The National Institute of Health (NIH) found no evidence of brain injury or biological abnormalities among federal employees experiencing symptoms related to what has become widely known as “Havana syndrome,” according to two studies published Monday.
The studies, published in JAMA, are a result of a nearly five-year probe by the NIH seeking to evaluate differences between a healthy control group and federal employees who experienced symptoms associated with what the U.S. government now describes as anomalous health incidents (AHIs).
These symptoms — which include head pressure followed by headache, dizziness, cognitive dysfunction, and others — were first reported in 2016 by government employees stationed in Cuba, leading the phenomenon to be dubbed Havana syndrome.
Many U.S. officials and lawmakers initially posited that the health ailments, which doctors and experts found difficult to diagnose, could stem from an attack by a foreign adversary. While many of the symptoms still are not easily explained, the U.S. intelligence community concluded last March that the health incidents were unlikely to be the result of interference by a foreign government.
The studies released Monday did not seek to determine the cause of the AHIs, NIH researchers said. The goal was to conduct evaluations to try to identify structural brain differences in those who reported AHIs.
One of the studies released Monday analyzed MRIs of 81 participants with AHIs and of 48 control participants, and it found “no significant MRI-detectable evidence of brain injury” among the group of participants reporting AHIs.
There also were “no significant differences in imaging measures of brain structure or function” between the two groups, according to the study.
“Our goal was to conduct thorough, objective and reproducible evaluations to see if we could identify structural brain or biological differences in people who reported AHIs,” the lead author on one of the papers, Leighton Chan, said in a statement. Chan is chief of rehabilitation medicine and acting chief scientific officer at the NIH Clinical Center.
A second study measured 86 participants reporting AHIs and 30 “vocationally matched control participants” and found that most biological tests — measuring auditory, vestibular, cognitive, visual function, and blood biomarkers — found “no significant differences” between the two groups.
In the second study, however, researchers concluded that the participants with AHIs performed significantly worse on self-reported and objective measures related to balance, symptoms of fatigue, post-traumatic stress disorder and depression.
About 28 percent of participants reporting AHIs “presented with functional neurological disorders.”
“While we did not identify significant differences in participants with AHIs, it’s important to acknowledge that these symptoms are very real, cause significant disruption in the lives of those affected and can be quite prolonged, disabling and difficult to treat,” Chan said in the statement.
Carlo Pierpaoli, lead author on the neuroimaging study, said while there is no evidence of brain injury on the MRIs, it is still possible that those reporting AHIs “may be experiencing the results of an event that led to their symptoms, but the injury did not produce the long-term neuroimaging changes that are typically observed after severe trauma or stroke.”
“A lack of evidence for an MRI-detectable difference between individuals with AHIs and controls does not exclude that an adverse event impacting the brain occurred at the time of the AHI,” said Pierpaoli, senior investigator and chief of the NIH’s Laboratory on Quantitative Medical Imaging at the National Institute of Biomedical Imaging and Bioengineering.
Mark Zaid — an attorney representing “AHIs victims from CIA, State, DIA, Commerce, USAID, FBI and NSA, as well as whistleblowers from within the USG” — echoed some of Pierpaoli’s sentiment, writing in a statement, “Of course, the absence of evidence is not evidence.”
Zaid added, however, that “these studies therefore do nothing to undermine the theory that a foreign adversary is harming US personnel and their families with a form of directed energy.”
Zaid stressed his concern that these studies provide fodder to detractors undermining the experiences reported by those with AHIs. He also raised “substantive and ethical concerns” with the way subjects were allegedly approached about participating in the study.
“The problem, however, is that the absence of conclusive proof is disingenuously relied upon by the Intelligence Community and naysayers to support their public assertion that AHI does not exist,” Zaid wrote. “The government is knowingly weaponizing the lack of science that exists in this area and intentionally hiding behind.”
An NIH spokesperson responded to Zaid’s concerns in a statement to The Hill, saying, “We understand that some patients may be disappointed that researchers were unable to identify clear markers of injury.”
The spokesperson stressed that the researchers were not focused on determining the cause of the symptoms. The studies focused narrowly on evaluating the structural brain and biological differences that “might explain their symptoms.”
At that point, the researchers did not look to identify an alternative explanation for the symptoms. The spokesperson also noted that researchers said explicitly that it is possible some physiological markers would no longer be detectible in patients.
In response to Zaid’s “substantive and ethical concerns” with the study, the spokesperson said, “NIH takes these allegations very seriously and will be reviewing the performance of the research in accordance with policy, which will determine next steps by the appropriate offices. Beyond this, we wouldn’t discuss a review.”
Story updated at 7:34 p.m.