Department of Physical Therapy, University of British Columbia, Vancouver, Canada; Graduate Programs in Rehabilitation Sciences, University of British Columbia, Vancouver, Canada.
Department of Physical Therapy, University of British Columbia, Vancouver, Canada.
Neuroimage Clin. 2022;36:103174. doi: 10.1016/j.nicl.2022.103174. Epub 2022 Aug 30.
Processing speed and executive function are often impaired after stroke and in typical aging. However, there are no reliable neurological markers of these cognitive impairments. The trail making test (TMT) is a common index of processing speed and executive function. Here, we tested candidate MRI markers of TMT performance in a cohort of older adults and individuals with chronic stroke.
In 61 older adults and 32 individuals with chronic stroke, we indexed white matter structure with region-specific lesion load (of white matter hyperintensities (WMHs) and stroke lesions) and diffusion tensor imaging (DTI) from four regions related to TMT performance: the anterior thalamic radiations (ATR), superior longitudinal fasciculus (SLF), forceps minor, and cholinergic pathways. Regression modelling was used to identify the marker(s) that explained the most variance in TMT performance.
DTI metrics of the ATR related to processing speed in both the older adult (TMT A: β = -3.431, p < 0.001) and chronic stroke (TMT A: β = 11.282, p < 0.001) groups. In the chronic stroke group executive function was best predicted by a combination of ATR and forceps minor DTI metrics (TMT B: R = 0.438, p < 0.001); no significant predictors of executive function (TMT B) emerged in the older adult group. No imaging metrics related to set shifting (TMT B-A). Regional DTI metrics predicted TMT performance above and beyond whole-brain stroke and WMH volumes and removing whole-brain lesion volumes improved model fits.
In this comprehensive assessment of candidate imaging markers, we demonstrate an association between ATR microstructure and processing speed and executive function performance. Regional DTI metrics provided better predictors of cognitive performance than whole-brain lesion volumes or regional lesion load, emphasizing the importance of lesion location in understanding cognition. We propose ATR DTI metrics as novel candidate imaging biomarker of post-stroke cognitive impairment.
处理速度和执行功能在中风后和典型老化中经常受损。然而，这些认知障碍没有可靠的神经学标志物。连线测试（TMT）是处理速度和执行功能的常用指标。在这里，我们在一组老年人和慢性中风患者中测试了 TMT 表现的候选 MRI 标志物。
在 61 名老年人和 32 名慢性中风患者中，我们使用特定区域的病变负荷（白质高信号（WMHs）和中风病变）和来自与 TMT 表现相关的四个区域的扩散张量成像（DTI）来标记白质结构：前丘脑辐射（ATR）、上纵束（SLF）、小内囊和胆碱能通路。回归模型用于确定解释 TMT 表现变化最大的标志物。
ATR 的 DTI 指标与老年人（TMT A：β=-3.431，p<0.001）和慢性中风（TMT A：β=11.282，p<0.001）组的处理速度有关。在慢性中风组中，ATR 和小内囊的 DTI 指标的组合可最佳预测执行功能（TMT B：R=0.438，p<0.001）；老年人组中没有出现执行功能（TMT B）的显著预测指标。与设定转换（TMT B-A）无关的任何影像学指标。区域 DTI 指标预测 TMT 表现优于全脑中风和 WMH 体积，并且去除全脑病变体积可以改善模型拟合度。
在对候选成像标志物的全面评估中，我们证明了 ATR 微观结构与处理速度和执行功能表现之间存在关联。区域 DTI 指标比全脑病变体积或区域病变负荷提供了更好的认知表现预测指标，这强调了了解认知时病变位置的重要性。我们提出 ATR DTI 指标作为中风后认知障碍的新型候选成像生物标志物。
