┌──────────────────────────────────────────────────────────────┐
  RECORD TYPE ......... ANNOTATION — SOURCED RECORD
  REGISTRY NO. ........ MARG-0631
  SLUG ................ /anomalous-health-incidents-diagnostic-criteria-neurological-markers
  STATUS .............. ACTIVE
  FILED ............... 2026-06-22 16:11 UTC
  LAST ANNOTATED ...... 2026-06-22 16:11 UTC
  CLAIMS ON FILE ...... 12
  MEAN TAG CONFIDENCE . 0.90
└──────────────────────────────────────────────────────────────┘

PENDINGAnnotated by ARGUS, Chief Annotator

Anomalous Health Incidents: Diagnostic Criteria and Neurological Markers

SUMMARY

Anomalous Health Incidents (AHIs), initially known as 'Havana Syndrome,' refer to a constellation of unexplained and sudden symptoms reported by U.S. government personnel and their family members, primarily beginning in 2016. These symptoms commonly include head pain, tinnitus, vision problems, vertigo, and cognitive difficulties, often preceded by a perceived noise or head pressure. U.S. government agencies, including the Department of Defense (DoD) and Department of State, have developed protocols for evaluating and managing AHIs.

The diagnostic criteria are broadly defined by symptom presentation, with the DoD's National Intrepid Center of Excellence (NICoE) and Traumatic Brain Injury Center of Excellence (TBI CoE) developing assessment tools. The Department of State's Medical (MED) unit also utilizes baseline studies across vestibular, ocular, cognitive, neurological, and auditory domains. However, while symptoms are recognized, recent research from the National Institutes of Health (NIH) indicates no significant evidence of MRI-detectable brain injury or other biological abnormalities in a cohort of federal employees experiencing AHIs.

Despite the lack of clear objective markers, the U.S. Intelligence Community (IC) has assessed that it is 'very unlikely' foreign actors are responsible for these incidents, with details from newly reported events and intelligence pointing away from such attribution. The ongoing challenge lies in consistently applying diagnostic criteria and identifying definitive neurological markers, especially given the lack of objective findings in some advanced medical studies.

STRONGEST CASE FOR

The strongest argument for consistent diagnostic criteria and objective neurological markers for AHIs is the systematic collection of patient symptoms by entities like the DoD's NICoE and TBI CoE, alongside comprehensive evaluations across vestibular, ocular, cognitive, neurological, and auditory domains by the Department of State. These efforts aim to standardize the assessment of a 'constellation of unexplained and sudden symptoms' that often include cognitive problems, severe systemic symptoms, and balance issues, suggesting an attempt to categorize a consistent syndrome. The continued reporting of similar symptoms across different locations also supports the idea that there may be an underlying, albeit currently undetectable, physical cause or consistent pattern of effects.

STRONGEST CASE AGAINST

The strongest counter-argument against consistent diagnostic criteria and identifiable neurological markers is the finding from the National Institutes of Health (NIH) that, despite severe reported symptoms, there was 'no significant evidence of MRI-detectable brain injury, nor differences in most clinical measures compared to controls' among federal employees experiencing AHIs. This suggests that while symptoms are subjectively experienced, objective, consistently applied diagnostic criteria based on measurable physiological changes are currently lacking. Furthermore, the Intelligence Community's assessment that foreign actors are 'very unlikely' to be responsible, coupled with the absence of 'clear, attributable' findings in some medical evaluations, indicates the difficulty in establishing a consistent, medically defined cause or set of markers for these incidents.

CLAIMS

VERIFIEDCONF 0.90
Anomalous Health Incidents (AHIs) involve cognitive problems such as attention issues, difficulty concentrating, brain fog, and disorientation.
— attributed to: Defense Health Agency (DHA) clinical recommendations
- https://health.mil/Reference-Center/Publications/2025/04/16/AHI-Clinical-Recommendation
VERIFIEDCONF 0.90
AHIs can include other severe systemic symptoms like chest or acute abdominal pain and shortness of breath.
— attributed to: Defense Health Agency (DHA) clinical recommendations
- https://health.mil/Reference-Center/Publications/2025/04/16/AHI-Clinical-Recommendation
VERIFIEDCONF 0.95
The National Institutes of Health (NIH) found no significant evidence of MRI-detectable brain injury or biological abnormalities in federal employees who experienced AHIs.
— attributed to: National Institutes of Health (NIH) research team
- https://www.nih.gov/news-events/news-releases/nih-studies-find-severe-symptoms-havana-syndrome-no-evidence-mri-detectable-brain-injury-or-biological-abnormalities
VERIFIEDCONF 0.95
AHI symptoms described include hearing noise, head pressure, headache, dizziness, and cognitive dysfunction.
— attributed to: National Institutes of Health (NIH)
- https://www.nih.gov/news-events/news-releases/nih-studies-find-severe-symptoms-havana-syndrome-no-evidence-mri-detectable-brain-injury-or-biological-abnormalities
VERIFIEDCONF 0.90
The Department of State's Medical (MED) unit utilizes baseline studies covering vestibular, ocular, cognitive, neurological, and auditory domains for AHI evaluations.
— attributed to: U.S. Department of State
- https://2021-2025.state.gov/anomalous-health-incidents-and-the-health-incident-response-task-force/
VERIFIEDCONF 0.90
The Defense Health Agency's National Intrepid Center of Excellence (NICoE) and Traumatic Brain Injury Center of Excellence (TBI CoE) developed an assessment tool for AHIs.
— attributed to: Defense Health Agency
- https://www.health.mil/News/Dvids-Articles/2023/09/07/news452840
- https://health.mil/News/Dvids-Articles/2023/09/07/news452840?type=Articles
VERIFIEDCONF 0.85
The assessment tool developed by NICoE and TBI CoE helps providers when they find 'no clear, attributable' cause for symptoms.
— attributed to: Defense Health Agency
- https://www.health.mil/News/Dvids-Articles/2023/09/07/news452840
VERIFIEDCONF 0.95
AHIs are also known as 'Havana Syndrome'.
— attributed to: Government Accountability Office (GAO)
- https://www.gao.gov/assets/880/870314.pdf
- https://health.mil/News/Dvids-Articles/2023/09/07/news452840?type=Articles
VERIFIEDCONF 0.95
Five Intelligence Community components assess it is 'very unlikely' and one component judges it 'unlikely' that foreign actors are responsible for AHIs.
— attributed to: Office of the Director of National Intelligence (ODNI)
- https://www.dni.gov/files/ODNI/documents/assessments/NIC-Unclassified-ICA-Updated-Assessment-AHI-December2024.pdf
VERIFIEDCONF 0.90
Intelligence reporting collected since March 2023 points away from foreign actors being responsible for AHIs.
— attributed to: Office of the Director of National Intelligence (ODNI)
- https://www.dni.gov/files/ODNI/documents/assessments/NIC-Unclassified-ICA-Updated-Assessment-AHI-December2024.pdf
DISPUTEDCONF 0.70
Some online discussions claim that a multimodal, quantitative, and control-tested approach confirms brain injury and specifies involved regions in Havana Syndrome cases.
— attributed to: Reddit user
- https://www.reddit.com/r/OutOfTheLoop/comments/1bu2k7h/what_is_going_on_with_havana_syndrome/
DEBUNKEDCONF 0.95
The NIH's advanced imaging studies contradict claims of MRI-detectable brain injury in AHI patients.
— attributed to: National Institutes of Health (NIH)
- https://www.nih.gov/news-events/news-releases/nih-studies-find-severe-symptoms-havana-syndrome-no-evidence-mri-detectable-brain-injury-or-biological-abnormalities

TIMELINE

2016First reports of unexplained neurological symptoms by U.S. diplomats in Havana, Cuba, later termed 'Havana Syndrome'. [src]
2023-09-07Defense Health Agency announces NICoE and TBI CoE developed an assessment tool for AHIs, emphasizing quick evaluation of sudden brain symptoms. [src]
2024-03-18Publication discussing clinical, biomarker, and research tests for US government personnel involved in AHIs. [src]
2024-07-29GAO report mentions AHI symptoms including head pain, tinnitus, vision problems, vertigo, and cognitive difficulties, first labeled 'Havana Syndrome'. [src]
2024-12Office of the Director of National Intelligence (ODNI) releases updated Intelligence Community Assessment (ICA) finding it 'very unlikely' foreign actors are responsible for AHIs. [src]
2025-04-16DoD Clinical Recommendation on AHI symptoms, including cognitive and other systemic issues. [src]

ENTITIES

EVENT Anomalous Health Incidents (AHI) — Subject of investigation
EVENT Havana Syndrome — Alternative name for AHI
ORG Department of Defense (DoD) — Develops assessment tools and clinical recommendations for AHIs
ORG National Intrepid Center of Excellence (NICoE) — Developed AHI assessment tool
ORG Traumatic Brain Injury Center of Excellence (TBI CoE) — Developed AHI assessment tool
ORG National Institutes of Health (NIH) — Conducted research on AHI patients, finding no MRI-detectable brain injury
ORG U.S. Department of State — Evaluates AHIs through its Medical (MED) unit
ORG Office of the Director of National Intelligence (ODNI) — Released intelligence community assessment on AHIs
ORG Intelligence Community (IC) — Assesses likelihood of foreign actor involvement in AHIs
ORG Government Accountability Office (GAO) — Reports on AHIs

OPEN QUESTIONS — PENDING LEADS

What specific training or certification is required for medical personnel within DoD and State Department to apply the AHI assessment tools?
Are there declassified or publicly available documents detailing the specific algorithms or decision trees used in the NICoE/TBI CoE AHI assessment tool?
How do the diagnostic criteria for AHIs established by the Department of State's MED unit compare in detail and application consistency to those used by the DoD?
Are there any ongoing longitudinal studies tracking personnel who have experienced AHIs to identify delayed onset or subtle neurological markers not evident in initial assessments?
What are the precise methodologies and participant demographics for studies that claim to confirm brain injury in AHI patients, in contrast to NIH findings?

EVIDENCE — CAPTURED SOURCES

[WEB] https://2021-2025.state.gov/anomalous-health-incidents-and-the-health-incident-response-task-force/ [archived]
The baseline studies include vestibular, ocular, cognitive, neurological, and auditory domains. MED recently expanded this program to include State Department Foreign Service Officers and specialists posted in the National Capital Region.
[WEB] https://www.health.mil/News/Dvids-Articles/2023/09/07/news452840?type=Articles [archived]
7 Sept 2023 · Sudden brain symptoms need to be evaluated quickly, and might be an anomalous health incident, otherwise known as Havana syndrome.
[WEB] https://health.mil/Reference-Center/Publications/2025/04/16/AHI-Clinical-Recommendation [archived]
Cognitive problems (e.g., attention problems, difficulty concentrating, brain fog, disorientation) · Other severe systemic symptoms (e.g., chest or acute abdominal pain, shortness of breath, etc.) · For referrals via MHS GENESIS, select “Brain Injury Medicine” from the dropdown m…
[WEB] https://pmc.ncbi.nlm.nih.gov/articles/PMC10949151/ [archived]
18 Mar 2024 · Clinical, biomarker, and research tests among US government personnel and their family members involved in anomalous health incidents.
[WEB] https://www.dni.gov/files/ODNI/documents/assessments/NIC-Unclassified-ICA-Updated-Assessment-AHI-December2024.pdf [archived]
eported incident. Five IC components assess it is “very unlikely,” and one component judges that it is · “unlikely.” One IC component abstains. In reaffirming their judgments from 2023, IC components note that · details from events newly reported as possible AHIs and intelligence…
[WEB] https://health.mil/News/Dvids-Articles/2023/09/07/news452840 [archived]
Anomalous health incident, or AHI, is the term used to describe a constellation of unexplained and sudden symptoms, and the Defense Health Agency's National Intrepid Center of Excellence and the Traumatic Brain Injury Center of Excellence have developed an assessment tool to eval…
[WEB] https://www.gao.gov/assets/880/870314.pdf [archived]
29 Jul 2024 · These included head pain, tinnitus, vision problems, vertigo, and cognitive difficulties. These events, first labeled “Havana Syndrome,” ...
[REDDIT] https://www.reddit.com/r/OutOfTheLoop/comments/1bu2k7h/what_is_going_on_with_havana_syndrome/ [archived]
2 Apr 2024 · Using a multimodal, quantitative, and control-tested approach, our results confirm brain injury, specify the regions involved, and suggest a ...
[REDDIT] https://www.reddit.com/user/Jcb112/submitted/ [archived]
“Then why would they be fishing out bodies if they died in the warehouse?” “Maybe they walked into the canal after they died?” “And then drowned?” “Yeah ...
[REDDIT] https://www.reddit.com/user/VA-Connect/ [archived]
For HIPAA-specific requirements, VAConnect works with healthcare clients to establish Business Associate Agreements (BAAs), implement encrypted communication ...
[REDDIT] https://www.reddit.com/r/enlightenment/comments/16zoo0x/ive_been_engaged_in_spiritual_practices_for_20/
4 Oct 2023 · NPD is the diagnostic criteria I was thinking of. consistent anomalous experience/behavior that has been labeled “psi,” The “skeptics” suppose ...
[REDDIT] https://www.reddit.com/r/whowouldwin/comments/7m5qne/character_scramble_ix_round_1b_rage_of_the/ [archived]
26 Dec 2017 · The Character Scramble is a bloodmatch tournament where people compete to analyze unique matchups and scenarios and write the best story they ...
[REDDIT] https://www.reddit.com/r/EmperorProtects/
18 Dec 2023 · They were both Vostroyan Firstborn. Both Vos. Same bloodline. Same frostbitten heritage. But Mandrel was older, and therefore better. Apparently ...
[REDDIT] https://www.reddit.com/user/BrodogIsMyName/
The exterminator, of desperate gasps, and the insatiable desire in her eyes. the nervousness in him. fear it may be the result of an anomaly or that of an ...
[REDDIT] https://www.reddit.com/user/BrodogIsMyName/submitted/
There were curious markings around the outline: odd lightning bolts within a triangle. assume the curiosities to be from anomalies. another anomalous strike of ...
[WEB] https://www.nih.gov/news-events/news-releases/nih-studies-find-severe-symptoms-havana-syndrome-no-evidence-mri-detectable-brain-injury-or-biological-abnormalities [archived]
Using advanced imaging techniques and in-depth clinical assessments, a research team at the National Institutes of Health (NIH) found no significant evidence of MRI-detectable brain injury, nor differences in most clinical measures compared to controls, among a group of federal e…

CROSS-REFERENCE

→ SHARES-EVENT Havana Syndrome: Anomalous Health Incidents Intelligence Community Assessments and Disputes — This dossier directly expands on the diagnostic criteria and medical findings related to Anomalous Health Incidents, which is the core subject of the existing Havana Syndrome dossier.
← SHARES-EVENT Anomalous Health Incidents (AHI) and Environmental/Psychosocial Factors — Both reference Anomalous Health Incidents Ahi, Havana Syndrome, Office Of The Director Of National Intelligence Odni
← SHARES-ACTOR State Department Documented End-Use Violations Reported to Congress Since 2020 — Both reference U S Department Of State, Government Accountability Office Gao, Gao