Changes In Pressure Pain Sensitivity Research Articles

Pressure Pain Sensitivity in Patients With Suspected Opioid-Induced Hyperalgesia.

This study was designed to test whether a brief quantitative sensory testing assessment could be used to detect hyperalgesia in patients with suspected opioid-induced hyperalgesia (OIH). Twenty patients on long-term opioid therapy with suspected OIH were recruited along with 20 healthy controls. Pressure pain threshold, Pain50, a measure of intermediate suprathreshold pressure pain sensitivity, and tolerance levels were evaluated. As a secondary outcome, changes in pressure pain sensitivity after intravenous administration of placebo (saline) and fentanyl (1.5 μg/kg) were assessed. There were no significant differences in pain measures between healthy controls and patients. However, there was an association between higher doses of opioids and having a lower pain tolerance (r = -0.46, P = 0.041) and lower Pain50 (r = -0.46, P = 0.044), which was consistent with the hypothesis. Patients on more than 100 mg oral morphine equivalents displayed decreased pressure pain tolerance compared with patients taking less than 100 mg oral morphine equivalents (P = 0.042). In addition, male patients showed a hyperalgesic response to fentanyl administration, which was significant for the Pain50 measure (P = 0.002). Whereas there were no differences between patients suspected of having OIH and the healthy controls, the finding that higher doses of opioids were associated with more sensitivity suggests that dose might be an important factor in the development of hyperalgesia. In addition, male patients demonstrated a hyperalgesic response after a bolus of fentanyl. Future studies are needed to develop better diagnostics for detecting hyperalgesia in the clinical setting.

Immediate changes in pressure pain sensitivity after thoracic spinal manipulative therapy in patients with subacromial impingement syndrome: A randomized controlled study

BackgroundThoracic SMT can improve symptoms in patients with subacromial impingement syndrome. However, at this time the mechanisms of SMT are not well established. It is possible that changes in pain sensitivity may occur following SMT. ObjectivesTo assess the immediate pain response in patients with shoulder pain following thoracic spinal manipulative therapy (SMT) using pressure pain threshold (PPT), and to assess the relationship of change in pain sensitivity to patient-rated outcomes of pain and function following treatment. DesignRandomized Controlled Study. MethodsSubjects with unilateral subacromial impingement syndrome (n = 45) were randomly assigned to receive treatment with thoracic SMT or sham thoracic SMT. PPT was measured at the painful shoulder (deltoid) and unaffected regions (contralateral deltoid and bilateral lower trapezius areas) immediately pre- and post-treatment. Patient-rated outcomes were pain (numeric pain rating scale – NPRS), function (Pennsylvania Shoulder Score – Penn), and global rating of change (GROC). ResultsThere were no significant differences between groups in pre-to post-treatment changes in PPT (p ≥ 0.583) nor were there significant changes in PPT within either group (p ≥ 0.372) following treatment. NPRS, Penn and GROC improved across both groups (p < 0.001), but there were no differences between the groups (p ≥ 0.574). ConclusionThere were no differences in pressure pain sensitivity between participants receiving thoracic SMT versus sham thoracic SMT. Both groups had improved patient-rated pain and function within 24–48 h of treatment, but there was no difference in outcomes between the groups.

The association between changes in pressure pain sensitivity and changes in cardiovascular physiological factors associated with persistent stress

Objectives. To evaluate the possible association between pressure pain sensitivity of the chest bone (PPS) and cardiovascular physiological factors related to persistent stress in connection with a three-month PPS-guided stress-reducing experimental intervention programme. Methods. Forty-two office workers with an elevated PPS (≥ 60 arbitrary units) as a sign of increased level of persistent stress, completed a single-blinded cluster randomized controlled trial. The active treatment was a PPS (self-measurement)-guided stress management programme. Primary endpoints: Blood pressure (BP), heart rate (HR) and work of the heart measured as Pressure-Rate-Product (PRP); Secondary endpoints: Other features of the metabolic syndrome. Results. PPS decreased and changes in PPS after the intervention period were significantly associated with HR, PRP, body mass index (BMI) and visceral fat index (all correlation coefficients > 0.2, p < 0.05). Compared to the control cluster group, the active cluster group obtained a significant reduction in PPS, Low-density lipoprotein (LDL) cholesterol and total number of elevated risk factors (p < 0.05). On an individual level, significant and clinically relevant between-group reductions were observed in respect to BP, HR, PRP, total and LDL cholesterol, and total number of elevated risk factors (p < 0.05). Conclusions. The stress intervention method applied in this study induced a decrease in PPS which was associated with a clinically relevant decrease in resting blood pressure, heart rate, work of the heart and serum cholesterols.

Effects of Deep Cervical Flexor Training on Pressure Pain Thresholds Over Myofascial Trigger Points in Patients With Chronic Neck Pain

ObjectiveThe purpose of this study was to assess the effects of a low-load training program for the deep cervical flexors (DCFs) on pain, disability, and pressure pain threshold (PPT) over cervical myofascial trigger points (MTrPs) in patients with chronic neck pain. MethodsThirty patients with chronic idiopathic neck pain participated in a 6-week program of specific training for the DCF, which consisted of active craniocervical flexion performed twice per day (10-20 minutes) for the duration of the trial. Perceived pain and disability (Neck Disability Index, 0-50) and PPT over MTrPs of the upper trapezius, levator scapulae, and splenius capitis muscles were measured at the beginning and end of the training period. ResultsAfter completion of training, there was a significant reduction in Neck Disability Index values (before, 18.2 ± 12.1; after, 13.5 ± 10.6; P < .01). However, no significant changes in PPT were observed over the MTrPs. ConclusionPatients performing DCF training for 6 weeks demonstrated reductions in pain and disability but did not show changes in pressure pain sensitivity over MTrPs in the splenius capitis, levator scapulae, or upper trapezius muscles.

Normalization of Widespread Pressure Pain Hypersensitivity After Total Hip Replacement in Patients With Hip Osteoarthritis Is Associated With Clinical and Functional Improvements

To evaluate the relevance of ongoing nociceptive joint inputs to the maintenance of widespread pain hypersensitivity in patients with hip osteoarthritis (OA) and to determine whether a reversal in the widespread pressure hypersensitivity together with an improvement in pain and function occurs after total hip replacement in these patients. Forty patients with hip OA participated. Twenty patients underwent total hip replacement, and the other 20 patients were assigned to a waiting list. Pressure-pain thresholds (PPTs) over the second metacarpal bone and the gluteus medius, vastus medialis, vastus lateralis, and tibialis anterior muscles were assessed bilaterally with a pressure algometer before and 3 months after total hip replacement surgery. Assessments of pain intensity (by visual analog scale [VAS]), physical function (by the Western Ontario and McMaster Universities Osteoarthritis Index), and health status (by the Short Form 12 health survey and the EuroQol 5-domain index) were also performed. Patients who underwent total hip arthroplasty exhibited a reduction in widespread pressure pain hyperalgesia (increases in PPTs) over local and distant pain-free areas, as compared with before surgery and as compared with the patients assigned to the waiting list. PPTs were related to hip pain intensity, and significant correlations were found between higher VAS scores and lower average PPTs over all points assessed (-0.409 < r < -0.306, P < 0.05). Patients who underwent total hip arthroplasty exhibited a greater decrease in pain intensity and greater increases in function and health status than did those who were on the waiting list. Changes in the intensity of hip pain were moderately associated with changes in pressure pain sensitivity in the hip arthroplasty group. Normalization of widespread pressure pain hyperalgesia was found after successful hip joint replacement in patients with hip OA. Altered pain processing seems to be driven by ongoing peripheral joint pathology, which stresses the importance of reducing pain in OA.

Sensory Mapping of the Upper Trapezius Muscle in Relation to Consecutive Sessions of Eccentric Exercise

The aim of this study was to evaluate the changes in pressure pain sensitivity maps in untrained subjects over 2 subsequent sessions of eccentric exercise (ECC) expected to result in (a) delayed onset muscle soreness (DOMS) and (b) adaptation/recovery, respectively. Eleven healthy male subjects participated in this study. Pressure pain threshold (PPT), rate of perceived exertion (RPE), pain intensity, soreness area drawing, maximal voluntary contraction (MVC), and shoulder range of motion were assessed in session 1 before, immediately after, and 24 hours after ECC. The ECC protocol that was used to induce DOMS consisted of 50 eccentric contractions of the right shoulder that were divided into 5 bouts, including 10 contractions at MVC level separated by a 2-minute resting period. Session 2 was identical to session 1 and performed exactly 1 week later. There was only a significant increase in the RPE assessed before the exercise and 24 hours after the exercise in session 1 (p = 0.001). The average PPT only decreased significantly from before the exercise (660.2 ± 76.2 kPa) to 24 hours after the exercise (435.6 ± 59.3 kPa) in session 1 (p = 0.016). The present study confirmed a heterogeneous distribution of mechanical sensitivity before and after sessions of ECC. The first session of ECC underlined increased mechanical sensitivity because of DOMS, whereas the second session reflected an adaptation process. Our results support the potential role of ECC bouts in training regimens.

Pressure Pain Sensitivity Mapping in Experimentally Induced Lateral Epicondylalgia

The aim of this study was to apply topographical techniques to investigate changes in pressure pain sensitivity after induction of delayed onset muscle soreness (DOMS) in the elbow region in healthy subjects. Pressure pain thresholds (PPT) were assessed over 12 points forming a 3 x 4 matrix (4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle) over the dominant elbow in 13 healthy men, and pressure sensitivity maps were calculated. DOMS, as a model for lateral epicondylalgia (LE), was induced by repetitive high-level eccentric contractions of the wrist extensor muscles. PPT maps were assessed before, immediately after, and 24 h after eccentric exercise (DOMS). The two-way repeated-measure ANOVA detected significant differences in mean PPT for the measurement points (F = 5.96, P < 0.001), with lower PPT over the points located over the extensor carpi radialis brevis muscle. There was also a significant effect of time (F = 121.3, P < 0.001) but no time x point location interaction (F = 0.7, P = 0.8). PPT were lower 24 h after (P < 0.001) but not immediately after (P > 0.05) eccentric exercise. The study provides new key information regarding mechanical pain hyperalgesia in experimentally induced LE. Topographical pressure pain sensitivity maps from the elbow region revealed heterogeneously distributed mechanical sensitivity before and during DOMS. The most sensitive localizations for PPT assessment correspond to the muscle belly of the extensor carpi radialis brevis. Our results support the implication of the extensor carpi radialis brevis muscle in LE.

Pressure Pain Sensitivity Mapping of the Temporalis Muscle Revealed Bilateral Pressure Hyperalgesia in Patients with Strictly Unilateral Migraine

Previous studies on pressure pain sensitivity in patients with migraine have shown conflicting results. There is emerging evidence suggesting that pain sensitivity is not uniformly distributed over the muscles, indicating the existence of topographical changes in pressure pain sensitivity. The aim of this study was to calculate topographical pressure pain sensitivity maps of the temporalis muscle in a blind design in patients with strictly unilateral migraine compared with controls. For this purpose, an electronic pressure algometer was used to measure pressure pain thresholds (PPT) over nine points of the temporalis muscle: three points in the anterior, medial and posterior parts, respectively. Pressure pain sensitivity maps of both sides (dominant or non-dominant; symptomatic or non-symptomatic) were calculated. The analysis of variance showed significant differences in PPT values between both groups (F = 279.2; P < 0.001) and points (F = 4.033; P < 0.001). Patients showed lower PPT at all nine points than healthy controls (P < 0.001). We also found lower PPT in the centre of the muscle compared with the posterior part of the muscle within both groups (P < 0.01). Interaction between group and points (F = 1.9; P < 0.05) was also found. Within the migraine group, PPT levels were decreased bilaterally from the posterior to the anterior column of the temporalis muscle (Student-Newman- Keuls analysis; P < 0.05), with the most sensitive in the anterior part of the muscle. For controls, PPT did not follow such anatomical distribution, the most sensitive point being the centre of the mid-muscle belly. This study showed bilateral sensitization to pressure in unilateral migraine, suggesting the involvement of central components.

Changes in Pressure Pain Sensitivity in Latent Myofascial Trigger Points in the Upper Trapezius Muscle After a Cervical Spine Manipulation in Pain-Free Subjects

Objective This study analyzed the immediate effects on pressure pain threshold (PPT) in latent myofascial trigger points (MTrPs) in the upper trapezius muscle of a single cervical spine manipulation directed at the C3 through C4 level. Methods Seventy-two volunteers (27 men and 46 women; mean age, 31 years; SD, 10 years) participated in this study. Subjects underwent a screening process to establish both the presence of MTrPs in the upper trapezius muscle as described by Simons et al (Myofascial pain and dysfunction: the trigger point manual, vol 2. 3rd ed. Baltimore: Williams & Wilkins, 1999. p. 23-34) and the presence of intervertebral joint dysfunction at the C3 through C4 level by the lateral gliding test for the cervical spine. Subjects were divided randomly into 2 groups: manipulative group, which received a cervical spine manipulation directed at the C3 through C4 level, and a placebo group, which received a sham manual procedure. The outcome measure was the PPT on the MTrP in the upper trapezius muscle ipsilateral to the side of the joint dysfunction, which was assessed pretreatment and 1, 5, and 10 minutes posttreatment by an assessor blinded to the treatment allocation of the subject. Results The analysis of variance showed a significant effect for time (F = 5.157; P = .02) but not for side (F = 0.234; P = .63). Furthermore, an interaction between group and time was also found (F = 37.240; P < .001). The experimental group showed a trend toward an increase in PPT levels after the manipulative procedure, whereas the control group showed a trend toward a decrease in PPT. Positive within-group effect sizes ranging from medium to small were found in the manipulative group (0.1 < d < 0.5), whereas negative within-group effect sizes ranging from large to medium were found in the placebo group (0.3 < d < 1). Conclusions Our results suggest that a cervical spine manipulation directed at the C3 through C4 segment induced changes in pressure pain sensitivity in latent MTrPs in the upper trapezius muscle. Different therapeutic mechanisms, either segmental or central, may be involved at the same time.