Connecting a battery across the front of the head can boost verbal skills, says a team from the US National Institutes of Health.

A current of two thousandths of an ampere (a fraction of that needed to power a digital watch) applied for 20 minutes is enough to produce a significant improvement, according to data presented this week at the annual meeting of the Society for Neuroscience, held in San Diego. And apart from an itchy sensation around the scalp electrode, subjects in the trials reported no side-effects.