The implant has been developed at the University of Southern California and Wake Forest Baptist Medical Centre over a decade.
The project is funded by the US military as a way of helping injured soldiers overcome memory loss.
An elderly woman undergoes testing for Alzheimer’s and memory loss
This isn’t something that people with dementia can expect to be readily available in the next decade
Dr Clare Walton, of the Alzheimer’s Society, said: “A prosthetic memory device is a very exciting prospect, but it has taken decades of research to get this far and there are still many unknowns that need to be worked out by the scientists.
Brain scans of a patient with Alzheimers show the damaged areas of the brain
Alzheimer’s causes the brain to degenerate and the damage interferes with the formation of new long-term memories while old ones survive.
The new US technology has already been tested on nine people with epilepsy who had electrodes implanted in their brains to treat chronic seizures.
Researchers read the electrical signals created in the patients’ brains as they conducted simple tasks.
News of the breakthrough will by welcomed by families caring for relatives suffering with the diseas
The next step will be to send the translated signal back into the brain of a patient with damage to their hippocampus – the memory centre – in the hope that this will bypass the trouble spot and form accurate long-term memories.
It is the first time scientists anywhere in the world have used computers to manipulate memory signals directly in the human brain.
Researchers have previously implanted devices so paralysed people can move false arms and their own limbs.