Purpose: Exposure to ionizing radiation following environmental contamination (e.g.
the Chernobyl and Fukushima nuclear accidents), radiotherapy and diagnostics,
occupational roles and space travel has been identified as a possible risk-factor for
cognitive dysfunction. The deleterious effects of high doses (≥ 1.0 Gy) on ...
Purpose: Exposure to ionizing radiation following environmental contamination (e.g.
the Chernobyl and Fukushima nuclear accidents), radiotherapy and diagnostics,
occupational roles and space travel has been identified as a possible risk-factor for
cognitive dysfunction. The deleterious effects of high doses (≥ 1.0 Gy) on cognitive
functioning are fairly well-understood, while the consequences of low (≤ 0.1 Gy) and
moderate doses (0.1 - 1.0 Gy) have been receiving more research interest over the past
decade. In addition to any impact of actual exposure on cognitive functioning, the
persistent psychological stress arising from perceived exposure, particularly following
nuclear accidents, may itself impact cognitive functioning. In this review we offer a novel
interdisciplinary stance on the cognitive impact of radiation exposure, considering
psychological and epidemiological observations of different exposure scenarios such as
atomic bombings, nuclear accidents, occupational and medical exposures while
accounting for differences in dose, rate of exposure and exposure type. The purpose is to
address the question that perceived radiation exposure - even where the actual absorbed
dose is 0.0 Gy above background dose - can result in psychological stress, which could
in turn lead to cognitive dysfunction. In addition, we highlight the interplay between the
mechanisms of perceived exposure (i.e. stress) and actual exposure (i.e. radiation induced cellular damage), in the generation of radiation-induced cognitive dysfunction.
In all, we offer a comprehensive and objective review addressing the potential for
cognitive defects in the context of low- and moderate-dose IR exposures.
Conclusions: Overall the evidence shows prenatal exposure to low and moderate doses
to be detrimental to brain development and subsequent cognitive functioning, however
the evidence for adolescent and adult low- and moderate-dose exposure remains
uncertain. The persistent psychological stress following accidental exposure to low doses in adulthood may pose a greater threat to our cognitive functioning. Indeed, the
psychological implications for instructed cohorts (e.g. astronauts and radiotherapy
patients) is less clear and warrants further investigation. Nonetheless, the psychosocial
consequences of low- and moderate-dose exposure must be carefully considered when
evaluating radiation effects on cognitive functioning, and to avoid unnecessary harm
when planning public health response strategies.