认知储备对不同认知阶段脑白质高信号人群脑白质纤维束完整性的影响

目的 探讨认知储备（cognitive reserve，CR）对不同认知阶段脑白质高信号（white matter hyperintensity，WMH）患者白质纤维束完整性的影响。 

Effect of Cognitive Reserve on the Integrity of White Matter Tracts in Patients with White Matter Hyperintensities at Different Cognitive Stage

Objective To investigate the effect of cognitive reserve (CR) on the integrity of white matter tractsin patients with white matter hyperintensities (WMH) across different cognitive stages.Methods This study prospectively enrolled the consecutive patients with WMH who were admittedin Department of Neurology, Nanjing Drum Tower Hospital from January 2017 to December 2020.All subjects underwent neuropsychological tests, cognitive reserve assessment and multimodalMRI scans. According to the MoCA score, the patients were divided into WMH with cognitiveimpairment (CI) group (WMH-CI) and WMH without CI group (WMH-nonCI). According to themedian cognitive reserve index (CRI), the patients were further divided into WMH-CI high CRgroup, WMH-CI low CR group, WMH-nonCI high CR group and WMH-nonCI low CR group.The integrity of white matter tracts was measured by the fractional anisotropy (FA), a diffusionparameter of white matter tracts, which was calculated by PANDA software. The two-factorANOVA was used to analyze the effects of cognitive status and CR level on cognitive function,brain volume and FA value of white matter tracts, and the correlation analysis of cognitive function,brain volume and FA value was performed.Results A total of 137 patients with WMH were included, including 39 subjects with WMHnonCIand low CR, 42 with WMH-nonCI and high CR, 35 with WMH-CI and low CR, and 21 withWMH-CI and high CR. The scores of MMSE (F =5.872, P =0.017), MoCA (F =19.310, P <0.001),executive function (F =4.329, P =0.039) and processing speed (F =15.136, P <0.001) in patients withhigh CR were significantly higher than those in patients with low CR. Cognitive status and CR levelhad an interactive effect in the FA in the left uncinate tract (F =4.324, P =0.040). For patients withoutCI, there was no statistical difference in FA value between the low CR group and high CR group(t =−0.138, P =0.891); while for patients with CI, the FA in high CR group was significantly lowerthan that in low CR group (t =2.999, P =0.004). Cognitive status and CR level had an interactioneffect in gray matter volume (F =4.949, P =0.028). In addition, both the FA in the left uncinatetract (r =0.368, P =0.003) and gray matter volume (r =0.292, P =0.020) were significantly positivelycorrelated with MoCA in patients with high CR.Conclusions In patients with WMH and normal cognitive function, there was no correlationbetween CR level and the integrity of white matter tracts. Whereas for patients with WMH and CI,the integrity of white matter tracts was significantly decreased in those with high CR and correlatedwith cognitive function.