Brain training games have kept human minds sharp for centuries and they can also keep dogs switched on in old age, research shows.

Like us, dogs' brains can be kept sharper for longer if they play specially designed computer games.

Dog owners often become more forgiving of their pets' disobedience and stubbornness as they grow old, which can actually speed mental slowdown.

But a study revealed challenging pooches with specially developed touch-screen games, including a 'dog sudoku', exercises their minds and slows brain ageing.