Temporal Pattern of Cortical Hypoxia in Multiple Sclerosis and Its Significance on Neuropsychological and Clinical Measures of Disability

• Published in: Annals of neurology Vol. 94; no. 6; pp. 1067 - 1079
• Main Authors: Adingupu, Damilola D., Evans, Taelor, Soroush, Ateyeh, Hansen, Ayden, Jarvis, Scott, Brown, Lenora, Dunn, Jeff F.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.12.2023
• Subjects: Autoimmune diseases; Central nervous system; Chronic illnesses; Cognition; Cognitive ability; Demyelination; Fatigue - etiology; Hemoglobin; Humans; Hypoxia; Infrared spectroscopy; Microvasculature; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting; Near infrared radiation; Oxygenation; Parameters; Pathogenesis; Reproducibility; Reproducibility of Results
• ISSN: 0364-5134; 1531-8249; 1531-8249
• DOI: 10.1002/ana.26769

Multiple sclerosis (MS) is a degenerative disease of the central nervous system (CNS) characterized by inflammation, demyelination, and axonal damage. It has been hypothesized that hypoxia plays a role in the pathogenesis of MS. This study was undertaken to investigate the reproducibility of non-invasively measured cortical microvascular hemoglobin oxygenation (S O ) using frequency domain near-infrared spectroscopy (fdNIRS), investigate its temporal pattern of hypoxia in people with MS (pwMS), and its relationship with neurocognitive function and mood. We investigated the reproducibility of fdNIRS measurements. We measured cortical hypoxia in pwMS, and the relationships between S O , neurocognitive function, fatigue, and measures of physical disability. Furthermore, we cataloged the temporal pattern of S O measured at 1-week intervals for 4 weeks, and at 8 weeks and ~1 year. We show that fdNIRS parameters were highly reproducible in 7 healthy control participants measured over 6 days (p > 0.05). There was low variability between and within subjects. In line with our previous findings, we show that 33% of pwMS (n = 88) have cortical microvascular hypoxia. Over 8 weeks and at ~1 year, S O values for normoxic and hypoxic groups did not change significantly. There was no significant association between cognitive function and S O . This conclusion should be revisited as only a small proportion of the relapsing-remitting MS group (21%) was cognitively impaired. The fdNIRS parameters have high reproducibility and repeatability, and we have demonstrated that hypoxia in MS is a chronic condition, lasting at least a year. The results show a weak relationship between cognitive functioning and oxygenation, indicating future study is required. ANN NEUROL 2023;94:1067-1079.