New York, Mar 31 (IANS): Training memory with random and unpredictable methods can be an effective way in enhancing episodic memory and cut dementia risk, scientists, including an India-origin researcher, have found.

Episodic memories are those associated with autobiographical events such as a past birthday party or first trip to an amusement park. This type of memory is crucial to our ability to accurately retell stories.

The researchers tested episodic memory in 46 adults between the ages of 60 and 86 at three different stages: before memory training, immediately after training and one and a half months after completing the training.

Participants were separated into two groups -- predictable training or unpredictable training.

For both groups, sequences of digits in different colours were presented. The participants were asked to indicate when the colour of the current digit matched an earlier one of the same colour.

"Completing the task when the colour changes occur unpredictably requires more cognitive resources, or control," said Chandramallika Basak from University of Texas at Dallas.

In training that involved a predictable element, the changing colours occurred in a fixed order, whereas the colour switching was random in the training that involved unpredictability.

"When you have multiple items to remember, you need to focus your attention on what is most relevant and up-to-date, setting aside what may be distracting," Basak added in the paper published in the journal Frontiers in Psychology.

The two groups of participants demonstrated equivalent story recall before training, but the group given training with the unpredictable element was able to narrate a previously heard story more accurately than the other group.

"It seems that improving the efficiency of focusing attention to the target using unpredictable training strategy led to more accurate episodic memory," Bhaskar explained.

According to researchers, the findings could lead to better cognitive training for those at risk of dementia.