Spontaneous cerebrovascular reactivity at rest in older adults with and without mild cognitive impairment and memory deficits

Allison C Engstrom; John Paul M Alitin; Arunima Kapoor; Shubir Dutt; Trevor Lohman; Isabel J Sible; Anisa J Marshall; Fatemah Shenasa; Aimée Gaubert; Farrah Ferrer; Amy Nguyen; David Robert Bradford; Kathleen Rodgers; Lorena Sordo; Elizabeth Head; Xingfeng Shao; Danny J J Wang; Daniel A Nation

doi:10.1002/alz.14396

Spontaneous cerebrovascular reactivity at rest in older adults with and without mild cognitive impairment and memory deficits

Alzheimers Dement. 2024 Nov 18. doi: 10.1002/alz.14396. Online ahead of print.

Authors

Allison C Engstrom¹, John Paul M Alitin², Arunima Kapoor¹, Shubir Dutt³, Trevor Lohman², Isabel J Sible⁴, Anisa J Marshall⁴, Fatemah Shenasa¹, Aimée Gaubert², Farrah Ferrer², Amy Nguyen², David Robert Bradford⁵, Kathleen Rodgers⁵, Lorena Sordo⁶, Elizabeth Head⁶, Xingfeng Shao⁷, Danny J J Wang⁷, Daniel A Nation^{2

8}

Affiliations

¹ Department of Psychological Science, University of California, Irvine, Irvine, California, USA.
² Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA.
³ Memory and Aging Center, Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, California, USA.
⁴ Department of Psychology, University of Southern California, Los Angeles, California, USA.
⁵ Center for Innovations in Brain Science, Department of Pharmacology, University of Arizona, Tucson, Arizona, USA.
⁶ Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, California, USA.
⁷ Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, California, USA.
⁸ Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

PMID: 39555916
DOI: 10.1002/alz.14396

Abstract

Introduction: Older adults with mild cognitive impairment (MCI) exhibit deficits in cerebrovascular reactivity (CVR), suggesting CVR is a biomarker for vascular contributions to MCI. This study examined if spontaneous CVR is associated with MCI and memory impairment.

Methods: One hundred sixty-one older adults free of dementia or major neurological/psychiatric disorders were recruited. Participants underwent clinical interviews, cognitive testing, venipuncture for Alzheimer's disease (AD) biomarkers, and brain magnetic resonance imaging. Spontaneous CVR was quantified during 5 minutes of rest. Respiratory gases analyzed through nasal cannula to quantify end-tidal carbon dioxide (_ETCO₂) levels were used to estimate CVR.

Results: Whole brain CVR was negatively associated with age, but not MCI. Lower CVR in the parahippocampal gyrus (PHG) was found in participants with MCI and was linked to worse memory performance on memory tests. Results remained significant after adjusting for AD biomarkers and vascular risk factors.

Discussion: Spontaneous CVR deficits in the PHG are observed in older adults with MCI and memory impairment, suggesting medial temporal microvascular dysfunction is observed in cognitive decline.

Highlights: Aging is associated with decline in whole brain spontaneous cerebrovascular reactivity (CVR). Older adults with mild cognitive impairment exhibit deficits in spontaneous CVR in the parahippocampal gyrus (PHG). Memory impairment is correlated with reduced spontaneous CVR in the PHG.

Keywords: amnestic mild cognitive impairment; memory impairment; mild cognitive impairment; spontaneous cerebrovascular reactivity.

Abstract

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