Former Montana Sen. Conrad Burns (R) has been upgraded from critical to serious condition following a stroke he suffered last week.

His status was upgraded Monday morning, according to a spokeswoman for Georgetown University Hospital, where Burns has been hospitalized since Wednesday. A key difference between the two conditions is that critical usually means the person is not breathing on his or her own, said the spokeswoman.

Burns, 74, was found “disoriented— by his wife Wednesday night at his computer in their home in Arlington, Va. He served in the Senate from 1989 to 2007.