This study aimed to create a better understanding of the neurobiological mechanisms underlying the induction of nocebo hyperalgesia. Nocebo hyperalgesia refers to an increased pain perception...Show moreThis study aimed to create a better understanding of the neurobiological mechanisms underlying the induction of nocebo hyperalgesia. Nocebo hyperalgesia refers to an increased pain perception resulting from negative outcome expectations, a phenomenon that can negatively influence a patient’s clinical outcome. Much concerning the mechanisms underlying the induction of nocebo hyperalgesia is still unknown, although it can be hypothesized that NMDA receptor-dependent learning may play a role. The current study tested this hypothesis by pharmacologically manipulating NMDA receptor- dependent learning in healthy participants, expecting that the pharmacological manipulation would facilitate the induction of nocebo hyperalgesia. Participants (n = 50) received either a placebo or an 80 mg dose of D-cycloserine (DCS), a partial NMDA receptor agonist. Nocebo hyperalgesia was induced in both groups with verbal suggestions and a classical conditioning paradigm consisting of an induction and evocation phase. In the induction phase, high intensity heat-pain stimuli were given during trials where a sham electrical stimulation device was supposedly turned on (nocebo trials), while moderate heat-pain stimuli were given during trials where a sham electrical stimulation device was supposedly turned off (control trials). During the evocation phase, only moderate pain stimuli were given. Nocebo hyperalgesia was indicated when participants rated their pain higher during nocebo trials compared to control trials. A significant paired-samples t-test (t (49) = -8.55, p < .001) suggested that nocebo hyperalgesia was successfully induced in both groups, further confirming that nocebo hyperalgesia can be induced by classical conditioning and verbal suggestions. Nevertheless, the pharmacological manipulation of NMDA receptor-dependent learning with 80 mg DCS did not facilitate the magnitude of the induced nocebo hyperalgesia more than a placebo, as indicated by a one-way ANOVA (F (1, 49) = 0.028, p = 0.867). The usability of DCS in nocebo research was discussed, and further research was recommended. It is important that the current study is replicated, possibly with the use of another glutamatergic agent. The results from future studies could play a significant role in diminishing the impact of nocebo hyperalgesia on clinical practice.Show less
Background Dementia, a clinical syndrome characterized by a progressive decline of cognitive and physical functions. The prevalence has doubled between 1990 and 2016 to 43.8 million people. Pain,...Show moreBackground Dementia, a clinical syndrome characterized by a progressive decline of cognitive and physical functions. The prevalence has doubled between 1990 and 2016 to 43.8 million people. Pain, discomfort and lack of stimulation are the most common unmet needs in people with dementia. Namaste Care, a multisensory intervention, has been shown to be somewhat effective in addressing these needs. Evidence for Namaste Care effectiveness is inconclusive and there is a need for more randomized controlled trials with large sample sizes to further solidify the evidence base for the workings and effectiveness of this intervention . This study aims to further establish the if the Namaste Care Family programme, an adapted version of Namaste Care, is capable of addressing these unmet needs. Method 19 nursing homes participated in this study, resulting in 231 participants separated into the control and intervention condition. Measurements took place from baseline, through 1, 3, 6 and 12 months follow-up. Observations were carried out by trained researchers using the Pain Assessment in Advanced Dementia (PAINAD), the Discomfort Scale-Dementia or Alzheimer Type (DSDAT) and through observing frequency of positive vocalizations, which is an important dimension of being stimulated (engagement). Results The Namaste Care Family programme led to higher frequencies of positive vocalizations over time (F(2.771, 322.266) = 4.608 , p = .005). Discomfort scores at 6 and 12 months follow-up were significantly lower than those of controls (t(58) = 2.926, p = .005 and t(31) = 3.338, p = .002). This effect on discomfort seemed to translate to daily life as there was no significant difference in discomfort scores between Namaste sessions and daily life. There was a dose-response relationship between pain and Namaste dosage. Pain scores were significantly lower at 12 months follow-up as frequency and duration of attended Namaste Care Family sessions increased (F(1, 51) = 7.088 p = 0.01). Discussion and conclusion This large scale randomized controlled trial suggests that the Namaste Care Family programme could be an effective intervention component in providing stimulation, pain and discomfort management.Show less
Nocebo hyperalgesia can be defined as an increased sensitivity to pain caused by a nocebo effect. Expectancies are fundamental to nocebo effects. How pain is experienced can be modified by...Show moreNocebo hyperalgesia can be defined as an increased sensitivity to pain caused by a nocebo effect. Expectancies are fundamental to nocebo effects. How pain is experienced can be modified by expectancies and avoidance behavior. This is the basis of the fear-avoidance model. The aim of this study was to gain a better understanding of the relationship between pain, expectancies and avoidance behavior. More specifically, we wanted to assess whether negative expectancies induce nocebo hyperalgesia, and whether nocebo hyperalgesia predicts avoidance. A total of 116 participants were included in the study. Participants were randomly assigned to either the control (n = 58) or nocebo group (n = 58). The pain stimuli were administered electrically. In the nocebo group, expectancies about pain stimuli were induced by verbal suggestions and conditioning. The verbal suggestions included telling participants that a specific color cue would increase the intensity. The conditioning consisted of consistently pairing a specific color cue with a higher stimulus. In the control group, no expectancies were induced and stimuli were administered randomly. Avoidance was measured through a pain avoidance task for which the Tower of Hanoi was used. Results indicated a significant interaction between type of color cue and group (F(1,114) = 34.08, p < .001, ηp2 = .230), indicating a significant difference between the pain ratings of the color cues of both groups. Participants in the nocebo group gave higher pain ratings than the control group, indicating that nocebo hyperalgesia increased when negative expectancies were induced. However, nocebo hyperalgesia did not predict avoidance behavior (χ² (1) = .51, p = .477). The results are in line with studies on nocebo effects on pain and add to the importance of verbal suggestions. As pain can be hugely modified by expectancies, it is recommended for clinicians to be mindful of their communication with patients. By effectively managing patients’ expectancies, nocebo effects can be minimized. Results do not completely corroborate the fear-avoidance model. Therefore, future research should focus on developing objective measurement instruments of avoidance. This could provide more insight into the development of pain and improve pain treatments.Show less
The nocebo effect, which occurs when an inert intervention results in the worsening of symptoms due to negative expectations, affects the experience of pain. Negative expectations may be shaped...Show moreThe nocebo effect, which occurs when an inert intervention results in the worsening of symptoms due to negative expectations, affects the experience of pain. Negative expectations may be shaped through verbal suggestions and classical conditioning, but it is unclear how these learning processes affect anticipatory brain processing related to nocebo-enhanced pain. Therefore, this within-subjects study explored whether stimulus-preceding negativity (SPN), a slow-wave event-related potential component that reflects perceptual and emotional anticipation, would increase in response to cues that predicted high heat pain compared to cues that predicted moderate heat pain. A positive relationship between SPN amplitude and the nocebo effect was expected during evocation. The sample consisted of 36 healthy adults (24 females). SPN was measured from -500 ms to 0 ms relative to pain stimulus onset using electroencephalography, and pain intensity was measured using a numeric rating scale. A nocebo effect was induced through a negative verbal suggestion and classical conditioning. During induction participants learned to associate the sham activation of a Transcutaneous Electrical Nerve Stimulation device with high pain stimuli (nocebo), relative to moderate intensity stimuli when the device was turned off (control). During evocation only moderate pain was applied. Results showed a significant nocebo effect, p < .001. There was no difference in SPN amplitude between nocebo and control trials in the evocation phase, p = .26. There was a trend towards greater negativity for nocebo trials. There was no relationship between SPN and the nocebo effect during evocation, p = .41. Post-hoc, there was a positive relationship between SPN and pain ratings, p = .002. These results suggest that SPN does not directly reflect anticipatory processing related to nocebo-enhanced pain, but that it does become larger as an individual experiences more intense pain. This finding is clinically relevant because it argues that the estimation of SPN could perhaps aid in the assessment and treatment of pain. Future research should explore SPN further with the use of standardized experimental designs and multiple levels of pain intensity, and with the inclusion of clinical groups.Show less
Pain is a common complaint that can interfere with daily life severely. Expectations play a crucial role in pain perception. It has been found that fear of pain interacts with these expectations....Show morePain is a common complaint that can interfere with daily life severely. Expectations play a crucial role in pain perception. It has been found that fear of pain interacts with these expectations. Research investigating the influence of fear of pain on pain perception is sparse. The aim of the present study is to investigate whether increased pain sensitivity can be induced by conditioning and verbal suggestion of negative expectations. Moreover, the study investigated if fear of pain could predict increased sensitivity to pain. Data of 27 healthy young adults (22 females) was used in this study. Participants received induction of negative expectations regarding electrical pain. Fear of pain was measured prior to the induction of electrical pain by using the minor pain subscale of the Fear of Pain Questionnaire III. Pain was electrically induced and measured by numerical pain rating scales. The participants were randomized into an experimental (induction of negative expectations) or a control group (expectations not manipulated). The results show that the experimental group scored higher on increased sensitivity to pain than the control group. Therefore, it can be concluded that an increased sensitivity to pain can be induced by a negative expectation learning procedure. This effect is strong and can have a strong negative effect on treatment outcomes. Furthermore, it has been found that fear of pain cannot predict nocebo hyperalgesia. This may relate to the healthy sample. It is important to investigate the relation of expectations, increased pain sensitivity and fear of pain. Doing so optimizes treatment and therefore prevents patients with chronic pain to experience increased pain.Show less
Recent research proposes that psychological factors might influence individuals’ pain experiences via descending endogenous pain modulation. This can be studied using the experimental paradigm of...Show moreRecent research proposes that psychological factors might influence individuals’ pain experiences via descending endogenous pain modulation. This can be studied using the experimental paradigm of conditioned pain modulation (CPM). Two types of psychological variables suggested to influence individuals’ pain experience are self-efficacy beliefs and dispositional optimism. It is further proposed that self-efficacy might predict dispositional optimism. The present study aims to investigate whether self-efficacy and dispositional optimism affect individuals’ CPM response. The primary research question asks whether the influence of self-efficacy on CPM is mediated by dispositional optimism. This is investigated by three hypotheses: First, self-efficacy affects CPM; second, dispositional optimism affects CPM; third, dispositional optimism mediates the effect of self-efficacy on CPM. The provisional research question asks whether verbal suggestions are effective in changing self-efficacy beliefs and is tested with a hypothesis stating that verbally manipulation self-efficacy is successful. Participants (N = 17) are university students or adults, randomly grouped into a high versus low self-efficacy condition in which they are accordingly manipulated. The Life Orientation Test-Revised (LOT-R) is administered to measure dispositional optimism. The CPM paradigm is executed using an algometer and the cold-pressor test as stimuli. The primary hypotheses are analysed using linear regression and the PROCESS macro procedure. The results were not statistically significant at p ≤ .05 and, followingly, neither of the hypotheses could be confirmed. However, secondary findings might potentially point towards an effect of self-efficacy on CPM (β = .17) and dispositional optimism on CPM (β = .15). The provisional hypothesis, tested using a one-way ANOVA, revealed non-significant results at p ≤ .05. Thus, the manipulation of self-efficacy was not successful. The present research represents one of the first studies investigating the role of self-efficacy and dispositional optimism in CPM. The current findings suggest that future research into this field is highly needed. This would help to uncover the impact of self-efficacy and dispositional optimism on CPM or to show that a different approach including other psychological variables is more suitable. Investigating the field of CPM further could help to improve pain treatments and prevent the development of persistent pain conditions.Show less
A dysfunction in conditioned pain modulation (CPM) is believed to be an important mechanism in chronic pain. Few studies investigated the role of expectations in pain modulation, while there are...Show moreA dysfunction in conditioned pain modulation (CPM) is believed to be an important mechanism in chronic pain. Few studies investigated the role of expectations in pain modulation, while there are indications that pain sensitivity can be affected by expectations. The present study examined whether expectations modulated the effect of conditioned pain stimulation. Since earlier research indicated gender differences and physiological stress levels might play a role in CPM as a response to positive or negative information, the present study will take gender differences and objective stress levels (heartrate and skin conductance levels) into account. Healthy participants (57 of each sex) between 18 – 35 years of age were randomly assigned to three experimental groups: 1) participants were told positive expectations, that holding the non-dominant hand in a cold-water bath will decrease the pain intensity of the test stimulus (analgesia group), 2) participants received the information that the conditioned stimuli will increase the pain intensity of the test stimulus (hyperalgesia group), 3) participants received no information about the effect (control condition). Results were analyzed with a mixed ANOVA. The results show that positive or negative expectations modulated the CPM effect compared to the control condition (p = .006). This effect was not dependent on gender. Conditioning stimulation increased skin conductance levels, but not heart rate in the hyperalgesia group. Higher skin conductance levels as a response to negative information were more visible in males compared to females. The present study suggests that inhibitory CPM can be influenced by verbal suggestions, and that a dysfunction of descending inhibitory pathways seems not the only possible cause of a reduced inhibitory CPM. Future research could examine if positive expectations can influence the altered CPM efficacy in patients with chronic pain.Show less
Elaine Scarry’s The Body in Pain: the Making and Unmaking of the World (1985) proposed an analysis of pain and the concepts of language, imagination, subjectivity, social isolation. This thesis...Show moreElaine Scarry’s The Body in Pain: the Making and Unmaking of the World (1985) proposed an analysis of pain and the concepts of language, imagination, subjectivity, social isolation. This thesis examines the link between language and pain in relation to Scarry’s assumption that it is extremely hard to accurately describe sentient pain in verbal and written forms of expression. Despite pain’s resistance to language, language holds the healing potential of softening pain. The process of “externalization” (the act of externalizing one’s pain into the material world outside the painful inner existence) is a starting point from which the treatment of pain can begin. However, in order to carry out the externalization, one has to express pain in language. I employ three case studies in order to determine whether Scarry’s assumption about pain’s resistance to language can be overcome: Leo Tolstoy’s novel The Death of Ivan Ilyich, Alphonse Daudet’s collection of personal notes In the Land of Pain and a scientific instrument– the McGill Pain Questionnaire. The thesis employs a multidisciplinary approach to pain in which cultural, social and biological aspects are taken into account. It also seeks to re-evaluate the single label of ‘pain’ and proposes to view pain as a multitude of experiences.Show less
