Department of Radiology, Albert Einstein College of Medicine, Gruss Magnetic Resonance Research Center, Bronx, NY, USA.
Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, NY, USA.
Neurorehabil Neural Repair. 2023 Apr;37(4):205-217. doi: 10.1177/15459683231164787. Epub 2023 Apr 18.
Mobility impairment is common in older persons with multiple sclerosis (MS), and further compounded by general age-related mobility decline but its underlying brain substrates are poorly understood.
Examine fronto-striatal white matter (WM) integrity and lesion load as imaging correlates of mobility outcomes in older persons with and without MS.
Fifty-one older MS patients (age 64.9 ± 3.7 years, 29 women) and 50 healthy, matched controls (66.2 ± 3.2 years, 24 women), participated in the study, which included physical and cognitive test batteries and 3T MRI imaging session. Primary imaging measures were fractional anisotropy (FA) and WM lesion load. The relationship between mobility impairment, defined using a validated short physical performance battery cutoff score, and neuroimaging measures was assessed with stratified logistic regression models. FA was extracted from six fronto-striatal circuits (left/right): dorsal striatum (dStr)-to-anterior dorsolateral prefrontal cortex (aDLPFC), dStr-to-posterior DLPFC, and ventral striatum (vStr)-to-ventromedial prefrontal cortex (VMPFC).
Mobility impairment was significantly associated with lower FA in two circuits, left dStr-aDLPFC ( = .003) and left vStr-VMPFC ( = .004), in healthy controls but not in MS patients ( > .20), for fully adjusted regression models. Conversely, in MS patients but not in healthy controls, mobility impairment was significantly associated with greater lesion volume ( < .02).
Comparing older persons with and without MS, we provide compelling evidence of a double dissociation between the presence of mobility impairment and two neuroimaging markers of white matter integrity, fronto-striatal fractional anisotropy, and whole brain lesion load.
多发性硬化症（MS）患者中常见行动障碍，且随着年龄增长，行动能力进一步下降，但目前对其潜在的大脑基础知之甚少。
探讨额纹状体白质（WM）完整性和病变负荷作为有和无 MS 的老年人运动能力结果的影像学相关因素。
51 名老年 MS 患者（年龄 64.9±3.7 岁，29 名女性）和 50 名健康、匹配的对照者（66.2±3.2 岁，24 名女性）参与了本研究，其中包括身体和认知测试组合以及 3T MRI 成像检查。主要影像学指标为各向异性分数（FA）和 WM 病变负荷。使用验证过的短体能表现测试电池截止评分定义的行动障碍与神经影像学指标之间的关系，通过分层逻辑回归模型进行评估。FA 从六个额纹状体回路（左/右）中提取：左侧/右侧纹状体（dStr）至前背外侧前额叶皮层（aDLPFC）、dStr 至后背外侧前额叶皮层（dStr）和腹侧纹状体（vStr）至腹内侧前额叶皮层（VMPFC）。
在健康对照组中，行动障碍与两个回路的 FA 显著相关，左侧 dStr-aDLPFC（ = .003）和左侧 vStr-VMPFC（ = .004），但在 MS 患者中则无显著相关性（ > .20），在完全调整的回归模型中。相反，在 MS 患者中，行动障碍与更大的病变体积显著相关（ < .02），但在健康对照组中则无显著相关性。
通过比较有和无 MS 的老年人，我们提供了有力的证据，证明了行动障碍与额纹状体 WM 完整性的两个影像学标志物（FA 和全脑病变负荷）之间存在双重分离。
