Data and analysis scripts: sleep fragmentation hypersensitizeshealthy young women to deep and superficial experimental pain

This repository contains the analytical data, analysis scripts, and the markdown document and figure outputs produced by those scripts.There are three analysis sections:<i>Demographics</i>, which provides summaries of basic demographic information for the participants, and information on participant menstrual cycles, sleep quality, and general health.<br><i>Regression</i>, which describes the regression modelling of the effect of sleep fragmentation on the intensity of ischaemic pain over a ten-minute period on the morning after each nights sleep.<br><i>Other</i>, which describes the analysis of the effect sleep fragmentation had on mood, sleep quality, morning vigilance, and somatosensory thersholds to noxious (pin-prick) and innocuous (von Frey hairs) punctate mechanical stimuli.Each of the sections has its own README which describes the content in more detail.In addition, the scripts (and the output from those scripts) that were used to process the data for publication (i.e., publication-ready figures and tables) can be found in: <i>Manuscript</i>.Overview of the studyBackgroundPatients experiencing chronic pain frequently complain of night-time awakenings. This fragmentation of their sleep is a consequence of their pain, but the relationship between pain and sleep is bidirectional, such that sleep disruption may also contribute directly to the maintenance and/or exacerbation of pain.ObjectivesTo establish whether sleep fragmentation (rather then deprivation) affects pain perception, we investigated whether two nights of sleep fragmentation alters the sensitivity of healthy, pain-free, women to experimentally-induced deep muscle ischaemic pain. As a secondary outcome, we also assessed whether sleep fragmentation altered somatosensory threshold to punctate mechanical stimuli (von Frey hairs and pin-prick).MethodsEleven healthy females were studied over 1 baseline night (control night), and two successive nights of sleep fragmentation (experimental nights). The order of the baseline night and fragmentation nights were randomized. Sleep fragmentation involved 8 forced awakenings (1/hour of sleep) of variable duration. On the morning after each intervention (control and experimental nights 1 and 2) the sub-maximal effort tourniquet test was used to induce forearm ischaemia. Participants rated the intensity of the ischaemic pain on a 100mm visual analogue scale (VAS, anchored at: 0 = no pain, 100 = worst pain ever experienced) at 1-minute intervals over a 10-minute period starting immediately after the sub-maximal exercise. The tourniquet remained in place until the end of the 10-minute measurement period.Participants also completed assessments of mechanical thresholds for innocuous (von Frey hairs) and noxious (pin-prick) stimuli, mood (profile of mood states), sleep quality (VAS) and morning vigilance (VAS).ResultsAfter 1 night of sleep fragmentation, ischaemic pain perception increased compared to the control night, despite no changes being observed in thresholds for noxious and innocuous mechanical stimuli. Sleep fragmentation was also associated with lower mood, sleep quality, and morning vigilance.A second successive night of sleep fragmentation was also associated with increased ischaemic pain perception compared to the control night (but not worse than the first night of sleep fragmentation). Moreover, the second night of sleep disruption was associated with reduced pin-prick thresholds. A second successive night of sleep fragmentation was associated with worsening of the already lower mood, sleep quality, and morning vigilance seen after the first night.ConclusionOur data support a role for sleep fragmentation in increased pain perception.

本仓库包含分析数据、分析脚本，以及由这些脚本生成的Markdown文档与图表输出。本研究包含三个分析模块：**人口统计学（Demographics）**模块，用于汇总受试者的基础人口学信息、月经周期、睡眠质量与整体健康状况；**回归分析（Regression）**模块，旨在针对睡眠碎片化（sleep fragmentation）对受试者在每晚睡眠次日清晨10分钟内缺血性疼痛（ischaemic pain）强度的影响开展回归建模分析；**其他（Other）**模块，则分析睡眠碎片化对受试者情绪、睡眠质量、晨间警觉性，以及有害（针刺）和无害（von Frey hairs，冯·弗雷纤维）点状机械刺激的体感阈值的影响。每个模块均配有独立的README文件，可查阅更详细的内容说明。

此外，用于生成符合出版标准的图表与表格的脚本（及对应输出）可在**手稿（Manuscript）**目录中获取。

### 研究概述
#### 研究背景
慢性疼痛患者常主诉夜间觉醒，这种睡眠碎片化是疼痛导致的结果，但疼痛与睡眠的关系是双向的：睡眠中断同样可能直接加剧或维持疼痛症状。
#### 研究目的
为明确睡眠碎片化（而非睡眠剥夺）如何影响疼痛感知，本研究探究连续两晚的睡眠碎片化是否会改变健康无痛女性对实验诱导的深部肌肉缺血性疼痛的敏感性。作为次要结局指标，本研究同时评估睡眠碎片化是否会改变点状机械刺激（冯·弗雷纤维与针刺）的体感阈值。
#### 研究方法
本研究纳入11名健康女性受试者，分别进行1晚基线睡眠（对照夜）与连续两晚的睡眠碎片化干预（实验夜），基线夜与干预夜的顺序采用随机化设计。睡眠碎片化操作包含每小时1次、共8次时长不定的强制觉醒。在每一次干预（对照夜、实验夜1与实验夜2）后的次日清晨，采用亚最大负荷止血带试验（sub-maximal effort tourniquet test）诱导前臂缺血。受试者在亚最大运动结束后即刻开始的10分钟内，以每分钟1次的频率，在100mm视觉模拟评分表（Visual Analogue Scale, VAS，锚点设定为：0=无痛，100=曾经历的最剧烈疼痛）上对缺血性疼痛强度进行评分。止血带将持续佩戴至10分钟测量期结束。

受试者同时完成了无害刺激（冯·弗雷纤维）与有害刺激（针刺）的机械阈值评估、情绪轮廓量表（profile of mood states）评估、睡眠质量（VAS）评估与晨间警觉性（VAS）评估。
#### 研究结果
与对照夜相比，仅1晚睡眠碎片化后，受试者的缺血性疼痛感知显著升高，而有害与无害机械刺激的阈值未出现明显变化。睡眠碎片化同时伴随情绪、睡眠质量与晨间警觉性的下降。

与对照夜相比，连续第二晚的睡眠碎片化同样会升高缺血性疼痛感知，但效果并未显著差于第一晚的睡眠碎片化干预。此外，第二晚睡眠中断与针刺阈值降低相关。连续第二晚的睡眠碎片化还会加剧第一晚干预后已出现的情绪、睡眠质量与晨间警觉性下降情况。
#### 研究结论
本研究数据证实，睡眠碎片化可提升疼痛感知能力。