Researchers have found regular playing of the game can improve complex planning skills, critical thinking, reasoning and language. Tetris requires players to think quickly by slotting various-sized cascading blocks into homogenous shapes on the screen.

The study is one of the first to use MRI scanning technology to investigate the effects of game-playing on the brain. Tetris, played by millions of people on everything from mobiles to PCs, is celebrating the 25th anniversary of its release.

The three-month study, by the Mind Research Network, found adolescent girls who played Tetris not only displayed greater brain efficiency, but developed a thicker brain cortex, a sign of increased grey matter.

Clinical neuropsychologist Dr Rex Jung said one of the most surprising findings of brain research in the past five years was that juggling game play increased grey matter in the motor areas of the brain. Study co-author Dr Richard Haier said Tetris had proved useful for brain researchers.

"Tetris for the brain is quite complex," he said. "It requires many cognitive processes like attention, hand-eye co-ordination, memory and visual spatial problem solving all working together quickly.

"It's not surprising that we see changes throughout the brain."

The researchers plan to expand their study to determine whether the changes in the brain revert back to normal when people stop playing.