Cognitive impairments are frequent in patients with Multiple Sclerosis (MS). Yet, the influence of MS-related symptoms on cognitive status is not clear. Studies investigating the impact of trait fatigue along with anxio-depressive symptoms on cognition are seldom, and even less considered fatigue as multidimensional. Moreover, these studies provided conflicting results. Twenty-nine MS patients and 28 healthy controls, matched on age, gender and education underwent a full comprehensive neuropsychological assessment. Anxio-depressive and fatigue symptoms were assessed using the HAD scale and the MFIS, respectively. Six composite scores were derived from the neuropsychological assessment, reflecting the cognitive domains of working memory, verbal and visual learning, executive functions, attention and processing speed. Stepwise regression analyses were conducted in each group to investigate if trait cognitive and physical fatigue, depression and anxiety are relevant predictors of performance in each cognitive domain. In order to control for disease progression, patient's EDSS score was also entered as predictor variable. In the MS group, trait physical fatigue was the only significant predictor of working memory score. Cognitive fatigue was a predictor for executive functioning performance and for processing speed (as well as EDSS score for processing speed). In the healthy controls group, only an association between executive functioning and depression was observed. Fatigue predicted cognition in MS patients only, beyond anxio-depressive symptoms and disease progression. Considering fatigue as a multidimensional symptom is paramount to better understand its association with cognition, as physical and cognitive fatigue are predictors of different cognitive processes.

中文翻译：

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多发性硬化症特征疲劳与认知之间的复杂相互作用。

多发性硬化症 (MS) 患者经常出现认知障碍。然而，MS 相关症状对认知状态的影响尚不清楚。很少有研究调查特质疲劳以及焦虑抑郁症状对认知的影响，甚至更少将疲劳视为多维度的。此外，这些研究提供了相互矛盾的结果。29 名 MS 患者和 28 名健康对照，在年龄、性别和教育方面相匹配，接受了全面的神经心理学评估。分别使用 HAD 量表和 MFIS 评估焦虑抑郁和疲劳症状。六个综合分数来自神经心理学评估，反映了工作记忆、语言和视觉学习、执行功能、注意力和处理速度的认知领域。在每组中进行逐步回归分析，以调查特质认知和身体疲劳、抑郁和焦虑是否是每个认知领域表现的相关预测因子。为了控制疾病进展，患者的 EDSS 评分也作为预测变量输入。在 MS 组中，特质身体疲劳是工作记忆评分的唯一显着预测因子。认知疲劳是执行功能表现和处理速度（以及处理速度的 EDSS 评分）的预测指标。在健康对照组中，仅观察到执行功能与抑郁之间的关联。除了焦虑抑郁症状和疾病进展之外，疲劳仅预测 MS 患者的认知。