Purpose

Our study examines brain metabolic connectivity in SARS-CoV-2 survivors during the acute-subacute and chronic phases, aiming to elucidate the mechanisms underlying the persistence of neurological symptoms in long-COVID patients.

Methods

We perfomed a cross-sectional study including 44 patients (pts) with neurological symptoms who underwent FDG-PET scans, and classified to timing infection as follows: acute (7 pts), subacute (17 pts), long-term (20 pts) phases. Interregional correlation analysis (IRCA) and ROI-based IRCA were applied on FDG-PET data to extract metabolic connectivity in resting state networks (ADMN, PDMN, EXN, ATTN, LIN, ASN) of neuro-COVID pts in acute/subacute and long-term groups compared with healthy controls (HCs). Univariate approach was used to investigate metabolic alterations from the acute to sub-acute and long-term phase.

Results

The acute/subacute phase was characterized by hyperconnectivity in EXN and ATTN networks; the same networks showed hypoconnectivity in the chronic phase. EXN and ATTN hypoconnectivity was consistent with clinical findings in long-COVID patients, e.g. altered performances in neuropsychological tests of executive and attention domains. The ASN and LIN presented hyperconnectivity in acute/subacute phase and normalized in long-term phase. The ADMN and PDMN presented a preseverved connectivity. Univariate analysis showed hypometabolism in fronto-insular cortex in acute phase, which reduced in sub-acute phase and disappeared in long-term phase.

Conclusion

A compensatory EXN and ATTN hyperconnectivity was found in the acute/subacute phase and hypoconnectivity in long-term. Hypoconnectivity and absence of hypometabolism suggest that connectivity derangement in frontal networks could be related to protraction of neurological symptoms in long-term COVID patients.

中文翻译：

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伴有认知症状的长期 COVID 脑代谢连接持续功能障碍

 目的

我们的研究检查了 SARS-CoV-2 幸存者在急性-亚急性和慢性阶段的脑代谢连接，旨在阐明长期 COVID 患者神经系统症状持续存在的潜在机制。

 方法

我们进行了一项横断面研究，包括 44 例接受 FDG-PET 扫描的有神经系统症状的患者 （pts），并分为以下时间感染：急性 （7 pts）、亚急性 （17 pts）、长期 （20 pts） 期。对 FDG-PET 数据应用区域间相关分析 （IRCA） 和基于 ROI 的 IRCA，以提取与健康对照 （HCs） 相比，急性/亚急性和长期组神经 COVID pts 的静息态网络 （ADMN、PDMN、EXN、ATTN、LIN、ASN） 中的代谢连接。采用单变量方法研究从急性期到亚急性期和长期期的代谢改变。

 结果

急性/亚急性期的特征是 EXN 和 ATTN 网络的超连接性;相同的网络在慢性期显示连接性低下。EXN 和 ATTN 连接性低下与长期 COVID 患者的临床发现一致，例如 执行和注意力领域的神经心理学测试表现改变。ASN 和 LIN 在急性/亚急性期表现出超连接性，在长期期恢复正常。ADMN 和 PDMN 提供了预先断开的连接。单因素分析显示急性期额岛叶皮层代谢减退，亚急性期降低，长期消失。

 结论

在急性/亚急性期发现代偿性 EXN 和 ATTN 超连接，在长期发现低连接性。连接性低下和缺乏代谢减退表明，额叶网络的连接性紊乱可能与长期 COVID 患者神经系统症状的延长有关。