Background

The COVID-19 pandemic has had severe negative effects on populations worldwide. The seriousness of the pandemic necessitated local and even national lockdowns. In Singapore a national lockdown with aStay-at-Home Order (SHO) lasted for over 7 weeks. The impact of the pandemic and of the long SHO period on neuropsychophysiological functioning remains unknown. Studies prior to the pandemic highlighted the beneficial role of nature exposure on mental health and well-being, although this has not yet been explored in the post-pandemic world. This is the first study to investigate the longitudinal changes in (1) brain frontal alpha asymmetry (FAA; neuroelectric marker of approach-related motivation), (2) depressive mood and (3) symptoms, and (4) emotional response to videos of various urban spaces from before COVID-19 to immediately after the SHO in Singapore was over. Finally, we examined whether higher vs lower exposure to nature during the SHO moderated changes over time.

Methods

The sample included 25 healthy adult Singaporeans (56% female, M_age = 40.4 y, SD = 17.8), who attended two electroencephalography (EEG) lab sessions, within a year before the COVID-19 pandemic (T1) and immediately following the SHO (T2). The participants viewed 9 fixed-frame videos, filmed before the pandemic, from 3 urban public spaces (Busy Downtown, Residential Green, Lush Garden) on the roll-up screen. They rated their emotional response (arousal, valence) after each video and completed Becks Depression Inventory-II (BDI-II) as a measure of depressive symptoms, Profile of Mood Scale (POMS), as a measure of momentary mood, and self-reported the frequency and duration of their nature visits during the SHO.

Results

Linear mixed models were fitted to examine changes over time, and effect moderation by amount of nature exposure during the SHO. The results showed decrease in FAA (p < 0.001), increase in depressive symptoms (p = 0.046), and a trend for marginal increase in momentary mood disturbance (p = 0.097) after the SHO. Importantly, people with high nature exposure during SHO had greater decrease in FAA over time (p = 0.005) than those with low nature exposure, FAA scores decreased the most for Residential Green. Valence and Arousal did not change over time, but Arousal towards Busy Downtown decreased among high nature exposure individuals (p = 0.002).

Conclusions

Post SHO, brain activity and responsiveness to landscapes changed, and showed a general reduction in positive emotions and increased depressive symptoms among participants. The higher nature exposure during the SHO did not help mitigate this depressive symptoms, as previous research would suggest. This can be due to the modified quality of nature exposure during lockdown, which highlights the importance of high quality nature experience in cities and the provision of diversified visual exposures. Potential neuropsychophysiological consequences of SHO should be considered by policy makers in the post-COVID-19 world.

中文翻译：

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与 COVID-19 相关的居家令对城市空间神经心理生理反应的影响：接触大自然的有益作用？

背景

COVID-19 大流行对全世界人口产生了严重的负面影响。大流行的严重性需要地方乃至全国的封锁。在新加坡，实行居家令 (SHO) 的全国封锁持续了 7 个多星期。大流行和长期 SHO 对神经心理生理功能的影响仍然未知。大流行之前的研究强调了自然暴露对心理健康和福祉的有益作用，尽管在大流行后的世界中尚未对此进行探索。这是第一项调查以下纵向变化的研究：(1) 大脑额叶 alpha 不对称性（FAA；接近相关动机的神经电标记），(2) 抑郁情绪和 (3) 症状，(4) 从 COVID-19 之前到新加坡 SHO 结束后对各种城市空间视频的情绪反应。最后，我们检查了在 SHO 期间较高与较低的自然接触是否随着时间的推移缓和了变化。

方法

样本包括 25 名健康成年新加坡人（56% 为女性，M_年龄 = 40.4 岁，SD = 17.8），他们在 COVID-19 大流行 (T1) 前一年内和 SHO 之后立即参加了两次脑电图 (EEG) 实验室课程(T2)。参与者在卷帘屏幕上观看了来自 3 个城市公共空间（繁忙的市中心、住宅绿地、郁郁葱葱的花园）的 9 个定格视频，这些视频是在大流行之前拍摄的。他们在观看每个视频后对自己的情绪反应（唤醒度、效价）进行评分，并完成贝克斯抑郁量表-II (BDI-II) 作为抑郁症状的衡量标准，情绪量表概况 (POMS) 作为瞬间情绪的衡量标准，以及自我评估。报告了他们在 SHO 期间进行自然访问的频率和持续时间。

结果

拟合线性混合模型以检查随时间的变化，并通过 SHO 期间的自然暴露量来调节效果。结果显示 FAA 减少 (p < 0.001)，抑郁症状增加 (p = 0.046)，以及 SHO 后瞬间情绪障碍边缘增加的趋势 (p = 0.097)。重要的是，与自然暴露程度低的人相比，在 SHO 期间自然暴露程度高的人的 FAA 随着时间的推移下降幅度更大 (p = 0.005)，住宅绿色的 FAA 分数下降幅度最大。Valence 和 Arousal 没有随着时间的推移而改变，但是在自然暴露程度高的个体中，对繁忙市中心的 Arousal 有所下降 (p = 0.002)。

结论

SHO 后，大脑活动和对景观的反应发生了变化，并显示参与者的积极情绪普遍减少，抑郁症状增加。正如之前的研究表明的那样，SHO 期间较高的自然暴露无助于减轻这种抑郁症状。这可能是由于封锁期间自然暴露的质量发生了变化，这凸显了城市中高质量自然体验和提供多样化视觉暴露的重要性。后 COVID-19 世界的政策制定者应考虑 SHO 的潜在神经心理生理后果。