Quantitative and Qualitative Pain Evaluation in Response to OnabotulinumtoxinA for Chronic Migraine: An Observational Real-Life Study

(1) Background: Randomized controlled trials and real-life studies demonstrated the efficacy of OnabotulinumtoxinA (OBT-A) for CM prevention. However, no studies specifically addressed its effect on pain's quantitative intensity and qualitative characteristics. (2) Methods: This is an ambispective study: a post-hoc retrospective analysis of real-life prospectively collected data from two Italian headache centers on CM patients treated with OBT-A over one year (i.e., Cy1-4). The primary endpoint was the changes in pain intensity (Numeric Rating Scale, NRS; the Present Pain Intensity (PPI) scale, the 6-point Behavioral Rating Scale (BRS-6)) and quality scale (the short-form McGill Pain Questionnaire (SF-MPQ)) scores. We also assessed the relationship between changes in intensity and quality of pain and disability scale (MIDAS; HIT-6) scores, monthly headache days (MHDs), and monthly acute medication intake (MAMI) (3) Results: We retrieved 152 cases (51.5 years SD 11.3, 80.3% females). From baseline to Cy-4, MHDs, MAMI, NRS, PPI, and BRS-6 scores decreased (consistently p < 0.001). Only the throbbing (p = 0.004), splitting (p = 0.018), and sickening (p = 0.017) qualities of pain collected in the SF-MPQ were reduced. Score variations in MIDAS related to those in PPI scales (p = 0.035), in the BRS-6 (p = 0.001), and in the NRS (p = 0.003). Similarly, HIT-6 score changes related to PPI score modifications (p = 0.027), in BRS-6 (p = 0.001) and NRS (p = 0.006). Conversely, MAMI variation was not associated with qualitative or quantitative pain score modifications except BRS-6 (p = 0.018). (4) Conclusions: Our study shows that OBT-A alleviates migraine by reducing its impact on multiple aspects, such as frequency, disability, and pain intensity. The beneficial effect on pain intensity seems specific to pain characteristics related to C-fiber transmission and is associated with a reduction in migraine-related disability.

A Novel Measure of Pain Location in Adults with Sickle Cell Disease

BACKGROUND

Pain intensity remains a primary focus clinically for sickle cell disease pain assessment despite the fact that pain quality and pain location and distribution are critical for clinical diagnosis and treatment of its etiology. However, in part because of measurement issues, scant evidence is available about pain location or its relationship to intensity and quality in adults with SCD.

AIM

Our study aim was to examine sickle cell disease pain location for relationships with pain quality and intensity measured in outpatient and inpatient settings.

METHODS

We used an existing longitudinal dataset prospectively collected with the valid and reliable tablet-based PAINReportItⓇ. Adults with sickle cell disease (n = 99) reported pain location, intensity, and quality during a routine outpatient clinic visit and again during a subsequent hospitalization. From their digital body outline drawings and using the ImageJ software, we computed the pain-affected body surface area. With Pearson's correlations and paired t tests, we examined relationships between pain-affected body surface area and other pain variables across outpatient and inpatient visits.

RESULTS

The mean pain-affected body surface area was 14.4% ± 15.0% of the total body surface area for outpatient visits (min-max: 0.0%-90.2%) and 13.5% ± 14.7% (min-max: 0.0%-73.0%) for inpatient stay. Pain-affected body surface area was positively correlated with pain quality scores for both visits but not significantly correlated with pain intensity at either visit. Compared with the outpatient visit, mean pain intensity for inpatient stay was higher (p < .001); pain quality (p = .12) and pain-affected body surface area (p = .60) did not differ significantly between visits.

CONCLUSIONS

Unknown is the explanation for pain-affected body surface area association with SCD pain quality but not pain intensity at outpatient and inpatient visits. Additional research is warranted to explore these findings and examine the clinical utility of pain-affected body surface area for chronic sickle cell disease pain and acute sickle cell disease crisis pain.

Pain quality of thermal grill illusion is similar to that of central neuropathic pain rather than peripheral neuropathic pain

OBJECTIVES

Application of spatially interlaced innocuous warm and cool stimuli to the skin elicits illusory pain, known as the thermal grill illusion (TGI). This study aimed to discriminate the underlying mechanisms of central and peripheral neuropathic pain focusing on pain quality, which is considered to indicate the underlying mechanism(s) of pain. We compared pain qualities in central and peripheral neuropathic pain with reference to pain qualities of TGI-induced pain.

METHODS

Experiment 1:137 healthy participants placed their hand on eight custom-built copper bars for 60 s and their pain quality was assessed by the McGill Pain Questionnaire. Experiment 2: Pain quality was evaluated in patients suffering from central and peripheral neuropathic pain (42 patients with spinal cord injury, 31 patients with stroke, 83 patients with trigeminal neuralgia and 131 patients with postherpetic neuralgia).

RESULTS

Experiment 1: Two components of TGI-induced pain were found using principal component analysis: component 1 included aching, throbbing, heavy and burning pain, component 2 included itching, electrical-shock, numbness, and cold-freezing. Experiment 2: Multiple correspondence analysis (MCA) and cross tabulation analysis revealed specific pain qualities including aching, hot-burning, heavy, cold-freezing, numbness, and electrical-shock pain were associated with central neuropathic pain rather than peripheral neuropathic pain.

CONCLUSIONS

We found similar qualities between TGI-induced pain in healthy participants and central neuropathic pain rather than peripheral neuropathic pain. The mechanism of TGI is more similar to the mechanism of central neuropathic pain than that of neuropathic pain.

Acute experimentally-induced pain replicates the distribution but not the quality or behaviour of clinical appendicular musculoskeletal pain. A systematic review

OBJECTIVES

Experimental pain is a commonly used method to draw conclusions about the motor response to clinical musculoskeletal pain. A systematic review was performed to determine if current models of acute experimental pain validly replicate the clinical experience of appendicular musculoskeletal pain with respect to the distribution and quality of pain and the pain response to provocation testing.

METHODS

A structured search of Medline, Scopus and Embase databases was conducted from database inception to August 2020 using the following key terms: "experimental muscle pain" OR "experimental pain" OR "pain induced" OR "induced pain" OR "muscle hyperalgesia" OR ("Pain model" AND "muscle"). Studies in English were included if investigators induced experimental musculoskeletal pain into a limb (including the sacroiliac joint) in humans, and if they measured and reported the distribution of pain, quality of pain or response to a provocation manoeuvre performed passively or actively. Studies were excluded if they involved prolonged or delayed experimental pain, if temporomandibular, orofacial, lumbar, thoracic or cervical spine pain were investigated, if a full text of the study was not available or if they were systematic reviews. Two investigators independently screened each title and abstract and each full text paper to determine inclusion in the review. Disagreements were resolved by consensus with a third investigator.

RESULTS

Data from 57 experimental pain studies were included in this review. Forty-six of these studies reported pain distribution, 41 reported pain quality and six detailed the pain response to provocation testing. Hypertonic saline injection was the most common mechanism used to induce pain with 43 studies employing this method. The next most common methods were capsaicin injection (5 studies) and electrical stimulation, injection of acidic solution and ischaemia with three studies each. The distribution of experimental pain was similar to the area of pain reported in clinical appendicular musculoskeletal conditions. The quality of appendicular musculoskeletal pain was not replicated with the affective component of the McGill Pain Questionnaire consistently lower than that typically reported by musculoskeletal pain patients. The response to provocation testing was rarely investigated following experimental pain induction. Based on the limited available data, the increase in pain experienced in clinical populations during provocative maneuvers was not consistently replicated.

CONCLUSIONS

Current acute experimental pain models replicate the distribution but not the quality of chronic clinical appendicular musculoskeletal pain. Limited evidence also indicates that experimentally induced acute pain does not consistently increase with tests known to provoke pain in patients with appendicular musculoskeletal pain. The results of this review question the validity of conclusions drawn from acute experimental pain studies regarding changes in muscle behaviour in response to pain in the clinical setting.

Age- and sex-related differences in the presentation of paediatric migraine: A retrospective cohort study

Introduction Although migraine is a common headache complaint in children and adolescents there remains a significant gap in understanding the unique aspects of the disease in these age groups and their evolution with development. The aim of this retrospective cohort study was to identify migraine features that are influenced by age and sex. Methods The headache characteristics of 359 paediatric patients with a clinical diagnosis of migraine from a tertiary paediatric headache clinic were assessed. Patients retrospectively reported headache characteristics during a structured intake interview and clinical exam. Headache characteristics, description and associated symptoms were compared between children (age ≤ 12 years) and adolescents (age > 12 years), and between male and female migraineurs. Results Several migraine features differed significantly with age and/or sex, including: (i) a marked change from a 1:1 sex ratio in children to a 2:1 predominance of girls in adolescents; (ii) a higher frequency of headache attacks per month in adolescents and female migraineurs; (iii) a higher proportion of adolescents endorsed a 'throbbing' pain quality; (iv) a higher proportion of children reporting nausea and vomiting; and (v) a higher proportion of adolescents, particularly female migraineurs, had a diagnosis of a co-morbid anxiety. Conclusion The presentation of migraine, both in terms of its headache characteristics and associated symptoms, appear to vary as a function of age and sex. Given that migraine symptoms have a neural basis, it is not surprising that during the key period of neurodevelopment from childhood to adolescence this may impact their presentation.

Words that describe chronic musculoskeletal pain: implications for assessing pain quality across cultures

Background

People from different cultures who speak different languages may experience pain differently. This possible variability has important implications for evaluating the validity of pain quality measures that are directly translated into different languages without cultural adaptations. The aim of this study was to evaluate the impact of language and culture on the validity of pain quality measures by comparing the words that individuals with chronic pain from Nepal use to describe their pain with those used by patients from the USA.

Methods

A total of 101 individuals with chronic musculoskeletal pain in Nepal were asked to describe their pain. The rates of the different pain descriptor domains and phrases used by the Nepali sample were then compared to the published rates of descriptors used by patients from the USA. The content validity of commonly used measures for assessing pain quality was then evaluated.

Results

While there was some similarity between patients from Nepal and the USA in how they describe pain, there were also important differences, especially in how pain quality was described. For example, many patients from Nepal used metaphors to describe their pain. Also, the patients from Nepal often used a category of pain descriptor – which describes a physical state – not used by patients from the USA. Only the original McGill Pain Questionnaire was found to have content validity for assessing pain quality in patients from Nepal, although other existing pain quality measures could be adapted to be content valid by adding one or two additional descriptors, depending on the measure in question.

Conclusion

The findings indicate that direct translations of measures that are developed using samples of patients from one country or culture are not necessarily content valid for use in other countries or cultures; some adaptations may be required in order for such measures to be most useful in new language and culture.

Valence and Arousal Value of Visual Stimuli and Their Role in the Mitigation of Chronic Pain: What Is the Power of Pictures?

The present study investigated the pain-reducing effects of various pictures in a sample of 88 patients receiving inpatient treatment for chronic pain. We investigated whether the pain-attenuating effects of the pictures were mediated by picture valence, arousal, or change in subjective social support. The study was carried out over 4 consecutive days. Patients were presented with photographs of loved ones, strangers, landscapes, or optical illusions via digital albums and were asked to rate their pain intensity and their sensory and affective experience of pain immediately before and after viewing the pictures. They also evaluated the valence of the pictures and the extent to which they were arousing. Before and after participation in the study, patients provided information on their subjective social support. The valence attributed to the pictures varied; photographs of loved ones elicited the greatest pleasure. Pictures of varying emotional content and arousal value all reduced affective and sensory perceptions of pain. Viewing photographs of loved ones reduced pain intensity more than viewing other picture types. The association between picture type and decrease in pain intensity was mediated by picture valence. These findings suggest an easy to implement supplementary intervention that could be used in multidisciplinary pain treatment.

PERSPECTIVE

To our knowledge, this is the first demonstration that pictures mitigate pain in chronic pain patients receiving treatment in a multidisciplinary pain center. The procedure could be used routinely to treat pain, particularly severe pain.

Creating a better picture of chronic pain: improving pain pictogram designs through systematic evaluation of user responses

This article discusses the challenges of visually representing pain qualities in pictogram design. An existing set of 12 pictograms designed for people with literacy problems was evaluated to understand more about misunderstandings of pictogram interpretation. Two sets of university students from different disciplines were asked to interpret the pictograms, and a novel classification system was developed to categorise answer types, as 'location', 'affective', temporal' or 'literal'. Several design recommendations are made as a result that will help improve the design of pain pictograms as a whole as well as guide designers of related pictogram work. We demonstrate how, through the robust classification of incorrect responses, it is possible to extract useful comprehension error patterns to inform future design.

Can pictorial images communicate the quality of pain successfully?

Chronic pain is common and difficult for patients to communicate to health professionals. It may include neuropathic elements which require specialised treatment. A little used approach to communicating the quality of pain is through the use of images. This study aimed to test the ability of a set of 12 images depicting different sensory pain qualities to successfully communicate those qualities. Images were presented to 25 student nurses and 38 design students. Students were asked to write down words or phrases describing the quality of pain they felt was being communicated by each image. They were asked to provide as many or as few as occurred to them. The images were extremely heterogeneous in their ability to convey qualities of pain accurately. Only 2 of the 12 images were correctly interpreted by more than 70% of the sample. There was a significant difference between the two student groups, with nurses being significantly better at interpreting the images than the design students. Clearly, attention needs to be given not only to the content of images designed to depict the sensory qualities of pain but also to the differing audiences who may use them. Education, verbal ability, ethnicity and a multiplicity of other factors may influence the understanding and use of such images. Considerable work is needed to develop a set of images which is sufficiently culturally appropriate and effective for general use.

Validation of the Short-form McGill Pain Questionnaire-2 (SF-MPQ-2) in acute low back pain

The Short-form McGill Pain Questionnaire (SF-MPQ-2) assesses the major symptoms of both neuropathic and nonneuropathic pain and can be used in studies of epidemiology, natural history, pathophysiologic mechanisms, and treatment response. Previous research has demonstrated its reliability, validity, and responsiveness in diverse samples of patients with chronic pain. However, the SF-MPQ-2 has not been evaluated for use in patients with acute pain. Data were examined from a double-blind, randomized clinical trial of immediate-release tapentadol versus immediate-release oxycodone in patients with acute low back and associated radicular leg pain (N = 666). Analyses of internal consistency, convergent validity, and confirmatory factor structure were conducted using baseline data, and analyses of responsiveness were conducted using baseline and endpoint data. The SF-MPQ-2 total score and its 4 subscale scores (continuous pain, intermittent pain, predominantly neuropathic pain, and affective descriptors) generally showed good psychometric properties and 1) were internally consistent, 2) displayed good convergent validity, 3) fit the a priori factor structure, and 4) were highly responsive to analgesic treatment. These data extend previous evidence of the reliability, validity, and responsiveness of the SF-MPQ-2 in patients with chronic pain to those with acute low back and associated radicular leg pain.

PERSPECTIVE

Considered together with the results of other recent studies, the data suggest that the SF-MPQ-2 can provide a valid, responsive, and efficient assessment of both neuropathic and nonneuropathic pain qualities for clinical trials and other clinical research examining patients with various acute and chronic pain conditions.

Effect of intravenous lidocaine on the neuropathic pain of failed back surgery syndrome

BACKGROUND

An intravenous infusion of lidocaine has been used on numerous occasions to produce analgesia in neuropathic pain. In the cases of failed back surgery syndrom, the pain generated as result of abnormal impulse from the dorsal root ganglion and spinal cord, for instance as a result of nerve injury may be particularly sensitive to lidocaine. The aim of the present study was to identify the effects of IV lidocaine on neuropathic pain items of FBSS.

METHODS

The study was a randomized, prospective, double-blinded, crossover study involving eighteen patients with failed back surgery syndrome. The treatments were: 0.9% normal saline, lidocaine 1 mg/kg in 500 ml normal saline, and lidocaine 5 mg/kg in 500 ml normal saline over 60 minutes. The patients underwent infusions on three different appointments, at least two weeks apart. Thus all patients received all 3 treatments. Pain measurement was taken by visual analogue scale (VAS), and neuropathic pain questionnaire.

RESULTS

Both lidocaine (1 mg/kg, 5 mg/kg) and placebo significantly reduced the intense, sharp, hot, dull, cold, sensitivity, itchy, unpleasant, deep and superficial of pain. The amount of change was not significantly different among either of the lidocaine and placebo, or among the lidocaine treatments themselves, for any of the pain responses, except sharp, dull, cold, unpleasant, and deep pain. And VAS was decreased during infusion in all 3 group and there were no difference among groups.

CONCLUSIONS

This study shows that 1 mg/kg, or 5 mg/kg of IV lidocaine, and palcebo was effective in patients with neuropathic pain attributable to FBSS, but effect of licoaine did not differ from placebo saline.