According to the AP:

U.S. Chief Justice John Roberts, the senior judge in the United States, was reported alert and fully recovered from a seizure and fall at his seaside summer home, in which he experienced minor scrapes but no serious injuries.

Supreme Court spokeswoman Kathy Arberg said Monday that Roberts, 52, would remain overnight in a hospital in the northeasternmost U.S. state, Maine. "It's my understanding he's fully recovered," said Christopher Burke, a spokesman for Penobscot Bay Medical Center, where Roberts was taken. . . .

Roberts was taken by ambulance to the medical center, where he underwent a «thorough neurological evaluation, which revealed no cause for concern,» Arberg said in a statement.

Roberts had a similar episode in 1993, she said.

Doctors called Monday's incident «a benign idiopathic seizure,» Arberg said. The White House described the January 1993 episode as an «isolated, idiosyncratic seizure. A benign seizure means that doctors performed an MRI and other tests to conclude there was no tumor, stroke or other explanation.

In addition, doctors quickly would have ruled out simple explanations such as dehydration or low blood sugar.

By definition, someone who has had more than one seizure without any other cause is determined to have epilepsy, said Dr. Marc Schlosberg, a neurologist at Washington Hospital Center, who is not involved in the Roberts case.

Whether Roberts will need anti-seizure medications to prevent another is something he and his doctor will have to decide.

But after two seizures, the likelihood of another at some point is greater than 60 percent.

"When it's going to occur, obviously nobody knows," Schlosberg said.

The incident occurred in midafternoon on a dock near Roberts' home in Port Clyde on Maine's Hupper Island. Port Clyde, which is part of the town of St. George, is about 90 miles by car northeast of Portland, midway up Maine's Atlantic coast.

Roberts was taken by private boat to the mainland, then transferred to an ambulance, St. George Fire Chief Tim Polky said.

"He was conscious and alert when they put him in the rescue (vehicle)," Polky said. . . .

Larry Robbins, a Washington attorney who worked with Roberts at the Justice Department in 1993, said he drove Roberts to work for several months after Roberts' seizure. Robbins said Roberts never mentioned what the problem was, and he never heard of it happening again. . . .

UPDATE: Interesting perspective from Ace of Spades.