Some designs beam energy to a receiving coil in an implanted device, and others use an external pacemaker that wirelessly stimulates an electrode implanted in the heart.Another possibility is to scavenge energy from the natural processes occurring in the patient's body.
"I am afraid we get quite a lot of complaints from members of the public who say, for example, 'When I was 14, I had my tonsils removed and I believe that MI5 implanted electronic equipment in me.' "Very often the sign is whether they are resident in a mental institution.
The couple wound up with three embryos, implanted two and had a boy.
"But at the end of the day I always come back to, 'Well we just need to try it because I don't know if I can live with all the other decisions and options.'" So some time early next year, they've agreed, the final embryo will be implanted.
A diabetic, Di Stéfano underwent a quadruple aorta-coronary bypass with a pacemaker implanted in December 2005 after suffering a myocardial infarction.
But is it really possible, as the Felsteads insist, for a person to have memories "implanted" by a therapist?
The former prime minister John Howard has been discharged from a Sydney hospital after having two stents implanted.
Chances are that, when you woke up this morning, you realised you'd been suddenly implanted into a hellishly bleak post-apocalyptic dystopia.
Enter the Catalan-based Neil Harbisson, who, having been born unable to see colours, has been implanted with a device to "hear" them.
The doctors then implanted three, one of which resulted in a viable pregnancy.
In the past year, we've also had Joss Whedon's enjoyable TV series Dollhouse, in which secret agents are wiped clean of their memories and personalities, so as to be implanted with new, temporary ones.
