Billionaire entrepreneur Elon Musk's brain-chip startup Neuralink said on Tuesday it has received approval from an independent review board to begin recruitment for the first human trial of its brain implant for paralysis patients.

Those with paralysis due to cervical spinal cord injury or amyotrophic lateral sclerosis may qualify for the study, it said, but did not reveal how many participants would be enrolled in the trial, which will take about six years to complete.

The study will use a robot to surgically place a brain-computer interface (BCI) implant in a region of the brain that controls the intention to move, Neuralink said, adding that its initial goal is to enable people to control a computer cursor or keyboard using their thoughts alone.

The company, which had earlier hoped to receive approval to implant its device in 10 patients, was negotiating a lower number of patients with the U.S. Food and Drug Administration (FDA) after the agency raised safety concerns, according to current and former employees. It is not known how many patients the FDA ultimately approved.

Musk has grand ambitions for Neuralink, saying it would facilitate speedy surgical insertions of its chip devices to treat conditions like obesity, autism, depression and schizophrenia.

In May, the company said it had received clearance from the FDA for its first-in-human clinical trial, when it was already under federal scrutiny for its handling of animal testing.

Even if the BCI device proves to be safe for human use, it would still potentially take more than a decade for the startup to secure commercial use clearance for it, according to experts.