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Psychophysiologic aftereffects of prenatal irradiation
A I Nyagu1, K N Loganovsky, T K Loganovskaja
1Neurology Department, Academy of Medical Sciences of the Ukraine, Kiev, Ukraine.
Insights
Children exposed to Chernobyl radiation in utero showed increased mental retardation and behavioral disorders. Radiation-induced thyroid issues and left hemisphere brain dysfunction are implicated mechanisms. Further study on schizophrenia risk is recommended.
Area of Science:
- Neuroscience
- Endocrinology
- Pediatrics
Background:
- Chernobyl disaster led to radioactive contamination in Ukraine.
- Prenatal exposure to radiation poses potential risks to child development.
- Thyroid-pituitary system function is crucial for neurodevelopment.
Purpose of the Study:
- To assess the psychometric and clinical effects of prenatal Chernobyl radiation exposure on children.
- To investigate the biological mechanisms underlying potential radiation-induced mental disorders.
- To identify children irradiated in utero at risk for future neurological conditions.
Main Methods:
- Psychometric testing and clinical examinations of 544 prenatally irradiated children and 759 controls.
- Computerized EEG, thyroid function tests, and dosimetric reconstruction in a subset of 100 children.
- Comparison of IQ, emotional, and behavioral outcomes between exposed and control groups.
Main Results:
- Significantly higher rates of mental retardation (IQ < 70), borderline/low IQ, and emotional/behavioral disorders in the irradiated group.
- Reduced incidence of high IQ (IQ > 110) in children exposed prenatally.
- A thyroid exposure dose threshold of 0.30 Sv was linked to thyroid-pituitary system malfunction.
Conclusions:
- Prenatal Chernobyl radiation exposure is associated with significant mental and behavioral deficits in children.
- Radiation-induced thyroid-pituitary dysfunction and left hemisphere limbic-reticular abnormalities are potential mechanisms.
- Children irradiated in utero may be at increased risk for schizophrenia, warranting follow-up studies.
Abstract:
Prenatally irradiated children (n = 544), who were born between 26 April 1986 and 26 February 1987, in regions of the Ukraine which were radioactively contaminated as a result of the Chernobyl disaster, their mothers and teachers have been examined with psychometric tests. The control group of relevant children (n = 759), their mothers and teachers, were living at the radioecological 'clear' regions (Kharkov and Kharkov Region). Further, we randomly selected 50 prenatally irradiated children whose mothers were evacuated from the Chernobyl exclusion zone and 50 age-and-gender-matched non-exposed children. At this phase clinical examinations, psychometric tests, computerized EEG, thyroid function assessment and dosimetric reconstruction were used. We found a significant increase in mental retardation (IQ < 70) and of borderline and low range IQ, as well as emotional and behavioral disorders and a decrease in high IQ (IQ > 110) in children irradiated in utero as a result of the Chernobyl disaster, in comparison with the controls. One important biological mechanism in the genesis of mental disorders in prenatally irradiated children is the radiation-induced malfunction of the thyroid-pituitary system with the effect threshold of 0.30 Sv of thyroid exposure dose. We hypothesize that the cerebral basis of mental disorders in the prenatally irradiated children is the malfunction of the left hemisphere limbic-reticular structures, particularly in those exposed at the most critical period of cerebrogenesis (8-25 weeks of gestation). The data obtained reveal mental disorders in prenatally irradiated children and obviously reflect developmental abnormalities of brain structure and function as a result of the interaction of prenatal and post-natal factors where it is possible to assume radiation effects on the developing brain. A follow-up study of the children irradiated in utero, who may be at risk for schizophrenia, is proposed because of its particular importance to clinical medicine and neuroscience.