Recent investigations into the enigmatic ‘Havana syndrome’ haven’t pinpointed a physical origin, yet they hint a potential mental health connection might exist.
Initiated by reports from over a thousand US government staff globally since 2016, these individuals have described hearing penetrative noises and experiencing head pressures, which then lead to severe headaches, vertigo, and cognitive impairments. This cluster of symptoms, first identified amongst federal workers in Havana, Cuba, has been commonly referred to as the ‘Havana syndrome’.
The National Institutes of Health (NIH) spearheaded US research efforts and have now disclosed that brain scans and other biological evaluations didn’t reveal notable disparities between Havana syndrome sufferers and healthy individuals.
Although these findings don’t shed much light on the biological underpinnings of the symptoms, the study’s authors stress that the results must be viewed through a multifaceted lens.
“Just because our MRI’s didn’t show a visible difference between those with AHIs and the controls, it doesn’t mean no brain event happened at the AHI time,” explained NIH neuroscientist Carlo Pierpaoli, who is the lead author on one study.
“It might be that the individuals who had an AHI are dealing with aftermaths of an incident that triggered their symptoms, but the incident didn’t cause long-lasting changes in neuroimaging that you’d typically see after major trauma or a stroke.
“We’re hopeful that these findings will help to lessen worries about AHI being tied to severe neurodegenerative changes in the brain.”
The research team examined various MRI scans assessing brain volume, structure, and functionality in 81 participants who had experienced AHIs against 48 healthy controls, which included 29 with similar occupational roles but without reported AHIs.
An additional study involved 86 individuals with AHIs and 30 controls with comparable job roles undergoing a battery of tests ranging from blood biomarkers to clinical and neuropsychological evaluations.
Employing diverse methodologies and models for data analysis, and investigating a range of observable traits, including biochemical markers, the researchers aimed to detect significant clinical alterations that might align with neuroimaging outcomes.
“Our objective was to conduct exhaustive, unbiased, and reliable assessments to see if we could pinpoint structural brain or biological distinctions in those reporting AHIs,” mentions Leighton Chan, a public health scientist and acting chief scientific officer at NIH.
MRI scans were performed roughly 80 days following the onset of symptoms, with certain participants scanned as soon as 14 days after reporting. Despite their comprehensive approach, the team didn’t encounter consistent imaging irregularities that would differentiate AHI sufferers from healthy controls.
Contrasting with a 2019 study which found significant disparities in a smaller cohort of AHI reporters, the latest research did not corroborate those earlier findings. Nevertheless, it did observe that individuals with Havana syndrome reported more balance issues and elevated levels of fatigue, depression, and post-traumatic stress disorder than those in the control group.
“The reported post-traumatic stress and mood symptoms aren’t unexpected, considering the ongoing worries of many participants,” says neuropsychologist Louis French from the Walter Reed National Military Medical Center.
“Such individuals often face substantial life disruptions and persisting health and future uncertainties. This kind of stress can greatly hinder the recovery process.”
Regarding symptoms, 41 percent of those impacted by AHIs fulfilled the criteria for functional neurological disorders (FNDs) – a spectrum of motor and sensory dysfunctions originating from atypical brain functioning, frequently associated with stress, depression, and anxiety. Many also reported dizziness, vertigo, and a lack of balance.
The researchers propose that if Havana syndrome symptoms were induced by an external agent, it’s conceivable that the effects are now beyond the detection capabilities of current tests and sample sizes.
“While we didn’t find notable differences in those with AHIs,” Chan remarks, “we must recognize the symptoms are genuinely impactful, causing considerable disruptions for the affected and can be enduring, debilitating, and challenging to manage.”
