Noland Arbaugh received the implant in January, but things didn't go to plan. Weeks after the procedure, some of the device's wires pulled away from his brain.

A Reuters report said Neuralink knew the wires could retract from its device after it carried out tests on animals. Neuralink decided the device didn't need to be reconfigured as it believed the risk of the wires retracting was low.

Elon Musk's company carried out experiments on animals, including monkeys, before it got approval last May from the US Food and Drug Administration to conduct human trials. It's starting by testing the implant, called "The Link," on people with paralysis to enable them to control devices using their thoughts.

The Link has more than 1,000 electrodes and at least 64 wires each thinner than a strand of human hair, some of which pulled out of position.

That caused the impact to be less effective, which resulted in a weaker control of Arbaugh's ability to move a cursor around a computer screen.