Last year I reported on a study involving 210 subjects aged 7 to 31 that found that in contrast to the adult brain, most of the tightest connections in a child's brain are between brain regions that are physically close to each other. As the child grows to adulthood, the brain switches from an organization based on local networks based on physical proximity to long-distance networks based on functionality. Now the same researchers, using five-minute scans from 238 people aged 7 to 30, have looked at nearly 13,000 functional (rather than structural) connections and identified 200 key ones.
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A number of studies have found evidence that fruits and vegetables help fight age-related cognitive decline, and this has been thought to be due to their antioxidant and anti-inflammatory effects. A new study shows there may be an additional reason why polyphenols benefit the aging brain. One reason why the brain works less effectively as it gets older is that the cells (microglia) that remove and recycle biochemical debris not only fail to do their housekeeping work, but they actually begin to damage healthy cells.
On the subject of the benefits of walking for seniors, it’s intriguing to note a recent pilot study that found frail seniors who walked slowly (no faster than one meter per second) benefited from a brain fitness program known as Mindfit. After eight weeks of sessions three times weekly (each session 45-60 minutes), all ten participants walked a little faster, and significantly faster while talking. Walking while talking requires considerably more concentration than normal walking.
A two-year study involving 271 older adults (70+) with mild cognitive impairment has found that the rate of brain atrophy in those taking folic acid (0.8 mg/d), vitamin B12 (0.5 mg/d) and vitamin B6 (20 mg/d), was significantly slower than in those taking a placebo, with those taking the supplements experiencing on average 30% less brain atrophy. Higher rates of atrophy were associated with lower cognitive performance. Moreover those who with the highest levels of homocysteine at the beginning of the trial benefited the most, with 50% less brain shrinkage.
There’s been a lot of discussion, backed by some evidence, that groups are ‘smarter’ than the individuals in them, that groups make better decisions than individuals. But it is not, of course, as simple as that, and a recent study speaks to the limits of this principle. The study involved pairs of volunteers who were asked to detect a very weak signal that was shown on a computer screen. If they disagreed about when the signal occurred, then they talked together until they agreed on a joint decision.
No big surprise, surely: a new study has found that computers do not magically improve students’ study skills — they tend to study online material using the same techniques they would use with traditional texts. Which means, it appears, poor strategies.
Following on from indications that gum disease might be a risk factor for dementia, analysis of data from 152 subjects in the Danish Glostrop Aging Study has revealed that periodontal inflammation at age 70 was strongly associated with lower cognitive scores (on the Digit Symbol Test). Those with periodontal inflammation were nine times more likely to test in the lower range compared to those with little or no periodontal inflammation. A larger follow-up study, among a more ethnically diverse range of subjects, is planned. I hope they also plan to extend the cognitive testing.
Metamemory (understanding your own memory capabilities) is important for learning. Now a study involving 28 alcoholics has found that, compared to controls, they not only performed more poorly on a test of episodic memory, but they were less accurate in their assessments of how good their memory was. The episodic memory task involved learning 20 pairs of items, followed by a recall and a recognition test 20 minutes later. Before the recognition test, participants rated their ability to recognize each nonrecalled word among 4 items.
While brain training programs can certainly improve your ability to do the task you’re practicing, there has been little evidence that this transfers to other tasks. In particular, the holy grail has been very broad transfer, through improvement in working memory. While there has been some evidence of this in pilot programs for children with ADHD, a new study is the first to show such improvement in older adults using a commercial brain training program.
Amnestic mild cognitive impairment often leads to Alzheimer's disease, but what predicts aMCI? A study involving 94 older adults has revealed that lower performance on tests measuring learning, in conjunction with either slower visuomotor processing speed or depressive symptoms, predicted the development of aMCI a year later with an accuracy of 80-100%. It is worth emphasizing that poor learning alone was not predictive in that time-frame, although one learning measure was predictive of aMCI two years later.