Electrophysiological Correlates of Nocebo Effects on Pain
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 36
- 试验地点
- 2
- 主要终点
- Magnitude of induced nocebo hyperalgesia
研究概览
简要总结
Pain is a nociceptive somatosensory process that can arise as a debilitating and chronic symptom in various diseases or following an injury. How pain is experienced can vary widely within and across individuals, and can be shaped by cognitive processes such as learning. Nocebo effects, negative changes in symptom severity attributed to learned outcome-expectations, demonstrate how learning processes can be detrimental for the experience of pain. Research to date has produced inconclusive findings regarding the electrophysiological correlates on nocebo effects. The few studies that have applied electroencephalography (EEG) in this field have pointed towards a potential involvement of alpha-band activity, but the direction of this involvement remains unclear. For example, an EEG study of conditioned nocebo hyperalgesia found a pre to post increase in resting state alpha band power that was correlated with pain catastrophizing scores and not with the magnitude of the nocebo effect. Later, other studies also found pre to post changes in alpha band power, however, these changes were correlated with the magnitude of nocebo effects and not pain catastrophizing. Given the discrepancy in findings, in this study the investigators plan to primarily investigate whether EEG components predict the magnitude of nocebo responses to thermal-pain stimuli. The investigators will also explore electrophysiological correlates during pain anticipation and whether nocebo responses would be significantly related to spectral and temporal EEG biomarkers. This study will utilize a validated model of instructional and associative learning methods (i.e., negative suggestions and classical conditioning, respectively) to experimentally induce nocebo effects on heat-evoked pain. Developing objective, brain-derived markers for nocebo responses, or the detection of individuals most susceptible to nocebo hyperalgesia, will aid in the comprehensive management of pain. This study is conducted at Leiden University.
详细描述
Main outcome variable for nocebo responses:
- The magnitude of induced nocebo hyperalgesia is defined as the difference in pain ratings for the first nocebo trial compared to the first control trial of the evocation phase.
Note: A significant difference will be assessed using a Repeated Measures ANOVA as a manipulation check. Then, calculated difference scores represent the magnitude of induced nocebo hyperalgesia and will be used for the primary and first and second secondary hypotheses.
Definitions of other outcome variables:
- The magnitude of nocebo responses (and nocebo-augmented pain) during the evocation phase is defined in the specific nocebo evocation trials that show heightened pain relative to the preceding control trials, for each subject. For EEG analyses, all trials that show the experience of heightened pain in nocebo trials relative to the preceding control trials, during the evocation phase will be used.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
盲法说明
A double-blind randomization list was created by an independent researcher to randomize participants into two counterbalanced conditions: participants either receive the nocebo sham medical gel in a blue or in a brown jar. Complete blinding of the researchers during the experiment is not possible due to the nature of conditioning/ suggestion paradigms. Participants are blind with respect to the conditioning/nocebo manipulation.
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Aged 18 - 35 years
- •Good understanding of the English language
- •Normal or corrected to normal vision
排除标准
- •Ever having experienced serious medical or psychiatric conditions (e.g., heart or lung disease, panic attacks, drug addiction, clinical depression),
- •Ever having experienced chronic pain complaints (pain for more than 6 months),
- •Having experienced persisting painful health problems in the last 6 months,
- •Experiencing acute physical pain (e.g., headache, or having used pain medication on the day of testing,
- •Pregnancy or breastfeeding,
- •Having recent injuries to the wrists or arms on the day of testing,
- •Previous participation in this or similar studies (e.g., using conditioning or thermal pain).
- •Having consumed psychotropic medication, recreational drugs, analgesic medication, or more than 3 units of alcohol, in the 24 hours prior to the study appointment.
- •After inclusion, participants who do not reach a sensation of high pain (at least 6 on the NRS) with the highest administered temperature or participants will also be excluded.
- •After inclusion, participants who do not reliably report a difference (a mean of at least 1,5 on the NRS) between the administered temperatures for control and nocebo trials in the induction phase will also be excluded. Nocebo conditioning relies upon the pairing of high-pain stimuli to the nocebo stimulus and lower pain to the control stimulus, therefore it is deemed that participants who do not experience this difference do not receive the necessary conditioning manipulation.
结局指标
主要结局
Magnitude of induced nocebo hyperalgesia
时间窗: Through study completion, an average of 3 months
The magnitude of induced nocebo hyperalgesia is defined as the difference in pain ratings for the first nocebo trial compared to the first control trial of the nocebo block evocation phase. A significant difference here is assessed within the mixed model ANOVA. Then, calculated difference scores represent the magnitude of induced effects and will be used in further analyses of EEG data.
次要结局
- Nocebo-augmented pain(Through study completion, an average of 3 months)
- Magnitude of nocebo responses during evocation(Through study completion, an average of 3 months)
研究者
AWMEvers
Principal Investigator
Leiden University Medical Center