Placebo analgesia persists during sleep: An experimental study

Sleep disorders and orofacial pain: insights for dental practice

In dental sleep medicine several sleep disorders commonly coexist with pain, contributing to complex clinical presentations which might affect the provision of appropriate and timely treatment. There are associations between sleep disorders and pain in general, as well as with specific orofacial pain conditions. As many as five of six patients with orofacial pain can present with sleep problems. The comorbidity of orofacial pain and sleep disorders overlays a complex web of altered neurobiological mechanisms that predispose to the chronification of orofacial pain. This review discusses the relationship between orofacial pain and sleep disorders and highlights their interactions and the neurobiological mechanisms underlying those relationships.

Conclusions Regarding the Role of Expectations in Placebo Analgesia Studies May Depend on How We Investigate It: A Meta-Analysis, Systematic Review, and Proposal for Methodological Discussions

OBJECTIVE

Expectations are highlighted as a key component in placebo effects. However, there are different approaches to whether and how placebo studies should account for expectations, and the direct contribution has yet to be estimated in meta-analyses. Using different methodological approaches, this meta-analysis and systematic review examines the extent to which expectations contribute to pain in placebo studies.

METHODS

The databases PubMed, PsycINFO, Embase, and Web of Science were searched for placebo analgesia mechanism studies with numerical measures of both expectations and pain. Thirty-one studies, comprising 34 independent study populations (1566 subjects: patients and healthy participants) were included. Two meta-analyses were conducted: meta-analysis 1, using study-level data, estimated the effect of expectation interventions without taking measures of expectations into account (expectations assumed); and meta-analysis 2, using individual-level data, estimated the direct impact of participants' expectations on pain (expectations assessed). Risk of bias was assessed using the Cochrane risk-of-bias tool.

RESULTS

Meta-analysis 1 showed a moderate effect of expectation interventions over no expectation intervention on pain intensity (Hedges g = 0.45, I2 = 54.19). Based on 10 studies providing individual-level data, meta-analysis 2 showed that expectations predicted pain intensity in placebo and control groups ( b = 0.36, SE = 0.05), although inconsistently across study methodologies.

CONCLUSIONS

Participants' expectations contributed moderately to pain in placebo analgesia studies. However, this may largely be influenced by how we measure expectations and how their contribution is conceptualized and analyzed-both within and across studies.

The face of Dental Sleep Medicine in the 21st century

It becomes increasingly clear that some sleep disorders have important diagnostic and/or management links to the dental domain, hence the emergence of the discipline ‘Dental Sleep Medicine’. In this review, the following topics are discussed: 1. the reciprocal associations between oro‐facial pain and sleep; 2. the associations between sleep bruxism and other sleep‐related disorders; 3. the role of the dentist in the assessment and management of sleep bruxism; and 4. the dental management of obstructive sleep apnoea. From these topics' descriptions, it becomes clear that the role of the dentist in the recognition and management of sleep‐related oro‐facial pain, sleep bruxism and obstructive sleep apnoea is large and important. Since many dental sleep disorders can have severe consequences for the individual's general health and well‐being, it is imperative that dentists are not only willing to take on that role, but are also able to do so. This requires more attention for Dental Sleep Medicine in the dental curricula worldwide, as well as better postgraduate training of dentists who are interested in specialising in this intriguing domain. This review contributes to increasing the dental researcher's, teacher's and care professional's insight into the discipline ‘Dental Sleep Medicine’ as it has taken shape in the 21st century, to the benefit of all patients suffering from dental sleep disorders.

Hypnotizability-Related Effects of Pain Expectation on the Later Modulation of Cortical Connectivity

This study examined hypnotizability-related modulation of the cortical network following expected and nonexpected nociceptive stimulation. The electroencephalogram (EEG) was recorded in 9 high (highs) and 8 low (lows) hypnotizable participants receiving nociceptive stimulation with (W1) and without (noW) a visual warning preceding the stimulation by 1 second. W1 and noW were compared to baseline conditions to assess the presence of any later effect and between each other to assess the effects of expectation. The studied EEG variables measured local and global features of the cortical connectivity. With respect to lows, highs exhibited scarce differences between experimental conditions. The hypnotizability-related differences in the later processing of nociceptive information could be relevant to the development of pain-related individual traits. Present findings suggest a lower impact of nociceptive stimulation in highs than in lows.

Investigating Knowledge, Attitude, and Beliefs Regarding Placebo Interventions in Clinical Practice: A Comparative Study of Nursing and Medical University Students

BACKGROUND

Placebo interventions are commonly used in medical practice for alleviating symptoms of illnesses. Placebo is considered a pseudo-medication and its use is debatable ethically, professionally, and legally. Despite that there is also a lack of evidence on understanding of placebo interventions among health profession students. Further, no previous studies have been conducted to investigate whether future nurses and physicians differ in their knowledge, attitudes, and beliefs regarding placebo intervention.

MATERIALS AND METHODS

A comparative cross-sectional study was carried out for exploring knowledge, attitude, and beliefs about placebo interventions among a convenient sample of 187 medical and nursing students at King Saud bin Abdulaziz University for Health Sciences. Data were collected using a sociodemographic data sheet and a 32-item placebo knowledge, beliefs, and attitude scale, which was developed from the evidence-based literature. Validity and reliability were ensured through utilizing a panel of experts and internal consistency analysis.

RESULTS

Overall mean participants' knowledge score was 7.68±2.07 (out of 15). Nursing students showed significantly higher knowledge than medical students (P=0.028). More nursing than medical students believed in the effectiveness of placebo (P˂0.001). Medical students had a stronger belief that the placebo effect is mental, while nursing students reported that it is both mental and physiologic (P˂0.006). Concerning placebo attitude, medical students significantly pointed out that it should generally be prohibited and should not be permitted unless research supports its use (P˂0.001). Both groups agreed that impure placebo intervention involves deception.

CONCLUSION

Participants' overall placebo knowledge was low. Inconsistencies in attitude and beliefs were shown among students. Current study findings offered a unique opportunity to better study misunderstandings for placebo, which might open the gate for misuse and place patients at risk of deception. Additionally, study findings were imperative as a relevant evidence-based recommendation for nursing and medical educators could be achieved.