Parameters of cerebral blood flow of 7- to 11-year-old children living in northern European Russia

Abstract

Doppler sonography and rheoencephalography were used to study cerebral hemodynamics of young schoolchildren in the village of Klimovskoe (Konosha raion, Arkhangel’sk oblast, Russia). Mean linear blood flow velocities (LBVs) in the major cerebral vessels did not differ significantly from the velocities measured in age-matched children living in St. Petersburg. The index of resistivity was lower in the residents of the North than in their counterparts in St. Petersburg, which suggests a decreased tone of resistive vessels of the children living in the North. Asymmetry of the LBVs through the homonymous cerebral arteries of the left and right hemispheres was found in 67% of children examined. Asymmetry of the LBVs in the anterior, middle, and posterior cerebral and vertebral arteries (VAs) was correlated with a malformed posture (such as scoliosis or a slouch). In most children examined, sideward head rotation was accompanied by compression of VAs at the level of the C1 and C2 cervical vertebrae; in 71% of them, this condition could be regarded as a hemodynamically significant stenosis. In all children, a decreased LBV observed in one of the VAs was completely compensated by an increased LBV in its contralateral counterpart. Doppler sonographic signs of dystonic VAs and/or asymmetrical LBVs in the VAs were found in 79% of children examined. These children can be supposed to have latent disorders of blood flow in the VA basins caused by vertebral influences (related to irritation of the periarterial nervous plexus or cervical autonomic plexuses). The schoolchildren living in the North exhibited a lower reactivity of their cerebral vessels to hypo-and hypercapnia than their counterparts living in the central parts of the Russian Federation or in St. Petersburg. Regional differences were found in the sensitivity of cerebral vessels to hypocapnia. The volume of blood in the basins of the internal carotid arteries determined in a hypocapnic test was decreased; it was increased in the basins of VAs. This fact can be interpreted as a regional redistribution of the cerebral circulation caused by extreme environmental factors stimulating vital regulatory sites of the brainstem.