Supplementary Material for: White Matter Hyperintensities Are Associated with Slower Gait Speed in Older Adults Without Dementia

Background: Slow gait speed is associated with poor health outcomes in aging, but the relationship between cerebral small vessel disease (CSVD) pathologies and gait speed in aging is not well understood. We investigated the relationships between cerebral small vessel disease (CSVD) imaging markers and gait speed during simple (normal pace walking (NPW)) and complex (walking-while talking (WWT)) as both measures are associated with shared health outcomes such as falls, frailty, disability, mortality, and dementia.
Methods: A total of 113 Ashkenazi Jewish adults over 65 (M age=78.6±6.3 years, 45.8% women) and without dementia were examined. Established rating systems were used to quantify white matter hyperintensities (WMH) and lacunes of presumed vascular origin from Fluid Attenuated Inversion Recovery (FLAIR) images. Linear regression models adjusted for age, sex, global health, and total intracranial volume were used to examine associations between CSVD markers and gait speed during NPW and WWT. Student t-tests were used to contrast gait speed in those with “confluent-diffuse” WMH and those with “mild or no” WMH.
Results: The number of WMH in the basal ganglia (β=-3.274 cm/s p=.047) and temporal lobes (β=-3.113 cm/s p=.048) were associated with slower NPW speed in adjusted models. Participants with higher CSVD burden (confluent-diffuse pattern) in the frontal lobe (94.65 cm/s vs. 105.21 cm/s, p=.018) and globally (98.98 cm/s vs. 107.24 cm/s, p=.028) also had lower NPW speed. WMH were not associated with WWT speeds. Lacunes were not associated with NPW or WWT speed.
Conclusion: Adjusted models found higher CSVD burden as measured by the presence of WMH in the basal ganglia and temporal lobes were associated with slower normal pace gait speed in older adults, but not with complex walking speeds. Participants with confluent-diffuse WMHs in the frontal lobes were found to have slower average normal gait speed. Further studies are needed to establish the temporality of WMH and gait speed decline as well as mechanistic links between the two.

研究背景：步态速度缓慢与老年人群的不良健康结局相关，但目前学界对脑小血管病（cerebral small vessel disease, CSVD）病理改变与老年人群步态速度之间的关联尚不清楚。本研究探讨了脑小血管病影像学标志物与简单步态（正常步速行走，normal pace walking, NPW）及复杂步态（边行走边交谈，walking-while talking, WWT）时的步态速度之间的关联，因为这两种步态测量指标均与跌倒、衰弱、残疾、死亡及痴呆等共同的健康结局相关。
研究方法：本研究共纳入113名65岁以上、无痴呆的阿什肯纳兹犹太裔成年人，平均年龄为78.6±6.3岁，女性占比45.8%。研究采用已建立的评分系统，从液体衰减反转恢复（Fluid Attenuated Inversion Recovery, FLAIR）影像中量化白质高信号（white matter hyperintensities, WMH）及推测为血管源性的腔隙灶。本研究采用校正了年龄、性别、整体健康状况及颅内总体积的线性回归模型，分析脑小血管病标志物与正常步速行走及边行走边交谈时的步态速度之间的关联。采用学生t检验对比存在“融合弥漫型”白质高信号与“轻度或无”白质高信号人群的步态速度差异。
研究结果：在校正模型中，基底节区的白质高信号数量（β=-3.274 cm/s，p=0.047）及颞叶的白质高信号数量（β=-3.113 cm/s，p=0.048）与较慢的正常步速行走速度相关。额叶存在更高脑小血管病负荷（融合弥漫型表现）的参与者（94.65 cm/s vs 105.21 cm/s，p=0.018）以及全脑存在更高脑小血管病负荷的参与者（98.98 cm/s vs 107.24 cm/s，p=0.028）的正常步速行走速度也更慢。白质高信号与边行走边交谈时的步态速度无关联。腔隙灶与正常步速行走或边行走边交谈时的步态速度均无关联。
研究结论：校正模型显示，以基底节区及颞叶白质高信号存在情况评估的更高脑小血管病负荷，与老年人群较慢的正常步速步态速度相关，但与复杂行走时的步态速度无关。额叶存在融合弥漫型白质高信号的参与者，其平均正常步态速度更慢。未来仍需开展进一步研究，以明确白质高信号与步态速度下降的时间先后关系，以及二者之间的潜在机制关联。