Impairments to Higher Mental Functions and Cognitive Auditory Evoked Potentials in Chernobyl Clean-Up Workers

• Published in: Neuroscience and behavioral physiology 2013-09, Vol.43 (7), p.887-895
• Main Authors: Zhavoronkova, L. A., Belostotskii, A. P., Kholodova, N. B., Kuptsova, S. V., Snegireva, I. P., Kulikov, M. A., Oknina, L. B.
• Format: Article
• Language: English
• Subjects: Aging; Behavioral Sciences; Biomedical and Life Sciences; Biomedicine; Chromosomes; Hypotheses; Information processing; Memory; Neurobiology; Neuropsychology; Neurosciences; Older people; Radiation; Workers
• ISSN: 0097-0549; 1573-899X
• DOI: 10.1007/s11055-013-9824-y

Complex investigations including neuropsychological studies and analysis of cognitive auditory evoked potentials using a three-stimulus oddball paradigm were performed in 10 participants in the Chernobyl power station clean-up operation and 10 healthy subjects. Impairments to higher mental functions, including exhaustion, fatigue, and decreases in auditory-verbal and visual memory and motor functions, were seen in clean-up workers. Decreases in the amplitudes of all EP components (N1, N2, and P3) were seen in clean-up workers for all stimuli in both experimental situations (hearing all stimuli and counting target stimuli) as compared with normal. The latent periods (LP) of the N1 and N2 EP components were shorter in clean-up workers, while that of P3 was longer. The greatest differences in LP between groups were seen in the frontal areas of the left hemisphere for N1 and P3 and in the right hemisphere for N2. Correlation analysis between EP and neuropsychological investigations showed that changes in the LP of N1 correlated with impairments to short-term memory and postural praxis of the right hand, while changes in the LP of N2 correlated with impairments to long-term memory and postural praxis of the left hand. Changes in the LP of P3 correlated with impairments to complex cognitive activity. Thus, complex investigations revealed impairments to the perception, processing, and analysis of information, combined with reduced inhibition and an “uneconomical” type of responding, accompanied by impairments to higher mental functions in clean-up workers as compared with healthy subjects of the same age. Impairments seen in clean-up workers were similar to those seen in elderly people and support the hypothesis of early cerebral aging in clean-up workers induced by low doses of radiation.