ROME — His grueling schedule complete, a visibly exhausted Pope John Paul II returned here tonight from a trip to Slovakia that demonstrated his desire to continue traveling but sowed fresh doubts about whether he could.
Over four days and across three regions in Slovakia, his appearances provided the most vivid examples yet of the heavy toll that Parkinson's disease has taken on him.
Some Vatican officials said privately that they wondered if the trip might signal a turning point of sorts for John Paul, 83, whose frequent journeys around the globe have defined his papacy.
In Slovakia, his 102nd foreign trip as pope, he struggled through his events, unable to support himself physically without help and often unable to squeeze his words out. In striking contrast to his performances during other trips in the last year, he did not once deliver all or even the bulk of a planned sermon, turning parts of it over to someone else to read. He did not try, at least in public, to stand or walk.
But he did not substantially abbreviate his itinerary, and simply by appearing this morning before tens of thousands of worshipers at an outdoor Mass in the Slovak capital, Bratislava, he was able to have an effect on them. He proclaimed a blessing to "the beloved Slovak people," and they erupted in a mighty roar.
The Vatican has not confirmed any more foreign trips for the pope.
During the visit to Slovakia, the pope's spokesman, Dr. Joaquín Navarro-Valls, found himself riddled by questions from reporters about whether it would be the pope's last journey outside Vatican City and Italy. Dr. Navarro-Valls predicted that the pope would press on, mentioning four other countries that had invited him to visit next year.
"Knowing the Holy Father, I think it's very difficult to say this will be the last trip of his pontificate," he told reporters at the Mass. "It's obvious there are some physical limitations there that everybody can see," he said, later adding, "Those physical limitations don't hamper in any way the way he performs his duties."
But Vatican officials have played down the extent of the pope's ailments in the past, and neither they nor the pope's physicians publicly discuss his medical treatment in detail. That dearth of information makes it impossible to assess the pope's condition.
Outside experts on Parkinson's disease, a degenerative neurological disorder, can judge the pope only from what they see on television. They say the disease has clearly progressed.
He can still live for many years, they say. But they say it is uncertain how much longer he can continue speaking in public and traveling.
"Certainly, there are patients who have had Parkinson's disease for 35 years," said Dr. Ole Isacson, a specialist in neuroscience at McLean Hospital near Boston. "But at some point, they're totally frozen."