Cancer survivors who underwent chemotherapy often suffer long-term cognitive problems. Until now, most research has been occupied with establishing that this is in fact the case, and studies investigating how to help have been rare. I recently reported on studies suggesting that help with sleep problems and stress can be beneficial. It has also been suggested that exercise can help. None of these suggestions are special to cancer survivors (although cancer survivors may well be one of several groups that derive particular benefit). Similarly, a new study investigates another familiar approach to improving cognitive decline.

The pilot study involved 82 post-menopausal breast cancer survivors (average age 56) who had received chemotherapy and who were worried about their cognitive abilities. The women were randomly assigned to one of three groups: one group received memory training adapted from the ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly) trial; another received processing speed training using Posit Science’s Insight program (commercially available); the third was a wait-listed control group.

Training consisted of ten 1-hour small-group (3-5 people) sessions over 6-8 weeks. Memory training involved learning strategies and applying them to word lists, sequences, and texts. Strategies included mnemonic techniques, as well as instruction in principles of meaningfulness, organization, visualization, and association. Strategies were taught and practiced in the first five sessions, and further practiced in the remaining sessions.

In the Insight program, stimulus duration is progressively shortened during a series of progressively more difficult information-processing tasks, such as time-order judgment, discrimination, spatial-match, forward-span, instruction-following, and narrative-memory tasks. Exercises automatically adjust to maintain an 85% correct rate.

Both programs proved beneficial. The memory training group showed significant improvement in immediate and delayed memory, which was maintained at the two-month follow-up. There was of course individual variability: 39% showed significant improvement on immediate memory (compared to 18% of controls) and 42% on delayed memory (compared to 11% of controls). While the group as a whole didn’t show significant improvement in processing speed, some 73% of the group showed reliable improvement at the two-month follow-up.

The Insight group showed significant improvement on both memory and processing speed. Some 68% improved processing speed (compared to 43% of controls). But note that at the 2-month follow-up, the 67% of the Insight group is not that much greater than the 61% of the controls (demonstrating very clearly the benefits of even the small amount of practice received in testing) and is in fact less than the 73% of the memory group.

The Insight group also showed significant improvement in memory. At two-month follow-up, some 30% of the Insight group had improved immediate memory (compared to the 18% of controls), and 33% had improved delayed memory (vs 11%).

Both training programs had a positive effect on perceived cognitive functioning and symptom distress (mood, anxiety, fatigue), and there was no difference between the groups in terms of satisfaction with the training (both groups were very satisfied).

The researchers concluded that, while both training programs were promising, the dual effect of processing speed training (on memory as well as processing speed) argued for its broader benefits.

However, I note that, although the size of the effect of memory training on processing speed was too small to reach statistical significance, the fact that the number of participants showing reliable improvement was greater than that of the Insight group points to an equally broad effect of memory training. If the memory training was supplemented by a small amount of practice on tasks designed to boost processing speed, it would seem to me that this might produce greater cognitive benefits than the processing speed training. Indeed, the Insight program was, I believe, first developed in the context of the ACTIVE program, and I have, of course, talked before about the value of training that includes multiple domains.

Still, the main message of this study should not be overlooked: it demonstrates that many cancer survivors suffering from cognitive decline can improve their cognitive performance through training and practice.

We know that stress has a complicated relationship with learning, but in general its effect is negative, and part of that is due to stress producing anxious thoughts that clog up working memory. A new study adds another perspective to that.

The brain scanning study involved 60 young adults, of whom half were put under stress by having a hand immersed in ice-cold water for three minutes under the supervision of a somewhat unfriendly examiner, while the other group immersed their hand in warm water without such supervision (cortisol and blood pressure tests confirmed the stress difference).

About 25 minutes after this (cortisol reaches peak levels around 25 minutes after stress), participants’ brains were scanned while participants alternated between a classification task and a visual-motor control task. The classification task required them to look at cards with different symbols and learn to predict which combinations of cards announced rain and which sunshine. Afterward, they were given a short questionnaire to determine their knowledge of the task. The control task was similar but there were no learning demands (they looked at cards on the screen and made a simple perceptual decision).

In order to determine the strategy individuals used to do the classification task, ‘ideal’ performance was modeled for four possible strategies, of which two were ‘simple’ (based on single cues) and two ‘complex’ (based on multiple cues).

Here’s the interesting thing: while both groups were successful in learning the task, the two groups learned to do it in different ways. Far more of the non-stressed group activated the hippocampus to pursue a simple and deliberate strategy, focusing on individual symbols rather than combinations of symbols. The stressed group, on the other hand, were far more likely to use the striatum only, in a more complex and subconscious processing of symbol combinations.

The stressed group also remembered significantly fewer details of the classification task.

There was no difference between the groups on the (simple, perceptual) control task.

In other words, it seems that stress interferes with conscious, purposeful learning, causing the brain to fall back on more ‘primitive’ mechanisms that involve procedural learning. Striatum-based procedural learning is less flexible than hippocampus-based declarative learning.

Why should this happen? Well, the non-conscious procedural learning going on in the striatum is much less demanding of cognitive resources, freeing up your working memory to do something important — like worrying about the source of the stress.

Unfortunately, such learning will not become part of your more flexible declarative knowledge base.

The finding may have implications for stress disorders such as depression, addiction, and PTSD. It may also have relevance for a memory phenomenon known as “forgotten baby syndrome”, in which parents forget their babies in the car. This may be related to the use of non-declarative memory, because of the stress they are experiencing.

Meditation may improve multitasking

I recently reported that developing skill at video action games doesn’t seem to improve general multitasking ability, but perhaps another approach might be more successful. Meditation has, of course, been garnering growing evidence that it can help improve attentional control. A new study extends that research to multitasking in a realistic work setting.

The study involved three groups of 12-15 female human resource managers, of whom one group received eight weeks of mindfulness-based meditation training, another received eight weeks of body relaxation training, and another initially received no training (control), before receiving the mindfulness training after the eight weeks.

Before and after each eight-week period, the participants were given a stressful test of their multitasking abilities, requiring them to use email, calendars, instant-messaging, telephone and word-processing tools to perform common office tasks (scheduling a meeting; finding a free conference room; writing a draft announcement of the meeting, eating snacks and drinking water, writing a memo proposing a creative agenda item for the meeting). Necessary information came from emails, instant messages, telephone calls, and knocks on the door. The participants had 20 minutes to complete the tasks.

The meditation group reported lower levels of stress during the multitasking test compared to the control and relaxation groups. They also spent more time on tasks and switched tasks less often, while taking no longer to complete the overall job than the others. Both meditation and relaxation groups showed improved memory for the tasks they were performing.

After the control group underwent the meditation training, their results matched those of the meditation group.

The meditation training emphasized:

• control of attentional focus
• focusing attention in the present moment or task
• switching focus
• breath and body awareness.

The relaxation training emphasized progressive tensing and relaxing of major muscle groups, aided by relaxation imagery.

It's interesting that overall time on task didn't change (the researchers remarked that the meditators didn't take any longer, but of course most of us would be looking for it to become shorter!), but I wouldn't read too much into it. The task was relatively brief. It would be interesting to see the effects over the course of, say, a day. Nor did the study look at how well the tasks were done.

But it is, of course, important that meditation training reduced task-switching and stress. Whether it also has a postitive effect on overall time and quality of work is a question for another day.

IBMT improves white matter efficiency

A recent imaging study has found that four weeks of a form of mindfulness meditation called integrative body–mind training (IBMT) improved white matter efficiency in areas surrounding the anterior cingulate cortex, compared to controls given relaxation training.

The anterior cingulate is part of the brain network related to self-regulation. Deficits in activation in this part of the brain have been associated with attention deficit disorder, dementia, depression, schizophrenia, and other disorders.

Using the data from a 2010 study involving 45 U.S. college students, and another involving 68 Chinese students, researchers found that axon density (one factor in white matter efficiency) had improved after two weeks, but not myelin formation. After a month (about 11 hours of meditation), both had improved. Mood improved by two weeks.

Previous studies involving computer-based training for improving working memory have found changes in myelination, but not axon density.

Meditators’ better cognitive control may be rooted in emotional regulation

Previous work has found that people who engage in meditation show higher levels of executive control on laboratory tasks.

An electrical signal called the Error Related Negativity (ERN) occurs in the brain within 100 ms of an error being committed. When meditators and non-meditators were given the Stroop Test, meditators not only tended to do better on the test, but their ERNs were stronger.

The interesting thing about this is that the best performers were those who scored highest on emotional acceptance. Mindful awareness was less important. It’s suggested that meditators may be able to control their behavior better not because of their sharper focus, but because they are more aware of their emotions and regulate them better.

Something to think about!

I have reported previously on research suggesting that rapamycin, a bacterial product first isolated from soil on Easter Island and used to help transplant patients prevent organ rejection, might improve learning and memory. Following on from this research, a new mouse study has extended these findings by adding rapamycin to the diet of healthy mice throughout their life span. Excitingly, it found that cognition was improved in young mice, and abolished normal cognitive decline in older mice.

Anxiety and depressive-like behavior was also reduced, and the mice’s behavior demonstrated that rapamycin was acting like an antidepressant. This effect was found across all ages.

Three "feel-good" neurotransmitters — serotonin, dopamine and norepinephrine — all showed significantly higher levels in the midbrain (but not in the hippocampus). As these neurotransmitters are involved in learning and memory as well as mood, it is suggested that this might be a factor in the improved cognition.

Other recent studies have suggested that rapamycin inhibits a pathway in the brain that interferes with memory formation and facilitates aging.

A British study looking at possible gender differences in the effects of math anxiety involved 433 secondary school children (11-16 years old) completing customized (year appropriate) mental mathematics tests as well as questionnaires designed to assess math anxiety and (separately) test anxiety. These sources of anxiety are often confounded in research studies (and in real life!), and while they are indeed related, reported correlations are moderate, ranging from .30 to .50.

Previous research has been inconsistent as regards gender differences in math anxiety. While many studies have found significantly greater levels of math anxiety in females, many studies have found no difference, and some have even found higher levels in males. These inconsistencies may stem from differences in how math anxiety is defined or measured.

The present study looked at a rather more subtle question: does the connection between math anxiety and math performance differ by gender? Again, previous research has produced inconsistent findings.

Findings in this study were very clear: while there was no difference between boys and girls in math performance, there were marked differences in both math and test anxiety. Girls showed significantly greater levels of both. Both boys and girls showed a positive correlation between math anxiety and test anxiety, and a negative correlation between math anxiety and math performance, and test anxiety and performance. However, these relationships between anxiety and performance were stronger for girls than boys, with the correlation between test anxiety and performance being only marginally significant for boys (p<0.07), and the correlation between math anxiety and performance disappearing once test anxiety was controlled for.

In other words, greater math anxiety was linked to poorer math performance, but it was significant only for girls. Moreover, anxiety experienced by boys may simply reflect test anxiety, rather than specific math anxiety.

It is worth emphasizing that there was no gender difference in performance — that is, despite laboring under the burden of greater levels of anxiety, the girls did just as well as boys. This suggests that girls might do better than boys if they were free of anxiety. It is possible, however, that levels of anxiety didn’t actually differ between boys and girls — that the apparent difference stems from girls feeling more free to express their anxiety.

However, the finding that anxiety is greater in girls than boys is in line with evidence that anxiety (and worry in particular) is twice as prevalent in women as men, and more support for the idea that the girls are under-performing because of their anxiety comes from another recent study.

In this study, 149 college students performed a relatively simple task while their brain activity was measured. Specifically, they had to identify the middle letter in a series of five-letter groups. Sometimes the middle letter was the same as the other four ("FFFFF") while sometimes it was different ("EEFEE"). Afterward the students completed questionnaires about their anxiety and how much they worry (Penn State Worry Questionnaire and the Anxious Arousal subscale of the Mood and Anxiety Symptom Questionnaire).

Anxiety scores were significantly negatively correlated with accuracy on the task; worry scores were unrelated to performance.

Only girls who identified themselves as particularly anxious or big worriers recorded high brain activity when they made mistakes during the task (reflecting greater performance-monitoring). Although these women performed about the same as others on simple portions of the task, their brains had to work harder at it. Then, as the test became more difficult, the anxious females performed worse, suggesting worrying got in the way of completing the task.

Greater performance monitoring was not evident among anxious men.

[A reminder: these are group differences, and don't mean that all men or all women react in these ways.]