PORTSMOUTH, VA—According to increasingly concerned campaign sources, Republican presidential candidate Mitt Romney entered his 400th consecutive hour of uneasy chuckling Monday, apparently stuck in an endless loop of discomfort and apprehension that so far has shown no sign of abating.

Staffers confirmed Romney’s interminable nervous laughter has prevented him from sleeping, eating, or speaking a word for the past 16 days, leaving him visibly fatigued and haggard. Yet the presumptive GOP nominee has maintained a full schedule of campaign appearances, reportedly attending fundraisers, headlining rallies, and sitting for televised interviews, all while emitting an unending stream of anxious chuckles.

“Mitt will chuckle for 10 to 12 seconds at a time, pause for a moment, and then start right over again from the top,” said campaign manager Matt Rhoades, who explained how the candidate will take the podium in front of veterans groups or high-profile donors and chuckle uncomfortably for his entire allotted speaking time. “You can tell by the desperation on his face and in his body language that he wants nothing more than to stop chuckling, but he can’t. He’s just trapped in this infinite loop.”

“Last night I put my ear to the door of his hotel room after he was in bed, and I could still hear him chuckling in there,” Rhoades continued. “Everyone’s really worried about him.”

Sources reported that the never-ending cycle of chuckling was triggered at a July 20 town hall event in Dayton, OH, when a local reporter asked the candidate to explain the differences between the individual health insurance mandate he approved as governor of Massachusetts and the one contained in the Affordable Care Act. In response, Romney is said to have broken into a series of tense, ill-at-ease chortles that, as of press time, has yet to cease.

“Sometimes his laughter will skip a beat or he’ll raise his arm up as if to gesture, and you’ll think he’s finally going to stop and say something,” Romney aide Ashley O’Connor said. “But then he’ll just shrug his shoulders a little and fall right back into the same endlessly repeating pattern of troubled laughter.”

“The saddest part is that he’s not even smiling when he laughs—his face is locked in this pained, wincing sort of expression,” O’Connor added. “You can see in his eyes that he’s really suffering.”

This is not the first time the former governor has found himself stuck in a ceaseless cycle of discomfort. Many observers pointed to a December 2011 primary debate in which a silent, blinking Romney smiled blankly and stared straight ahead for the remainder of the broadcast after moderator Diane Sawyer pressed him on past statements he made in support of a woman’s right to choose. Others noted an incident last month when Romney responded to allegations he might be sheltering money in offshore accounts by continuously repeating the phrase “I don’t believe I have anything to hide” for three straight days in a tone of forced astonishment and indignation.

Many pundits, however, have argued that the duration and severity of the ongoing chuckling spell are particularly troubling, warning that the candidate’s condition bodes poorly for the future.

“Romney has faced a lot of pressure during this campaign, but it’s nothing compared to what he’ll have to deal with if he’s elected president,” said political analyst William Schneider of George Mason University. “Imagine him having to appear relatable in front of the media for four straight years, or having to meet one-on-one with hundreds of grieving victims of a tragic shooting or natural disaster. What will happen when he’s directly and repeatedly confronted about his contradictory views on immigration, gun control, or same-sex unions? It could be disastrous. We could easily see Mitt Romney chuckling uncomfortably throughout his entire term.”

At press time, Romney staffers confirmed the candidate was staring solemnly out the window of his campaign bus, chuckling softly to himself as a pair of tears made their way down his cheeks.