So far the people who participated in experiments by having electrodes surgically placed on the surfaces of their brains were only able to make letters appear by thinking about them, but eventually, with tiny computers implanted in their heads, people with various disabilities may be able to control things like artificial legs and hands.
The idea of having computers implanted in human brains sounds a bit scary, especially for those of us who read and watch Sci-Fi, but people with special needs probably consider becoming able to walk and use their hands again well worth the risk that someday bad guys will be able to control the human race with similar contraptions. ;-)
In fact many prosthetic devices currently in use would have been considered science fiction a few decades ago. We live in amazing times and I hope it will only take a few years for those Florida researchers to develop instruments that will make life much easier for thousands of people.
If you would like to read more about their study, here's a link to the story: