Measures of vascular dysfunction may serve as valuable clinical markers for the early detection of dementia, and for monitoring its progression. Near-Infrared Spectroscopy (NIRS) can non-invasively measure brain oxygenation by quantifying concentration changes of oxygenated (HbO) and deoxygenated haemoglobin (HbR). NIRS shows much promise for clinical translation: it has few contraindications, it can be performed at the bedside, and it is low-cost. High-Density Diffuse Optical Tomography (HD-DOT) extends this method by combining high-density NIRS with anatomical information to produce volumetric or topographical maps of brain oxygenation. Here we present an observational cohort study for Alzheimer's disease, dementia with Lewy bodies or mild cognitive impairment (n=32), which for the first time evaluates the possibility of using HD-DOT to develop biomarkers for dementia. Our early findings show that visual stimulation elicits a reduction in the magnitude of concentration changes of both HbO and HbR in Alzheimer’s Disease compared to healthy controls.
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