Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
Brain Res. 2021 Dec 15;1773:147687. doi: 10.1016/j.brainres.2021.147687. Epub 2021 Oct 9.
Multiple Sclerosis (MS) is a neurodegenerative disease in which pathophysiology and symptom progression presents differently between the sexes. In a cohort of people with MS (n = 110), we used transcranial magnetic stimulation (TMS) to investigate sex differences in corticospinal excitability (CSE) and sex-specific relationships between CSE and cognitive function. Although demographics and disease characteristics did not differ between sexes, males were more likely to have cognitive impairment as measured by the Montreal Cognitive Assessment (MoCA); 53.3% compared to females at 26.3%. Greater CSE asymmetry was noted in females compared to males. Females demonstrated higher active motor thresholds and longer silent periods in the hemisphere corresponding to the weaker hand which was more typical of hand dominance patterns in healthy individuals. Males, but not females, exhibited asymmetry of nerve conduction latency (delayed MEP latency in the hemisphere corresponding to the weaker hand). In males, there was also a relationship between delayed onset of ipsilateral silent period (measured in the hemisphere corresponding to the weaker hand) and MoCA, suggestive of cross-callosal disruption. Our findings support that a sex-specific disruption in CSE exists in MS, pointing to interhemispheric disruption as a potential biomarker of cognitive impairment and target for neuromodulating therapies.
多发性硬化症（MS）是一种神经退行性疾病，其病理生理学和症状进展在性别之间存在差异。在一组多发性硬化症患者（n=110）中，我们使用经颅磁刺激（TMS）来研究皮质脊髓兴奋性（CSE）的性别差异，以及 CSE 与认知功能之间的性别特异性关系。尽管男女之间的人口统计学和疾病特征没有差异，但男性更有可能出现认知障碍，这是通过蒙特利尔认知评估（MoCA）来衡量的；53.3%的男性比 26.3%的女性更有可能出现认知障碍。与男性相比，女性的 CSE 不对称性更高。女性在与较弱手相对应的半球中表现出更高的主动运动阈值和更长的静息期，这更符合健康个体的手优势模式。男性而不是女性表现出神经传导潜伏期的不对称性（较弱手相对应的半球中的 MEP 潜伏期延迟）。男性的同侧静息期起始延迟（在较弱手相对应的半球中测量）与 MoCA 之间也存在关系，提示交叉胼胝体中断。我们的研究结果支持多发性硬化症中存在 CSE 的性别特异性破坏，这指向了半球间中断作为认知障碍的潜在生物标志物和神经调节治疗的目标。
