In my book on remembering what you’re doing and what you intend to do, I briefly discuss the popular strategy of asking someone to remind you (basically, whether it’s an effective strategy depends on several factors, of which the most important is the reliability of the person doing the reminding). So I was interested to see a pilot study investigating the use of this strategy between couples.
A study comparing activity in the dorsolateral prefrontal cortex in young, middle-aged and aged macaque monkeys as they performed a spatial working memory task has found that while neurons of the young monkeys maintained a high rate of firing during the task, neurons in older animals showed slower firing rates. The decline began in middle age.
A standard test of how we perceive local vs global features of visual objects uses Navon figures — large letters made up of smaller ones (see below for an example). As in the Stroop test when colors and color words disagree (RED), the viewer can focus either on the large letter or the smaller ones. When the viewer is faster at seeing the larger letter, they are said to be showing global precedence; when they’re faster at seeing the component letters, they are said to be showing local precedence.
Most research into the importance of folate and B12 levels has centered on seniors, and it does seem clear now that having adequate levels of these vitamins is important for maintaining cognitive functioning as you get older. Folic acid levels are of course also regarded as crucial when the brain is developing, which is why pregnant women are urged to take supplements, and why some countries fortify their bread with it. There is less research in the extensive ground between these two end-points.
DHEA is a naturally-occurring hormone in the human body that declines with age. Previous research looking at the effect of DHEA supplementation on cognitive function and quality-of-life has produced inconsistent results. In the first long-term study (12 months) of healthy older adults, 110 men and 115 women aged 55-85 received either daily 50 mg doses of DHEA or a similar looking placebo pill for 1 year. It was found that, although youthful levels of DHEA were restored in the treatment group, the supplements had no benefits for cognitive function or quality-of-life in this representative sample.
Kritz-Silverstein, D., von Mühlen, D., Laughlin, G. A., & Bettencourt, R. (2008). Effects of Dehydroepiandrosterone Supplementation on Cognitive Function and Quality of Life: The DHEA and Well-Ness (DAWN) Trial. Journal of the American Geriatrics Society, 56(7), 1292-1298. Retrieved from http://dx.doi.org/10.1111/j.1532-5415.2008.01768.x
http://www.eurekalert.org/pub_releases/2008-05/w-ema052108.php
A double-blind, placebo controlled, matched pairs study examined the effects of Pycnogenol (an antioxidant plant extract from the bark of the French maritime pine tree) on a range of cognitive and biochemical measures in 101 senior individuals aged 60-85 years old. Participants had a daily dose of 150mg for three months. Pycnogenol improved both numerical working memory as well as spatial working memory. Blood samples revealed that F2-isoprostanes significantly decreased with Pycnogenol, a sign of reduced oxidation of nerve membranes, suggesting that the antioxidant activity of Pycnogenol plays a major role for the clinical effects. Several recent research studies have found Pycnogenol reduced ADHD symptoms such as hyperactivity and improved attention, concentration and motor-visual coordination in children with ADHD. Pycnogenol extract has been studied for 35 years and is available in more than 600 dietary supplements.
Ryan, J., Croft, K., Mori, T., Wesnes, K., Spong, J., Downey, L., … Stough, C. (2008). An examination of the effects of the antioxidant Pycnogenol(R) on cognitive performance, serum lipid profile, endocrinological and oxidative stress biomarkers in an elderly population. J Psychopharmacol, 22(5), 553-562. Retrieved from http://jop.sagepub.com/cgi/content/abstract/22/5/553
http://www.eurekalert.org/pub_releases/2008-03/mg-nsp031708.php
A large, long-running study has found that men who took beta carotene supplements for 15 years or longer had significantly higher scores on several cognitive tests compared with men who took placebo. There was no such effect in those men who took the supplements for a year. The researchers suggest that although the benefits were modest in themselves, they may predict substantial differences in eventual risk of dementia. However, it should be noted that beta carotene is not without risks—for example, it may increase the risk of lung cancer in smokers — and that it would be premature to advise use of such supplements.
Grodstein, F., Kang, J. H., Glynn, R. J., Cook, N. R., & Gaziano, M. (2007). A Randomized Trial of Beta Carotene Supplementation and Cognitive Function in Men: The Physicians’ Health Study II. Arch Intern Med, 167(20), 2184-2190. Retrieved from http://archinte.ama-assn.org/cgi/content/abstract/167/20/2184
http://www.eurekalert.org/pub_releases/2007-11/jaaj-lbc110807.php
After only a month, older rats fed two chemicals normally found in the body's cells and available as dietary supplements — acetyl-L-carnitine and an antioxidant, alpha-lipoic acid — performed better on memory tests, and had noticeably more energy (on a par with a “middle-aged” rat). It is thought that these chemicals act on the mitochondria, the “power-houses” of the cells. Mitochondria are increasingly being implicated as especially vulnerable to the aging process. Carnitine is a natural compound produced in the cell and obtained in the diet through meats and vegetables. It has been shown to improve balance and short-term memory in human. Lipoic acid is found in green, leafy vegetables.
The University of California has patented use of the combination of the two supplements to rejuvenate cells. Human clinical trials are currently underway.
Hagen, T. M., Liu, J., Lykkesfeldt, J., Wehr, C. M., Ingersoll, R. T., Vinarsky, V., … Ames, B. N. (2002). Feeding acetyl-l-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 1870-1875. Retrieved from http://www.pnas.org/content/99/4/1870.abstract
Liu, J., Head, E., Gharib, A. M., Yuan, W., Ingersoll, R. T., Hagen, T. M., … Ames, B. N. (2002). Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: Partial reversal by feeding acetyl-l-carnitine and/or R-α-lipoic acid. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 2356-2361. Retrieved from http://www.pnas.org/content/99/4/2356.abstract
Liu, J., Killilea, D. W., & Ames, B. N. (2002). Age-associated mitochondrial oxidative decay: Improvement of carnitine acetyltransferase substrate-binding affinity and activity in brain by feeding old rats acetyl-l- carnitine and/or R-α-lipoic acid. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 1876-1881. Retrieved from http://www.pnas.org/content/99/4/1876.abstract
http://www.eurekalert.org/pub_releases/2002-02/uoc--dsm021502.php
http://www.eurekalert.org/pub_releases/2002-02/osu-crr021902.htm
Following on from research showing that long-term meditation is associated with gray matter increases across the brain, an imaging study involving 27 long-term meditators (average age 52) and 27 controls (matched by age and sex) has revealed pronounced differences in white-matter connectivity between their brains.
Another study showing the value of exercise for preserving your mental faculties in old age. This time it has to do with the development of small brain lesions or infarcts called "silent strokes." Don’t let the words “small” and “silent” fool you — these lesions have been linked to memory problems and even dementia, as well as stroke, an increased risk of falls and impaired mobility.
It wasn’t so long ago we believed that only young brains could make neurons, that once a brain was fully matured all it could do was increase its connections. Then we found out adult brains could make new neurons too (but only in a couple of regions, albeit critical ones). Now we know that neurogenesis in the hippocampus is vital for some operations, and that the production of new neurons declines with age (leading to the idea that the reduction in neurogenesis may be one reason for age-related cognitive decline).
The brain tends to shrink with age, with different regions being more affected than others. Atrophy of the hippocampus, so vital for memory and learning, is associated with increased risk of developing Alzheimer’s, and has also been linked to depression.
A number of studies have demonstrated the cognitive benefits of music training for children. Now research is beginning to explore just how long those benefits last. This is the second study I’ve reported on this month, that points to childhood music training protecting older adults from aspects of cognitive decline. In this study, 37 adults aged 45 to 65, of whom 18 were classified as musicians, were tested on their auditory and visual working memory, and their ability to hear speech in noise.