Features of Age-Related Changes in the Organization of Human Brain Activity During Cognitive Performance Testing

Introduction. Any type of activity requires high-speed indicators, which are reflected in reaction time, thinking speed, etc. Cognitive performance characterizes the ability to perform tasks flawlessly over an extended period, the ability for painstaking, possibly monotonous work, and perseverance. Thus, this indicator together with peculiarities of the neuron networks formation are useful markers for assessment of individual suitability for certain work and monitoring professional skills. Purpose. To investigate age-related differences in the functioning of brain neural networks during a test assessing cognitive performance in representatives of various military professions, with the aim of implementing age-based professional suitability control procedures and effective personnel selection. Methods. Forty-seven healthy volunteers, representing various military professions, aged 18-54 years, were divided into three groups (Group I – 18-23 years, n=16; Group II – 24-34 years, n=19; Group III – 35-54 years, n=12). They underwent a test to determine cognitive performance using an authorial computer-based methodology. Simultaneously, electroencephalogram (EEG) recordings were made, followed by coherence analysis. Result. Comparative analysis using the Mann-Whitney test revealed that the relative number of errors was significantly lower in Group II compared to Group I (p<0.01), with no differences observed between Groups I and III or II and III (p=0.39 and p=0.52, respectively). The Kruskal-Wallis test revealed differences across the three groups in connections with significant synchronization in the δ-range for O2 – P4 and O2 – T6 (only present in Group III), in the θ-range for C3 – Fz, P3 – Fz, Pz – Fz, Pz – C3, Pz – P3 (present in all three groups) and for O1 – P3, O2 – T6 (only in Group III); in the α-range for Pz – Fp1, P3 – Fp1, Pz – F3, P3 – Fz, P3 – F3, Pz – Fz, O1 – Fz, Pz – C3, P3 – C3 (only in Group III) and Pz – P3 (in Groups I and III), and in the β2-range for the O1 – Pz connection (only present in Group II). Such increased connectivity in Group III in the θ- and α-ranges in the frontal, parietal and occipital regions could be due to functional compensation of reduced sensory processing, which is the common reason of cognitive aging. Originality. Age-related adaptive changes of the neural during testing of the brain performance are revealed. In context of our previous work on functional motility of nervous processes, the current study shows the difference between neuron network performance in people with an individual predisposition to error-free performance of a monotonous, repetitive task (brain performance test) and for rapid adaptation to new conditions (test on the functional motility of nervous processes). Conclusion. The performance of the task with the fewest errors in Group II was achieved due to an optimal neural network and higher brain connectivity in the θ- and α-ranges, as well as in the β2-range, which, in addition to central and parietal regions (as in Groups I and III), more actively involved visual regions (O1Pz, O2P4).