A brain exercise designed to help people improve memory also boosted their problem-solving abilities, scientists said in a study that may lead to techniques to improve learning and stave off brain illnesses.

Young adults who performed the exercise, a complex matching game of sounds and pictures, improved about twice as much on problem-solving tests as those who didn't participate, University of Michigan researchers said in the Proceedings of the National Academy of Sciences.

Problem-solving ability, sometimes called fluid intelligence, is one of the hardest brain functions to build with training, said Susanne Jaeggi, who led the study. High levels of fluid intelligence are prized because they are linked to success in the professional world, she said.

"Until now it was thought that this capacity was very fixed and that the brain didn't show much change after a certain age,'' she said today in a telephone interview. "It now looks as though it may be possible to boost fluid intelligence in young adults.''

About 4.5 million Americans have incurable, memory-robbing Alzheimer's disease. Companies including Kyoto-based Nintendo Co. and San Francisco-based Posit Science Corp. sell computer programs and games to help older people and soon-to-be-elderly baby boomers exercise their thinking ability. Such activities can help people use it, rather than lose it, said Andrew Carle, director of the program in senior housing administration at George Mason University in Fairfax, Virginia.

Mental Exercise

"Anything you can do to force your brain to work harder, just like physical exercise, can make your brain stronger,'' said Carle, who jokingly described his specialty, which involves working with grandmothers, as "Nana-technology.'' "If they've come across a technique that really challenges and drives people to push the limits of their cognitive skills to a new level, that could work.''

Jaeggi and her co-author Martin Buschkuehl put 34 graduate students at the University of Bern, Switzerland, through the demanding training. The students got two cues simultaneously. One was a visual pattern, the other a recorded voice saying a letter of the alphabet.

The subjects had three seconds to determine if either the pattern or the letter, or both, matched up with the second-to- last cue they'd heard. When they performed well, the bar rose: they had to match the current cue with the third-last, fourth- last, or fifth-last letter or pattern. When the subjects stumbled, the matching interval was decreased.

Memory, Problem-Solving

After eight days to 19 days of training, all of the students improved their ability to memorize a list of numbers. In addition, their scores improved by as much as 40 percent on standardized tests of problem solving that involve finding the right pattern to finish an incomplete drawing. On average, the trained students performed twice as well on problem-solving tests as 35 students who didn't participate in the memory exercises, the study said.

This is one of few examples of skill "transfer,'' where training in one area leads to improvement in another cognitive ability, Jaeggi said. That proves that the subjects aren't getting better at the test simply by practicing it, she said.

"It's a very exciting study,'' said Robert Wilson, a Rush University Medical Center neuropsychologist in Chicago who studies brain exercises for older people. "We can improve people's skill on a particular task, but most of the time that doesn't improve their performance on other tasks that are important for living in the world. They seem to have done that here.''

The study also suggests that one type of training might improve brain health broadly and efficiently, he said.

"For cognitive effect to have any practical relevance it has to transfer to other kinds of skills,'' he said. "You can't train for each and every kind of cognitive skill; it just isn't practical.''