With hyperventilation in relatives of patients with BA, SCP increased significantly in the frontal and temporal areas; the average SCP also increased significantly. Compared with similar parameters in healthy subjects according to single-factor analysis of variance in relatives of AD, hypertensioning SCP was significantly increased in the left temporal region ( F = 6.57; p = 0.0162; where F is Fisher’s test).
The nature of EEG activity during hyperventilation in this group changed significantly. Paroxysmal discharges of high-amplitude bilateral synchronous theta and delta oscillations, as well as sharp waves, were recorded.
Relative spectral power of EEG frequency ranges in relatives of Alzheimer’s patients with hyperventilation.
It is noteworthy that the changes in SCP and EEG were more pronounced in the frontal region than in the occipital and in the left hemisphere than in the right. Normally, neurophysiological changes are more significant in the right hemisphere. Such a nature of neurophysiological changes in relatives of patients with asthma indicates a predominance of impaired energy exchange and functional activity in the left hemisphere compared with the right.
With hyperventilation in relatives of BA, the nature of the relationship between the UPP and the relative spectral power of the EEG frequency ranges changed fundamentally. The relative spectral power of the delta activity in the occipital region was associated with a positive correlation with SCP in the same brain region ( r = 0.61 p = 0.02) (Fig. 8.14). The relative spectral power of the delta activity average for all leads also positively correlated with the SCP in the occipital region ( r = 0.66; p = 0.01). Recall that in healthy people alone and with hyperventilation, as well as in relatives of patients with asthma alone, the correlation between the relative spectral power of the delta oscillations and the SCP was negative.
Correlation between the relative spectral power of delta activity and SCP in the occipital regions of relatives of patients with asthma during hyperventilation
The correlation between the relative spectral power of alpha activity and the UPP in the occipital region did not reach the 0.05 level of significance ( r = –0.47 ; p = 0.093).
The SCP in the right temporal region was associated with a negative correlation with the relative spectral power of beta1 activity in the same brain region ( r = -0.65; p = 0.012), and also with the average spectral power of beta1 activity for all leads ( r = -0.57; p = 0.035).
Thus, relatives of patients with asthma represent a group with neurophysiological abnormalities that are not very pronounced at rest and significantly increase in conditions of hyperventilation. The appearance of high-amplitude bilaterial synchronous theta and delta vibrations and sharp waves during hyperventilation indicates dysfunction of the median brain structures and a decrease in the convulsive readiness threshold in people genetically predisposed to asthma. Such changes may be a consequence of latent neurodegenerative changes that occur under the action of low concentrations of beta-amyloid protein, the neurotoxic effect of which may be accompanied by epileptic activity of neurons (F. LaFerla, 1995). More significant, than normal, acidification of brain structures, revealed during hyperventilation in relatives of patients with asthma according to AMR,apparently reflects more pronounced than normal changes in the energy metabolism of the brain.
In relatives of BA with hyperventilation, the occurrence of paroxysmal bilaterial slow-wave activity correlates with an increase in SCP, and the more SCP increases, the greater the increase in spectral power of the delta activity. The growth of SCP is obviously a consequence of epileptiform activity, the development of which leads to significant changes in energy exchange and a decrease in pH, and consequently, an increase in SCP (F. Plum, T. Dufy, 1977). In addition, it cannot be ruled out that the increase in SCP is associated with more pronounced than normal vascular spasm and hypoxia during hyperventilation in individuals genetically predisposed to asthma. This is possible, as with other functional loads, changes in cerebral blood flow in such people are more significant than in the rest of the population (S. Bookheimer et al., 2000). In any case, there is no doubtthat the increase in SCP is associated with lactic acidosis of the brain, in conditions of its hypoxia and the development of epileptiform activity in relatives of BA. It can be assumed that this nature of the relationship between EEG and SCP occurs not only in this group, but also in other cases of lowering the threshold of convulsive readiness. Thus, in patients with epilepsy, in the presence of generalized epileptic activity in the EEG, the brain SCP, as a rule, significantly exceeds the norm. Figure 8.15 shows the EEG recorded during the interictal period with an outbreak of generalized epileptic activity.but in other cases of lowering the threshold of convulsive readiness. Thus, in patients with epilepsy, in the presence of generalized epileptic activity in the EEG, the brain SCP, as a rule, significantly exceeds the norm. Figure 8.15 shows the EEG recorded during the interictal period with an outbreak of generalized epileptic activity.but in other cases of lowering the threshold of convulsive readiness. Thus, in patients with epilepsy, in the presence of generalized epileptic activity in the EEG, the brain SCP, as a rule, significantly exceeds the norm. Figure 8.15 shows the EEG recorded during the interictal period with an outbreak of generalized epileptic activity.
SCP of the brain in a patient with epilepsy is 31 years old, and in the controla group of healthy subjects