Radiation-Induced Cerebro-Ophthalmic Effects in Humans.

Exposure to ionizing radiation (IR) could affect the human brain and eyes leading to both cognitive and visual impairments. The aim of this paper was to review and analyze the current literature, and to comment on the ensuing findings in the light of our personal contributions in this field. The review was carried out according to the PRISMA guidelines by searching PubMed, Scopus, Embase, PsycINFO and Google Scholar English papers published from January 2000 to January 2020. The results showed that prenatally or childhood-exposed individuals are a particular target group with a higher risk for possible radiation effects and neurodegenerative diseases. In adulthood and medical/interventional radiologists, the most frequent IR-induced ophthalmic effects include cataracts, glaucoma, optic neuropathy, retinopathy and angiopathy, sometimes associated with specific neurocognitive deficits. According to available information that eye alterations may induce or may be associated with brain dysfunctions and vice versa, we propose to label this relationship "eye-brain axis", as well as to deepen the diagnosis of eye pathologies as early and easily obtainable markers of possible low dose IR-induced brain damage.

Neuropsychiatric characteristics of antiterrorist operation combatants in the Donbass (Ukraine).

OBJECTIVE: The present paper aimed to explore the neuropsychiatric characteristics of the antiterrorism (ATO) combatants in the Donets Basin (Donbass) and to propose therapeutic strategies for managing their mental healthcare. METHODS: A total of 54 ATO combatants were included in our study and compared with four groups of subjects exposed to other emergencies, including the Chernobyl disaster and the war in Afghanistan. The neuropsychiatric features were assessed through psychopathological assessments, neurological examinations, and quantitative electroencephalography (qEEG). RESULTS: The ATO combatants were characterized by low health self-estimation, somatic concerns, a high prevalence of posttraumatic stress disorder, anxiety, insomnia, depression, social dysfunction, mild cognitive impairment, and neurological soft signs, similar to individuals involved in the Chernobyl disaster and veterans of the Afghan War. Quantitative EEG showed abnormalities suggestive of irritation of the corticolimbic system and diencephalic structures. Some post-conflict personality changes in ATO combatants were recorded. The treatment of ATO combatants included a comprehensive strategy: from psychotropic drugs to different psychotherapies. CONCLUSIONS: On the basis of 30 years of experience in the management of the consequences of Chernobyl disaster and the available studies on war veterans, the authors proposed a method for assessment and an approach to providing mental healthcare for ATO combatants, refugees, and migrants from the Donbass, which perhaps can be used as guidelines for other conflicts. Taken together, the findings of the study suggest that voluntary participation in war may decrease but does not eliminate the risk of developing the neuropsychiatric consequences caused by such conflicts. A comprehensive strategy-one that would encompass psychopharmacological, psychological, and rehabilitation techniques-seems to be the most successful approach to managing the main symptoms and disorders involved.

Cerebral basis of posttraumatic stress disorder following the Chernobyl disaster.

BACKGROUND: Whether posttraumatic stress disorder (PTSD) following radiation emergency has psychopathological, neurocognitive, and neurophysiological peculiarities is at issue. OBJECTIVE: The goal was to explore the features and cerebral basis of "radiation" PTSD in the survivors of the Chernobyl accident. Subjects and Methods The cross-sectional study included 241 people, 219 of whom have been diagnosed with PTSD according to the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) criteria, among them 115 clean-up workers of the Chernobyl accident (34 with acute radiation sickness), 76 evacuees from the Chernobyl exclusion zone, 28 veterans of the war in Afghanistan, and 22 healthy unexposed individuals. Psychometric examinations, neurocognitive assessments, computerized electroencephalography, and cerebral vascular Doppler were used. RESULTS: "Radiation" PTSD includes "flashforward" phenomena and anticipating stress (projection of fear and danger to the future); somatoform disorders (depression, trait and state anxiety); and neurocognitive deficit (impaired memory and attention, auditory-verbal memory and learning, proactive and retroactive interference, cerebellar and stem symptoms, intellectual changes). The intima-media component, thickness of common carotid arteries, and common and left internal carotid arteries stenosis rates are increased in the liquidators. Changes of bioelectrical brain activity as a decrease of beta- and theta-power, together with an increase of alpha-power, were found in the Chernobyl accident survivors with PTSD. CONCLUSIONS: PTSD following radiation emergency is characterized by comorbidity of psychopathology, neurocognitive deficit, and cerebrovascular pathology with increased risk of cerebral atherosclerosis and stroke. The cerebral basis of this PTSD is proposed to be an abnormal communication between the pyramidal cells of the neocortex and the hippocampus, and deep brain structures. It is recommended that a system of emergency and long-term psychological and psychiatric care be organized for the survivors in Fukushima Daichi, Japan.

Disrupted development of the dominant hemisphere following prenatal irradiation.

One hundred children, exposed prenatally to radiation after the Chernobyl nuclear power plant accident, and 50 nonexposed classmates were examined between the ages of 11 and 13 years old using neuropsychiatric tests, WISC, EEG, and visual evoked potentials. Individual prenatal radiation doses were reconstructed for all examined children. The exposed children were found to have more neuropsychiatric disorders, left-brain neurological signs, lower full-scale and verbal IQ, IQ discrepancies with verbal decrement, disorganized EEG patterns, an excess of lateralized-to-left frontotemporal region delta and beta power with depression of theta and alpha power, and interhemispheric inversion visual information processing. Mothers' mental health, stress, and prenatal irradiation contributed to these effects, along with several confounding factors.

Whether ionizing radiation is a risk factor for schizophrenia spectrum disorders?

The neural diathesis-stressor hypothesis of schizophrenia, where neurobiological genetic predisposition to schizophrenia can be provoked by environmental stressors is considered as a model of the effects of exposure to ionizing radiation. Analysis of information from electronic databases (MEDLINE, PsycINFO, EMBASE, Current Contents, Elsevier BIOBASE) and hand-made search was carried out. There are comparable reports on increases in schizophrenia spectrum disorders following exposure to ionizing radiation as a result of atomic bombing, nuclear weapons testing, the Chernobyl accident, environmental contamination by radioactive waste, radiotherapy, and also in areas with high natural radioactive background. The results of experimental radioneurobiological studies support the hypothesis of schizophrenia as a neurodegenerative disease. Exposure to ionizing radiation causes brain damage with limbic (cortical-limbic) system dysfunction and impairment of informative processes at the molecular level that can trigger schizophrenia in predisposed individuals or cause schizophrenia-like disorders. It is supposed that ionizing radiation can be proposed as a risk factor for schizophrenia spectrum disorders. The hypothesis that ionizing radiation is a risk factor for schizophrenia spectrum disorders can be tested using data from the Chernobyl accident aftermath. Implementation of a study on schizophrenia spectrum disorders in Chernobyl accident victims is of significance for both clinical medicine and neuroscience.

EEG patterns in persons exposed to ionizing radiation as a result of the chernobyl accident. Part 2: quantitative EEG analysis in patients who had acute radiation sickness.

Cross-sectional quantitative electroencephalogram (qEEG) study (1996-2001) among Chernobyl accident survivors, who had confirmed acute radiation sickness and were irradiated in dose of 1-5 Gy, revealed the neurophysiological markers of ionizing radiation. Neuropsychological markers were: left fronto-temporal dominant frequency reduction; absolute delta-power lateralization to the left (dominant) hemisphere; relative delta-power increase in the fronto-temporal areas; absolute theta-power decrease in the left temporal region; absolute and relative alpha-power diffusive decrease, which may reflect cortico-limbic dysfunction lateralized to the left, dominant hemisphere, with the fronto-temporal cortical and hippocampal damage. Quantitative electroencephalogram proposed for differentiation of radiation and nonradiation brain damages and as a new biological dosymetry method. High radiosensitivity of the brain, neocortex, and dominant hemisphere higher radiosensitivity are discussed.