WASHINGTON - Chief Justice John Roberts suffered a seizure at his summer home in Maine on Monday, causing a fall that resulted in minor scrapes, Supreme Court spokeswoman Kathy Arberg said.

Supreme Court Chief Justice John Roberts smiles as he is introduced before speaking to students and faculty at the Northwestern University School of Law Thursday, Feb. 1, 2007 in Chicago. [AP]

He will remain in a hospital in Maine overnight.

"It's my understanding he's fully recovered, said Christopher Burke, a spokesman for Penobscot Bay Medical Center, where Roberts was taken.

Roberts, 52, 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 would have quickly 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 around 2 p.m. EDT on a dock near the 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 the coast of Maine.

Roberts was taken by private boat to the mainland and 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.

Named to the court by President Bush in 2005, Roberts is the youngest justice on a court in which the senior member, John Paul Stevens, is 87. Bush was informed of the hospitalization by his chief of staff, Josh Bolten, the White House said.

Roberts is the father of two young children.

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 the incident. Robbins said Roberts never mentioned what the problem was and he never heard of it happening again.

In 2001, Roberts described his health as "excellent," according to Senate Judiciary Committee records.

Roberts became chief justice after the death of William Rehnquist in September 2005, although Bush had first chosen him to take Sandra Day O'Connor's seat when she announced her retirement earlier that year.

He had served as an appellate judge in Washington and spent more than a decade before that as a lawyer at the Hogan and Hartson law firm, where he specialized in arguing cases before the Supreme Court.

Roberts also served in the Reagan and Bush administrations in the 1980s and '90s. He was a clerk for Rehnquist after graduating from Harvard Law School.

Roberts spent a couple of weeks in Europe in July, teaching a course in Vienna and attending a conference in Paris. He was at the court in Washington late last week.