Brain Entangled in Radio Waves

Cognitive Decline or Political Games? Unraveling the Cuba Mystery

Rhea Morgan in Health & Wellness August 2025 • 4 min read.

"A critical look at the controversial study on US government personnel in Cuba and the validity of its cognitive impairment claims."

In 2018, a study published in JAMA (Journal of the American Medical Association) reported that a group of US government employees working in Havana, Cuba, exhibited cognitive symptoms consistent with post-concussive syndrome. These symptoms were allegedly triggered by unusual auditory phenomena of unknown origin. The study assessed 21 individuals using a battery of 37 neuropsychological tests, classifying them as cognitively impaired if they scored below the 40th percentile on at least one test.

However, the methodology and conclusions of this study have faced intense scrutiny from neuropsychologists and statisticians. Critics argue that the chosen diagnostic criteria are inconsistent with established practices in evidence-based neuropsychology, questioning the statistical validity of labeling individuals as impaired based on such a low threshold.

This article delves into the heart of the controversy, examining the flaws in the original study’s methods and exploring alternative interpretations of the data. It sheds light on the importance of rigorous scientific standards when investigating complex health issues, especially those intertwined with geopolitical tensions.

The Problem with Percentiles: Why 40% is a Failing Grade for Science

One of the primary criticisms of the JAMA study revolves around its use of the 40th percentile as the cut-off for cognitive impairment. Statistically, this means that 40% of any normal population would automatically be flagged as impaired, regardless of their actual cognitive function. This raises serious concerns about the validity of the study’s findings, as it essentially guarantees a high rate of false positives.

Critics argue that relying on such a low percentile threshold is not only statistically unsound but also deviates from established neuropsychological practices. Evidence-based neuropsychology typically employs more stringent criteria and considers a range of factors beyond simple percentile scores to determine cognitive impairment.

Here's why the 40th percentile is problematic:

Guaranteed Impairment: 40% of any population will score below this threshold, regardless of cognitive health.
False Positives: It leads to a high number of individuals being incorrectly identified as cognitively impaired.
Deviation from Standards: Conflicts with established neuropsychological practices that emphasize comprehensive assessment.

In response to criticism, the authors of the JAMA study suggested they used another criterion. They stated that impaired patients had “several scores that deviated by more than 1 SD from their respective means, some exceeding 2 SDs, which translates to more than 40 percentile points below their means (below 10th percentile relative to their average performance). This meets standard criteria for neuropsychological impairment.” However, this explanation introduces further ambiguity and raises additional questions about the study’s methodology.

The Ethical Imperative: Clarity and Accuracy in Cognitive Assessments

The controversy surrounding the JAMA study highlights the importance of adhering to rigorous scientific standards in neuropsychology, especially when dealing with sensitive health issues that have broader political implications. Misdiagnosing cognitive impairment can have significant consequences, leading to unnecessary anxiety, stigma, and potentially inappropriate interventions. It is therefore crucial for researchers to uphold the highest ethical standards, ensuring that their methods are transparent, their conclusions are well-supported by the data, and their findings are communicated clearly and accurately to the public.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1016/j.cortex.2018.10.002, Alternate LINK

Title: Cognitive Symptoms In Us Government Personnel In Cuba: The Mending Is Worse Than The Hole

Subject: Cognitive Neuroscience

Journal: Cortex

Publisher: Elsevier BV

Authors: Sergio Della Sala, Robert D. Mcintosh, Roberto Cubelli, Jason A. Kacmarski, Holly M. Miskey, Robert D. Shura

Published: 2018-11-01

Everything You Need To Know

What did the JAMA study find about the health of US government employees in Cuba?

The JAMA study, published in 2018, reported that US government employees in Havana, Cuba, showed cognitive symptoms resembling post-concussive syndrome. These symptoms were supposedly caused by unusual auditory phenomena. The study classified individuals as cognitively impaired if they scored below the 40th percentile on at least one of 37 neuropsychological tests. The study's methods have been questioned by neuropsychologists and statisticians due to concerns about the diagnostic criteria used.

What does it mean that the JAMA study used the 40th percentile to define cognitive impairment, and why is that important?

The 40th percentile was used as a cut-off for cognitive impairment in the JAMA study. This means that if someone scored below the 40th percentile on a neuropsychological test, they were classified as cognitively impaired. This is significant because it is statistically unsound since 40% of any normal population would fall below this threshold, leading to many false positives.

How does evidence-based neuropsychology usually determine cognitive impairment?

Evidence-based neuropsychology uses more stringent criteria and considers a range of factors beyond simple percentile scores to determine cognitive impairment. This approach emphasizes comprehensive assessment to ensure accurate diagnoses and avoid misclassifying individuals as cognitively impaired based on arbitrary thresholds, like the 40th percentile used in the JAMA study.

Why is it so important to have clarity and accuracy in cognitive assessments, especially in situations like this?

The potential consequences of misdiagnosing cognitive impairment include unnecessary anxiety, stigma, and potentially inappropriate interventions. It’s essential that researchers adhere to rigorous scientific standards to ensure transparency and accuracy in their methods and findings, especially when dealing with sensitive health issues that have broader political implications.

What was the response of the JAMA study authors to the criticisms of their methods?

The JAMA study authors stated that impaired patients had "several scores that deviated by more than 1 SD from their respective means, some exceeding 2 SDs, which translates to more than 40 percentile points below their means (below 10th percentile relative to their average performance)." This was presented as meeting standard criteria for neuropsychological impairment. However, this explanation introduced further ambiguity and raises additional questions about the study’s methodology.