Additional statistical analysis showed a number of deviations from the linear dynamics of SCP with age, as well as gender differences. The piecewise continuous regression method was used, with the help of which men and women found those age periods in which violations of the linearity of changes in SCP are manifested. Three main periods of SCP dynamics were revealed, within which linear changes are observed, and between them linearity violation occurs. This is the period of childhood (from 3 to 11 years), maturity (20 – 40 years), late maturity and old age (45 – 75 years). Violations of linearity occur in the puberty (from about 12 to 17 years), as well as in the range from 41 to 45 years (the age preceding menopause in women). It should be noted that a group of women (41 people) from 75 to 92 years old was represented in the population examined by us, while there were no men older than 75 years. Therefore, women studied another additional period – senile.
To develop the dependence, the average SCP was calculated for ages adjacent to the beginning and end of each period. According to the results of the regression analysis, it was assumed that between the periods there is a linear dynamics of the SCP, which was confirmed by statistical calculations.
There is a general pattern for all monopolar leads of SCP, namely: SCP is significantly higher in the first period of life compared with the next two. However, only in some cases, the decrease in SCP is monotonous, and it is most noticeable in the central and occipital leads. In other cases, AMR changes in a phase manner, which is especially pronounced in men.
The simplest pattern is observed for SCP in the central lead. In men, SCP in childhood is maximum, and then it decreases monotonously. In women, similar changes are noted, except that the maximum SCP values do not occur at the beginning, but at the end of childhood.
The latter pattern is manifested in almost all other monopolar leads. In the occipital region, the dynamics of the SCP is closest to that in the central lead. In the frontal lead there is a pronounced phase dynamics
potentials. As in other areas, the highest potentials in boys are observed at the beginning, and in girls at the end of childhood. Then there is a significant decrease in SCP, reaching its minimum in men by the beginning, and in women by the end of the maturity period. After this, there is a secondary rise in SCP, continuing up to senile age. There are statistically significant differences between the values of SCP in men and women in the second age period – maturity: in men, secondary growth of SCP is faster. The secondary rise is probably associated with a decrease in the frontal cortex of cerebral blood flow and increased anaerobic metabolism, which is accompanied by the development of acidosis. It is also possible that these changes are due to an age-related increase in stress sensitivity with corresponding accumulation in the brain, which is especially noticeable in old age. In temporal leads, in principle, the same dynamics are observed as in the frontal lead, however, the secondary increase in potential is less than in the frontal areas. Sexual differences are less pronounced in these leads.
Thus, there is a certain parallelism between the dynamics of LMC, the consumption of glucose by the brain and SCP, especially in the first half of life. In early childhood, cerebral energy metabolism increases and reaches a maximum in boys at the beginning, and in girls at the end of the childhood period. Then, according to AMR, LMC and brain glucose consumption, energy metabolism decreases. In old age, there is a certain discrepancy between the dynamics of glucose metabolism and changes in CRC: glucose consumption decreases with aging, but the acidity in the brain tissue increases, which may be due to a complex of reasons: decreased blood flow and energy metabolism, destructive processes. Therefore, in old age, in some areas, a secondary slight increase in SCP is recorded, reflecting a decrease in cerebral pH, which is most pronounced in the frontal areas, where age-related changes are predominant, decreased blood flow and glucose hypometabolism.