Introduction

Cognitive complaints are common shortly after mild traumatic brain injury (mTBI) but may persist up to years. Age-related cognitive decline can worsen these symptoms. However, effects of age on mTBI sequelae have scarcely been investigated.

Methods

Fifty-four mTBI patients (median age: 35 years, range 19–64 years, 67% male) and twenty age- and sex-matched healthy controls were studied using resting state functional magnetic resonance imaging in the sub-acute phase. Independent component analysis was used to identify intrinsic connectivity networks (ICNs). A multivariate approach was adopted to evaluate the effects of age and group on the ICNs in terms of (static) functional network connectivity (FNC), intensities of spatial maps (SMs) and time-course spectral power (TC).

Results

We observed significant age-related changes for a) FNC: changes between 10 pairs of ICNs, mostly involving the default mode (DM) and/or the cognitive-control (CC) domains; b) SMs: intensity decrease in clusters across three domains and intensity increase in clusters across two domains, including the CC but not the DM and c) TC: spectral power decrease within the 0–0.15 Hz range and increase within the 0.20–0.25 Hz range for increasing age within networks located in frontal areas, including the anterior DM. Groups only differed for TC within the 0.065–0.10 Hz range in the cerebellar ICN and no age × group interaction effect was found.

Conclusions

We showed robust effects of age on connectivity between and within ICNs that are associated with cognitive functioning. Differences between mTBI patients and controls were only found for activity in the cerebellar network, increasingly recognized to participate in cognition. Our results suggest that to allow for capturing the true effects related to mTBI and its effects on cognitive functioning, age should be included as a covariate in mTBI studies, in addition to age-matching groups.

中文翻译：

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阐明年龄和轻度创伤性脑损伤对大脑网络连接的影响：静息态功能磁共振成像研究

介绍

轻度创伤性脑损伤 (mTBI) 后不久就会出现认知症状，但可能会持续数年。与年龄相关的认知能力下降会使这些症状恶化。然而，年龄对 mTBI 后遗症的影响几乎没有被研究过。

方法

54 名 mTBI 患者（中位年龄：35 岁，范围 19-64 岁，67% 为男性）和 20 名年龄和性别匹配的健康对照者在亚急性期使用静息态功能磁共振成像进行了研究。独立成分分析用于识别内在连接网络（ICN）。采用多变量方法来评估年龄和群体在（静态）功能网络连接（FNC）、空间图强度（SM）和时程频谱功率（TC）方面对ICN的影响。

结果

我们观察到 a) FNC 与年龄相关的显着变化：10 对 ICN 之间的变化，主要涉及默认模式 (DM) 和/或认知控制 (CC) 域；b) SM：三个域中簇的强度降低，两个域中簇的强度增加，包括 CC，但不包括 DM；c) TC：光谱功率在 0–0.15 Hz 范围内减少，在 0.20–0.25 Hz 范围内增加位于额叶区域（包括前部 DM）的网络中年龄增长的范围。各组仅在小脑 ICN 的 0.065–0.10 Hz 范围内 TC 存在差异，并且未发现年龄 × 组交互效应。

结论

我们发现，年龄对与认知功能相关的 ICN 之间和内部的连接有显着影响。mTBI 患者和对照组之间的差异仅存在于小脑网络的活动上，人们越来越认识到小脑网络参与认知。我们的结果表明，为了捕捉与 mTBI 相关的真实影响及其对认知功能的影响，除了年龄匹配组之外，年龄还应作为 mTBI 研究的协变量。