Vascular risk factors and fMRI activation in a prodromal dementia population

Abstract

AbstractBackgroundVascular risk factors (VRF) are associated with an increased risk of developing dementia (1). Functional magnetic resonance imaging (fMRI) demonstrates the ability to detect early changes in neuronal activation before cognitive changes are clinically measurable (2). We investigate whether the number of VRF in cognitively healthy persons with a minimum of two VRF present was associated with a change in neuronal activation in the brain measured with task‐based fMRI.Methods56 cognitively healthy, defined by Mini‐Mental State Exam (MMSE) and clinical dementia rating (CDR), elderly persons completed an fMRI examination with task‐based fMRI and N‐Back paradigm to access Working Memory (WM). Vascular risk factors included in the study were stable coronary artery disease or cerebrovascular disease according to MRI criteria, hypercholesterolemia, hypertension, diabetes mellitus and overweight (3).We analyzed the fMRI data at a single time point using the FMRIB Software Library (FSL v6.0; Analysis Group, Oxford, UK).ResultsThe mean age was 68.4 (± 5.4) years. The number of VRF present were VRF2 (n = 21), VRF3 (n = 25) and VRF4 (n = 10). The median MMSE were: VRF2: 29 (IQR 29 ‐ 30), VRF3: 30 (IQR 28.8 ‐ 30) and VRF4: 29.5 (IQR 28.3 ‐ 30). A low number of VRF (VRF2) revealed higher neuronal activation than the groups with a higher number of VRF (VRF3 and VRF4). The regional activated clusters in the VRF2 group showed activation in the superior parietal lobule, visual cortex, premotor cortex, Broca’s area and anterior intra‐parietal sulcus.ConclusionOur results show that a lower neuronal activation measured with fMRI is associated with a higher number of VRF. We suggest further studies to assess whether altered neuronal activation measured by fMRI in cognitively healthy elderly persons with VRFs can be associated with a higher risk of developing cognitive decline and dementia.1. O'Brien JT, Thomas A. Vascular dementia. The Lancet. 2015;386(10004):1698‐706.2. Chen J, Glover G. Functional Magnetic Resonance Imaging Methods. Neuropsychology Review. 2015;25(3):289‐313.3. Khalifa K, Bergland AK, Soennesyn H, Oppedal K, Oesterhus R, Dalen I, et al. Effects of Purified Anthocyanins in People at Risk for Dementia: Study Protocol for a Phase II Randomized Controlled Trial. Front Neurol. 2020;11:916.