White Matter and Cognitive Function in T2DM

Type 2 diabetes mellitus (T2DM) patients have a greater risk than the general population for developing dementia; this is particularly true among patients with mild cognitive impairment (MCI). A better understanding of the microstructural change of white matter between T2DM patients with amnesic MCI (T2DM-aMCI) and T2DM patients with normal cognition (T2DM-NC), as well as how these correlate with cognitive performances, may shed light on brain variations associated with T2DM-related amnesic cognitive impairment. In this paper, researchers evaluated 36 T2DM-aMCI patients, 40 T2DM-NC patients, and 40 healthy controls using diffusion tensor image and T1-weighted MRI scans as well as comprehensive cognition assessments. White matter integrity did not significantly differ between the T2DM-NC patients and healthy controls. Compared to the T2DM-NC patients and healthy controls, the T2DM-aMCI group presented disrupted integrity in numerous white matter tracts; the researchers observed in particular that the damaged white matter integrity of the right inferior fronto-occipital fasciculus and the right inferior longitudinal fasciculus were significantly correlated with episodic memory and attention function impairment in T2DM patients. An association was also observed between cognitive impairment-related white matter microstructural damage and the degeneration of the cortex connected to the affected white matter tract. The authors concluded that there is significant degeneration in white matter tracts in T2DM-aMCI patients, but there is no brain white matter damage in T2DM-NC.