Perceived Pain Intensity Research Articles

EFFECT OF PRENATAL STRESS ON NOC CEPTIVE SENSITIVITY OF MALE AND FEMALE RATS AT DIFFERENT PERIODS 173 OF POSTEMBRYONIC DEVELOPMENT

A change of pain sensitivity in rats of different sex and age (21st day, suckling period; 30th day, infantile period; and 60th day, juvenile period) was studied after prenatal stress of forced swimming in cold water. The perceptual component of nociception in prenatally stressed animals was shown to decrease on the 60th day of life compared to that in 21-day-old specimens. Importantly, the intensity of pain perception in juvenile rats subjected to intrauterine stress was smaller than control specimens. After prenatal stress, the emotional component of nociception in juvenile males and females was lower than in younger specimens. Therefore, prenatal stress is accompanied by a decrease in the perceptual and emotional components of nociception during the juvenile period, but not at the earlier stages of postembryonic development. The observed fluctuations in the degree of perception of the pain stimulus in male animals are slightly greater than those in females.

Simultaneous measurement of intra-epidermal electric detection thresholds and evoked potentials for observation of nociceptive processing following sleep deprivation

Sleep deprivation has been shown to increase pain intensity and decrease pain thresholds in healthy subjects. In chronic pain patients, sleep impairment often worsens the perceived pain intensity. This increased pain perception is the result of altered nociceptive processing. We recently developed a method to quantify and monitor altered nociceptive processing by simultaneous tracking of psychophysical detection thresholds and recording of evoked cortical potentials during intra-epidermal electric stimulation. In this study, we assessed the sensitivity of nociceptive detection thresholds and evoked potentials to altered nociceptive processing after sleep deprivation in an exploratory study with 24 healthy male and 24 healthy female subjects. In each subject, we tracked nociceptive detection thresholds and recorded central evoked potentials in response to 180 single- and 180 double-pulse intra-epidermal electric stimuli. Results showed that the detection thresholds for single- and double-pulse stimuli and the average central evoked potential for single-pulse stimuli were significantly decreased after sleep deprivation. When analyzed separated by sex, these effects were only significant in the male population. Multivariate analysis showed that the decrease of central evoked potential was associated with a decrease of task-related evoked activity. Measurement repetition led to a decrease of the detection threshold to double-pulse stimuli in the mixed and the female population, but did not significantly affect any other outcome measures. These results suggest that simultaneous tracking of psychophysical detection thresholds and evoked potentials is a useful method to observe altered nociceptive processing after sleep deprivation, but is also sensitive to sex differences and measurement repetition.

Correlation between the perceived pain intensity and psychophysical tests in patients with chronic pain

Introduction. Pain perception varies due to many factors. Quantitative sensory testing is a panel of diagnostic tests used to assess somatosensory function. The aim of the study was to determine how psychophysical variables are related to the perceived pain intensity in patients with chronic pain. Material and Methods. The cross-sectional study included 88 subjects (average age 51.3 ? 9.4 years, 76 (86.4%) women) diagnosed with chronic pain syndrome and fibromyalgia or chronic neuropathic pain associated with lumbosacral radiculopathy. Current and average pain intensities in the past 4 weeks were rated on a numerical rating scale. Quantitative sensory testing included pressure pain thresholds, heat pain thresholds, and cold pain thresholds. Patients filled out the Fear Avoidance Component Scale, a questionnaire that examines the fear avoidance phenomenon. Results. The highest correlations were found between the Fear Avoidance Component Scale scores and current and average pain intensity (r = 0.438 and r = 0.253, respectively); between pain duration and current and average pain intensity in the past 4 weeks (r = 0.340 and r = 0.308, respectively). Moderate and negative correlations were found between pressure pain thresholds and current and average pain intensity (r = - 0.233 and r = -0.300, respectively). Conclusion. Low to moderate, significant positive correlations were found between fear-avoidance and pain intensity. Significant but low negative correlations were found between pressure pain threshold and current pain intensity, as well as between pressure pain threshold and average pain intensity.

Pain coping skills training un-locks patient-centered pain care during the COVID- 19 lockdown

BackgroundIn 2020, the COVID-19 virus sparked a crisis constituting a nationwide public health emergency that rapidly altered the provision of healthcare services for all Americans. Infectious disease mitigation led to widespread lockdowns of perceived nonessential services, programs, and non-emergent healthcare interventions. This lockdown exacerbated the public health dyad of uncontrolled pain and the opioid epidemic, which was already in a crisis state. Current literature supports the management of uncontrolled pain with a biopsychosocial approach, empowering patients to explore self-care to enhance activities of daily living. Pain Coping Skills Training (PCST) delivers real-life strategies that improve quality of life and strengthen self-efficacy. Self-efficacy has been identified as a patient outcome measure that demonstrates improved patient-perceived function and quality of life despite pain intensity. Studies have shown that nurse practitioners (APRN) are well-positioned to provide PCST to chronic pain sufferers. MethodsA pretest-posttest design was utilized for this project to enhance pain self- efficacy through an APRN-led community-based intervention. InterventionCommunity-dwelling adults treated in a specialty pain management practice were self-selected to participate in a 6-week telehealth delivered PCST Program. This APRN delivered program presented basic pain education and a broad range of evidence-based nonpharmacologic pain management self-care tools. The primary outcome was improved Pain Self-efficacy measured with the pain self-efficacy questionnaire (PSEQ), with secondary outcomes of improved perceived pain intensity and function measured with the pain, enjoyment, and general activity (PEG) scale tracked weekly. ResultsBaseline PSEQ and weekly PEG scores were obtained and compared to scores after the program. Collateral data points included confidence in using complementary and alternative nonpharmacologic interventions, satisfaction with the program, and a qualitative patient statement regarding pre-and post-intervention participation. ConclusionsThis project concluded that a Nurse Practitioner delivered PCST program via telehealth technology could provide community-dwelling adults with an intervention that improves pain self-efficacy, enhances self-reported PEG measures, and meets the social distancing requirements that continue to impact patients during the COVID-19 pandemic.

Comparison of Pain Location and Extent Between Adults with Ankylosing Spondylitis-related Inflammatory versus Chronic Nonspecific Low Back Pain

Introduction: Pain among adults with ankylosing spondylitis-related inflammatory low back pain (AS-ILBP) is not well-characterized, and individuals with AS-ILBP are frequently misdiagnosed with chronic nonspecific low back pain (CNSLBP). This study digitally quantifies and compares the location and extent of pain between adults with AS-ILBP and those with CNSLBP and examines the relationship between the pain extent and functional, psychological, and condition-specific factors in those with AS-ILBP.
 Methodology: The location and extent of pain in adults with AS-ILBP (n = 27) or CNSLBP (n = 22) was quantified using a digital pain drawing analysis. Relationships between pain extent and perceived pain intensity and disability, pain-related cognitive factors (back beliefs, fear of movement, pain catastrophizing, pain coping, and self-efficacy), psychological distress, and AS-specific features were examined in those with AS-ILBP.
 Result: Pain extent in the dorsal region of the body was greater in those with AS-ILBP than in CNSLBP (P < 0.05). In AS-ILBP, the most prevalent pain location was the lumbar region (88.9%), followed by the buttock (70.4%); the frequencies of reported pain in these regions were similar between groups (P > 0.05). The AS-ILBP group more frequently reported pain in the thoracic (70.4%) and cervical (51.8%) regions (P < 0.05). In the AS-ILBP group, larger pain extent was moderately associated with negative back beliefs (rs = –0.44 to –0.41, P < 0.05) and lower self-efficacy (rs = –0.58 to –0.42, P < 0.05), but not with any of functional outcomes. Larger pain extent was associated with higher disease activity (P < 0.05).
 Conclusion: Adults with AS-ILBP perceive larger pain extent in spinal regions and the degree of pain extent is associated with negative back beliefs, lower self-efficacy, and higher disease activity. Pain drawings may assist in the differential diagnosis of CNSLBP and AS-ILBP. Further, they may aid psychological screening in adults with AS-ILBP.

Olfactory stimulation Inhibits Nociceptive Signal Processing at the Input Stage of the Central Trigeminal System

The spinal trigeminal nucleus caudalis (SpVc) in the mammalian brainstem serves a pivotal function in pain processing. As the main relay center for nociceptive signals, SpVc conducts pain-related signals from various regions of the head toward higher levels of central processing such as the thalamus. SpVc also receives modulatory signals from other brain areas, which can alleviate the perception of headache. We studied the impact of olfactory co-stimulation on pain-related behavior and SpVc neural activity in mice. Using the TRPA1 agonist allyl isothiocyanate (AITC) as noxious stimulus, we quantified the aversive response and the perceived pain intensity by evaluating explorative running and the mouse grimace scale, respectively. We found that the floral odorants phenylethyl alcohol (PEA) and lavender oil mitigated the aversive response to AITC. Consistent with this finding, a newly developed, automated quantification of c-Fos expression in SpVc revealed that co-stimulation with PEA or lavender profoundly reduced network activity in the presence of AITC. These results demonstrated a substantial analgesic potential of odor stimulation in the trigeminal system and provide an explanation for the palliative effect of odors in the treatment of headache.

Hypoalgesic effects of a blood flow restriction technique at moderate intensity with or without motor imagery: a single-blind randomized controlled trial

Purpose The main objective was to assess the hypoalgesic effect of adding blood flow restriction (BFR) training with or without motor imagery (MI) to moderate-intensity exercise. The secondary objective was to analyse the correlations of the pain pressure thresholds (PPTs) regarding perceived pain intensity, perceived fatigue, and cuff pressure discomfort. Methods A sample of 42 asymptomatic participants were randomly assigned to 3 groups: control group (CG), BFR group, and BFR with MI group. All participants performed a squat exercise at an intensity of 60% of 1RM. For the BFR groups, blood occlusion occurred at 80% of maximal arterial occlusive pressure. Local, bilateral, and distal PPT were assessed pre-intervention, post-intervention and 48 h post-intervention. The perceived fatigue was assessed post-intervention, and pain intensity was assessed only 48 h post-intervention. Results There were intragroup differences in the CG and BFR + MI group in the local PPT between the pre-intervention and post-intervention measurements (p = 0.039, d= −0.32 and p = 0.009, d= −0.46, respectively) and only in the CG in the bilateral PPT (p = 0.002, d= −0.41). The CG and BFR group showed significant differences at 48 h post-intervention, with a decrease in local PPT (p = 0.009, d = 0.51 and p = 0.049, d = 0.43, respectively) and bilateral PPT (p = 0.004, d = 0.53 and p = 0.021, d = 0.46, respectively). There was a negative moderate correlation between local PPT at the post-intervention time and perceived discomfort of the occlusion device only in the BFR group (r=-0.54, p = 0.045). Conclusion Moderate-intensity resistance training with high occlusion did not generate hypoalgesia but did appear to generate a hyperalgesic response within 48 h after the intervention.

A bifactor structural model of the Hungarian Pain Catastrophizing Scale and latent classes of a clinical sample

Pain catastrophizing is an exaggerated cognitive-affective response to actual or anticipated pain, usually measured by the Pain Catastrophizing Scale (PCS). Our study aimed to test the bifactor measurement model of the Hungarian PCS and to identify a catastrophizing risk group with a clinically meaningful cut-off score.The data of 404 chronic spine-related (neck, back and low-back) pain patients (mean age: 58.61 (SD = 14.34)) were used in our cross-sectional study. Besides pain-related and demographic data, pain catastrophizing and depressive symptoms were measured with questionnaires. Confirmatory factor analyses confirmed that the bifactor model outperformed the other tested measurement models, and the general catastrophizing factor was responsible for 81.5% of the explained variance. Using latent class analysis, we found that even moderately elevated pain catastrophizing score was related to more depressive symptoms and higher perceived pain intensity, and 22 score could be used as a cut-off score. Our results support the concept of global pain catastrophizing and the validity of the Hungarian PCS. Further studies are needed to evaluate the bifactor structure of this scale and the predictive value of the proposed cut-off score.

Standardized palpation of the temporalis muscle evoke referred pain and sensations in individuals without TMD.

This study aimed to determine if standardized palpations of the temporalis muscle evoke referred pain and/or sensations in individuals without TMD. This was a randomized, single-blinded study. The mechanical sensitivity of the right temporalis muscle was assessed in 32 participants without TMD with nine different stimulations to 15 test sites using palpometers (different stimulus intensities (0.5, 1.0, and 2.0kg) and durations (2, 5, and 10s). After each stimulus, participants were asked to score perceived pain intensity and intensity of unpleasantness on a 0-100 numeric rating scale as an indicator of mechanical sensitivity in the temporalis muscle and to indicate any areas of referred pain/sensations on a body chart. Pain intensity significantly differed between palpation durations, intensities, and test sites (P < 0.001). In contrast, unpleasantness significantly differed between palparation duration and intensities (P < 0.001), but not test sites. Participants more frequently reported referred pain/sensations evoked by the 10-s (34.4%) as opposed to the 2-s (6.3%) and 5-s (15.6%) palpation duration at the 2.0-kg stimulus intensity (P < 0.05). Our present results indicate that referred pain/sensations in the orofacial region can be evoked by standardized palpation of the temporalis muscle and influenced by the palpation duration in individuals without TMD. Referred pain/sensations from the temporalis muscle were duration- and intensity-dependent processes originating from local stimuli.

English

BACKGROUND This study intended to evaluate the prevalence of chronic orofacial pain in diabetic patients and its characteristics. METHODS In this cross-sectional study, 1300 patients referred to the Diabetes Centre of Taleghani Hospital in Kermanshah in 2019 were studied. The data collection tool was a questionnaire including demographic sections, medical history, and clinical findings. Data analysis was performed using SPSS software version 18, and the significance level was considered 0.05. RESULTS The prevalence of chronic orofacial pain in diabetics was 11.8 %. Headaches with a prevalence of 6.7 % were the most common chronic pain, followed by neuropathic pain with 2.54 % and TMJ pain with 2.38 %. The results showed that with an increase in FBS (Fasting Blood Sugar) and HbA1c (Haemoglobin A1c) variables, the prevalence of chronic orofacial pain also increased (P &lt; 0.001). People under 40 and over 60 years were more likely to have TMJ pain (P &lt; 0.001). Also, the duration of pain showed a statistically significant relationship with age and FBS. In patients under 50 years of age, the highest frequency was related to pain persistence less than 30 minutes, and in older ages, the prevalence of pain lasting more than 3 hours was higher (P &lt; 0.02). Also, with an increase in FBS, the duration of pain increased (P &lt; 0.05). The relationship between perceived pain intensity and type of diabetes was significant (P &lt; 0.001). There was also a statistically significant and inverse relationship between pain intensity and age (P &lt; 0.001, ρ = - 0.473). CONCLUSIONS Migraine headaches, chronic neuropathic pain, and TMJ complication have high prevalence in diabetic patients, and management of these pain should be put under consideration by clinicians. KEY WORDS Diabetes, Chronic Orofacial Pain, Prevalence

Clinical outcomes of using erythritol powder by means of air polishing with ultrasonic debridement in the treatment of initial periodontal pockets in hand of dental students: A split-mouth, randomized, comparative, controlled study. Part I.

The purpose of this trial was to evaluate the clinical efficacy and patient acceptance of using the erythritol powder air polishing with mechanical debridement in non-surgical periodontal therapy. The trial was conducted as a split-mouth design study of 6weeks' duration including 13 patients with gingivitis and stage I periodontitis with grade A. Each patient received ultrasonic debridement and polishing (UD+P) on one side, whereas the contralateral side was treated by erythritol powder air polishing and ultrasonic instrumentation (EPAP+UI) when required. Clinical variables were as follows: papillary bleeding index (PBI), bleeding on probing (BOP), full mouth plaque index (FMPI), calculus index (CI), modified gingival index (MGI), probing pocket depth (PPD), the time needed and rate the pain for each group. The FMPI, MGI, CI, PBL and BOP parameters improved significantly for both treatment procedures; however, there were no statistically significant differences between the two groups at any of the examinations intervals, except for MGI and CI which showed a significant reduction at 2weeks compared with baseline. PPD was significantly decreased in EPAP+UI group. Perceived pain intensity was lower for EPAP+UI group than UD+P group without any significant difference during follow-up periods between the two groups. Seven patients favoured air polishing. The treatment's time was (24.92±9.260 and 34.08±9.106) minutes for the test and control side, respectively. This study generally revealed no significant differences in clinical outcomes between two groups for gingivitis and stage I periodontitis treatment. However, EPAP+UI had higher patient's preference and less time-consuming compared with UD+P.

IMI2-PainCare-BioPain-RCT3: a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by electroencephalography (EEG)

BackgroundIMI2-PainCare-BioPain-RCT3 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics, by providing a quantitative understanding between drug exposure and effects of the drug on nociceptive signal processing in human volunteers. IMI2-PainCare-BioPain-RCT3 will focus on biomarkers derived from non-invasive electroencephalographic (EEG) measures of brain activity.MethodsThis is a multisite single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from scalp EEG measurements (laser-evoked brain potentials [LEPs], pinprick-evoked brain potentials [PEPs], resting EEG) will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose in separate study periods. Medication effects will be assessed concurrently in a non-sensitized normal condition and a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin). Patient-reported outcomes will also be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between LEP and PEP under tapentadol. Remaining treatment arm effects on LEP or PEP or effects on EEG are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modeling are exploratory.DiscussionLEPs and PEPs are brain responses related to the selective activation of thermonociceptors and mechanonociceptors. Their amplitudes are dependent on the responsiveness of these nociceptors and the state of the pathways relaying nociceptive input at the level of the spinal cord and brain. The magnitude of resting EEG oscillations is sensitive to changes in brain network function, and some modulations of oscillation magnitude can relate to perceived pain intensity, variations in vigilance, and attentional states. These oscillations can also be affected by analgesic drugs acting on the central nervous system. For these reasons, IMI2-PainCare-BioPain-RCT3 hypothesizes that EEG-derived measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.Trial registrationThis trial was registered 25/06/2019 in EudraCT (2019%2D%2D001204-37).

Effects of transcranial direct current stimulation on experimental pain perception: A systematic review and meta-analysis

ObjectiveMany studies have examined the effectiveness of transcranial direct current stimulation (tDCS) on human pain perception in both healthy populations and pain patients. Nevertheless, studies have yielded conflicting results, likely due to differences in stimulation parameters, experimental paradigms, and outcome measures. Human experimental pain models that utilize indices of pain in response to well-controlled noxious stimuli can avoid many confounds present in clinical data. This study aimed to assess the robustness of tDCS effects on experimental pain perception among healthy populations. MethodsWe conducted three meta-analyses that analyzed tDCS effects on ratings of perceived pain intensity to suprathreshold noxious stimuli, pain threshold and tolerance. ResultsThe meta-analyses showed a statically significant tDCS effect on attenuating pain-intensity ratings to suprathreshold noxious stimuli. In contrast, tDCS effects on pain threshold and pain tolerance were statistically non-significant. Moderator analysis further suggested that stimulation parameters (active electrode size and current density) and experimental pain modality moderated the effectiveness of tDCS in attenuating pain-intensity ratings. ConclusionThe effectiveness of tDCS on attenuating experimental pain perception depends on both stimulation parameters of tDCS and the modality of experimental pain. SignificanceThis study provides some theoretical basis for the application of tDCS in pain management.

Factors Associated with Pain Intensity in Patients Undergoing Orthodontic Treatment Based on Mini-Implants

Abstract Introduction: Pain is currently reported as the most common side effect associated with orthodontic treatment. The aim of this study was to evaluate the factors associated with the intensity of pain perception during orthodontic procedures consisting in anesthesia, orthodontic mini-implant placement and removal, as well as during the postoperative period following these procedures. Material and Methods: The study included 50 young adults with a permanent dentition in need of orthodontic treatment. The pain assessment was based on visual analogue scale (VAS), using self-report questions from approved questionnaires. Pain severity was analyzed in relation to: anesthesia, implant placement, implant removal, implant movement, elastic traction and gingiva/bone pain around the implant. The study lot was divided into Group 1 – patients experiencing a pain degree of 1 or 2, and Group 2 – patients experiencing a pain degree of 3 or 4 during implant placement. Results: The maximum pain intensity (PI) was recorded during implant placement, which has been associated with a PI of 2.4 ± 0.8 (95% CI: 2.17–2.63), followed by implant removal (PI = 2.36 ± 0.66, 95% CI: 2.17–2.54), gingiva/bone pain around the implant (PI = 2.32 ± 2.58, 95% CI: 2.15–2.48), and elastic traction (PI = 2.26 ± 0.63, 95% CI: 2.08–2.44). Male gender was present in a significantly higher extent in the group of patients presenting a high intensity pain during implant placement (86.3% in Group 2 vs. 3.5% in Group 1, p &lt;0.0001). The age group most sensitive to pain was 18 to 21 years. Conclusions: In our study, pain perception was significantly higher in males and in the 18–21 years age group. The most painful procedure during surgery was the initial moment of implant placement, followed by the moment of implant removal, gingival/bone pain around the implant, and the elastic tractions placed on the implant during anchorage.

The correlation of small fiber neuropathy with pain intensity and age in patients with Fabry's disease: A cross sectional study within a large Taiwanese family

BackgroundThe relationships among small fiber neuropathy, age, sex and pain intensity in the context of Fabry's disease remain unclear. We aim to study the correlations of small fiber neuropathy, age, sex and pain intensity in Fabry patients. MethodsWe evaluated C-fiber function by recording the withdrawal latencies to painful heat stimulus (WLPHS) when each subject's right hand was immersed in a 50 °C hot water bath and correlated this parameter with the patient's perceived pain intensity and quality of life assessed by the short-form McGill Pain Questionnaire (SF-MPQ) in a large Taiwanese Fabry family and normal controls. ResultsMale Fabry patients showed a significantly increased WLPHS compared to that of normal controls. Furthermore, male Fabry patients showed a positive correlation of increased WLPHS with patient age. The SF-MPQ of male Fabry patients showed a bell distribution with age, and maximal pain scores were detected between the ages of the early 20s and late 40s. In contrast, the female Fabry patients had variable associations of WLPHS and SF-MPQ with age. ConclusionsWe proposed a probable mechanism by which globotriaosylceramide (Gb3) or globotriaosylsphingosine (lyso-Gb3) is gradually deposited into the small nerve bundles with increasing age, which induces continuous damage and produces injury discharges to sustain neuropathic pain in young male Fabry patients. However, once the small fibers are reduced to a certain degree, they no longer produce enough noxious discharges to sustain neuropathic pains in older male Fabry patients, which leads these patients to have lower SF-MPQ scores. In contrast, female Fabry patients had less and variable small fiber damage, pain intensity and clinical signs/symptoms.

Evaluation of Electronic Dental Anesthesia as a Non-Invasive Method in Children: A Review Study

Background The findings of various studies have supported the analgesic effect of transcutaneous electrical nerve stimulation (TENS). Studies yielded contradictory findings on electronic dental anesthesia (EDA) as a non-invasive method. This review study aims to evaluate the EDA as a non-invasive method. Materials and Methods This review study was conducted by screening all clinical trials evaluating the EDA in children. An electronic search was performed in Scopus, EMBASE, Cochrane, Web of Science, and Medline with no language or time restrictions. Results Six clinical trials were included in this study. The results of the first study showed that EDA was less effective than local anesthesia. Another study indicated no statistically significant difference between the two groups in terms of perception of pain intensity and comfort. The third study revealed no significant differences between the two methods in terms of the level of pain in the first deciduous molars, but a higher level of pain was reported in the second deciduous molar in the case of the injection method. A comparison of behavioral responses and changes in vital signs of children in local anesthesia and electronic anesthesia methods showed positive responses to the latter. A combination of music and electronic anesthesia was reported to be effective in the relief of pain in children under the treatment of two corresponding deciduous molars. Another study showed that the vibraject technique led to a statistically significant reduction in pain among children. Conclusion The findings of this review study emphasize the importance of analgesic techniques in pediatric dental procedures. The use of new techniques along with conventional methods of analgesia should be taken into consideration, especially in pediatric dentistry.

MorphFace: A Hybrid Morphable Face for a Robopatient

Physicians use pain expressions shown in a patient's face to regulate their palpation methods during physical examination. Training to interpret patients’ facial expressions with different genders and ethnicities still remains a challenge, taking novices a long time to learn through experience. This letter presents MorphFace: a controllable 3D physical-virtual hybrid face to represent pain expressions of patients from different ethnicity-gender backgrounds. It is also an intermediate step to expose trainee physicians to the gender and ethnic diversity of patients. We extracted four principal components from the Chicago Face Database to design a four degrees of freedom (DoF) physical face controlled via tendons to span <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim\!85\%$</tex-math></inline-formula> of facial variations among gender and ethnicity. Details such as skin colour, skin texture, and facial expressions are synthesized by a virtual model and projected onto the 3D physical face via a front-mounted LED projector to obtain a hybrid controllable patient face simulator. A user study revealed that certain differences in ethnicity between the observer and the MorphFace lead to different perceived pain intensity for the same pain level rendered by the MorphFace. This highlights the value of having MorphFace as a controllable hybrid simulator to quantify perceptual differences during physician training.

A task-relevant experimental pain model to target motor adaptation.

Motor adaptation is thought to be a strategy to avoid pain. Current experimental pain models do not allow for consistent modulation of pain perception depending on movement. We showed that low-frequency sinusoidal stimuli delivered at painful intensity result in minimal habituation of pain perception (over 60s) and minimal stimulation artefacts on electromyographic signals. When the amplitude of the low-frequency sinusoidal stimuli was modulated based on the vertical force participants applied to the ground with their right leg while standing upright, we demonstrated a strong association between perceived pain and motor adaptation. By enabling task-relevant modulation of perceived pain intensity and the recording electromyographic signals during electrical painful stimulation, our novel pain model will permit direct experimental testing of the relationship between pain and motor adaptation. Contemporary pain adaptation theories predict that motor adaptation occurs to limit pain. Current experimental pain models, however, do not allow for pain intensity modulation according to one's posture or movements. We developed a task-relevant experimental pain model using low-frequency sinusoidal electrical stimuli applied over the infrapatellar fat pad. In fourteen participants, we compared perceived pain habituation and stimulation-induced artefacts in vastus medialis electromyographic recordings elicited by sinusoidal (4, 10, 20 and 50Hz) and square electrical waveforms delivered at constant peak stimulation amplitude. Next, we simulated a clinical condition where perceived knee pain intensity is proportional to the load applied on the leg by controlling sinusoidal current amplitude (4Hz) according to the vertical force the participants applied with their right leg to the ground while standing upright. Pain ratings habituated over a 60s period for 50Hz sinusoidal and square waveforms but not for low-frequency sinusoidal stimuli (P<0.001). EMG filters removed most stimulation artefacts for low-frequency sinusoidal stimuli (4Hz). While balancing upright, participants' pain ratings were correlated with the force applied by the right leg (R2 =0.65), demonstrating task-relevant changes in perceived pain intensity. Low-frequency sinusoidal stimuli can induce knee pain of constant intensity for 60s with minimal EMG artefacts while enabling task-relevant pain modulation when controlling current amplitude. By enabling task-dependent modulation of perceived pain intensity, our novel experimental model replicates key temporal aspects of clinical musculoskeletal pain while allowing quantification of neuromuscular activation during painful electrical stimulation. This approach will enable researchers to test the predicted relationship between movement strategies and pain.

An intensity matched comparison of laser- and contact heat evoked potentials

Previous studies comparing laser (LEPs) and contact heat evoked potentials (CHEPs) consistently reported higher amplitudes following laser compared to contact heat stimulation. However, none of the studies matched the perceived pain intensity, questioning if the observed difference in amplitude is due to biophysical differences between the two methods or a mismatch in stimulation intensity. The aims of the current study were twofold: (1) to directly compare the brain potentials induced by intensity matched laser and contact heat stimulation and (2) investigate how capsaicin-induced secondary hyperalgesia modulates LEPs and CHEPs. Twenty-one healthy subjects were recruited and measured at four experimental sessions: (1) CHEPs + sham, (2) LEPs + sham, (3) CHEPs + capsaicin, and (4) LEPs + capsaicin. Baseline (sham) LEPs latency was significantly shorter and amplitude significantly larger compared to CHEPs, even when matched for perceived pain. Neither CHEPs nor LEPs was sensitive enough to detect secondary hyperalgesia. These differences provide evidence that a faster heating rate results in an earlier and more synchronized LEPs than CHEPs. To our knowledge, this was the first study to match perceived intensity of contact heat and laser stimulations, revealing distinct advantages associated with the acquisition of LEPs.

Functional and Cognitive Improvement After an Intensive Inpatient Multidisciplinary Rehabilitation Program in Mild to Severe Parkinson's Disease: A Retrospective and Observational Study.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor (resting tremor, rigidity, bradykinesia, postural instability, and gait disturbances) and nonmotor symptoms (cognitive, neuropsychiatric, and autonomic problems). In recent years, several studies demonstrated that neurorehabilitation therapy is an effective treatment in addition to pharmacological personalized interventions in persons with PD (PwPD). The main aim of this study was to explore the short-term changes in functional, cognitive, and geriatric domains after a multidimensional rehabilitation program in PwPD (as primary condition) in mild–moderate (M-Ms) to severe (Ss) stages. Our second aim was to compare the effects of multidimensional rehabilitation in M-Ms versus Ss of PD. Twenty-four PwPD in M-Ms to Ss [age (mean ± SD) = 76.25 ± 9.42 years; male/female = 10/14; Hoehn and Yahr (median; IQR) = 4.00; 1.75] were included in a retrospective, observational study. Motor, cognitive, functional, and neuropsychiatric aspects were collected in admission (T0) and in discharge (T1). PwPD were involved in a person-tailored (to individual's needs), inpatient, intensive (5–7 days per week), multidisciplinary (combining cognitive, physical, occupational, and speech therapies), comprehensive, and rehabilitative program. According to Movement Disorders Society Unified Parkinson's Disease Rating Scale III cutoff, PwPD were classified in M-Ms or Ss (M-Ms ≤59; Ss >59); 87.50% of our sample reported significant reduction of functional disability at Barthel Index (p < 0.001). A significant improvement in Token test (p = 0.021), semantic fluency (p = 0.036), Rey's Figure-Copy (p < 0.001), and Raven's Colored Progressive Matrices (p = 0.004) was observed. The pain intensity perception (p < 0.001) and the risk of developing pressure ulcers (p < 0.001) as assessed, respectively, by the Numeric Rating Scale and by the Norton Scale were improved. With regard to the second aim, in M-Ms group, we found a positive correlation between the number of neuromotor sessions and the change in functional disability and language comprehension; in the Ss group, on the other hand, despite a higher number of hospitalization days, the total number of completed sessions was positively associated with the change in visuoconstructional abilities. Our findings suggest that an intensive, inpatient, and multidisciplinary rehabilitation program may improve functional abilities, some strategic cognitive functions, and geriatric aspects in PwPD with mild–moderate motor impairment.