OBJECTIVE: Neuroinflammation, which occurs in knee osteoarthritis and sarcopenia, has attracted attention as a mechanism of central sensitization, but the relationship between central sensitization and these conditions has not been widely studied. This study investigates differences in self-reported signs of central sensitization and pressure pain threshold in individuals with knee osteoarthritis and sarcopenia.
METHODS: We examined 340 patients (mean age ± standard deviation: 76 ± 5.9, women were 86.9%) with knee osteoarthritis scheduled to undergo total knee arthroplasty. For comparison, 129 community-dwelling older people (mean age ± standard deviation: 76 ± 5.5, women were 68.9%) individuals without a history of knee osteoarthritis or any other diagnosed illnesses were matched for age and sex. We assessed central sensitization inventory-9, pressure pain threshold, pain-related factors, skeletal muscle mass index, and hand grip strength. ANCOVA using 2 (patients with knee osteoarthritis and community older people without knee osteoarthritis) × 2 (sarcopenia and robust) was performed to assess outcome measurements.
RESULTS: The prevalence of sarcopenia among patients with knee osteoarthritis was 50.3%. ANCOVA revealed an interaction effect for the central sensitization inventory-9. For the main effect of knee osteoarthritis, there was a significant difference in central sensitization inventory-9, and for the main effect of sarcopenia, there was a significant difference in pressure pain threshold.
CONCLUSIONS: Discrepancies in the evaluation of central sensitization were identified between knee osteoarthritis and sarcopenia. Individuals with knee osteoarthritis had elevated score of self-reported indications of central sensitization, whereas sarcopenic patients had reduced pressure pain thresholds.

OBJECTIVE: This study explored the relationship between central sensitization symptoms, assessed using the Central Sensitization Inventory (CSI), and psychophysical factors in patients with chronic masticatory myofascial pain (MMP) transitioning from the acute to chronic stages.
METHODS: In this study, 23 patients with MMP and 22 healthy volunteers were assessed using psychophysical tests, including measurements of pressure pain threshold (PPT) and temporal summation of pain (TSP). Additionally, CSI scores were recorded to evaluate central sensitization symptoms.
RESULTS: Patients with chronic MMP showed significantly lower PPT in all masticatory muscles and extratrigeminal areas compared with controls. However, there was no significant correlation between CSI scores and psychophysical test results in patients with MMP.
CONCLUSIONS: The significant enhancement of TSP in patients with subchronic MMP suggests a potential role in the onset of myofascial pain. The main finding suggests that sub-chronic symptom patients show higher CSI scores despite no sensory testing changes, indicating that central sensitization possibly precedes observable symptoms.

Dynamic resistance exercise may produce reductions in pain locally at the exercising muscle and systemically at non-exercising sites. However, limited research has examined these changes with multiple noxious stimuli. This study examined changes in heat pain threshold (HPT) and pressure pain threshold (PPT) on different musculature after an upper and lower body exercise to compare local and systemic effects. A crossover design with 28 participants (mean age: 21 ± 4 years, 21 female) completed three sessions. Visit one included baseline quantitative sensory testing and 5-repetition maximum (RM) testing for upper (shoulder press) and lower (leg extension) body. In subsequent sessions, participants performed upper or lower body exercises using an estimated 75% 1-RM with pre/post assessment of HPT and PPT at three sites: deltoid, quadriceps, and low back. A significant three-way interaction was observed for HPT (F (1.71, 3.80) = 2.19, p = 0.036, η2p = 0.12) with significant increases in HPT over the quadriceps (p = 0.043) after leg extension and over the deltoid (p = 0.02) after shoulder press. Significant systemic changes were not observed for HPT or PPT. Local but not systemic effects were demonstrated after an acute bout of exercise. Peripheral pain sensitivity may be more responsive to heat stimuli after resistance exercise.

BACKGROUND: Pain sensitivity is the main finding of central sensitization (CS) and can occur in patients with chronic shoulder pain. However, there is limited evidence concerning the distribution of pain sensitivity in shoulders, forearms, and legs in patients with CS associated with chronic shoulder pain. The present study aimed to determine the distribution of pain sensitivity in patients with CS associated with chronic subacromial pain syndrome (SPS).
METHODS: This cross-sectional study included 58 patients with chronic SPS and CS (patient group) and 58 healthy participants (control group). The presence of CS was determined using the Central Sensitization Inventory (CSI). To determine the distribution of pain sensitivity, pressure pain threshold (PPT) measurements were performed from the shoulders, forearms, and legs.
RESULTS: There was no significant difference between the two groups in terms of sociodemographic data (p > 0.05). The patient group had a significantly higher CSI score (p < 0.001) and lower PPTs in all regions (p < 0.05) than the control group. Unlike the control group, the patient group had lower PPTs on the affected side for the shoulder [mean difference (MD) 95% confidence interval (CI): 1.2 (-1.7 to -0.6)], forearm [MD 95% CI: 1.1 (-1.7 to -0.6)], and leg [MD 95% CI: 0.9 (-1.4 to -0.3)] compared with the contralateral side (p < 0.001).
CONCLUSIONS: Pain sensitivity is more pronounced in the affected shoulder and the forearm and leg located on this side than in those on the contralateral side in patients with CS associated with chronic SPS.

UNASSIGNED: Persistent neck pain is a prevalent musculoskeletal condition that affects the quality of life and functional abilities of individuals. Blood Flow Restriction Training (BFRT) is a novel therapeutic approach that involves restricting blood flow to exercising muscles to enhance strength and function. However, limited research has been conducted on the effects of BFRT on pressure pain threshold and hand function in adults with persistent neck pain. This randomized controlled trial aims to investigate the potential benefits of BFRT as a treatment intervention for this population.
UNASSIGNED: This study will be a prospective 1:1 allocation, parallel group active controlled trail conducted at Physiotherapy Department, Galgotias University. The trial was prospectively registered with the Clinical Trial Registry India CTRI/2023/06/053439. Informed consent will be obtained from all the participants who are eligible to be included in the study. A total of 110 patients with persistent neck pain will be randomly allocated into two groups. The BFRT group will receive supervised training sessions three times a week for eight weeks, performing low-load resistance exercises with blood flow restriction applied using personalized cuff pressure. The control group will receive standard care for neck pain, which may include general advice, manual therapy, and/or home exercises without BFRT. The primary outcome measures will be the pressure pain threshold, assessed using a pressure Algometer, and hand function, evaluated using standardized tests such as Hand Grip Strength and Purdue Peg board Test.
UNASSIGNED: The data obtained will be analyzed using appropriate statistical methods, and the significance level will be set at p<0.05.
UNASSIGNED: This trial will contribute valuable contribution highlighting the potential benefits of BFR training in improving pressure pain threshold and hand function in adults with persistent neck pain.

OBJECTIVE: Exercise induces a hypoalgesic response and improves affect. However, some individuals are unable to exercise for various reasons. Motor imagery, involving kinesthetic and visual imagery without physical movement, activates brain regions associated with these benefits and could be an alternative for those unable to exercise. Virtual reality also enhances motor imagery performance because of its illusion and embodiment. Therefore, we examined the effects of motor imagery combined with virtual reality on pain sensitivity and affect in healthy individuals.
METHODS: Randomized crossover study.
METHODS: Laboratory.
METHODS: Thirty-six participants (women: 18) were included.
METHODS: Each participant completed three 10-min experimental sessions, comprising actual exercise, motor imagery only, and motor imagery combined with virtual reality. Hypoalgesic responses and affective improvement were assessed using the pressure-pain threshold and the Positive and Negative Affect Schedule, respectively.
RESULTS: All interventions significantly increased the pressure-pain threshold at the thigh (P<0.001). Motor imagery combined with virtual reality increased the pressure-pain threshold more than motor imagery alone, but the threshold was similar to that of actual exercise (both P≥0.05). All interventions significantly decreased the negative affect of the Positive and Negative Affect Schedule (all P<0.05).
CONCLUSIONS: Motor imagery combined with virtual reality exerted hypoalgesic and affective-improvement effects similar to those of actual exercise.

OBJECTIVE: The aims of the current study were to investigate the presence of widespread pressure hyperalgesia, the presence of structural changes in the wrist extensor tendon and muscle, and their association in people with lateral epicondylalgia (LE).
METHODS: Thirty-seven patients with LE (43% women; mean age = 45.5 [SD = 9.5] years) and 37 controls matched for age and sex and free of pain participated in this study. Pressure pain thresholds (PPTs) were assessed bilaterally over the symptomatic area (elbow), 2 segment-related areas (C5-C6 joint, second intermetacarpal space), and 1 remote area (tibialis anterior) in a blinded design. Ultrasound measurements (eg, cross-sectional area, thickness, width) of the common wrist extensor tendon and extensor carpi radials brevis muscle as well as thickness of supinator muscle were assessed.
RESULTS: Patients with LE exhibited lower PPTs bilaterally at all points and lower PPTs at the lateral epicondyle and second intermetacarpal space at the symptomatic side as compared to the nonsymptomatic side (η2 from 0.123-0.369; large effects). Patients exhibited higher cross-sectional area and width of the common wrist extensor tendon (η2 from 0.268-0.311; large effects) than controls bilaterally, whereas tendon thickness was also higher (η2 = 0.039; small effects) on the painful side than on the nonpainful side.
CONCLUSIONS: This study reported bilateral widespread pressure pain hyperalgesia and morphological changes in the tendon, but not the muscle, in LE. Pressure pain sensitivity and morphological changes were not associated in individuals with LE.
UNASSIGNED: Management of LE should consider altered nociceptive pain processing and structural tendon changes as 2 different phenomena in patients with LE.

UNASSIGNED: To compare the effectiveness of instrument-assisted soft tissue mobilization (IASTM) and extracorporeal shock wave therapy (ESWT) used in myofascial pain syndrome (MPS) and to determine whether they are superior to conservative treatment (CT).
UNASSIGNED: A total of 42 female patients (aged 18-60 years) diagnosed with MPS were enrolled and randomly assigned to either the CT (n = 14), CT+IASTM (n = 14), or CT+ESWT group (n = 14). All of the groups received treatment for 3 weeks (CT: 5 sessions per week, 15 sessions in total, ESWT and IASTM: 2 sessions per week, 6 sessions in total). Neck stretching exercises were given to all of the patients as a home program. The pain intensity of the patients was determined using the visual analog scale (VAS). The pressure pain threshold (PPT) was measured with an algometer. Cervical joint range of motion (ROM) was measured with a cervical ROM (CROM) device. Pain, cervical disability, quality of life, and sleep disturbances were evaluated with the Neck Outcome Score (NOOS). Depression and anxiety parameters were evaluated with the Hospital Anxiety and Depression Scale (HADS). Evaluations were made before treatment and 3 days after the last treatment session.
UNASSIGNED: The CT+IASTM group was more successful than the other groups in terms of pain intensity, PPT, and improvements in the ROM parameters (p < 0.05). No significant difference was found between the NOOS and HADS scores of the groups when the posttreatment changes were compared to pretreatment (p > 0.05).
UNASSIGNED: All 3 of these treatments can be used to alleviate the negative effects of MPS. IASTM treatment can be preferred primarily in the creation of combined treatment programs for patients with ROM limitations and low PPTs.

OBJECTIVE: Individuals with chronic pain due to knee osteoarthritis (OA) are insufficiently physically active, and alterations of facilitatory and inhibitory nociceptive signaling are common in this population. Our objective was to examine the association of these alterations in nociceptive signaling with objective accelerometer-based measures of physical activity in a large observational cohort.
METHODS: We used data from the Multicenter Osteoarthritis Study. Measures of peripheral and central pain sensitivity included pressure pain threshold at the knee and mechanical temporal summation at the wrist, respectively. The presence of descending pain inhibition was assessed by conditioned pain modulation (CPM). Physical activity was quantitatively assessed over 7 days using a lower back-worn activity monitor. Summary metrics included steps/day, activity intensity, and sedentary time. Linear regression analyses were used to evaluate the association of pain sensitivity and the presence of descending pain inhibition with physical activity measures.
RESULTS: Data from 1873 participants was analyzed (55.9% female, age = 62.8 ± 10.0 years). People having greater peripheral and central sensitivity showed lower step counts. CPM was not significantly related to any of the physical activity measures, and none of the exposures were significantly related to sedentary time.
CONCLUSIONS: In this cohort, greater peripheral and central sensitivity were associated with reduced levels of objectively-assessed daily step counts. Further research may investigate ways to modify or treat heightened pain sensitivity as a means to increase physical activity in older adults with knee OA.

Introduction: The concept of acupoints is a key defining feature of acupuncture, yet the scientific basis of acupoints remains unclear. In recent years, there has been an emerging body of animal studies demonstrating an association between cutaneous sensitivity and visceral pathophysiology, through which acupoints over the skin are sensitized in pathologic conditions. Several studies with humans have also been conducted to assess whether the sensitivity of acupoints is distinct in healthy versus clinical populations. However, no systematic review has been conducted to collate and synthesize the status and quality of human studies on this topic. Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). Literature search was performed by combining variations of search terms related to acupoints and pain sensitivity in PubMed, EMBASE, and Alt HealthWatch (EBSCOHost). Screening of titles and abstracts and review of full-text articles for eligibility were performed by two independent investigators. Using a predefined template, information on subject characteristics, pathologic conditions, names of assessed acupoints, and relevant main findings were extracted from the included studies. The methodological quality of included studies was assessed using a modified Newcastle-Ottawa Scale (NOS) for case-control studies. A quality assessment checklist was also developed by the present authors to examine the quality of reporting of experimental variables that were considered important for evaluating acupoint sensitivity. Results: A total of 3453 studies were identified from the database search, of which 11 met the eligibility criteria to be included in this review. Six studies examined the mechanical sensitivity of body acupoints, and the remaining five studies examined the mechanical sensitivity of auricular points. Overall, findings suggest that the sensitivity of acupoints may be distinct in healthy versus clinical populations. However, there were various potential sources of bias and substantial heterogeneity across included studies in clinical conditions and acupoints. Conclusion: There is at present insufficient evidence to support or refute that acupoints in humans are sensitized in pathologic conditions. There were various methodological issues, including small sample size and poor reporting of experimental design and variables, which limit the ability to draw a definitive conclusion on this topic. It is also largely unclear whether it is the general body regions rather than specific acupoints that may be sensitized, as most studies did not include nonacupoint location(s) for comparison. Thus, further rigorous research is warranted.