More than half of patients who recover from COVID-19 experience fatigue. We studied fatigue using neuropsychological and neurophysiological investigations in post-COVID-19 patients and healthy subjects. Neuropsychological assessment included: Fatigue Severity Scale (FSS), Fatigue Rating Scale, Beck Depression Inventory, Apathy Evaluation Scale, cognitive tests, and computerized tasks. Neurophysiological examination was assessed before (PRE) and 2 min after (POST) a 1-min fatiguing isometric pinching task and included: maximum compound muscle action potential (CMAP) amplitude in first dorsal interosseous muscle (FDI) following ulnar nerve stimulation, resting motor threshold, motor evoked potential (MEP) amplitude and silent period (SP) duration in right FDI following transcranial magnetic stimulation of the left motor cortex. Maximum pinch strength was measured. Perceived exertion was assessed with the Borg-Category-Ratio scale. Patients manifested fatigue, apathy, executive deficits, impaired cognitive control, and reduction in global cognition. Perceived exertion was higher in patients. CMAP and MEP were smaller in patients both PRE and POST. CMAP did not change in either group from PRE to POST, while MEP amplitudes declined in controls POST. SP duration did not differ between groups PRE, increased in controls but decreased in patients POST. Patients' change of SP duration from PRE to POST was negatively correlated to FSS. Abnormal SP shortening and lack of MEP depression concur with a reduction in post-exhaustion corticomotor inhibition, suggesting a possible GABAB-ergic dysfunction. This impairment might be related to the neuropsychological alterations. COVID-19-associated inflammation might lead to GABAergic impairment, possibly representing the basis of fatigue and explaining apathy and executive deficits.

中文翻译：

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具有 COVID-19 神经系统表现的急性后患者疲劳的神经心理学和神经生理学相关性：对具有挑战性症状的洞察

超过一半的 COVID-19 康复患者会感到疲劳。我们在 COVID-19 后患者和健康受试者中使用神经心理学和神经生理学调查研究了疲劳。神经心理学评估包括：疲劳严重程度量表 (FSS)、疲劳评定量表、贝克抑郁量表、冷漠评估量表、认知测试和计算机化任务。在 1 分钟疲劳等长挤压任务之前 (PRE) 和之后 (POST) 2 分钟评估神经生理学检查，包括：尺神经刺激后第一背骨间肌 (FDI) 的最大复合肌肉动作电位 (CMAP) 振幅、静息运动左侧运动皮层经颅磁刺激后右侧 FDI 的阈值、运动诱发电位 (MEP) 幅度和静默期 (SP) 持续时间。测量最大挤压强度。使用 Borg-Category-Ratio 量表评估感知到的劳累。患者表现出疲劳、冷漠、执行缺陷、认知控制受损和整体认知能力下降。患者感知到的劳累程度更高。PRE 和 POST 患者的 CMAP 和 MEP 均较小。CMAP 在任何一组从 PRE 到 POST 都没有变化，而 MEP 振幅在对照 POST 中下降。SP 持续时间在 PRE 组之间没有差异，在对照组中增加，但在 POST 患者中减少。患者从 PRE 到 POST 的 SP 持续时间的变化与 FSS 呈负相关。异常的 SP 缩短和缺乏 MEP 抑制与疲劳后皮质运动抑制的减少一致，表明可能存在 GABAB 能功能障碍。这种损害可能与神经心理改变有关。