Brain hypoxia, neurocognitive impairment, and quality of life in people post-COVID-19

Abstract

Objective Systemic hypoxia occurs in COVID-19 infection; however, it is unknown if cerebral hypoxia occurs in convalescent individuals. We have evidence from other conditions associated with central nervous system inflammation that hypoxia may occur in the brain. If so, hypoxia could reduce the quality of life and brain function. This study was undertaken to assess if brain hypoxia occurs in individuals after recovery from acute COVID-19 infection and if this hypoxia is associated with neurocognitive impairment and reduced quality of life. Methods Using frequency-domain near-infrared spectroscopy (fdNIRS), we measured cerebral tissue oxygen saturation (StO2) (a measure of hypoxia) in participants who had contracted COVID-19 at least 8 weeks prior to the study visit and healthy controls. We also conducted neuropsychological assessments and health-related quality of life assessments, fatigue, and depression. Results Fifty-six percent of the post-COVID-19 participants self-reported having persistent symptoms (from a list of 18), with the most reported symptom being fatigue and brain fog. There was a gradation in the decrease of oxyhemoglobin between controls, and normoxic and hypoxic post-COVID-19 groups (31.7 ± 8.3 μM, 27.8 ± 7.0 μM and 21.1 ± 7.2 μM, respectively, p = 0.028, p = 0.005, and p = 0.081). We detected that 24% of convalescent individuals’ post-COVID-19 infection had reduced StO2 in the brain and that this relates to reduced neurological function and quality of life. Interpretation We believe that the hypoxia reported here will have health consequences for these individuals, and this is reflected in the correlation of hypoxia with greater symptomology. With the fdNIRS technology, combined with neuropsychological assessment, we may be able to identify individuals at risk of hypoxia-related symptomology and target individuals that are likely to respond to treatments aimed at improving cerebral oxygenation.

Cluster Analysis Identifies Long Covid Subtypes in Belgian Patients

“…Cluster 2, characterized by pure neurocognitive disorders (concentration, memory, and phasic disorders), might be a consequence of cerebral hypoxia, as this has been suggested as a pathophysiological mechanism for neurological symptoms associated with long Covid[25] [26]. In this group, an associated inflammatory component may also play a role in the onset of neurocognitive disorders.…”

Effect of oxygen therapy duration on cognitive impairment 12 months after hospitalization for SARS-COV-2 infection

“…A link between hypoxaemia and cognitive impairment has been reported in other nosological settings ( 36 ), providing additional support for this hypothesis. Finally, Adingupu et al ( 37 ) used the frequency-domain near-infrared spectroscopy (NIRS) to measure cerebral tissue oxygen saturation in patient at 8 month post-SARS-CoV-2 infection. They found correlation between persisting hypoxia, supposed to be related to inflammation, and brain fog and fatigue The use of NIRS in clinical practice seems thus to be an interesting work track.…”

“…It is also noteworthy that there was no correlation in the current study between cognitive impairment and the presence of symptoms of anxiety or depression, as assessed by the HADS scale, or fatigue assessed by the MFIS. This point is also debated in the literature, with some authors finding an association between cognitive impairments and psychiatric disorders (23,37,53,54), whereas others did not find any such relationship (49,61). There is potential for bias, such as the presence of anxiety or depressive symptoms after SARS-CoV-2 independently of any confirmed cognitive dysfunction (40).…”

Promising Strategies to Reduce the SARS-CoV-2 Amyloid Deposition in the Brain and Prevent COVID-19-Exacerbated Dementia and Alzheimer’s Disease

“…There is also indirect mechanism of COVID-19-related AD dementia. COVID-19 as a respiratory diseases causes hypoxic changes to which the brain is highly sensitive [ 93 , 94 , 95 , 96 ]. It is noted that dementia and Aβ depositions are often accompanied by hypoxia of brain tissues [ 97 , 98 , 99 , 100 , 101 , 102 , 103 ].…”