The research described this week in the journal Proceedings of the National Academy of Sciences, begins to explain how exercise and restricted-calorie diets help to stave off the mental and physical degeneration of aging.

“Caloric restriction and exercise have numerous, dramatic effects on our mental acuity and motor ability,” says Joshua Sanes, a professor of molecular and cellular biology and director of the Center for Brain Science at Harvard University.

“This research gives us a hint that the way these extremely powerful lifestyle factors act is by attenuating or reversing the decline in our synapses.”

The study was conducted in the labs of and Sanes and Jeff Lichtman.

Sanes says their research, conducted with mice genetically engineered so their nerve cells glow in fluorescent colors, shows some of the debilitation of aging is caused by deterioration of connections that nerves make with the muscles they control, structures called neuromuscular junctions.

These microscopic links are remarkably similar to the synapses (junction between nerve cells, where the club-shaped tip of a nerve fiber almost touches another cell in order to transmit signals) that connect neurons to form information-processing circuits in the brain.

In a healthy neuromuscular synapse, nerve endings and their receptors on muscle fibers are almost a perfect match, like two hands placed together, finger to finger, palm to palm. This lineup ensures maximum efficiency in transmitting the nerve’s signal from the brain to the muscle, which is what makes it contract during movement.

As people age, however, the neuromuscular synapses can deteriorate in several ways.

Nerves can shrink, failing to cover the muscle’s receptors completely. The resulting interference with transmission of nerve impulses to the muscles can result in wasting and eventually even death of muscle fibers. This muscle wasting, called sarcopenia, is a common and significant clinical problem in the elderly.

The new work shows that mice on a restricted-calorie diet largely avoid that age-related deterioration of their neuromuscular junctions (synapses), while those on a one-month exercise regimen when already elderly partially reverse the damage.

“With calorie restriction, we saw reversal of all aspects of the synapse disassembly. With exercise, we saw a reversal of most, but not all,” Sanes says.

Because of the study’s structure – mice were on calorie-restricted diets for their whole lives, while those that exercised did so for just a month late in life – Sanes cautions against drawing conclusions about the effectiveness of exercise versus calorie restriction.

He notes that longer periods of exercise might have more profound effects, a possibility he and Lichtman are now testing.

Though much of Sanes and Lichtman’s work focuses on brain synapses, both have investigated neuromuscular synapses for many years. Neuromuscular junctions are large enough to be viewed by light microscopy, and can be a jumping-off point for brain study, highlighting areas of inquiry and potential techniques.

“These findings in neuromuscular synapses make us curious to know whether similar effects might occur in brain synapses,” Sanes says.

While the changes to the synapses through caloric restriction and exercise were clear in the images the researchers obtained, Sanes cautioned that their work was structural, not functional, and they have not yet tested how well the synapses worked.

The research, largely conducted by postdoctoral researchers Gregorio Valdez, Juan Tapia, and Hyuno Kang at Harvard University, was funded by the National Institute on Aging, National Institute of Neurological Disorders and Stroke, and Ellison Medical Foundation.

“These data suggest that the 2008 federal recommendation for 150 minutes per week, while clearly sufficient to lower the risks of chronic diseases, is insufficient for weight gain prevention absent caloric restriction,” according to the report in the March 24 issue of JAMA

“Physical activity was inversely related to weight gain only among normal-weight women; among heavier women, there was no relation, emphasizing the importance of controlling caloric intake for weight maintenance in this group.”

The prevalence of overweight and obesity in the United States has increased dramatically over the past 2 decades, with 1 in 3 adults currently obese.

“Because the average U.S. adult gains weight with age, developing ways to prevent unhealthful weight gain would help them avoid having to lose weight and then trying to maintain that loss. Compared with the vast body of research on the treatment of overweight and obese individuals, little research exists on preventing weight gain,” the authors write.

“The amount of physical activity needed to prevent long-term weight gain is unclear.”

The study by I-Min Lee, M.B.B.S., Sc.D., of Brigham and Women’s Hospital and Harvard Medical School, Boston, and colleagues examined weight changes associated with different physical activity levels that included 34,079 healthy U.S. women who consumed a usual diet (average age, 54. years) from 1992-2007.

At the beginning of the study and at years 3, 6, 8, 10, 12 and 13, women reported their physical activity and body weight. Women were classified as expending less than 7.5, 7.5 to less than 21, and 21 or more metabolic equivalent hours per week of activity at each time. Analyses examined physical activity and weight change over intervals averaging 3 years.

Women gained an average of 5.7 lbs. throughout the study. Compared with women expending 21 or more MET hours per week, those expending 7.5 to less than 21 MET hours per week gained .2 lbs., whereas those expending less than 7.5 MET hours per week gained .3 lbs, a difference that was not statistically significant.

“There was a significant interaction with body mass index (BMI), such that there was an inverse dose-response relation between activity levels and weight gain among women with a BMI of less than 25 but no relation among women with a BMI from 25 to 29.9 or with a BMI of 30.0 or higher.

“A total of 4,540 women (13.3 percent) with a BMI lower than 25 at study start successfully maintained their weight by gaining less than 5.1 lbs. throughout. Their [average] activity level over the study was 21.5 MET hours per week ([approximately] 60 minutes a day of moderate-intensity activity),” the researchers

The study, in Frontiers in Aging Neuroscience, followed 65 adults, aged 59 to 80, who joined a walking group or stretching and toning group for a year.

All of the participants were sedentary before the study, reporting less than two episodes of physical activity lasting 30 minutes or more in the previous six months. The researchers also measured brain activity in 32 younger (18- to 35-year-old) adults.

Rather than focusing on specific brain structures, the study looked at activity in brain regions that function together as networks.

“Almost nothing in the brain gets done by one area – it’s more of a circuit,” said University of Illinois psychologyprofessor and Beckman Institute Director Art Kramer, who led the study with kinesiology and community healthprofessor Edward McAuley and doctoral student Michelle Voss. “These networks can become more or less connected. In general, as we get older, they become less connected, so we were interested in the effects of fitness on connectivity of brain networks that show the most dysfunction with age.”

Psychology professor and Beckman Institute director Art Kramer, doctoral student Michelle Voss and their colleagues found that a year of moderate walking improved the connectivity of specific brain networks in older adults. Photo by L. Brian Stauffer

Neuroscientists have identified several distinct brain circuits. Perhaps the most intriguing is the default mode network (DMN), which dominates brain activity when a person is least engaged with the outside world – either passively observing something or simply daydreaming.

Previous studies found that a loss of coordination in the DMN is a common symptom of aging and in extreme cases can be a marker of disease, Voss said.

“For example, people with Alzheimer’s disease tend to have less activity in the default mode network and they tend to have less connectivity,” she said. Low connectivity means that the different parts of the circuit are not operating in sync. Like poorly trained athletes on a rowing team, the brain regions that make up the circuit lack coordination and so do not function at optimal efficiency or speed, Voss said.

In a healthy young brain, activity in the DMN quickly diminishes when a person engages in an activity that requires focus on the external environment. Older people, people with Alzheimer’s disease and those who are schizophrenic have more difficulty “down-regulating” the DMN so that other brain networks can come to the fore, Kramer said.

A recent study by Kramer, Voss and their colleagues found that older adults who are more fit tend to have better connectivity in specific regions of the DMN than their sedentary peers. Those with more connectivity in the DMN also tend to be better at planning, prioritizing, strategizing and multi-tasking.

The new study used functional magnetic resonance imaging (fMRI) to determine whether aerobic activity increased connectivity in the DMN or other brain networks. The researchers measured participants’ brain connectivity and performance on cognitive tasks at the beginning of the study, at six months and after a year of either walking or toning and stretching.

At the end of the year, DMN connectivity was significantly improved in the brains of the older walkers, but not in the stretching and toning group, the researchers report.

The walkers also had increased connectivity in parts of another brain circuit (the fronto-executive network, which aids in the performance of complex tasks) and they did significantly better on cognitive tests than their toning and stretching peers.

Previous studies have found that aerobic exercise can enhance the function of specific brain structures, Kramer said. This study shows that even moderate aerobic exercise also improves the coordination of important brain networks.

“The higher the connectivity, the better the performance on some of these cognitive tasks, especially the ones we call executive control tasks – things like planning, scheduling, dealing with ambiguity, working memory and multitasking,” Kramer said.

These are the very skills that tend to decline with aging, he said.

It will be published in the July issue of Accident Analysis & Prevention.

The study involved 21 young-inexperienced, 19 experienced and 16 older drivers (37 years of experience) who viewed six hazard perception movies while connected to an eye tracking system and were requested to identify hazardous situations.

Four movies embedded planned, highly hazardous situations and the rest were used as control. The study showed that experienced and older-experienced drivers were equally proficient at hazard detection and detected potentially hazardous events continuously, whereas young-inexperienced drivers stopped reporting on hazards that followed planned, highly hazardous situations.

Moreover, while approaching T intersections, older and experienced drivers fixated more toward the merging road on the right, while young-inexperienced drivers fixated straight ahead, paying less attention to potential vehicles on the merging road.

According to BGU researcher Avinoam Borowsky, “We found that with older drivers, in general, their hazard perception abilities remained intact. However, they relied heavily on signs and signals (i.e. signals from other vehicles) to cope with the traffic environment. In their verbal comments, however, older drivers tended to claim that the other road users were responsible for putting them at risk and rarely considered themselves as responsible for hazardous events.”

The BGU Traffic Lab measures drivers’ eye movements and has a driving simulator equipped with an advanced simulation program, a panoramic screen and a 2008 luxury Cadillac sedan, donated by General Motors (GM). The Human Factors Engineering group has worked with GM for more than 10 years, studying driver interaction with vehicle systems to improve driver safety.

The research was supported in part by the Ran Naor Foundation and the Paul Ivanier Center for Robotics and Production at Ben-Gurion University of the Negev.

“According to a previous study, only 69 percent of rotator cuff repairs were completely healed when evaluated two years after the surgery,” said Scott Rodeo, M.D., co-chief of the Sports Medicine and Shoulder Service at Hospital for Special Surgery and senior author on the study.

“Although not all of the patients with failed rotator cuff tendon healing had poor clinical outcomes, we wanted to look for ways to further improve patient outcomes.”

The rotator cuff is a set of four smaller muscles in the shoulder that rotate the upper arm. A rotator cuff tear happens when the tendon part of the muscle tears away from the bone of the upper arm. The repair surgery reattaches the tendon to the bone, but the success depends on how well the interface between the tendon and bone heals.

Much of the time scar tissue forms at that interface, which is not as strong as the original tissue and can lead to a failed repair.

“The healing process occurs from both the bone and the tendon, which is made up of collagen,” said Carolyn Hettrich, M.D., MPH, fifth year resident in orthopedic surgery at Hospital for Special Surgery and lead author.

“We knew the drug Forteo is osteogenic and can stimulate bone growth, but we found reports in the literature that it is also chondrogenic, so it can promote cartilage formation as well.”

Forteo is a synthetic version of parathyroid hormone, which is the body’s primary regulator of calcium and phosphate levels in bone. Recently approved by the FDA, it is prescribed for osteoporosis as it not only stimulates bone growth but it also slows the rate of bone loss.

The researchers hypothesized that because Forteo stimulated both bone and cartilage formation, it might enhance the healing process after rotator cuff surgery. Using a rat model, they performed the surgery and then gave some rats Forteo injections in amounts comparable to human doses.

Initially, at two weeks after the surgery, the repair was not as strong in the rats who received the Forteo.

But when the researchers looked at weeks four through eight, the tendon to bone interface in those rats appeared much more like normal tissue.

Closer examination showed that not only had those rats that received Forteo produced more bone and cartilage cells, but the organization of the tissue was better and more closely resembled normal tissue.

The tendon was also significantly stiffer, a sign of proper healing, at 8 weeks.

“The results are positive, but now we want to understand why at week two the tendon wasn’t healing as well,” said Dr. Hettrich.

“Our next experiments will look to pinpoint these causes and determine the optimum delivery time of the drug after surgery.”

The researchers caution that it would be risky to use Forteo in patients undergoing rotator cuff surgery just yet as further studies are needed. Instead, they encourage patients to talk to their surgeons about other steps they can do to improve healing, such as not smoking after the surgery to optimize their biology.

Athletes who use overhead movements, like baseball or tennis players, are prone to this injury.

It is also common in adults over 40 because the tendons begin to degenerate and weaken.

“In some instances, the body’s own healing process does not produce ideal results,” said Dr. Rodeo. “We are trying to find ways to improve tendon to bone healing – ways to augment the healing process and go beyond what the body can do on its own. Although preliminary, the results here are promising and may eventually be applied to other tendon to bone surgeries, such as bicep

The research, led by scientists at University of California, San Francisco (UCSF), is also one of the first to measure both mental performance and changes in neural activity caused by a cognitive training program.

In the study, healthy older participants trained on a computer game designed to boost visual perception. After ten hours of training, they not only improved their perceptual abilities significantly, but also increased the accuracy of their visual working memory by about ten percent – bringing them up to the level of younger adults. Few brain training programs have been subjected to such rigorous research evaluation to reveal such a transfer of benefits, the researchers say.

Working memory is the ability to hold information in mind for brief periods. It is essential to accomplish immediate tasks, such as engaging in conversation with several people.

If improvements in a simple perception skill can transfer to a higher level function such as memory, as this research found, then other interventions might further improve brain function in aging people, the scientists say.

The researchers recorded participants’ brain activity before and after the visual perception training, and found a direct link between improved performance and changes in brain activity. After the training, activity had decreased in a key brain area involved in processing visual input. The people who improved the most in the visual training showed the biggest drop in neural activity – as if the brain didn’t have to work as hard to take in information.

The research was being published in the journal PLoS One on July 14, 2010.

Adam Gazzaley, MD, PhD

“This confirms our understanding that the brains of older adults, like those of young people, are ‘plastic’ – the brain can change in response to focused training,” said Adam Gazzaley, MD, PhD, director of the Neuroscience Imaging Center at UCSF and senior author of the research paper. Gazzaley is associate professor of neurology, physiology and psychiatry at UCSF.

“The study shows that perceptual improvements with simple discrimination training can transfer to improved working memory in older adults, and it also shows that this increase in memory accuracy is linked to changes at the neural level.”

There are many brain fitness programs being marketed, but there has been little rigorous testing and evaluations of their effectiveness, Gazzaley said.

“We zeroed in on one specific regimen, and we can see that at least with this approach, some brain fitness program claims may be warranted.”

Gazzaley’s team collaborated with researchers at Posit Science Corp., a producer and promoter of brain fitness programs. Posit Science was co-founded by Michael Merzenich, PhD, a leader in brain plasticity research and professor emeritus, Keck Center for Integrative Neuroscience and Otolaryngology at UCSF. Posit Science funded the research.

Memory improvement was measured about one week after the visual perception training ended. The scientists did not assess how long the memory improvement might last beyond that period without continued training.

A further test showed that if participants had to multi-task during the memory testing, they did not receive the memory boost from the previous perception training. Gazzaley hopes that more studies can lead to ways to help people improve their ability to mentally process simultaneous tasks – a skill that declines in many older adults.

The study involved two sets of 15 healthy adults from age 60 to 89. One group participated in the training. The second group served as the control, taking the memory tests but not the visual perception training.  No participants had dementia, but the group showed a range of mental fitness typical of an aging population. The average age was 72. Most were college educated, middle class people.

People in both groups were given a baseline working memory test consisting of watching dots move across the computer screen, followed by a short delay and then re-testing to see if they remembered exactly in which direction the dots had moved.  The memory test was given to both groups again after the experimental group had participated in ten hours of visual perception training. This training challenged players to discriminate between different shapes of sine waves, or S-shaped patterns, moving across the screen.

The training program was designed so that as a participant’s skill level improved, the task became progressively harder. The drills lasted 40 minutes, and were given three to five times a week for three to five weeks.  All trained participants improved their ability to distinguish between the two different moving shapes.

Scientists measured participants’ brain activity by electroencephalography, or EEG, during the memory tests, both before and after the visual training. People were fitted with caps consisting of non-invasive electrodes that measure electrical activity caused by neurons firing in the cerebral cortex, the site of higher cognitive functions.

The research team focused on brain activity known to be involved in processing visual information, in a region called the visual association cortex located near the back of the brain. Neurons at this site generate an internal representation of what is seen, Gazzaley said. The research team found that as peoples’ visual perception improved, activity generated by this region decreased.

“This suggests that the brain processed the visual input more efficiently,” Gazzaley said. “So, we find for the first time that improved perceptual learning transfers to improved working memory performance, and that this improvement may well be explained by changes in neural activity.  This gives us direction for developing even better interventions to improve brain function in older adults.”

When asked if older adults would have to continue these repetitive drills in order to maintain improved memory, Gazzaley says, “Well, I like to keep physically fit. I work out almost every day, and I know that if I stopped, I would get out of shape. Maybe it’s the same with the brain. You’ve got to continue to work it.”

Lead author on the paper is Anne S. Berry, a staff research associate in the UCSF departments of neurology and physiology. Co-authors are Theodore Zanto, PhD and Wesley Capp, PhD, both postdoctoral scientists at UCSF. Co-authors at Posit Science Corporation are Joseph L. Hardy, PhD, Peter Delahunt, PhD and Henry Mahncke, PhD

As the population continues to age, it is important for physicians and caregivers to be aware of and prepared to deal with this issue, which could significantly impact the overall health and wellbeing of older adults.

In contrast to falls from greater heights, ground-level falls – essentially falls from a standing position, with feet touching the ground prior to the fall – have traditionally been considered minor injuries. But, the new study found senior adults – 70 years or older – who experience ground-level falls are much more likely to be severely injured and less likely to survive their injuries compared to adults younger than 70 years.

lderly patients are three times as likely to die following a ground-level fall compared to their under-70 counterparts.

Trauma surgeon and researcher Julius Cheng, M.D., M.P.H, conducted the largest analysis to date of trauma patients experiencing ground-level falls. His team identified 57,302 patients with ground-level falls from 2001 through 2005 using the National Trauma Data Bank and analyzed demographics, type and severity of injuries and final outcomes.

“There is the potential to minimize what people see as a relatively trivial issue, such as slipping and falling on a wet tile floor. Our research shows that falls from low levels shouldn’t be underestimated in terms of how bad they can be, especially in older patients,” said Cheng, associate professor in the Department of Surgery at the University of Rochester Medical Center and lead author of the new study.

Between 1993 and 2003, there was a 55 percent increase in the rate of fatal falls for elderly adults. Because of the increasing age in the general population, the number of elderly patients visiting the emergency department with ground-level falls is increasing, and will likely continue to rise in the future.

It is now estimated that 30 percent of adults older than 65 years will experience an unintentional fall each year.

“Instead of an influx of ‘traditional’ knife-and-gun club victims, trauma centers of the future may need to prepare for treatment of a less dramatic but no less relevant form of injury that may very well have a substantial impact on the health and independence of our older citizens,” said Thomas S. Helling, M.D., from the Department of Surgery at the University of Mississippi Medical Center who wrote an editorial accompanying the study.

The negative effect of age on health outcomes has been well established in past studies in other areas as well. Many elderly adults are frail and have pre-existing medical conditions, such as heart disease. In these types of patients, a low-level fall that results in a broken hip could have serious, far-reaching consequences.

According to Cheng, “An 80 year old often can’t tolerate and recover from trauma like a 20 year old.”

Cheng’s team found that approximately 4.5 percent of elderly patients (70 years and above) died following a ground-level fall, compared to 1.5 percent of non-elderly patients.

Elderly patients remained in the hospital and the intensive care unit longer and only 22 percent were able to function on their own after they left the hospital, compared to 41 percent of non-elderly patients.

Though low-level falls can potentially lead to significant injury and death, the reality is that almost three-quarters of patients with ground-level falls are not severely injured. Given the limited resources available to most medical centers across the United States and the increasing number of elderly patients needing treatment, Cheng’s team identified two major predictors of death in patients who have experienced ground-level falls:
1. Age older than 70 years and
2. a Glasgow Coma Scale (a widely used indicator of brain injury) score of less than 15.

These specific factors may help emergency department staff better determine which patients have a higher risk of death and are more likely to require aggressive evaluation and treatment.

While more research is needed on the management and treatment of the ever-expanding subpopulation of elderly patients in trauma centers, Cheng emphasizes the need to focus on prevention as well.

“This study brings up the important question of what we need to do as a society to help our older folks take care of themselves,” said Cheng.

“Instead of just treating falls as they happen, the focus should be on what we can do to help older people avoid them in the first place. This can be as simple as making sure there is no loose carpeting in their home and putting railings on both sides of stairways and in bathtubs and showers.”

In addition to Cheng, Konstantinos Spaniolas, M.D., Mark Gestring, M.D., Ayodele Sangosanya, M.D., Nicole Stassen, M.D. and Paul Bankey, M.D., from the University of Rochester Medical Center contributed to the study.

The concerns are valid, but a new Stanford study shows there’s a silver lining to the graying of our nation. As we grow older, we tend to become more emotionally stable. And that translates into longer, more productive lives that offer more benefits than problems, said Laura Carstensen, the study’s lead author.

“As people age, they’re more emotionally balanced and better able to solve highly emotional problems,” said Carstensen, a psychology professor and director of the Stanford Center on Longevity.

“We may be seeing a larger group of people who can get along with a greater number of people. They care more and are more compassionate about problems, and that may lead to a more stable world.”

Between 1993 and 2005, Carstensen and her colleagues tracked about 180 Americans between the ages of 18 and 94.  Over the years, some participants died and others aged out of the younger groups, so additional participants were included.

For one week every five years, the study participants carried pagers and were required to immediately respond to a series of questions whenever the devices buzzed. The periodic quizzes were intended to chart how happy, satisfied and comfortable they were at any given time.

Carstensen’s study – which was published online Monday in the journal Psychology and Aging – was coauthored by postdoctoral fellows Bulent Turan and Susanne Scheibe as well as Stanford doctoral students and researchers at Pennsylvania State, Northwestern, the University of Virginia and the University of California’s campuses in San Francisco and Los Angeles.

While previous research has established a correlation between aging and happiness, Carstensen’s study is the first to track the same people over a long period of time to examine how they changed.

Laura Carstensen, a psychology professor and director of the Stanford Center on Longevity, is the study’s lead author. Photo L.A. Cicero

The undertaking was an effort to answer questions asked over and over again by social scientists: Are seniors today who say they’re happy simply part of a socioeconomic era that predisposed them to good cheer?

Or do most people – whether born and reared in boom times or busts – have it within themselves to reach their golden years with a smile? The answer has important implications for future aging societies.

“Our findings suggest that it doesn’t matter when you were born,” Carstensen said. “In general, people get happier as they get older.”

Over the years, the older subjects reported having fewer negative emotions and more positive ones compared with their younger days. But even with the good outweighing the bad, older people were inclined to report a mix of positive and negative emotions more often than younger test subjects.

“As people get older, they’re more aware of mortality,” Carstensen said.

“So when they see or experience moments of wonderful things, that often comes with the realization that life is fragile and will come to an end. But that’s a good thing. It’s a signal of strong emotional health and balance.”

Carstensen (who is 56 and says she’s happier now than she was a few decades ago) attributes the change in older people to her theory of “socio-emotional selectivity” – a scientific way of saying that people invest in what’s most important to them when time is limited.

While teenagers and young adults experience more frustration, anxiety and disappointment over things like test scores, career goals and finding a soul mate, older people typically have made their peace with life’s accomplishments and failures. In other words, they have less ambiguity to stress about.

“This all suggests that as our society is aging, we will have a greater resource,” Carstensen said. “If people become more even-keeled as they age, older societies could be wiser and kinder societies.”

So what, then, do we make of the “grumpy old man” stereotype?

“Most of the grumpy old men out there are grumpy young men who grew old,” Carstensen said. “Aging isn’t going to turn someone grumpy into someone who’s happy-go-lucky. But most people will gradually feel better as they grow older.”

Longitudinal test scores look good in part because repeat test-takers grow familiar with tests or testing strategies, said the University of Virginia psychologist. Factoring out these “practice effects” showed a truer picture of actual mental aging, according to Salthouse.

Still, the declines, although pervasive, are smaller than thought, according to the report in the July issue of Neuropsychology. That finding contradicts data gathered by the other major research approach to aging, cross-sectional studies, which compare the performance of different age groups at the same time.

With both methods subject to bias, “It remains important to recognize the limitations of each type of study design when interpreting results,” Salthouse said.

To learn what really happens as people age, Salthouse tackled how different research methods have led to different findings. Cross-sectional studies that compared the abilities of younger and older adults showed big drops in key areas. On the other hand, longitudinal studies suggested that, until about age 60, abilities are stable or even improve. Which type of study, if either, was right?

To find out, Salthouse analyzed data on five key cognitive abilities from the longitudinal Virginia Cognitive Aging Project. Scores were available for 1,616 adults age 18 to more than 80 on tests of reasoning, spatial visualization, episodic memory, perceptual speed and vocabulary. The data were collected over an average test-retest interval of two-and-a-half years.

First, Salthouse sorted participants into age brackets by decade, each with well more than 100 participants, except for the 80-89 bracket, with 87 participants.

Second, he estimated the size of practice effects by comparing scores earned on the second test by the longitudinal participants with scores on a first test by another group of participants. He also used statistical methods to adjust for the chance that weaker performers dropped out between the first and second tests.

Practice effects were evident across the board, allowing test-takers to score higher the second time around not because they truly were more able, but because they knew the test – an unavoidable byproduct of repeated testing. Although the numbers varied by ability and age, practice effects were found to be as large as or larger than the annual cross-sectional differences.

Numbers in hand, Salthouse removed the practice-related “bonus points.” Stripping them out generated a new set of cognitive scores that could be expected to reflect more accurately normal mental aging in healthy adults.

With practice effects taken into account, the age trends in the longitudinal data became more similar to results from cross-sectional studies in the places where they had diverged. The different methods now agreed on the downward direction of change.

However, the increments were smaller. In other words, the mental abilities of younger adults still rose over time, but not nearly as much. And the mental abilities of older adults still fell over time, but not quite as much.

Knowing how practice effects, selective attrition and actual maturation affect how people change over time will put psychologists in a better position “to evaluate true age changes, and how they might relate to late-life pathology and everyday functioning,” Salthouse said.

Salthouse also found that practice effects played a bigger role in younger than older adults, possibly because younger people learn better.

“Longitudinal comparisons in people of different ages may be even more complicated because the amount of longitudinal change may be partially determined by the individual’s learning ability at a given age,” he noted.

Salthouse is a fellow of the American Psychological Association and other scientific associations, and a past winner of the APA’s William James Award.

The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States and is the world’s largest association of psychologists. APA’s membership includes more than 152,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting health, education and human welfare

“There is often a striking discrepancy in the age trends obtained from cross-sectional and longitudinal comparisons of certain cognitive abilities, as the former frequently reveal nearly linear declines starting in the early twenties, whereas significant longitudinal decline seldom occurs until adults are 60 years of age or older,” according to the author.

Longitudinal test scores look good in part because repeat test-takers grow familiar with tests or testing strategies, said the University of Virginia psychologist. Factoring out these “practice effects” showed a truer picture of actual mental aging, according to Salthouse.

Still, the declines, although pervasive, are smaller than thought, according to the report in the July issue of Neuropsychology. That finding contradicts data gathered by the other major research approach to aging, cross-sectional studies, which compare the performance of different age groups at the same time.

With both methods subject to bias, “It remains important to recognize the limitations of each type of study design when interpreting results,” Salthouse said.

To learn what really happens as people age, Salthouse tackled how different research methods have led to different findings. Cross-sectional studies that compared the abilities of younger and older adults showed big drops in key areas. On the other hand, longitudinal studies suggested that, until about age 60, abilities are stable or even improve. Which type of study, if either, was right?

To find out, Salthouse analyzed data on five key cognitive abilities from the longitudinal Virginia Cognitive Aging Project. Scores were available for 1,616 adults age 18 to more than 80 on tests of reasoning, spatial visualization, episodic memory, perceptual speed and vocabulary. The data were collected over an average test-retest interval of two-and-a-half years.

First, Salthouse sorted participants into age brackets by decade, each with well more than 100 participants, except for the 80-89 bracket, with 87 participants.

Second, he estimated the size of practice effects by comparing scores earned on the second test by the longitudinal participants with scores on a first test by another group of participants. He also used statistical methods to adjust for the chance that weaker performers dropped out between the first and second tests.

Practice effects were evident across the board, allowing test-takers to score higher the second time around not because they truly were more able, but because they knew the test – an unavoidable byproduct of repeated testing. Although the numbers varied by ability and age, practice effects were found to be as large as or larger than the annual cross-sectional differences.

Numbers in hand, Salthouse removed the practice-related “bonus points.” Stripping them out generated a new set of cognitive scores that could be expected to reflect more accurately normal mental aging in healthy adults.

With practice effects taken into account, the age trends in the longitudinal data became more similar to results from cross-sectional studies in the places where they had diverged. The different methods now agreed on the downward direction of change.

However, the increments were smaller. In other words, the mental abilities of younger adults still rose over time, but not nearly as much. And the mental abilities of older adults still fell over time, but not quite as much.

Knowing how practice effects, selective attrition and actual maturation affect how people change over time will put psychologists in a better position “to evaluate true age changes, and how they might relate to late-life pathology and everyday functioning,” Salthouse said.

Salthouse also found that practice effects played a bigger role in younger than older adults, possibly because younger people learn better.

“Longitudinal comparisons in people of different ages may be even more complicated because the amount of longitudinal change may be partially determined by the individual’s learning ability at a given age,” he noted.

Salthouse is a fellow of the American Psychological Association and other scientific associations, and a past winner of the APA’s William James Award.

The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States and is the world’s largest association of psychologists. APA’s membership includes more than 152,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting health, education and human welfare

Frankly, I don’t know anyone (including me) that actually thinks they eat enough fruits and vegetables, but never mind that.  Produce nutrition is not what it used to be. Here are some fascinating produce nutrition facts:

• A team of researchers has tested 43 different fruits and vegetables from 1950 – 1999.  They discovered an alarming downward trend in nutritional value – Broccoli, for example, had 130 mg of calcium in 1950, but only has 48 mg. today.
• Synthetic fertilizers and selective breeding has decreased the produce ability to absorb nutrients from the soil.

Organic produce does not have this problem and in fact, organic tomatoes have been shown to have 30% more phytochemicals in them than conventional ones.

However, organic can be expensive and although it is still your best choice, here are other ways to increase the nutrients in your fruits and vegetables.

1.  Look for Strong Colors – for example, red leaf lettuce has more nutrients than iceberg. Darker orange carrots have more phytochemicals.

2. Smaller is Better – if the produce is smaller, then its level of nutrients will be more concentrated.  So those big tomatoes may not be more nutritious.

3. Cook Them Less – however, some fruits and vegetables release more nutrients when they are cooked. Broccoli and carrots are better steamed than boiled and tomatoes are better cooked than raw.

4. Eat Fruits and Vegetables Within a Week – If you keep them longer than week after you buy them, they’ll lose most of their nutritional value.

5. Skip the Pre-Done Bagged Produce – Peeling and cutting reduces the nutrients – that should be done just before preparing.

6. Try Variety – we all tend to buy the same types of produce, but if you mix them up, you’ll be getting more (and different) nutrients.  Example: try the purple cauliflower or the heirloom tomatoes.

7. Try Older Varieties – Speaking of Heirloom tomatoes, there are also older varieties of other vegetables, too. Plants that were bred prior to World War II are naturally hardier because they were established—and thrived—before the development of modern fertilizers and pesticides. They may be more difficult to find, which brings us to our next step:

8. Find a Farmer’s Market – Any local, freshly harvested, in-season fare is bound to have more nutrients than supermarket produce which has to be picked before it’s ripe.