Frequency analysis based on synchrosqueezed wavelet transforms of brain and heart rhythms in cases of cerebral vascular pathology

Introduction: The analysis of interrelationships between the bioelectric activity of the brain and heart is one of the topical issues in modern neuroscience. Special attention of researchers in this area is attracted by the study of these interrelationships in cases of cerebral vascular pathology. Purpose: The use of synchrosqueezed wavelet transforms to measure the relationship between the rhythms of the brain and heart in cases of vascular pathology of varying severity before and during hyperventilation load. Results: The analysis of instantaneous frequencies has been carried out in the low-frequency components of an electroencephalogram and the RR interval time series extracted from the electrocardiogram of patients with vascular pathology of varying severity before and during hyperventilation. The research shows that the time when a correlation between instantaneous frequencies of the infra-slow oscillations of an electroencephalogram and the RR interval time series occurs is related to the degree of severity of cerebral vascular pathology. It has been found that the greater the severity of the vascular pathology of the brain, the faster a correlation occurs between instantaneous frequencies in the low-frequency components of an electroencephalogram and heart rate variability. Practical relevance: The discovered peculiarities of the frequency interrelationships between the rhythms of the brain and heart during hyperventilation may be useful for the search of neurophysiological correlates of the degree of severity of cerebral vascular pathology.