Subclinical neurovascular alterations may precede cognitive decline in adults with type 1 diabetes. This study was presented at the European Association for the Study of Diabetes Congress 2025. 

Fifty-six adults with type 1 diabetes and seventy-one normoglycemic controls underwent fasting cognitive and cortical assessments using the Montreal Cognitive Assessment and functional near-infrared spectroscopy. Visual cortex responses to checkerboard stimuli and prefrontal/motor cortical responses during Stroop tasks were measured, assessing neurovascular unit function. 

Despite similar cognitive performance between groups, type 1 diabetes participants exhibited blunted oxyhemoglobin responses, shorter latency to peak in visual cortices, and reduced middle dorsolateral prefrontal cortex activation during executive function tasks. These changes were significantly correlated with glycemic control metrics, including HbA1c and time in/out of range, suggesting that both chronic hyperglycemia and glucose excursions negatively impact cortical oxygenation.

The findings underscore early, subclinical neurovascular unit dysfunction in type 1 diabetes, detectable with functional neuroimaging before overt cognitive deficits emerge. These results highlight the potential for cortical oxygenation metrics as sensitive biomarkers for monitoring neurovascular health and guiding early interventions in diabetes management.