scholarly journals A Review on Various Topics on the Thermal Grill Illusion

2021 ◽  
Vol 10 (16) ◽  
pp. 3597
Author(s):  
Dong Ah Shin ◽  
Min Cheol Chang

The thermal grill illusion (TGI) is a paradoxical perception of burning heat and pain resulting from the simultaneous application of interlaced warm and cold stimuli to the skin. The TGI is considered a type of chronic centralized pain and has been used to apply nociceptive stimuli without inflicting harm to human participants in the study of pain mechanisms. In addition, the TGI is an interesting phenomenon for researchers, and various topics related to the TGI have been investigated in several studies, which we will review here. According to previous studies, the TGI is generated by supraspinal interactions. To evoke the TGI, cold and warm cutaneous stimuli should be applied within the same dermatome or across dermatomes corresponding to adjacent spinal segments, and a significant difference between cold and warm temperatures is necessary. In addition, due the presence of chronic pain, genetic factors, and sexual differences, the intensity of the TGI can differ. In addition, cold noxious stimulation, topical capsaicin, analgesics, self-touch, and the presence of psychological diseases can decrease the intensity of the TGI. Because the TGI corresponds to chronic centralized pain, we believe that the findings of previous studies can be applied to future studies to identify chronic pain mechanisms and clinical practice for pain management.

2019 ◽  
Vol 374 (1785) ◽  
pp. 20190277 ◽  
Author(s):  
Edgar T. Walters

Chronic pain is considered maladaptive by clinicians because it provides no apparent protective or recuperative benefits. Similarly, evolutionary speculations have assumed that chronic pain represents maladaptive or evolutionarily neutral dysregulation of acute pain mechanisms. By contrast, the present hypothesis proposes that chronic pain can be driven by mechanisms that evolved to reduce increased vulnerability to attack from predators and aggressive conspecifics, which often target prey showing physical impairment after severe injury. Ongoing pain and anxiety persisting long after severe injury continue to enhance vigilance and behavioural caution, decreasing the heightened vulnerability to attack that results from motor impairment and disfigurement, thereby increasing survival and reproduction (fitness). This hypothesis is supported by evidence of animals surviving and reproducing after traumatic amputations, and by complex specializations that enable primary nociceptors to detect local and systemic signs of injury and inflammation, and to maintain low-frequency discharge that can promote ongoing pain indefinitely. Ongoing activity in nociceptors involves intricate electrophysiological and anatomical specializations, including inducible alterations in the expression of ion channels and receptors that produce persistent hyperexcitability and hypersensitivity to chemical signals of injury. Clinically maladaptive chronic pain may sometimes result from the recruitment of this powerful evolutionary adaptation to severe bodily injury. This article is part of the Theo Murphy meeting issue ‘Evolution of mechanisms and behaviour important for pain’.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
S. Mehta ◽  
D. Rice ◽  
A. McIntyre ◽  
H. Getty ◽  
M. Speechley ◽  
...  

Objective.The current study attempted to identify and characterize distinct CP subgroups based on their level of dispositional personality traits. The secondary objective was to compare the difference among the subgroups in mood, coping, and disability.Methods.Individuals with chronic pain were assessed for demographic, psychosocial, and personality measures. A two-step cluster analysis was conducted in order to identify distinct subgroups of patients based on their level of personality traits. Differences in clinical outcomes were compared using the multivariate analysis of variance based on cluster membership.Results.In 229 participants, three clusters were formed. No significant difference was seen among the clusters on patient demographic factors including age, sex, relationship status, duration of pain, and pain intensity. Those with high levels of dispositional personality traits had greater levels of mood impairment compared to the other two groups (p<0.05). Significant difference in disability was seen between the subgroups.Conclusions.The study identified a high risk group of CP individuals whose level of personality traits significantly correlated with impaired mood and coping. Use of pharmacological treatment alone may not be successful in improving clinical outcomes among these individuals. Instead, a more comprehensive treatment involving psychological treatments may be important in managing the personality traits that interfere with recovery.


Author(s):  
Claire Y. J. Wenham ◽  
Philip G. Conaghan

Osteoarthritis (OA) is a common condition which often causes pain and functional limitation, significantly impacting on a person’s quality of life. A comprehensive assessment of the impact of OA should be performed before selecting therapies and treatment goals. Current recommended therapies include a combination of pharmacological and non-pharmacological therapies, which should be considered for all people with OA, regardless of anatomical site of involvement. Non-pharmacological treatments include education, muscle strengthening and aerobic exercises, weight loss if appropriate, splints and devices, and aids. Pharmacological therapies include paracetamol, oral and topical non-steroidal anti-inflammatory drugs, topical capsaicin, intra-articular corticosteroid injections, and opioids. Many existing therapies have only a small analgesic effect size and, in the case of drug therapies, may be associated with important side effects, so an individual’s symptoms and comorbidities must be taken into account when selecting therapies. For those who do not respond to these treatments, surgery such as a total joint arthroplasty may be required. There is a strong need for new analgesic treatments for OA. As it is becoming increasingly clear that the sources of pain in OA are complex and multifactorial, future treatments for OA will need to target both peripheral and central pain mechanisms.


Rheumatology ◽  
2019 ◽  
Vol 58 (Supplement_4) ◽  
Author(s):  
Kathryn Shepherd ◽  
Nandita Pai ◽  
Ellie Potts ◽  
Ann-Maria Ahern ◽  
Swati BhagatJones ◽  
...  

Abstract Background We present a case that was referred and seen in our chronic pain clinic, and highlight the importance of keeping an open mind about alternative diagnoses when reviewing these patients. Methods Please refer to the results section. Results A 12 year-old girl was referred with right sided neck and shoulder pain associated with occasional pins and needles. The patient was a competitive swimmer, training and competing five times a week at her peak. She did not have a history of mottling or colour change, and clinically she had full range of motion of her joints and no neurological deficit. On repeated assessments, she had reproducible pain on horizontal flexion and reduced muscle bulk of the right shoulder, although power was preserved. Functionally the patient had to reduce her participation in swimming due to pain, and found it difficult to carry or lift things, brush or wash her hair, or write for extended periods of time. Imaging with shoulder X-ray and shoulder and cervical spine MRI did not reveal a cause, and she did not have an anatomical variation such as a thoracic rib. Due to the reproducibility on swimming, an ultrasound looking at the insertion of the biceps insertion during dynamic movements was arranged and was also normal with no subluxation noted. As she failed to improve with chronic pain education, chronic pain approach to physiotherapy sessions and graded reintroduction of swimming, ultrasound angiology was arranged. This showed minor disease in the right subclavian, axillary, brachial, radial and ulnar arteries, with significant reduction in right brachial arterial flow with the patient supine, right arm in horizontal flexion and contralateral head turn. This suggested arterial thoracic outlet syndrome (TOS). All other positions resulted in no significant difference in arterial flow. TOS is traditionally broken into two categories – neurogenic and vascular, the latter can be broken down further into arterial or venous. While in adults, the vast majority (90-95%) present as neurogenic, in the paediatric population there is a higher proportion of vascular cases. This has implications, as vascular TOS can be complicated by vessel disease and thrombus formation. There are a number of case reports in which management is reported as decompression of the thoracic outlet with partial first rib resection, with or without scalene muscle resection. Consideration of hypercoagulable states is also warranted. We have referred our patient to the vascular team for an urgent review and await their assessment and feedback about management. Conclusion A proportion of patients managed with chronic pain syndrome will have an alternative explanation for their pain. In particular, if a patient has focal pain or pain that is reproducible on a particular movement or activity, consider alternate diagnoses. Conflicts of Interest The authors declare no conflicts of interest.


2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Krzysztof Głód ◽  
Janusz Lasek ◽  
Krzysztof Słowik ◽  
Jarosław Zuwała ◽  
Daniel Nabagło ◽  
...  

Abstract During the combustion of solid fuels, the undesired effects of ash transformation include bed agglomeration, slagging, and fouling processes. In particular, a problematic consequence of bed agglomeration is the defluidization process, resulting from the disappearance of gaseous bubbles that are created behind air distributors. Different solutions can be applied against the agglomeration process. One possible method is to apply some additives that influence the ash behavior, thus inhibiting the agglomeration process. This paper presents the results of investigations into ash-related issues in a laboratory-scale bubbling fluidized bed (BFB) reactor. In particular, the impact of additives (kaolin, halloysite, fly ash, and the residuals from wet desulfurization system (IMOS)) on bed agglomeration was investigated. It was found that the addition of these compounds increased the defluidization time from ∼109 min (without additive) to ∼285 min in the BFB (with the addition of 0.1 g/min of kaolin). The morphology of additive (kaolin and halloysite) transformation after their addition into the combustion chamber was discussed. Another interesting phenomenon is that residuals from the IMOS exhibited the ability to be an additive against the agglomeration process. The defluidization time can be also significantly increased by the simultaneous application of the additive and the control of fluidization air velocity. The procedure of periodical bed moving by impulse primary air feeding against defluidization (PADM) is suggested and discussed. The PADM procedure resulted in a 36% reduction of additive, thus reducing the cost of measures against ash-related issues.


2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Fushui Liu ◽  
Jianyu You ◽  
Qi Li ◽  
Ting Fang ◽  
Mei Chen ◽  
...  

Objectives. Acupuncture has been widely used to relieve chronic pain-related insomnia (CPRI). However, the efficacy of acupuncture for CPRI is uncertain. The purpose of this study was to evaluate the efficacy of acupuncture for CPRI. Methods. Seven electronic databases were searched from inception to December 2018. Randomized controlled trials (RCTs) were included if acupuncture was compared to sham acupuncture or conventional drug therapies for treating CPRI. Two reviewers screened each study and extracted data independently. Statistical analyses were conducted by RevMan 5.3 software. Results. A total of nine studies involving 944 patients were enrolled. The pooled analysis indicated that acupuncture treatment was significantly better than control group in improving effective rate (OR = 8.09, 95%CI = [4.75, 13.79], P < 0.00001) and cure rate (OR = 3.17, 95%CI = [2.35, 4.29], P < 0.00001), but subgroup analysis showed that there was no statistically significant difference between acupuncture and sham acupuncture in improving cure rate (OR =10.36, 95% CI [0.53, 201.45], P=0.12) based on one included study. In addition, meta-analysis demonstrated that acupuncture group was superior to control group in debasing PSQI score (MD = -2.65, 95%CI = [-4.00, -1.30], P = 0.0001) and VAS score (MD = -1.44, 95%CI = [-1.58, -1.29], P < 0.00001). And there was no significant difference in adverse events (OR =1.73, 95%CI = [0.92, 3.25], P =0.09) between the two groups. Conclusions. Acupuncture therapy is an effective and safe treatment for CPRI, and this treatment can be recommended for the management of patients with CPRI. Due to the low quality and small sample size of the included studies, more rigorously designed RCTs with high quality and large sample size are recommended in future.


2019 ◽  
Vol 374 (1785) ◽  
pp. 20190288 ◽  
Author(s):  
Randolph M. Nesse ◽  
Jay Schulkin

Enormous progress in understanding the mechanisms that mediate pain can be augmented by an evolutionary medicine perspective on how the capacity for pain gives selective advantages, the trade-offs that shaped the mechanisms, and evolutionary explanations for the system's vulnerability to excessive and chronic pain. Syndromes of deficient pain document tragically the utility of pain to motivate escape from and avoidance of situations causing tissue damage. Much apparently excessive pain is actually normal because the cost of more pain is often vastly less than the cost of too little pain (the smoke detector principle). Vulnerability to pathological pain may be explained in part because natural selection has shaped mechanisms that respond adaptively to repeated tissue damage by decreasing the pain threshold and increasing pain salience. The other half of an evolutionary approach describes the phylogeny of pain mechanisms; the apparent independence of different kinds of pain is of special interest. Painful mental states such as anxiety, guilt and low mood may have evolved from physical pain precursors. Preliminary evidence for this is found in anatomic and genetic data. Such insights from evolutionary medicine may help in understanding vulnerability to chronic pain. This article is part of the Theo Murphy meeting issue ‘Evolution of mechanisms and behaviour important for pain’.


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