The critically injured sole survivor of a West Virginia coal mine explosion has shown signs that his condition is improving, his attending physician said Sunday.

Randal McCloy Jr. has been in a medically induced coma since last week's underground blast to allow his brain time to heal.

"We had a chance to see Randy as of last night, throughout the night and this morning and we would consider his condition still critical," Dr. Larry Roberts told reporters at West Virginia University Hospital. "However, he has shown some signs of improvement."

McCloy, of Simpson, W.Va., was rescued early Wednesday after being trapped in the Sago Mine near Tallmansville, in north-central West Virginia, for about 42 hours. Twelve other men who were inside the mine with him died.

The 26-year-old survivor was transferred to Pittsburgh's Allegheny General Hospital on Thursday for treatment in a hyperbaric oxygen chamber, which forces pressurized oxygen into the body to treat carbon monoxide poisoning.

The physicians in Pittsburgh "took fantastic care of Randy," Roberts said.

On Saturday night, still heavily sedated, McCloy was flown back to West Virginia University's Ruby Memorial Hospital in Morgantown.

McCloy's wife, Anna, also spoke to reporters.

"Our family's thoughts this morning continue to be with Randy's coworkers and their families. We are thinking of them today and throughout this difficult time and we ask you to please keep all the families in your thoughts and prayers," she said.