Data from more than 14,265 people older adults (51+) multiple times over a decade or more through the University of Michigan Health and Retirement Study has found that people with higher “multimorbidity scores” showed much faster cognitive decline than those with lower scores, even though most of the chronic conditions included in the index had no direct relationship with brain health. The higher the score, the faster the decline.
A study involving 65 older adults (average age 66), of whom 35 had type 2 diabetes, has found that after two years, those with diabetes had decreases in their ability to regulate blood flow in the brain, and a reduced ability to regulate blood flow was associated with lower cognitive scores.
Specifically, at the start of the study those with diabetes scored an average 46 points on a cognitive test, compared with 55 in the control group. After two years, the diabetics' scores had fallen to an average of 41, while the scores of the control group hadn't fallen at all.
Growing research has implicated infections as a factor in age-related cognitive decline, but these have been cross-sectional (comparing different individuals, who will have a number of other, possibly confounding, attributes). Now a large longitudinal study provides more evidence that certain chronic viral infections could contribute to subtle cognitive deterioration in apparently healthy older adults.
Short-term declines in cognitive function can occur in elderly subjects after surgery, and persists in a small percentage.
Heart bypass surgery in particular is associated with cognitive decline - estimates of its prevalence range from 33% to 82%. This decline may persist in as many as 42% of patients. Age and level of education are both factors in determining the likelihood of long-term decline. The presence of a gene (apolipoprotein E4) carried by some 25% of the population may also increase the likelihood of decline after bypass surgery. There also seems to be a link between post-operative fever and cognitive decline. Long-term decline in cognitive function may be more a result of cardiovascular risk factors than the surgery itself.
High blood pressure in those over 60 seems to be associated with greater risk of cognitive decline.
High blood pressure and other circulatory problems, such as cardiovascular risk factors and diabetes, are linked to cognitive decline, perhaps through causing abnormalities in the white matter of elderly persons' brains.
Those with the gene ApoE4 also appear to have more difficulty recovering from traumatic brain injury.
Two drugs used for Alzheimer's have also been found to help those suffering from dementia following stroke.
A specific skills approach is having some success in helping those who suffer from attention problems following stroke.
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A study of over 500 relatively healthy men aged 65 years or older with high blood pressure has found that chronic use of medications with anticholinergic properties was associated with impairment in verbal memory and the ability to perform daily living tasks. The degree of impairment increased proportionally to the total amount of drug exposure. This effect was independent of age, education, morbidities, and severity of hypertension.
Han, L., Agostini, J.V. & Allore, H.G. 2008. Cumulative Anticholinergic Exposure Is Associated with Poor Memory and Executive Function in Older Men. Journal of the American Geriatrics Society, 56 (12), 2203-2210.
http://www.eurekalert.org/pub_releases/2009-01/w-cma012609.php
The Religious Orders Study has thrown up more data, this time on the subject of anticholinergic medication. Over an eight year period, 679 of the 870 elderly participants took at least one medication with anticholinergic properties. The study found those people who took anticholinergic drugs saw their rate of cognitive function decline 1.5 times as fast as those people who did not take the drugs. Anticholinergic properties are found in many medicines, such as medicines for stomach cramps, ulcers, motion sickness, and urinary incontinence.
The research was presented at the American Academy of Neurology Annual Meeting in Chicago, April 12–19.
http://www.eurekalert.org/pub_releases/2008-04/aaon-uad040208.php
A rat study has found that a single intravenous injection of human umbilical cord blood mononuclear cells in aged rats significantly improved the microenvironment of the aged hippocampus and rejuvenated the aged neural stem/progenitor cells. The increase in neurogenesis seemed to be due to a decrease in inflammation. The results raise the possibility of cell therapy to rejuvenate the aged brain.
Bachstetter, A.D. et al. 2008. Peripheral injection of human umbilical cord blood stimulates neurogenesis in the aged rat brain. BMC Neuroscience, 9, 22.
http://www.physorg.com/news124384387.html
Previous studies of a link between statins (which protect against cardiovascular disease) and cognitive decline have produced inconsistent results. A three year epidemiological study of older African Americans has now found cognitive decline in statin users was less than those who did not take statins, but those who continued to take statins from 2001 to 2004 had greater cognitive decline than those who were taking statins in 2001 but were no longer taking them in 2004. The finding that the benefit is stronger for those who had discontinued use than for continuous users points to a complex association between statins and cognitive decline.
Szwast, S.J. et al. 2007. Association of statin use with cognitive decline in elderly African Americans. Neurology, 69, 1873-1880.
http://www.eurekalert.org/pub_releases/2007-11/iu-rbs110207.php
A study of 96 older adults has found that those with uric-acid levels at the high end of the normal range had the lowest scores on tests of mental processing speed, verbal memory and working memory. The correlation persisted even when controlled for age, sex, weight, race, education, diabetes, hypertension, smoking and alcohol abuse. Uric acid levels increase with age, and higher levels are linked with high blood pressure, atherosclerosis, Type 2 diabetes and the "metabolic syndrome" of abdominal obesity and insulin resistance — all known risk factors for dementia. Because uric acid levels are so easily tested, the finding may suggest a valuable biological marker for very early cognitive problems in old age.
Schretlen, D.J. et al. 2007. Serum Uric Acid and Cognitive Function in Community-Dwelling Older Adults. Neuropsychology, 21 (1)
http://www.eurekalert.org/pub_releases/2007-01/apa-hua122706.php
Rat studies suggest that a drug made to enhance memory triggers a natural mechanism in the brain that fully reverses age-related memory loss, even after the drug itself has left the body. In middle-aged rats given ampakines twice a day for four days, there was a significant increase in the production of brain-derived neurotrophic factor (BDNF), a protein known to play a key role in memory formation, and in long-term potentiation (LTP), the process by which the connection between the brain cells is enhanced and memory is encoded. Deficits in LTP occur with age. This restoration of LTP was found in the brains even after the ampakines had been cleared from the animals' bodies.
Rex, C.S. et al. 2006. Restoration of Long-Term Potentiation in Middle-Aged Hippocampus After Induction of Brain-Derived Neurotrophic Factor. Journal of Neurophysiology, 96, 677-685.
http://www.sciencedaily.com/releases/2006/07/060727154900.htm
A small preliminary clinical trial has found that four weeks of nicotine skin patches helped decision-making and attention in people with age-associated memory impairment (the mildest form of cognitive impairment in seniors). Given the health risks of smoking, and health risks associated with nicotine patches, it is too early to recommend the use of nicotine to improve memory, however. Nicotine mimics the brain chemical acetylcholine, a nerve signal that plays a role in learning and memory.
White, H.K. & Levin, E.D. 2004. Psychopharmacology
http://www.eurekalert.org/pub_releases/2003-12/dumc-npm120303.php
Two recent studies have documented cases of amnesia and other nervous-system side effects after taking statins, the cholesterol-lowering drugs being prescribed to millions of people at risk of heart disease. It is emphasized that this is a rare problem, but given the vast numbers of people taking statins, it might still add up to a significant number of problems.
http://www.eurekalert.org/pub_releases/2003-12/ns-ymw120303.php
A large study, involving 3,690 older adults, has found that drugs with strong anticholinergic effects cause memory and cognitive impairment when taken continuously for a mere two months. Moreover, taking multiple drugs with weaker anticholinergic effects, such as many common over-the-counter digestive aids, affected cognition after 90 days’ continuous use. In both these cases, the risk of cognitive impairment doubled (approximately).
Recent research has suggested that sleep problems might be a risk factor in developing Alzheimer’s, and in mild cognitive impairment. A new study adds to this gathering evidence by connecting reduced slow-wave sleep in older adults to brain atrophy and poorer learning.
The issue of the effect of menopause on women’s cognition, and whether hormone therapy helps older women fight cognitive decline and dementia, has been a murky one. Increasing evidence suggests that the timing and type of therapy is critical. A new study makes clear that we also need to distinguish between women who experience early surgical menopause and those who experience natural menopause.
A number of studies have come out in recent years linking age-related cognitive decline and dementia risk to inflammation and infection (put inflammation into the “Search this site” box at the top of the page and you’ll see what I mean). New research suggests one important mechanism.
Lesions of the brain microvessels include white-matter hyperintensities and the much less common silent infarcts leading to loss of white-matter tissue. White-matter hyperintensities are common in the elderly, and are generally regarded as ‘normal’ (although a recent study suggested we should be less blasé about them — that ‘normal’ age-related cognitive decline reflects the presence of these small lesions).
A six-year study involving over 1200 older women (70+) has found that low amounts of albumin in the urine, at levels not traditionally considered clinically significant, strongly predict faster cognitive decline in older women. Participants with a urinary albumin-to-creatinine ratio of >5 mcg/mg at the start of the study experienced cognitive decline at a rate 2 to 7 times faster in all cognitive measures than that attributed to aging alone over an average 6 years of follow-up. The ability most affected was verbal fluency.