NEUROPHYSIOLOGICAL BASIS OF THE COMBINED EFFECTS OF ACUTE STRESS AND LOW DOSES OF IONIZING RADIATION ON HUMAN BRAIN

Area of Science:

• Neuroscience
• Radiology
• Psychiatry

Background:

• Chronic cerebrovascular disease (small vessel disease - SVD) affects individuals exposed to various stressors.
• Chornobyl clean-up workers (liquidators) and nuclear power plant employees (SSE ChNPP) faced unique exposures: ionizing radiation (IR) and wartime psycho-emotional stress, respectively.
• Understanding the combined effects of IR and stress on brain function is crucial for long-term health management.

Purpose of the Study:

• To investigate clinical and neurophysiological differences in Chornobyl liquidators with SVD exposed to low-dose IR.
• To examine neurophysiological changes in SSE ChNPP employees exposed to wartime captivity stress.
• To compare these groups with a non-irradiated control group with SVD.

Main Methods:

• Cross-sectional clinical study with three parallel external control groups.
• Involved 62 male subjects: 22 Chornobyl liquidators (1986-1990, 0.03-2.30 Sv), 24 SSE ChNPP employees (wartime stress), and 16 non-exposed controls with SVD.
• Expert statistical analysis of clinical and neurophysiological characteristics.

Main Results:

• Chornobyl liquidators exhibited pronounced dysfunction of the left hemisphere's cortico-limbic system, with significant hippocampal involvement.
• SSE ChNPP employees showed novel disorders in cerebral neurodynamics: functional hypofrontality and right-hemisphere lateralized cortico-limbic hyperfunction.
• Both groups demonstrated distinct neurophysiological patterns linked to their specific exposures.

Conclusions:

• Robust evidence supports neurophysiological diagnosis for combined effects of IR and psycho-emotional stress from military conflicts.
• Neurophysiological technologies can aid professional selection for high-demand decision-making roles.
• SSE ChNPP employees require ongoing medical and psychological support due to elevated mental health risks.