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, says a paper presented to the Society for Neuroscience.
Volunteers were asked to name as many words as possible beginning with a particular letter. Given 90 seconds, most people get around 20 words but after the current was administered