They didn’t have brain injury. So concluded the recent National Institutes of Health clinical and brain imaging studies of about 80 individuals reporting “anomalous health incidents” (AHIs)—a variety of unexplained symptoms experienced by U.S. officials in the diplomatic and intelligence services that have created alarm and puzzlement since they were first reported in Havana in late 2016. The subjects reported diverse and nonspecific symptoms such as imbalance, migraine, “brain fog” and fatigue.
Less discussed is that nearly a third fulfilled diagnostic criteria for a condition called persistent postural perceptual dizziness (PPPD). PPPD is a disorder related to abnormal brain function that can be triggered by any cause of dizziness or vertigo, and, like other subtypes of functional neurological disorder, can’t be seen with conventional tests. This condition gives us some unexamined clues about “Havana syndrome.”
Presently, two competing narratives have emerged about this syndrome, both powerfully argued by experts. One holds the reported AHI events result from “mass psychogenic illness,” sometimes called mass hysteria, where real symptoms spread in psychosomatic fashion in closed social settings. The other is that real attacks have taken place, most likely by pulsed microwaves causing brain damage.
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Consider the first mass psychogenic illness explanation, proposed by medical sociologist Robert Bartholomew of the University of Auckland and neurologist Robert W. Baloh of the University of California, Los Angeles, based on publicly available information about the incidents. They describe how one embassy employee had been frightened by a loud Cuban cricket, and (quoting former CIA agent Fulton Armstrong) “was lobbying, if not coercing, people to report symptoms,” triggering an epidemic of health complaints throughout the government.
The second view, that deliberate attacks caused brain damage, was reported widely since the problem was first reported. The syndrome was even described as an ‘immaculate concussion’ by the authors of the first studies from the University of Pennsylvania in 2018. Hundreds of people have come forward reporting AHIs since then. Given the lack of clear diagnostic criteria and the common nature of the symptoms described, it is likely that many individuals were included with other medical conditions including migraine, vestibular disorders and anxiety that have been reattributed to “Havana Syndrome.”
There is, however, a plausible relation between pulsed microwave exposure and PPPD that doesn’t involve brain damage: The microwave auditory effect (also called the Frey effect) occurs when pulsed radiofrequency energy directed to the head causes a tiny temperature rise in the skull and brain, which in turn creates a pressure wave that propagates through the head, leading to an unusual audiovestibular sensation that is perceived as sound. One of us who studied this as long ago as the 1970s is on record as saying that the effect is too weak under foreseeable exposure conditions to cause brain damage. However, calculations show that it should be possible to beam strong enough pulses of microwaves, millimeter waves or laser energy to disturb the vestibular system at levels anticipated to produce symptoms similar to those initially reported from AHIs. While these vestibular and auditory experiences would be expected to be short-lived, they would be enough, as an unexpected or unpleasant experience of dizziness, to trigger PPPD of much longer duration. This would also explain why many individuals experienced worsening symptoms over time, as commonly seen in PPPD, rather than improvement as would be expected after a brain injury
A 2020 National Academies of the Sciences, Engineering and Medicine report described what must have been intensely unpleasant experiences for various individuals. Many had an unusual directional component to the experience with “sudden onset of a perceived loud sound, sometimes described as screeching, chirping, clicking, or piercing, a sensation of intense pressure or vibration in the head, and pain in the ear or more diffusely in the head”.
High-powered microwave or millimeter wave transmitters presently exist that, in principle, should be able to produce such effects but would be readily discoverable. Millimeter waves would be less easily detected than microwaves, which have been the focus of most conversation so far, because of their lesser ability to cause electromagnetic interference with other devices and smaller equipment size. To establish that microwaves or other forms of energy were involved in the AHIs requires forensic evidence such as detection of transmissions, a device or intercepted communications, none of which are currently available to the public. However this is clearly a sensitive topic for the government, which has redacted large sections about microwaves from its several reports on AHIs released to the public. A two-part story in the news program 60 Minutes alleged that some AHIs were result of attacks by a special unit of Russian military intelligence.
Whatever the cause or causes of AHIs may be, there is reason to be concerned about directed energy weapons being used in nonmilitary settings. Russia, China and the U.S. are all thought to have large programs to develop directed energy weapons using high-powered (gigawatt) microwave and laser technology. Their obvious military uses include shooting down drones.
Quite likely some energy weapon programs are developing antipersonnel weapons as well. In 2014, prominent Russian microwave engineers suggested using pulsed microwaves and the Frey effect to attack and cause confusion in Russia’s adversaries. China is known to be developing weapons for “neurostrike,” some of which involve high-powered microwaves. There is a dearth of studies involving possible health effects of high-peak-power microwave pulses, which are likely to be quite different from the comparatively well-studied pulsed microwaves at much lower peak power levels. Such studies are clearly needed, and they should be published in a way that is accessible to experts outside of government.
We need to move away from simplistic arguments of “brain damage” versus “mass hysteria” that have characterized much of the reporting. Pathophysiological events, including pulsed energy attacks, could trigger genuine illnesses involving a disturbance of brain function, like PPPD, even where there is no brain damage.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.