Causes, effects and connectivity changes in MS-related cognitive decline

Cognitive decline is a frequent but undervalued aspect of multiple sclerosis (MS). Currently, it remains unclear what the strongest determinants of cognitive dysfunction are, with grey matter damage most directly related to cognitive impairment. Multi-parametric studies seem to indicate that individual factors of MS-pathology are highly interdependent causes of grey matter atrophy and permanent brain damage. They are associated with intermediate functional effects (e.g. in functional MRI) representing a balance between disconnection and (mal) adaptive connectivity changes. Therefore, a more comprehensive MRI approach is warranted, aiming to link structural changes with functional brain organization. To better understand the disconnection syndromes and cognitive decline in MS, this paper reviews the associations between MRI metrics and cognitive performance, by discussing the interactions between multiple facets of MS pathology as determinants of brain damage and how they affect network efficiency.认知衰退是多发性硬化（multiple sclerosis, MS）的常见表现之一，却长期未得到足够重视。目前，学界尚未明确认知功能障碍最关键的致病因素，而灰质损伤与认知损害的关联最为直接。多参数研究表明，多发性硬化病理的各类独立因素彼此高度相互依存，均为引发灰质萎缩与永久性脑损伤的致病诱因。此类因素与中间功能效应密切相关——例如在功能磁共振成像（functional MRI）中观测到的中间功能效应，这类效应体现了脑连接断开与（异常）适应性连接改变之间的动态平衡。因此，亟需采用更为全面的磁共振成像策略，旨在将脑结构改变与脑功能组织模式建立关联。为更深入地理解多发性硬化患者的脑连接断开综合征与认知衰退，本文综述了磁共振成像指标与认知表现之间的关联，通过探讨多发性硬化病理的多个层面作为脑损伤致病因素时的相互作用，以及这些因素如何影响脑网络效率。