On Thursday afternoon, doctors told reporters that Wermbier was in 'a state of unresponsive wakefulness'.
North Korean officials claimed Warmbier fell into a coma in March a year ago due to botulism and a sleeping pill. She says Yun traveled with the doctors to North Korea on a private aircraft after being instructed by President Donald Trump to travel there to negotiate Warmbier's release.
"Joseph Yun went to Pyongyang to accompany Mr Warmbier home", Thomas Shannon, US Under Secretary of State for Political Affairs, told reporters in Seoul Wednesday.
Kanter said that while Warmbier has spontaneous moments of eye opening, he has not spoken or made any purposeful movements.
North Korean doctors had provided copies of brain scans dated to April 2016, consistent with the claim that he had been in a coma for more than a year. Otto's father, Fred Warmbier, gave a televised statement to the press on June 15, 2017.
"What did I say to my son?"
"There is no excuse for any civilized nation to have kept his condition secret and denied him top-notch medical care for so long".
"The burden of our ordeal has been eased by the support we have experienced, not only from our friends in Cincinnati, but through OH, at the University of Virginia, throughout the United States and, indeed, from around the world", Warmbier said.
Fred Warmbier said the family was only told a week ago that Otto Warmbier has been in a coma for the previous year.
The 22-year-old University of Virginia student was medically evacuated from North Korea and arrived in Cincinnati late Tuesday.
Otto Warmbier, 22, returned to OH on Tuesday after being detained and imprisoned for 18 months in North Korea.
He was given a 15-year prison sentence for attempting to steal a propaganda sign from a hotel.
Upon his release, Otto's parents said that they did not know he was in a coma until the week prior. The Telegraph reports he also accused the Chinese tour company that brought Otto into North Korea of "luring" Americans.
Richardson called on North Korean leaders to "Explain why you did not disclose to the United States or to the Swedish government, the state of his (Warmbier's) condition and then immediately release the three Americans being held".
The cause of Warmbier's condition remains uncertain.
"The results speak for themselves", he said in a news conference, adding that President Trump, by contrast, reached out to him personally.