A stunning exposé has revived speculation that 'Havana syndrome,' the mystery ailment plaguing US diplomats and spies, might be the work of covert Russian tech.

Russian intelligence Unit 29155, reputedly tasked with 'subversion, sabotage and assassination' programs against the West, may be responsible for the eerie and still as-yet-unexplained health incidents, according to a joint-investigative report.

For years, the alleged deployment of secret, directed-energy weapons against US officials has been linked to migraines, nausea, memory lapses, hearing loss, poor balance and dizziness — and now more vivid symptoms have come to light.

One FBI counterintelligence agent tasked with tracking Russian spies domestically described her purported brush with the covert weapon as feeling like 'a dentist drilling on steroids.'

The encounter left her with memory issues, trouble multitasking and chest pains, she said, and at one point the alleged energy weapon knocked her unconscious.

'My baseline changed,' as she told 60 Minutes. 'I was not the same person.'

Retired Army lieutenant colonel Greg Edgreen (above), who led a Pentagon investigation into Havana syndrome incidents, told 60 Minutes that he's 'confident' Russia is behind the attacks

'There's no environmental cause that causes the body damage that I saw,' an anonymous PhD source told DailyMail.com last year. 'I don't know how you create damage inside of a body, like what was seen, that comes on all of a sudden, and could be called 'pre-existing conditions''

CBS's 60 Minutes, German magazine Der Spiegel and a Latvian journalism outfit called The Insider pooled their reporting for the new investigative collaboration.

Their marquee scoop rests on explosive findings from The Insider's Christo Grozev that Russia's secretive Unit 29155 was 'rewarded for successfully testing "non-lethal acoustic weapons"' on American civil servants and spies.

But the team's bombshells have also revealed new case studies, expanding public understanding of what 'Havana syndrome' might be and how it impacts the body.

One US government employee affected, the CIA's former deputy chief of operations in Europe and Eurasia, Marc Polymeropoulos, told Der Spiegel that he had first confused his symptoms with 'food poisoning' six years ago.

But, when the painful 'attack' came again just a few days later, Polymeropoulos realized it had to be something else.

The ex-deputy CIA chief told the German magazine that it has felt like 'a vice on my skull' and that his vision has gotten so bad at times that he couldn't even drive a car.

'We were portrayed,' Polymeropoulos said about himself and the dozens of other US government employees who have suffered from Havana syndrome, 'as people who had fallen victim to mass hysteria.'

Above, an old American car passes by the US Embassy in Havana on December 17, 2015

One Georgetown neurologist told DailyMail.com that his own 2017 and 2018 analysis of Havana Syndrome patients for US Special Operations Command, found lasting problems in patients' brain function but not to their brain structure — similar to so-called 'mini-strokes'

This March, a government study tracking over 80 self-reported victims of 'Havana Syndrome' found no signs of brain injury — despite also identifying 'real symptoms' of the mystery ailment that researchers called 'quite profound' and 'disabling.'

As one Georgetown neurologist, Dr. James Giordano, who conducted early research into the syndrome for the Pentagon's Special Operations Command, told DailyMail.com, this absence should not be taken as evidence of 'mass hysteria.'

Dr. Giordano, who teaches neurology at the Georgetown University Medical Center in Washington DC, said the findings published last month risk creating 'a false conclusion that nothing happened to these people's brains.' 

That study, published last month by the Journal of the American Medical Association (JAMA), performed MRI scans on 81 out of 86 State Dept employees and their adult family members who reported 'anomalous health incidents (AHIs).'

The research team, part of the National Institutes of Health (NIH) in Maryland, weighed the results of these MRIs against the MRIs of 48 control participants.

Persistent dizziness and balance issues were among those real symptoms for 28 percent of the embassy officials and other patients studied, according to the report.

In a statement one year ago this March, Director of National Intelligence Avril Haines  said the 'symptoms reported by US personnel were probably the result of factors that did not involve a foreign adversary, such as preexisting conditions, conventional illnesses, and environmental factors'

'One of the considerations, here, was that if, in fact, these individuals were exposed to some form of electromagnetic and/or acoustic stimulus,' Dr. Giordano explained, 'the nature of the damage would be functional, rather than structural.'  

He described the new study as consistent with his own 2017 and 2018 analysis of Havana Syndrome patients for US Special Operations Command, which found lasting problems in patients' brain function but not to their brain structure — consequences similar to so-called 'mini-strokes' or transient ischemic attack cases.

'Let me be very definitive, we're not talking about a functional neurological disorder, which is a psychosomatic disorder,' Dr. Giordano told DailyMail.com.

'We're talking about a disruption of neurological function, that then created a host of effects, including downstream physiological effects that manifested themselves cognitively, motorically, and behaviorally.'

Unlike the 'mass hysteria' explanation that has plagued the State Department's self-reported victims of Havana Syndrome, the neurologist likened the findings to a variety of other long-term brain conditions where physical evidence of the damage quickly dissipates. 

For its part, Russia has previously denied any involvement and dismissed the allegations as 'groundless' today. Above, Russia's President Vladimir Putin chairs a meeting with members of his Security Council via video link in Moscow on March 29, 2024

After US officials and embassy staff reported hundreds of cases in nearly 70 countries, new reports of Havana syndrome declined sharply starting in early 2022. But the mystery of what caused the ailments and the alarm remains. (Above a timeline map of key incidents)

EXCLUSIVEREAD MORE: NIH study finds Havana Syndrome victims' symptoms are 'real' and 'quite profound' - injuries are much like a 'mini stroke,' one Pentagon medical consultant tells DailyMail.com

A new study by the National Institutes of Health tracked over 80 self-reported victims of 'Havana Syndrome' - finding no signs of brain injury on MRI despite identifying 'real symptoms' of the mystery ailment that they called 'quite profound' and 'disabling.' But one Georgetown neurologist, who conducted early research into the syndrome for the Pentagon's Special Operations Command, tells DailyMail.com that the NIH's new findings risk creating 'a false conclusion that nothing happened to these people's brains' 

'Sometimes when there's a mini stroke,' Dr. Giordano said, 'it very often does not produce what is a structurally evident artifact [in the brain] that is durable.' 

'You may see some initial changes during the TIA [transient ischemic attack] in evolution,' he added, 'but with time those are resolved.'

Cases of 'decompression sickness,' or the bends, he noted, have also manifested like mini-strokes or Havana syndrome, delivering long-lasting impairments to brain function that were not paired with visible forms of lasting brain damage. 

For its part, Russia has previously denied any involvement and dismissed the allegations as 'groundless' today.

'This topic has been talked up in the press for many years already. And from the very beginning most often it's linked to the Russian side,' Kremlin spokesman Dmitry Peskov told a news conference.

But retired Army lieutenant colonel Greg Edgreen, who led the Pentagon investigation into the Havana syndrome incidents, told 60 Minutes that he is 'confident' that Russia is behind the attacks and that acknowledging the potential use of sonic weapons would bring up security questions.

Lt. Col. Edgreen said the burden of proof under both the Trump and Biden administration was set impossibly high, explaining: 'I think it was set so high because we did not, as a country, and a government, want to face some very hard truths...' 

'Can we secure America? Are these massive counter intelligence failures? Can we protect American soil and our people on American soil? Are we being attacked and if we're being attacked, is that an act of war?'

Lt. Col. Edgreen also claimed that the attacks are part of a worldwide mission by Russia targeting US officials to 'neutralize' them.