence-study-reveals

Reference: 

Xin Zhang, Xi Chen, Xiaobo Zhang. 2018. The impact of exposure to air pollution on cognitive performance. Proceedings of the National Academy of Sciences Sep 2018, 115 (37) 9193-9197; DOI: 10.1073/pnas.1809474115

 

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Depression linked to faster cognitive decline in older adults

  • A review of 34 studies confirms depression is linked to faster cognitive decline in older adults.

A review of 34 longitudinal studies, involving 71,244 older adults, has concluded that depression is associated with greater cognitive decline.

The study included people who presented with symptoms of depression as well as those that were diagnosed as clinically depressed, but excluded any who were diagnosed with dementia at the start of study.

Previous research has found that depression is associated with an increased dementia risk.

The researchers recommend that preventative measures such as exercising, practicing mindfulness, and undertaking recommended therapeutic treatments, such as Cognitive Behaviour Therapy, might help protect cognitive health.

While the review included some studies into anxiety, the numbers were insufficient to draw a conclusion.

https://www.eurekalert.org/pub_releases/2018-05/uos-dsu052318.php

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Fruit & veges slow memory decline in long-running study

  • A large, long-running study has found an association between consumption of fruit & vegetables and subjectively assessed memory skills in older men.

A study following nearly 28,000 older men for 20 years has found that regular consumption of leafy greens, dark orange and red vegetables and berry fruits, and orange juice, was associated with a lower risk of memory loss.

The study looked at 27,842 male health professionals, who were an average age of 51 in 1986, when the study began. Participants filled out questionnaires about how many servings of fruits, vegetables and other foods they had each day, at the beginning of the study and then every four years.

Specifically:

  • those who consumed the most vegetables (around six servings a day) were 34% less likely to develop poor thinking skills than the men who consumed the least amount of vegetables (around two servings)
  • 6.6% of men who consumed the most vegetables developed poor cognitive function, compared to 7.9% of men who consumed the least
  • those who drank orange juice every day were 47% less likely to develop poor thinking skills than those who drank less than one serving per month
  • 6.9% of men who drank orange juice every day developed poor cognitive function, compared to 8.4 % of men who drank orange juice less than once a month

Interestingly, those who ate larger amounts of fruits and vegetables 20 years earlier were less likely to develop cognitive problems, whether or not they kept eating larger amounts of fruits and vegetables about six years before the memory test.

Cognition was not, however, assessed objectively, nor was it tested at baseline. In 2008 and 2012, participants were given a short cognitive test to assess their subjective judgments of their memory and cognition. The brief test included such questions as:

  • "Do you have more trouble than usual remembering a short list of items, such as a shopping list?"
  • "Do you have more trouble than usual following a group conversation or a plot in a TV program due to your memory?"

Just over half the participants (55%) had good thinking and memory skills, 38% had moderate skills, and 7% had poor thinking and memory skills.

https://www.eurekalert.org/pub_releases/2018-11/aaon-ojl111918.php

Reference: 

Changzheng Yuan et al. 2019. Long-term intake of vegetables and fruits and subjective cognitive function in US men. Neurology, 92 (1) e63-e75.

 

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Older adults' distractability can be used to help put a face to a name

  • A small study has used older adults’ inability to ignore irrelevant information to improve their memory for face-name pairs.

One important reason for the greater cognitive problems commonly experienced as we age, is our increasing difficulty in ignoring distracting and irrelevant information. But it may be that in some circumstances that propensity can be used to help memory.

The study involved 25 younger (17-23) and 32 older adults (60-86), who were shown the faces and names of 24 different people and told to learn them. The names were written in bright blue text and placed on the forehead, and each photo was shown for 3 seconds. After the learning session, participants were immediately tested on their recall of the name for each face. The test was self-paced. Following a 10 minute interval, during which they were given psychological tests, they were shown more photos of faces, but this time were told to ignore the text — their task was to push a button when they saw the same face appear twice in a row. The text was varied: sometimes names, sometimes words, and sometimes nonwords. Ten of the same faces and names from the first task were repeated in the series of 108 trials; all items were repeated three times (thus, 30 repeated face-name pairs; 30 other face-name pairs; 24 face-word pairs; 24 face-nonword pairs). The photos were each displayed for 1.5 seconds. A delayed memory test was given after another 10 minutes of psychological testing. A cued-recall test was followed by a forced-choice recognition test.

Unsurprisingly, overall younger adults remembered more names than older adults, and both groups remembered more on the second series, with younger adults improving more. But younger adults showed no benefit for the repeated face-name pairs, while — on the delayed recall task only — older adults did.

Interestingly, there was no sign, in either group, of repeated names being falsely recalled or recognized. Nor did they significantly affect familiarity.

It seems that this sort of inadvertent repetition doesn’t improve memory for items (faces, names), but, specifically, the face-name associations. The study builds on previous research indicating that older adults hyperbind distracting names and attended faces, which produces better learning of these face-name pairs.

It’s suggested that repetition as distraction might act as a sort of covert retrieval practice that relies on a nonconscious process specifically related to the priming of relational associations. Perhaps older adults’ vulnerability to distraction is not simply a sign of degeneration, but reflects a change of strategy to one that increases receptiveness to environmental regularities that have predictive value. Younger adults have narrowed attention that, while it allows them greater focus on the task, also stops them noticing information that is immediately irrelevant but helpful further down the track.

The researchers are working on a training program to help older adults with MCI use this benefit to better remember faces and names.

https://www.eurekalert.org/pub_releases/2018-03/bcfg-oad031618.php

Reference: 

Biss, Renée K., Rowe, Gillian, Weeks, Jennifer C., Hasher, Lynn, Murphy, Kelly J. 2018. Leveraging older adults’ susceptibility to distraction to improve memory for face-name associations. Psychology and Aging, 33(1), 158-164.

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Gist memory may be why false memories are more common in older adults

  • Gist processing appears to play a strong role in false memories.
  • Older adults rely on gist memory more.
  • Older adults find it harder to recall specific sensory details that would help confirm whether a memory is true.

Do older adults forget as much as they think, or is it rather that they ‘misremember’?

A small study adds to evidence that gist memory plays an important role in false memories at any age, but older adults are more susceptible to misremembering because of their greater use of gist memory.

Gist memory is about remembering the broad story, not the details. We use schemas a lot. Schemas are concepts we build over time for events and experiences, in order to relieve the cognitive load. They allow us to respond and process faster. We build schemas for such things as going to the dentist, going to a restaurant, attending a lecture, and so on. Schemas are very useful, reminding us what to expect and what to do in situations we have experienced before. But they are also responsible for errors of perception and memory — we see and remember what we expect to see.

As we get older, we do of course build up more and firmer schemas, making it harder to really see with fresh eyes. Which means it’s harder for us to notice the details, and easier for us to misremember what we saw.

A small study involving 20 older adults (mean age 75) had participants look at 26 different pictures of common scenes (such as a farmyard, a bathroom) for about 10 seconds, and asked them to remember as much as they could about the scenes. Later, they were shown 300 pictures of objects that were either in the scene, related to the scene (but not actually in the scene), or not commonly associated to the scene, and were required to say whether or not the objects were in the picture. Brain activity was monitored during these tests. Performance was also compared with that produced in a previous identical study, involving 22 young adults (mean age 23).

As expected and as is typical, there was a higher hit rate for schematic items and a higher rate of false memories for schematically related lures (items that belong to the schema but didn’t appear in the picture). True memories activated the typical retrieval network (medial prefrontal cortex, hippocampus/parahippocampal gyrus, inferior parietal lobe, right middle temporal gyrus, and left fusiform gyrus).

Activity in some of these regions (frontal-parietal regions, left hippocampus, right MTG, and left fusiform) distinguished hits from false alarms, supporting the idea that it’s more demanding to retrieve true memories than illusory ones. This contrasts with younger adults who in this and previous research have displayed the opposite pattern. The finding is consistent, however, with the theory that older adults tend to engage frontal resources at an earlier level of difficulty.

Older adults also displayed greater activation in the medial prefrontal cortex for both schematic and non-schematic hits than young adults did.

While true memories activated the typical retrieval network, and there were different patterns of activity for schematic vs non-schematic hits, there was no distinctive pattern of activity for retrieving false memories. However, there was increased activity in the middle frontal gyrus, middle temporal gyrus, and hippocampus/parahippocampal gyrus as a function of the rate of false memories.

Imaging also revealed that, like younger adults, older adults also engage the ventromedial prefrontal cortex when retrieving schematic information, and that they do so to a greater extent. Activation patterns also support the role of the mediotemporal lobe (MTL), and the posterior hippocampus/parahippocampal gyrus in particular, in determining true memories from false. Note that schematic information is not part of this region’s concern, and there was no consistent difference in activation in this region for schematic vs non-schematic hits. But older adults showed this shift within the hippocampus, with much of the activity moving to a more posterior region.

Sensory details are also important for distinguishing between true and false memories, but, apart from activity in the left fusiform gyrus, older adults — unlike younger adults — did not show any differential activation in the occipital cortex. This finding is consistent with previous research, and supports the conclusion that older adults don’t experience the recapitulation of sensory details in the same way that younger adults do. This, of course, adds to the difficulty they have in distinguishing true and false memories.

Older adults also showed differential activation of the right MTG, involved in gist processing, for true memories. Again, this is not found in younger adults, and supports the idea that older adults depend more on schematic gist information to assess whether a memory is true.

However, in older adults, increased activation of both the MTL and the MTG is seen as rates of false alarms increase, indicating that both gist and episodic memory contribute to their false memories. This is also in line with previous research, suggesting that memories of specific events and details can (incorrectly) provide support for false memories that are consistent with such events.

Older adults, unlike young adults, failed to show differential activity in the retrieval network for targets and lures (items that fit in with the schema, but were not in fact present in the image).

What does all this mean? Here’s what’s important:

  • older adults tend to use schema information more when trying to remember
  • older adults find it harder to recall specific sensory details that would help confirm a memory’s veracity
  • at all ages, gist processing appears to play a strong role in false memories
  • memory of specific (true) details can be used to endorse related (but false) details.

What can you do about any of this? One approach would be to make an effort to recall specific sensory details of an event rather than relying on the easier generic event that comes to mind first. So, for example, if you’re asked to go to the store to pick up orange juice, tomatoes and muesli, you might end up with more familiar items — a sort of default position, as it were, because you can’t quite remember what you were asked. If you make an effort to remember the occasion of being told — where you were, how the other person looked, what time of day it was, other things you talked about, etc — you might be able to bring the actual items to mind. A lot of the time, we simply don’t make the effort, because we don’t think we can remember.

https://www.eurekalert.org/pub_releases/2018-03/ps-fdg032118.php

Reference: 

[4331] Webb, C. E., & Dennis N. A.
(Submitted).  Differentiating True and False Schematic Memories in Older Adults.
The Journals of Gerontology: Series B.

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Lifestyle changes can prevent cognitive decline even in genetically at-risk individuals

  • A large study indicates that lifestyle changes, together with advice and support for managing vascular health, can help prevent cognitive decline even in carriers of the Alzheimer's gene.

A Finnish study involving over 1000 older adults suggests that a counselling program can prevent cognitive decline even among those with the Alzheimer’s gene.

The study involved 1,109 older adults (aged 60-77) of whom 362 were carriers of the APOE4 gene. Some of the participants received regular lifestyle counselling (general health advice), while the rest received “enhanced” lifestyle counselling, involving nutrition counselling, physical and cognitive exercises, and support in managing the risk of cardiovascular diseases.

Earlier findings from the FINGER (Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability) trial showed that the regular lifestyle counselling group had a significantly increased risk of cognitive and functional impairment compared to the group receiving enhanced counselling. This analysis shows that this holds true even for those with the Alzheimer's gene, and indeed, might even be more helpful for carriers of the risky gene.

The findings emphasize the importance of early prevention strategies that target multiple modifiable risk factors simultaneously.

https://www.eurekalert.org/pub_releases/2018-01/uoef-lcp012518.php

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Daily crosswords linked to sharper brain in later life

  • A very large online study has found that doing word puzzles regularly protects against age-related cognitive decline.

Data from more than 17,000 healthy people aged 50 and over has revealed that the more regularly participants engaged with word puzzles, the better they performed on tasks assessing attention, reasoning and memory.

Study participants took part in online cognitive tests, as well as being asked how frequently they did word puzzles such as crosswords. There was a direct relationship between the frequency of word puzzle use and the speed and accuracy of performance on nine cognitive tasks.

The effect was considerable. For example, on test measures of grammatical reasoning speed and short-term memory accuracy, performing word puzzles was associated with brain function equivalent to ten years younger than participants’ chronological age.

The next question is whether you can improve brain function by engaging in puzzles.

The study used participants in the PROTECT online platform, run by the University of Exeter and Kings College London. Currently, more than 22,000 healthy people aged between 50 and 96 are registered in the study. PROTECT is a 10 year study with participants being followed up annually to enable a better understanding of cognitive trajectories in this age range.

https://www.eurekalert.org/pub_releases/2017-07/uoe-dcl071417.php

Reference: 

The Relationship Between the Frequency of Word Puzzle Use and Cognitive Function in a Large Sample of Adults Aged 50 to 96 Years, was presented at the Alzheimer's Association International Conference (AAIC) 2017 on July 17.

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How risky is surgery for older adults' cognitive function?

Several studies suggest that post-operative cognitive decline in older adults is due to several factors:

  • the stress of hospitalization, if unexpected
  • brain inflammation caused by an immune response from the brain’s microglia
  • post-operative delirium.

It also seems that higher levels of cognitive function, higher levels of engagement in certain cognitive activities, and better cerebrovascular health, all protect against such decline.

Unplanned hospitalizations accelerate cognitive decline in older adults

Data from the Rush Memory and Aging Project has found that emergency and urgent hospitalizations are associated with an increased rate of cognitive decline in older adults.

Non-elective hospitalizations were associated with an approximately 60% acceleration in the rate of cognitive decline from before hospitalization. Elective hospitalizations, however, were not associated with acceleration in the rate of decline at all.

Of the 930 participants (average age 81), 613 were hospitalized at least once over an average of almost five years of observation. Of those who were hospitalized, 260 (28%) had at least one elective hospital admission, and 553 (60%) had at least one non-elective hospital admission. These groups included 200 participants (22%) who had both types of hospitalizations.

The data was presented at the Alzheimer's Association International Conference in London on July 17.

https://www.eurekalert.org/pub_releases/2017-07/rumc-hac071717.php

Inflammation triggered by brain's own immune cells behind post-surgical decline

There is growing evidence that inflammation might be responsible for the cognitive decline seen in many older adults after surgery. Now a mouse study provides evidence that brain inflammation and cognitive decline following surgery are triggered by the brain's microglia.

When mice had their microglia temporarily depleted before surgery, they didn’t show any cognitive decline several days after surgery. They also had much lower levels of inflammatory molecules in the hippocampus. Controls — those not receiving the experimental drug to deplete microglia to around 5% of normal levels — did typically show a drop in cognitive performance.

Microglia levels returned to normal within two days after the treatment was stopped, and there was no sign of any impairment in surgical wound healing as a result of the intervention.

https://www.eurekalert.org/pub_releases/2017-04/uoc--cda040517.php

Delirium in older patients after surgery linked to long-term cognitive decline

A 3-year study looking at short-term and long-term cognitive decline in older patients following a surgery found that those who experienced delirium after the surgery showed significantly greater decline than those who didn’t suffer such post-surgical confusion.

The study involved 560 patients (70+), of whom 134 experienced delirium. Both groups showed a significant cognitive decline at one month, followed by a return to their previous level of cognitive function at two months and then a gradual decline for the next 34 months. However, the rate of decline over the three year follow-up was not significant for those who hadn’t experienced delirium.

Those who suffered delirium also had significantly lower cognitive function before surgery.

The odd finding that even the delirium group recovered their cognitive function at two months, before once again declining, suggests that something about the delirium triggers a cascade of events which leads to progressive, long-lasting effects.

http://www.eurekalert.org/pub_releases/2016-07/hsif-dio071416.php

Who’s more likely to develop delirium after surgery?

Delirium after surgery can lead to long-term cognitive decline in older adults — but not always. So what makes the difference?

A preliminary study involving 126 older adults suggests the answer lies in their cognitive function before surgery. Their global cognition score explained the most variation, with other significant factors including: IQCODE score, cognitive independent activities of daily living impairment, living alone, cerebrovascular disease, Charlson comorbidity index score, and exhaustion level. Taken together, these factors explained 32% of the variation in people’s outcome.

Delirium, an acute state of confusion, is a common condition affecting up to 50% of hospitalized older adults.

https://www.eurekalert.org/pub_releases/2017-03/hsif-plc031417.php

Certain leisure activities may reduce post-surgical delirium among older adults

A study of 142 older adults who underwent elective surgery found that greater participation in cognitive activities was linked with a lower incidence and lower severity of delirium.

Nearly a third of the patients (average age 71) developed post-operative delirium. Those who did had participated in fewer leisure activities before surgery compared with people who didn't experience delirium.

Out of all the activities, reading books, using email, and playing computer games reduced the risk of delirium. Playing computer games and singing were the only two activities that predicted lower severity of delirium.

The protection afforded was dose-dependent, with each additional leisure activity reducing post-operative delirium by 8%.

http://www.eurekalert.org/pub_releases/2016-06/ags-cla062116.php

http://www.eurekalert.org/pub_releases/2016-06/w-crm062216.php

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Greater muscle strength = better cognitive function

  • While handgrip strength has been linked to dementia risk in the elderly, a new study indicates that less impaired or fragile older adults need upper and lower body strength tests — but that these, too, are correlated with cognitive function.

A Finnish study involving 338 older adults (average age 66) has found that greater muscle strength is associated with better cognitive function.

Muscle strength was measured utilising handgrip strength, three lower body exercises such as leg extension, leg flexion and leg press and two upper body exercises such as chest press and seated row.

Handgrip strength, easy to measure, has been widely used as a measure of muscle strength, and has been associated with dementia risk among the very old. However, in this study, handgrip strength on its own showed no association with cognitive function. But both upper body strength and lower body strength were independently associated with cognitive function.

It may be that handgrip strength is only useful for older, more cognitively impaired adults.

These are gender-specific associations — muscle strength was significantly greater in men, but there was no difference in cognitive performance between men and women.

The finding is supported by previous research that found a link between walking speed and cognition in older adults, and by a 2015 study that found a striking correlation between leg power and cognition.

This 10-year British study involved 324 older female twins (average age 55). Both the degree of cognitive decline over the ten year period, and the amount of gray matter, was significantly correlated with high muscle fitness (measured by leg extension muscle power). The correlation was greater than for any other lifestyle factor tested

https://www.eurekalert.org/pub_releases/2017-06/uoef-gms062617.php

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Rapid blood pressure drops in middle age linked to dementia in old age

  • A large study indicates that an inclination to dizziness on standing up is associated with a greater risk of developing cognitive impairment and dementia decades later.

Data from over 11,500 participants in the Atherosclerosis Risk in Communities (ARIC) cohort has found evidence that orthostatic hypotension in middle age may increase the risk of cognitive impairment and dementia 20 years later.

Orthostatic hypotension is the name for the experience of dizziness or light-headedness on standing up. Previous research has suggested an association between orthostatic hypotension and cognitive decline in older adults.

In this study, participants aged 45-64 were tested for orthostatic hypotension in 1987. Those with it (703, around 6%) were 40% more likely to develop dementia in the next 20 years. They also had some 15% more cognitive decline.

Orthostatic hypotension was defined as a drop of 20 mmHg or more in systolic blood pressure or 10 mmHg or more in diastolic blood pressure, when the individual stood up after 20 minutes lying down.

More work is needed to understand the reason for the association.

https://www.eurekalert.org/pub_releases/2017-03/jhub-rbp030817.php

Rawlings, Andreea. 2017. Orthostatic Hypotension is Associated with 20-year Cognitive Decline and Incident Dementia: The Atherosclerosis Risk in Communities (ARIC) Study. Presented March 10 at the American Heart Association's EPI|LIFESTYLE 2017 Scientific Sessions in Portland, Oregon.

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