Brain training can boost memory and thinking skills but not when done alone at home, a study has found.

Computer-based "brain training" is useful for older adults, but only if it's conducted in a group setting, research suggests.

Brain training - computerised cognitive training - can boost memory and thinking skills in people aged over 60 years, according to the University of Sydney.

But many programs promoted by the $1 billion industry are ineffective.

To reach this conclusion, the researchers analysed more than 50 studies involving 5000 participants, comparing the results of those who undertook brain training in a group environment and at home.

"We found it was effective when supervised and not effective when done at home," says group leader Associate Professor Michael Valenzuela of the University of Sydney's Brain and Mind Research Institute.

"As for the underlying reason why that is, we don't have any definitive answers."

Prof Valenzuela believes one reason may be because people practice mainly what they are good at when working individually.

"We know it's really important to keep people's motivation up, and being supported by a trainer means they can make sure people are doing exercises that not only they are good at, but also on exercises they are weak."

The social interaction people experience when taking part in group brain training may also synergise with the actual training program, he says.

THE BEST WAY TO TRAIN YOUR BRAIN:
* Train in a group setting
* Training one to three times a week is effective, but training more than this neutralises any cognitive benefits
* Have at least one rest day between training sessions, as you would with strenuous physical exercise.

(Source: University of Sydney's Brain and Mind Research Institute)

Copyright AAP 2014.