Studies using blood‐oxygenation‐level‐dependent functional magnetic resonance imaging (BOLD fMRI) have characterized how the resting brain is affected by concussion. The literature to date, however, has largely focused on measuring changes in the spatial organization of functional brain networks. In the present study, changes in the temporal dynamics of BOLD signals are examined throughout concussion recovery using scaling (or fractal) analysis. Imaging data were collected for 228 university‐level athletes, 61 with concussion and 167 athletic controls. Concussed athletes were scanned at the acute phase of injury (1–7 days postinjury), the subacute phase (8–14 days postinjury), medical clearance to return to sport (RTS), 1 month post‐RTS and 1 year post‐RTS. The wavelet leader multifractal approach was used to assess scaling ( c ₁) and multifractal ( c ₂) behavior. Significant longitudinal changes were identified for c ₁, which was lowest at acute injury, became significantly elevated at RTS, and returned near control levels by 1 year post‐RTS. No longitudinal changes were identified for c ₂. Secondary analyses showed that clinical measures of acute symptom severity and time to RTP were related to longitudinal changes in c ₁. Athletes with both higher symptoms and prolonged recovery had elevated c ₁ values at RTS, while athletes with higher symptoms but rapid recovery had reduced c ₁ at acute injury. This study provides the first evidence for long‐term recovery of BOLD scale‐free brain dynamics after a concussion.

中文翻译：

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从运动相关脑震荡恢复期间的无标度功能性脑动力学。

使用血氧水平依赖性功能磁共振成像 (BOLD fMRI) 的研究表征了静息大脑如何受到脑震荡的影响。然而，迄今为止的文献主要集中在测量功能性大脑网络空间组织的变化。在本研究中，BOLD 信号的时间动态变化在整个脑震荡恢复过程中使用缩放（或分形）分析进行检查。收集了 228 名大学级运动员的影像数据，其中 61 名患有脑震荡，167 名运动控制者。脑震荡的运动员在受伤的急性期（受伤后 1-7 天）、亚急性期（受伤后 8-14 天）、恢复运动的医疗许可 (RTS)、RTS 后 1 个月和 RTS 后 1 年进行扫描. 小波前导多重分形方法用于评估尺度（ c ₁ ) 和多重分形 ( c ₂ ) 行为。确定了c _{1 的}显着纵向变化，在急性损伤时最低，在 RTS 时显着升高，并在 RTS 后 1 年恢复到接近控制水平。c ₂没有发现纵向变化。二次分析表明，急性症状严重程度和 RTP 时间的临床测量与c _{1 的}纵向变化有关。与既有较高的症状和延长的恢复的运动员有升高Ç _1个在RTS值，而具有较高的症状，但迅速恢复减少了运动员Ç ₁ 在急性损伤。这项研究为脑震荡后 BOLD 无标度脑动力学的长期恢复提供了第一个证据。