An intelligence panel investigating the cause of a spate of mysterious incidents that have struck dozens of US officials across the globe has said that some of the episodes could "plausibly" have been caused by "pulsed electromagnetic energy" emitted by an external source, according to an executive summary of the panel"s findings released Wednesday. But the panel stopped short of making a definitive determination, saying only that both electromagnetic energy and, in limited circumstances, ultrasound could explain the key symptoms -- highlighting the degree to which the murky illness known colloquially as "Havana Syndrome" has remained one of the intelligence community"s most stubborn mysteries. "We"ve learned a lot," an intelligence official familiar with the panel"s work told reporters, speaking on anonymity under terms set by the Office of the Director of National Intelligence. "While we don"t have the specific mechanism for each case, what we do know is if you report quickly and promptly get medical care, most people are getting well." The finding largely confirms a National Academies of Science report from late 2020 that found "directed, pulsed radio frequency energy" to be "the most plausible mechanism in explaining these cases" -- but also stopped short of making a firm determination. The so-called experts panel is made up of medical, scientific and engineering specialists who have access to classified information about the incidents. Officials emphasized that its work was focused only on uncovering the potential mechanism behind what the government calls "anomalous health incidents" and did not examine who, if anyone, might be responsible. An interim report issued last month by a separate CIA task force examining who might be behind the episodes found that it was unlikely Russia or any other foreign adversary is conducting a widespread global campaign designed to harm US officials. But the agency also did not rule out that a nation state -- including Russia -- might be responsible for roughly two dozen cases that investigators have been unable to explain by any other known cause. The scientific panel emphasized that the cases it studied were "genuine and compelling," noting that some incidents have affected multiple people in the same space and clinical samples from a few victims have shown signs of "cellular injury to the nervous system." An executive summary of the panel"s work provided new details about how the government is categorizing cases as possible Havana Syndrome, a clinically vague illness that has long frustrated firm diagnosis because victims have suffered from such a diverse array of symptoms. Although officials declined to say how many cases the panel examined as part of its inquiry, they said they studied cases that met four "core characteristics": the acute onset of sounds or pressure, sometimes in only one ear or on one side of the head; simultaneous symptoms of vertigo, loss of balance and ear pain; "a strong sense of locality or directionality"; and the absence of any known environmental or medical conditions that could have caused the other symptoms. Victims have reported being struck by this confluence of symptoms in embassies and personal residences around the globe, and in at least one instance, at open-air stoplight in a foreign country. Both pulsed electromagnetic energy, "particularly in the radiofrequency range," and ultrasonic arrays could feasibly cause the four core symptoms, the panel found. Both could originate from "a concealable source." But ultrasound can"t travel through walls, the panel found, "restricting its applicability to scenarios in which the source is near the target." Sources of radiofrequency energy, on the other hand, are known to exist, "could generate the required stimulus, are concealable, and have moderate power requirements," the panel said. "Using nonstandard antennas and techniques, the signals could be propagated with low loss through air for tens to hundreds of meters, and with some loss, through most building materials." But intelligence officials familiar with the panel"s work emphasized that important information gaps remained, forestalling them from reaching firmer conclusions. "It"s frustrating but we"re just as persistent to help understand and elucidate what"s happening," one official said. Part of the challenge, this person said, is that the cases not only vary, but the combination of the four core characteristics is unique in medical literature. "When we focus on the core characteristics, it"s just a unique combination that we don"t have a lot of experience with in the medical and clinical fields," the official said. And for ethical reasons, there is limited study of the impact of radiofrequency energy or ultrasound on the human body. The experts panel was limited to the accounts of people who had been exposed to either "inadvertently" and were willing to describe their symptoms. "There is a dearth of systematic research on the effects of the relevant electromagnetic signals on humans," the executive summary of the report stated. In a victory for victims" advocates, the experts panel also ruled out one cause for those four characteristics: so-called psycho-social factors. Some victims have long complained that the CIA in the past had failed to take their reported symptoms seriously, brushing the cases aside as a psychosomatic episode or mass hysteria. Those four core characteristics could not by explained by psycho-social factors "alone," the report found -- although an intelligence official explained that in some cases, a victim"s symptoms might be "compounded" by a stress reaction or other psycho-social response. The panel also ruled out "ionizing radiation, chemical and biological agents, infrasound, audible sound, ultrasound propagated over large distances, and bulk heating from electromagnetic energy." The panel made seven recommendations, including developing better biomarkers that are "more specific and more sensitive for diagnosis and triage" of cases. It also recommended utilizing "detectors" and obtaining "devices to aid research." Details on those recommendations were heavily redacted in the panel"s executive summary. Finally, officials urged swift action by medical officials whenever a case is reported, emphasizing that individuals who have been treated immediately after an event have improved. "I think something the employee can do to help themselves is promptly report and get medical care," the intelligence official said. Officials stressed that the intelligence community will continue to investigate. "We continue to pursue complementary efforts to get to the bottom of Anomalous Health Incidents — and to deliver access to world-class care for those affected," Director for National Intelligence Avril Haines and CIA Director Bill Burns said in a joint statement. "We are making progress in both areas." — CNN