By Piumi Nakandala –
Pain can be defined as an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage (IASP, 2020). Pain can be resulted as a consequence of repetitive daily activities which stress various systems, acute trauma or various musculoskeletal and neurological disorders. It is a debilitating symptom which has created considerable impacts clinically, socially and economically worldwide. Chronic pain places extensive burden on patients and their family members exerting negative influences on perception towards general health.It also may lead to depressive symptoms and as well as may further interfere with poor social interactions. It is estimated that the cost for the management of non-oncological chronic pain may range between 34 and 635 billion dollars per year in Australia and USA (Henschke et al., 2015; Economics, A., 2007). It is found that only 30% of the pain sufferers are reacting to the treatments such as injections, surgery and physical rehabilitation (Turk et al., 2011) where most of the patients with chronic pain are not responding to the conventional treatments. Therefore the discovery of new treatment approaches which enhance the therapeutic benefits in terms of pain is a necessity in the clinical set up. As a point of fact, patient’s expectations towards the pain relief is a substantial predictor in the analgesic treatments (Cormier et al., 2016) where it is found that the expectation of pain relief can directly cause actual pain relief. Three common interventions that are executed to induce expectations in the clinical set up are verbal suggestions, conditioning and imagery strategies. In particular, these expectation interventions are triggering placebo effects where expectancy is known to be a core mechanism (Kirsch, 1997; Price et al., 2008). The effect of verbal suggestion in pain relief is more frequently studied in literature. Therefore, this review primarily focuses on the impact of verbal suggestions in the management of pain in pain sufferers.
Cuyul-Vásquez et al., (2019) have defined verbal suggestion as a communication process to convey the information about certain concepts and information to others and thereby to provoke beliefs, expectations, thoughts, emotions, behaviors or physical states in them consciously or unconsciously. It is a contextual factor which influences the therapeutic outcome by triggering placebo or nocebo effects (Wager and Atlas, 2015). Verbal suggestions are known to be strongly related with the hypnotic process where it induces alterations in patient’s sensations, feelings, perceptions and actions (Lynn and Kirsch, 2005). It is shown that the verbal suggestions are producing positive therapeutic results with regard to pain relief by inducing a placebo effect in pain sufferers (Testa and Rossettini, 2016; Morral et al., 2017). Verbal suggestions can be used to generate either positive or negative expectations. Positive expectations are related with positive anticipation towards the need of pain relief where negative expectations are associated with negative anticipation towards the treatment outcomes by means of fear or anxiety. These are directly related with placebo effects and nocebo effects respectively. It is identified that when positive verbal suggestions are integrated with other treatment regimes to manage pain, it gives better hypoalgesic results (Koban et al., 2017).Further, it is found that when positive verbal suggestions are combined with professional empathy, it may even increase the analgesic effect while neutral verbal communication combined with low levels of empathy has worsened the treatment outcomes (Rossettini et al., 2018; Mistiaen et al., 2016). This emphasizes the significance of patient-therapist interaction, communication style and it will positively cause the patient to stick into the treatment process successfully and in turn will enhance the satisfaction of the patient regarding the treatment. In literature, the clinical studies focusing on musculoskeletal pain have emphasized the importance of this effective and low cost strategy (Louw et al., 2016; Hsiao‐Wei Lo et al., 2016).
- Applications of positive verbal suggestions
The efficacy of positive verbal suggestions in the management of pain in pain sufferers have been extensively studied in literature. A double blinded randomized controlled study has been conducted to evaluate if the combination of music with therapeutic suggestion in the intra-operative period under general anesthesia would improve the recovery of hysterectomy patients. Results have shown that the group had required significantly less rescue analgesic on the day of surgery and had demonstrated significantly low levels of fatigue at the time of discharge (Nilsson et al., 2001). Moreover a study done by Kliempt et al., (1999) have shown reduced need of intra-operative analgesia for the patients who received combination of synchronized hemispheric sound and positive verbal suggestions compared to patients who received classical music or blank tape. A meta analysis have been conducted by Peerdeman et al., (2016) to see the efficacy of expectation interventions including verbal suggestion, conditioning and mental imagery on the relief of pain. Study has concluded that the verbal suggestions could improve acute procedural pain and the chronic pain to a lesser extent accounting for overall medium sized effect of the intervention on the pain relief. This is in contrast with the study done by Müller et al., (2016) who have shown stronger effect of verbal suggestion on relief of chronic pain.
Moreover a study done on patients with knee osteoarthritis has assessed the effectiveness of positive or neutral verbal suggestions about acupuncture along with acupuncture treatment (Hsiao‐Wei Lo et al., 2016). The results of this study have shown significantly low levels of pain perception with the positive verbal suggestion group and the results were persistent even after three months duration of the treatment. Moreover, the effect of conditioning and verbal suggestion on pain relief has been studied in the patients with lower back pain (Louw et al., 2016; Klinger et al., 2017).
- Applications of negative verbal suggestions
As discussed above, negative expectations via verbal suggestions or instructions can cause nocebo effects. These negative verbal suggestions could be ultimately resulted in poor therapeutic outcomes. A study done by Stovner et al., (2008) hasshown the experience of discomfort and headache by the participants after exposing to sham radiofrequencywhere the radiofrequency from the amplifier had been absorbed by a load. This is due to the negative expectations. Moreover, it is found that the verbal instructions could be utilized to alter the action of the drugs. In one study, although the participants were given muscle relaxants, they have experienced an increased level of tension due to the belief of given a stimulant (Flaten et al., 1999). This is further evidenced in a study done by (Dworkin et al., 1983) in which the usual action of 33% nitrous oxide have been modified from analgesia to hyperalgesia after giving negative information with regard to possible increase of pain. A study done by van Laarhoven et al., (2011), have also indicated strong nocebo effects induced by verbal suggestions. The results of the study have shown the experience of itch and pain sensations by the patients with high itch and pain expectations respectively. Similarly, another study was done by Staats et al., (1998) to evaluate the effects of positive and negative verbal suggestions on pain induced by hand immersion in ice water. The results have revealed significantly increased levels of pain tolerance, pain threshold and pain endurance in the positive verbal suggestion group compared to the control where they received neutral verbal messages. Contrastingly, the negative verbal suggestion group had demonstrated significantly decreased levels of pain tolerance, pain threshold and pain endurance.
Neurobiological involvement of placebo analgesia induced by verbal suggestions
According to the findings of many studies, the connection of cortical brain regions with the descending pain inhibitory pathways play a vital role in the modulation of pain (Medoff and Colloca, 2015). Placebo analgesia is known to be activating different areas of the brain generating activity changes and increased functional coupling in dorsolateral prefrontal cortex (DLPFC), anterior cingulated cortex (ACC), subcortical regions including hypothalamus, amygdale and the periaqueductal gray (PAG) (Bingel et al., 2006; Craggs et al., 2008; Eippert et al., 2009a; Wager et al., 2004). Further, placebo analgesia is found to be decreasing the pain increasing activity in thalamus, insula and somato-sensory cortex (Bingel et al., 2006; Eippert et al., 2009a; Wager et al., 2004; Lui et al., 2010). A study done by (Schweinhardt et al., 2009) has shown that the gray matter density in ventral striatum, insula and prefrontal cortex is associated with greater analgesic effects using Voxel-based morphometry of magnetic resonance imaging. Moreover, it is shown that the pretest resting state functional connectivity between the frontoparietal network and the rostral anterior cingulated cortex is associated with the magnitude of placebo analgesia (Kong et al., 2013). Reduction of nociceptive processing in the spinal cord is noted with placebo analgesia indicating the contribution of psychological factors at the early stages of pain processing in the central nervous system (Eippert et al., 2009b). When consider about the provision of positive expectations through verbal suggestions, it is found to be enhancing the neuronal activity in the areas of brain responsible for memory and semantic processing and thus influencing on the areas in brain responsible for producing analgesia. Also it is found that the verbal suggestion is decreasing the activity of brain regions that process pain (Morral et al., 2017). In addition, DLPFC, nucleus accumbens and dopaminergic systems are known to be playing essential roles in reward learning when expectations are provoked by verbal suggestions (Koban et al., 2017).
Biochemical involvement of placebo analgesia induced by verbal suggestions
The three main neurotransmitters that are known to be involving in the analgesic process are endogenous opiates, dopamine and cannabinoids. Increased release of these neurotransmitters is observed with high levels of expectations towards analgesia and thus has resulted in increased levels of analgesia (Morral et al., 2017). Additionally, oxytocin (Enckand Klosterhalfen, 2009; Kessner et al., 2013), nitric oxide (Fricchione and Stefano, 2005), and cholecyctokinins (Benedetti et al., 2006) are also suggested to be contributing to the placebo response. When verbal suggestions are used to induce the positive expectations towards the therapeutic outcomes, it is known to be augmenting the activity of opioids and dopaminergic systems (Cuyul-Vásquez et al., 2019). Increased dopaminergic activity is found in the nucleus accumbens during the process of verbal suggestion (Rossettini et al., 2018; Morral et al., 2017).
Verbal suggestion is a potent contextual factor that characterizes the therapeutic encounter with the patient. The influence of verbal suggestions in pain relief is extensively studied in literature and was found to be having promising results towards hypoalgesia.Positive expectations towards the treatment outcomes induced by positive verbal suggestions are known to be resulting in therapeutic benefits in terms of pain relief by triggering placebo effects. However, negative expectations induced by negative verbal suggestions are known to be worsening the treatment outcome measures by triggering nocebo effects. Indeed, this concept has been well understood as a mechanism which can arouse patient’s perceptions, feelings and sensations towards a particular outcome by accompanying hypnotic process. This can be further recognized as a persuasive communication method where either favorable or unfavorable environments are generated through positive, negative or neutral verbal communication approaches. By considering the above facts, it can be concluded that the communication style which entails the interaction between the therapist and the patient is a substantial predictor of the treatment outcomes. Therefore, positive verbal suggestions could be successfully integrated into the rehabilitation of the patients who are suffering from pain and are not responding to conventional treatments to enhance the therapeutic outcomes. This would not only develop the patient’s satisfaction with regard to the treatment but would also generate an overall optimized sentiment towards their general health.
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