TUESDAY, Dec. 19 (HealthDay News) -- Healthy seniors who underwent "mental training" to boost memory, reasoning and mental processing were still reaping the rewards five years later.

In fact, these improvements in cognitive functioning more or less compensated for the amount of cognitive decline associated with normal aging, researchers say. It also helped preserve the participants' independence.

"It really shows that older adults, with these readily available cognitive training techniques, actually improve their perception of activities of daily living and improved on an objective measure as well," said Dr. Gary J. Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City. "It really does look like it helps older adults maintain independence."

The results were seen in healthy adults, so it remains to be seen if such interventions will have any effect on people who already have some type of cognitive impairment or even dementia.

"Prior research has said that some of our interventions don't work if a person already has the onset of dementia," said study co-author Michael Marsiske, associate professor and associate chair of clinical and health psychology at the University of Florida, Gainesville. "But perhaps this can serve as an impetus for the design of a next generation of interventions that could work in people with cognitive impairment. Rehabilitation for people with dementia is going to go a little bit more slowly, but there's a great deal of intent to let that be the next question," he added.

With some 24 million individuals worldwide suffering from dementia, not to mention cognitive losses from normal aging, such interventions will be sorely needed.

The decline in cognitive abilities which frequently accompanies aging can lead to more difficulty in performing instrumental activities of daily living, such as cooking, taking medication and managing finances. It's unclear if there is a way to ameliorate this.

Prior interventions have looked primarily at people who already had cognitive deficits or functional limitations, thus focusing on remediation rather than prevention.

The current trial is the first multicenter, randomized controlled trial to look at the long-term outcomes of cognitive interventions on the daily functioning of older adults still living independently.

The study, which appears in the Dec. 20 issue of the Journal of the American Medical Association, involved over 2,800 adults aged 65 to 96 who were living independently in six U.S. cities. More than one-quarter of the participants were African-American. Five-year follow-up data was available for two-thirds of the original sample.

Participants were divided into four groups: One received 10 sessions of training for memory, one an equal amount of training for reasoning; and the third training for speed of processing. They also got four-session booster training at 11 and 35 months.

A fourth group received no training and served as the control group.

When tested right after training, 87 percent of individuals in speed-training, 74 percent of those in reasoning-training and 26 percent of those in memory-training showed improvements.

After five years, individuals in all three intervention groups reported more ease in performing those instrumental activities of daily living than the control group, although the effect was only significant for the reasoning group.

The booster training had an effect on the speed-of-processing group but not on the other two groups.

The strength and durability of the results were surprising to the authors. "There's virtually nothing in the literature to give us grounds to expect this, except our own optimism," Marsiske said. "The durability of the effects really is unprecedented. There was also a much more diverse sample than any other cognitive research had allowed. We showed that the training worked well for a broad cross-section of people."

One of the take-away messages is that new learning is "very possible" in later life, he added.

"What would happen if we could incorporate this into people's lives more generally, so they could do it like physical exercise for longer periods of time?" Marsiske asked.

The interventions used in this study are already being developed so that they can be made more widely accessible, with the speed-of-processing intervention under development by a private company.