Correlations between vascular properties and mental dysfunctions in long-COVID-19 support the vascular depression hypothesis

Objectives

Vascular depression hypothesis (VDH) bases on co-occurrence of vascular and mental dysfunctions in advanced age; however, there may be still a controversy about whether there is some direct association between vascular and mental properties or the co-occurrence is only a statistical artifact caused by commonness of these dysfunctions in the elderly. COVID-19 gave opportunity to test VDH under conditions different from aging.

Methods

25 patients were examined 3–6 month after SARS-CoV-2 infection. Subjective worsening of mental functions, presumably caused by the disease, was quantified with three psychometric tests. Blood flow waveforms were obtained for the left brachial and common carotid arteries. The waveform shape changes continuously with age; therefore, an individual shape can be characterized by the index WA being the calendar age (CA) of the average healthy rested subject having the most similar shape (consequently, in healthy rested subjects WA-CA = 0, in average). The mathematical functional analysis was used to calculate WA.

Results

Brachial WA-CA = 13 yrs, in average (p < 0.00005; Cohen’s d = 0.99), and was correlated with tests scores (r = 0.55, 0.65, 0.46). Mean carotid WA-CA were smaller (7.2 and 1.6) but they were also correlated with the scores (right: r = 0.44, 0.55, 0.32; left: r = 0.49, 0.51, 0.38). Scores of two tests were inversely correlated with the systolic (r = -0.54, −0.58) and diastolic (r = -0.46, −0.56) pressures.

Conclusions

Since neither vascular nor mental problems are common after COVID-19, these relatively high correlations indicate that vascular and mental properties are not independent, i.e., they support VDH. Note that this not only concerns cerebral vasculature.