Quantitative Sensory Testing Procedures Research Articles

Can preoperative quantitative sensory testing predict persistent post-operative knee pain following total knee replacement?: A systematic review

OBJECTIVE: To investigate whether pre-operative Quantitative Sensory Testing (QST) can identify patients who experience persistent post-operative knee pain following Total Knee Replacement (TKR). DATA SOURCES: PubMed, EMBASE, CINAHL, EBSCO and grey literature. STUDY SELECTION: 1056 studies were retrieved. The title and abstracts were screened by two independent reviewers, of which 45 were retrieved for full text analysis and 16 studies were included. Studies of any design were included if they recruited adults who underwent TKR; completed any component of the German Research Network on Neuropathic Pain QST or conditioned pain modulation testing preoperatively and assessed post-surgical joint pain using a self-reported outcome measure at a minimum of three months post TKR. DATA EXTRACTION: Data was independently extracted by two researchers. Disagreements were resolved through consensus. The extracted data was recorded in a predefined spreadsheet. Domains included demographic data, type and site of QST, pain outcome measure, follow up duration, statistical methods and associative data. Two independent reviewers assessed the quality of studies using Quality in Prognosis risk of bias tool and the certainty of evidence using the GRADE framework. DATA SYNTHESIS: Sixteen cohort studies met the eligibility criteria (n = 2051 patients). Data was analysed narratively because of the heterogeneity across the QST procedures (mechanical and thermal detection and pain thresholds, conditioned pain modulation and temporal summation of pain), measures of reporting pain (Western Ontario and McMaster Universities Osteoarthritis Index, visual analogue scale and numeric pain rating score) and follow up time points (3 to 18 months). CONCLUSIONS: Due to the heterogeneity and low-moderate quality studies included, it remains unclear whether QST can identify patients who are likely to experience persistent postoperative joint pain following TKR.

The association between changes in clinical pain severity and IL-6 reactivity among patients undergoing total knee Arthroplasty: The moderating role of change in insomnia

Knee osteoarthritis (KOA) is linked to an enhanced release of interleukin-6 (IL-6). Increased levels of IL-6 are associated with greater pain and insomnia. While total knee arthroplasty (TKA) typically results in the reduction of pain, for a subgroup of patients, pain does not improve. Understanding patients’ propensity to upregulate IL-6 may provide insight into variation in the clinical success of TKA for improving pain, and insomnia may play an important modulatory role. We investigated the association between pre- and post-surgical changes in clinical pain and IL-6 reactivity, and whether change in insomnia moderated this association.Patients (n = 39) with KOA came in-person before and 3-months after TKA. At both visits, patients completed validated measures of clinical pain and insomnia, as well as underwent quantitative sensory testing (QST). Blood samples were collected to analyze IL-expression both before and after QST procedures to assess changes in IL-6 in response to QST (IL-6 reactivity). Patients were categorized into two groups based on change in clinical pain from pre- to post-surgery: 1) pain decreased > 2 points (pain improved) and 2) pain did not decrease > 2 points (pain did not improve). Based on this definition, 49 % of patients had improved pain at 3-months. Among patients with improved pain, IL-6 reactivity significantly decreased from pre- to post-surgery, whereas there was no significant change in IL-6 reactivity among those whose pain did not improve. There was also a significant interaction between pain status and change in insomnia, such that among patients whose insomnia decreased over time, improved pain was significantly associated with a reduction in IL-6 reactivity. However, among patients whose insomnia increased over time, pain status and change in IL-6 reactivity were not significantly associated.Our findings suggest that the resolution of clinical pain after TKA may be associated with discernible alterations in pro-inflammatory responses that can be measured under controlled laboratory conditions, and this association may be moderated by perioperative changes in insomnia. Randomized controlled trials which carefully characterize the phenotypic features of patients are needed to understand how and for whom behavioral interventions may be beneficial in modulating inflammation, pain, and insomnia.

No effect of social interaction on experimental pain sensitivity: a randomized experimental study.

Quantitative sensory testing (QST) is a commonly applied paradigm to investigate pain, which is a subjective experience influenced by a myriad of social and contextual factors. Therefore, it is important to consider the potential sensitivity of QST to the test setting and the social interaction that naturally is a part of it. This may particularly be the case in clinical settings where patients have something at stake. Therefore, we investigated differences in pain responses using QST in different test setups with varying degrees of human interaction. In a parallel three-armed randomized experimental study, we included 92 participants with low back pain and 87 healthy volunteers allocated to 1 of the 3 QST setups: 1 setup with manual tests performed by a human tester, 1 setup with automated tests performed by a robot and orally guided by a human tester, and 1 setup with automated tests performed solely by a robot without social interaction with a human tester. All 3 setups consisted of the same pain tests in the same order, including pressure pain threshold and cold pressor tests. We found no statistically significant differences between setups on the primary outcome of conditioned pain modulation nor any secondary QST outcomes. While this study is not without limitations, the results indicate that QST procedures are robust enough not to be influenced by social interaction to an appreciable degree.

Compression garment wear and sensory variables after burn: a single-site study

ObjectiveCompression garments are well accepted as routine practice for scar management after burn. In a recent systematic review, six main reasons for compression garment non-adherence were identified including sensory disturbances. To further understand the impact of sensory issues, the aim of the present study is to investigate associations between sensory variables and compression garment wear. MethodAdults (N = 117) attending a quaternary adult burns outpatient clinic completed: The Adolescent/Adult Sensory Profile; a custom-designed compression garment wear questionnaire; and three quantitative sensory testing procedures (Two-Point Discrimination, Mechanical Detection Threshold and Pressure Pain Threshold). ResultsPatients who reported lower Pressure Pain Threshold or Mechanical Detection Threshold, higher acuity for Two Point Discrimination, and higher than average sensory avoiding and sensory sensitivity patterns were less adherent with garment wear. ConclusionsOverall, sensory factors assessed using both self-report and quantitative sensory testing were associated with compression garment adherence. This knowledge suggests the value in developing and evaluating sensory-informed treatment strategies to improve compression garment wear.

The immediate effect of end-range maitland mobilization on pain pressure threshold in patients with knee osteoarthritis

Purpose: Peripheral and central senzitization are two of the underlying mechanisms of pain in patients with knee osteoarthritis (KOA). From the quantitative sensory testing procedures, pain pressure threshold (PPT) measurement is a commonly used method for investigating the magnitude of peripheral and central senzitization in patients with KOA. Out of several interventions, manual mobilization has been proven to be effective in increase of PPT in patients with KOA. The effectiveness of Maitland mobilization in increase of pain threshold has also been shown in patients with KOA; however, the effect of end-range Maitland mobilization has not been studied yet.

Usefulness of Ramp & Hold Procedures for Testing of Pain Facilitation in Human Participants: Comparisons With Temporal Summation of Second Pain

Quantitative sensory testing (QST) is used to systematically interrogate normal responding and alterations of nervous system function, including pain-related central sensitization (CS). However, up to now, QST of CS in human subjects has been mostly focused on temporal summation of second pain (TSSP), has been difficult to perform, and has been associated with low reliability. In contrast, slow ramp & hold (RH) procedures are simpler tests of temporal summation and easier to perform. We examined the usefulness of RH procedures as reliable generators of CS using 2 validated QST procedures: decay of pain aftersensations and wind-down. Twenty-seven pain-free subjects (74% female) were enrolled into the study. Trains of sensitivity-adjusted TSSP or RH heat stimuli were applied to the hands of participants to achieve moderate temporal pain summation (50 Numerical Rating Scale [NRS] [0–100]). Fifteen-second aftersensations and 30-second wind-down related to TSSP or RH were used for CS comparisons. Reliability of all test procedures was tested over 24 hours. Use of sensitivity-adjusted TSSP and RH heat stimuli resulted in average pain ratings of 48.2 and 49.6 NRS, respectively. Aftersensations or wind-down decay were not significantly different after either TSSP or RH, (all P > .05), indicating that each procedure achieved similar levels of short-term CS. Sensitivity-adjusted RH stimuli were well tolerated and resulted in reliable pain increases of ∼50 NRS. The magnitude of short-term CS, determined by aftersensations and wind-down was similar after sensitivity-adjusted TSSP and RH stimuli (P > .05), suggesting that pain facilitation of healthy participants and likely chronic pain patients can not only be tested with TSSP but also with RH procedures. PerspectiveThis article examines the ability of RH procedures to generate similar central sensitivity augmentation than TSSP. The results suggest that RH is similarly well suited as TSSP to explore central pain mechanisms in healthy subjects and most likely also in chronic pain patients.

Endogenous Pain Modulation Profiles Among Individuals With Chronic Pain: Relation to Opioid Use

It is generally assumed that individuals exhibiting high pain inhibition also tend to exhibit low pain facilitation, but little research has examined this association in individuals with pain. The aims of this cross-sectional study were 1) to examine the association between measures of conditioned pain modulation (CPM) and temporal summation (TS) in individuals with chronic pain, and 2) to examine whether this association was moderated by demographic (age, sex), psychological (depression, catastrophizing), or medication-related (opioid use) variables. Individuals (N= 190) with back or neck pain completed questionnaires and underwent a series of quantitative sensory testing procedures assessing CPM and TS. Results indicated that individuals with higher levels of CPM showed lower levels of TS, r = –.20, P < .01. Analyses, however, revealed that the magnitude of this association was substantially weaker among opioid users (r= –.08, NS) than nonusers (r= −.34, P < .01). None of the demographic or psychological variables included in our study influenced the association between CPM and TS. The magnitude of CPM was lower for opioid users than nonusers, suggesting that opioid use might dampen the functioning of endogenous pain-inhibitory systems and possibly contribute to a discordance between measures of pain inhibition and pain facilitation. PerspectiveResults of the present study indicated that greater endogenous pain-inhibitory capacity is associated with lower levels of pain facilitation. This association, however, was not significant among opioid users, suggesting that opioids might compromise the functioning and interrelationship between endogenous pain modulatory systems.

Association Between the 2011 Fibromyalgia Survey Criteria and Multisite Pain Sensitivity in Knee Osteoarthritis.

The present study evaluated the relationship between the 2011 American College of Rheumatology fibromyalgia (FM) survey criteria and quantitative sensory testing (QST). Patients with knee osteoarthritis scheduled to undergo knee arthroplasty completed the FM survey criteria and self-report measures assessing clinical symptoms. Patients also underwent a battery of QST procedures at the surgical knee and remote body sites, including pressure algometry, conditioned pain modulation, and temporal summation. All assessments were completed before surgery. FM survey criteria were used to calculate a continuous FM score indicating FM severity. A total of 129 patients were analyzed. Of these, 52.7% were female, 93.8% were Caucasian, and 3.8% met the FM survey criteria for FM classification. Mean age for females (63.6 y) and males (64.7 y) was similar. Females and males differed significantly in nearly every outcome, including FM severity, clinical pain, anxiety, depression, and pressure pain sensitivity. In females, FM scores significantly correlated with pressure pain sensitivity, but not conditioned pain modulation or temporal summation, such that increased sensitivity was associated with greater FM severity at all body sites examined. In addition, as FM scores increased, the association between pain sensitivity at the surgical knee and pain sensitivity at remote body sites also increased. No relationship between FM score and QST was observed in males. We demonstrated an association between diffuse hyperalgesia as measured by QST and FM severity in females with knee osteoarthritis. These results suggest that the FM survey criteria may represent a marker of pain centralization in females with potential utility in clinical decision making.

The impact of anxiety and catastrophizing on interleukin-6 responses to acute painful stress.

ObjectiveTo examine the influence of anxiety and pain-related catastrophizing on the time course of acute interleukin-6 (IL-6) responses to standardized noxious stimulation among patients with chronic pain.MethodsData were collected from 48 participants in the following demographically matched groups: patients with chronic pain (n=36) and healthy controls (n=12). Participants underwent a series of Quantitative Sensory Testing (QST) procedures assessing responses to mechanical and thermal stimuli during two separate visits, in a randomized order. One visit consisted of standard, moderately painful QST procedures, while the other visit involved nonpainful analogs to these testing procedures. Blood samples were taken at baseline, and then for up to 2 hours after QST in order to study the time course of IL-6 responses.ResultsResults of multilevel analyses revealed that IL-6 responses increased across assessment time points in both visits (p<0.001). While patients with chronic pain and healthy controls did not differ in the magnitude of IL-6 responses, psychological factors influenced IL-6 trajectories only in the chronic pain group. Among patients, increases in catastrophizing over the course of the QST session were associated with elevated IL-6 responses only during the painful QST session (p<0.05). When controlling for anxiety, results indicated that the main multilevel model among patients remained significant (p<0.05).ConclusionUnder specific conditions (eg, application of a painful stressor), catastrophizing may be associated with amplified proinflammatory responses in patients with persistent pain. These findings suggest that psychosocial interventions that reduce negative pain-related cognitions may benefit patients’ inflammatory profiles.

Multifactorial assessment of measurement errors affecting intraoral quantitative sensory testing reliability

Background and purpose (aims)Measurement error of intraoral quantitative sensory testing (QST) has been assessed using traditional methods for reliability, such as intraclass correlation coefficients (ICCs). Most studies reporting QST reliability focused on assessing one source of measurement error at a time, e.g., inter- or intra-examiner (test–retest) reliabilities and employed two examiners to test inter-examiner reliability. The present study used a complex design with multiple examiners with the aim of assessing the reliability of intraoral QST taking account of multiple sources of error simultaneously. MethodsFour examiners of varied experience assessed 12 healthy participants in two visits separated by 48h. Seven QST procedures to determine sensory thresholds were used: cold detection (CDT), warmth detection (WDT), cold pain (CPT), heat pain (HPT), mechanical detection (MDT), mechanical pain (MPT) and pressure pain (PPT). Mixed linear models were used to estimate variance components for reliability assessment; dependability coefficients were used to simulate alternative test scenarios. ResultsMost intraoral QST variability arose from differences between participants (8.8–30.5%), differences between visits within participant (4.6–52.8%), and error (13.3–28.3%). For QST procedures other than CDT and MDT, increasing the number of visits with a single examiner performing the procedures would lead to improved dependability (dependability coefficient ranges: single visit, four examiners=0.12–0.54; four visits, single examiner=0.27–0.68). A wide range of reliabilities for QST procedures, as measured by ICCs, was noted for inter- (0.39–0.80) and intra-examiner (0.10–0.62) variation. ConclusionReliability of sensory testing can be better assessed by measuring multiple sources of error simultaneously instead of focusing on one source at a time. In experimental settings, large numbers of participants are needed to obtain accurate estimates of treatment effects based on QST measurements. This is different from clinical use, where variation between persons (the person main effect) is not a concern because clinical measurements are done on a single person. ImplicationsFuture studies assessing sensory testing reliability in both clinical and experimental settings would benefit from routinely measuring multiple sources of error. The methods and results of this study can be used by clinical researchers to improve assessment of measurement error related to intraoral sensory testing. This should lead to improved resource allocation when designing studies that use intraoral quantitative sensory testing in clinical and experimental settings.

Impact of Psychological Covariates on Experimental Pain Sensitivity in Children and Adolescents with SCD

Background: Children with Sickle Cell Disease (SCD) have increased sensitivity to heat and cold pain (Brandow et al) during steady state. However, the role of psychological factors such as anxiety, depressive symptoms and catastrophizing on pain sensitivity is not known in SCD. Characterization of these factors may provide an insight into the study of their possible roles in the transition to chronic pain.Aim: To determine if psychological factors impact pain sensitivity in patients with SCD.Methods: Patients with SCD were offered quantitative sensory testing (QST) when at steady state (at least 2 weeks following a VOE). QST procedures included estimation of pressure, mechanical and thermal pain thresholds (minimum intensity of stimulus which is first perceived as painful) and tolerances (maximum intensity of a pain-producing stimulus that a participant is willing to accept in a given situation) as well as windup values (increased pain perception to repetitive painful stimuli). At each time point, participants completed the PROMIS measures of pain intensity, pain interference, anxiety, depressive symptoms, sleep, fatigue and peer relationships. Participants also completed the Pain Catastrophizing Scale ((PCS)-Sullivan et al), Child Somatization Inventory (Walker et al), Pain Coping Inventory (Varni et al)* as well as Peds QL Generic and SCD specific measures of Quality of life*.Results: We determined the experimental pain phenotype (sensitivity to pressure, mechanical and thermal pain) of 29 patients with SCD during steady state (> 2 weeks from a vaso-occlusive episode). These participants were not receiving long-term opioids or adjunctive medications for pain. The median age of participants was 15 (IQR 10-19) and majority (69%) were female. Approximately half of the study sample had HbSS. Three quarters of the study sample were prescribed hydroxyurea. The median Hb level was 11.1 (IQR 10.2-11.6). The median number of VOC's in the year prior to testing was 1(IQR 0-2) and in 3 years prior to testing was 3 (IQR 2-5). The median PROMIS pain intensity T-score was 37.8, PROMIS pain interference T-score was 48.75, PROMIS Depressive symptom T-score was 44.35 and PROMIS anxiety was 43.9; these scores were not higher than the average T-score of 50 described in the pediatric population. High catastrophizing scores were reported on the PCS, with median score being 29. The median cold pain threshold was 23.6 degrees C (IQR 15.8-26.7) and median heat pain threshold was 39.1 degrees C (IQR 37.5-40.9).We noted that increase in scores on PROMIS depressive symptoms was associated with lower heat (Spearman's rho= -0.55), cold (Spearman's rho= 0.57) and mechanical (Spearman's rho= -0.4) pain thresholds. Scores on PROMIS depressive symptoms predicted heat and cold pain thresholds independent of age and VOC's in the past 3 years. Increased PROMIS anxiety scores were associated with lower mechanical pain thresholds (Spearman's rho= -0.43) and lower cold detection thresholds (Spearman's rho= 0.46). Increased scores on PCS were associated with lower heat detection thresholds (Spearman's' rho= -0.39). (All p-values were<0.05) Table 1OutcomeDepressive symptomsVOCs in 3 years prior to studyAge (years)Model signCoeffp-valueCoeffp-valueCoeffp-valueCold Pain Threshold0.40.003-0.190.6-0.410.16<0.0127Heat Pain Threshold-0.120.0130.380.0120.20.068<0.00128Conclusions: Depressive symptoms and anxiety are associated with lower experimental pain thresholds in patients with SCD. Higher scores on PROMIS depressive symptoms predict increased sensitivity to heat and cold pain independent of age and number of VOCs experienced in the past 3 years. Further studies are needed to determine the contribution of psychological factors in the transition to chronic pain in SCD.Acknowledgments: 1-Sickle Cell Disease Association of America 2- *PedsQL™ contact information and permission to use: Mapi Research Trust, Lyon, France. E-mail: PROinformation@mapi-trust.org - Internet: www.Mapi-trust.org and http://www.pedsql.org/index.html DisclosuresNo relevant conflicts of interest to declare.

Improving QST Reliability—More Raters, Tests, or Occasions? A Multivariate Generalizability Study

The reliability of quantitative sensory testing (QST) is affected by the error attributable to both test occasion and rater (examiner) and the interactions between them. Most reliability studies account for only 1 source of error. The present study employed a fully crossed, multivariate generalizability design to account for rater and occasion variance simultaneously. Nineteen healthy volunteers were examined with a battery of 7 QST procedures 4 times on 2 occasions by 2 raters. The QST battery was composed to include a mix of different pain stimuli and response domains, including threshold, intensity, tolerance, and modulation with mechanical, thermal, and chemical stimuli. The classical test-retest and interrater reliability (.19 < intraclass correlation coefficient <.92) was in line with the literature, and generalizability analysis indicated that the universe score was generally the dominant source of variation (relative contribution = 19%, 78%). Error attributable to the interaction between study participant and occasion was also influential. Dependability coefficients indicated that a substantial increase in reliability and feasibility could be achieved by employing a composite QST battery compared to single QST procedures. Reliability was improved more by repeated testing on separate occasions than by repeated testing by different raters. PerspectivesWhen balancing reliability and feasibility, the current findings suggest that a carefully selected battery of QST procedures repeated on a few occasions may be optimal.

Feasibility and Tolerability of Quantitative Sensory Testing in Patients with Sickle Cell Disease at the End of a Vasoocclusive Episode

Title: Feasibility and Tolerability of Quantitative Sensory Testing in Patients with Sickle Cell Disease at the End of a Vasocclusive EpisodeBackground: Children with Sickle Cell Disease (SCD) have increased sensitivity to heat and cold pain (Brandow et al) during steady state. It is unknown if sensitivity to pain varies with a Vaso-Occlusive Episode (VOE).Characterization of pain sensitivity during acute VOE is essential to the understanding of the transition to chronic pain. While the administration of pain stimuli associated with QST during a VOE is obviously untenable, it is unknown if patients will tolerate QST procedures at the end of a VOE.Aim: To determine feasibility and tolerability of QST procedures at the end of VOE.Methods: Patients with SCD were offered quantitative sensory testing (QST) at steady state (at least 2 weeks following a VOE) and prior to or following discharge from the hospital for a VOE-related admission. Patients were contacted during hospitalization for VOE and timing of QST was determined by patient preference and taking into account readiness for discharge from the hospital. QST procedures included estimation of pressure, mechanical and thermal pain thresholds and tolerance (excluding cold tolerance) as well as windup values. At each time point, participants completed the PROMIS measures of pain intensity, pain interference, anxiety, depressive symptoms, sleep, fatigue and peer relationships. Participants also completed the Pain Catastrophizing Scale ((PCS)-Sullivan et al), Child Somatization Inventory (Walker et al), Pain Coping Inventory (Varni et al)* as well as Peds QL Generic and SCD specific measures of Quality of life*. After the QST procedures, participants completed the Gracely box scales (0-20 scale rating pain unpleasantness/intensity).Results: Ten patients who had an episode of VOE during the study period underwent QST at a median of 3.8 days after admission. The median age of participants who underwent testing was 16.5 years (IQR 11-20). 6 of 10 patients were female. Sixteen patients in VOE were offered QST testing. Eight of 12 patients who had undergone QST testing at steady state and 2 of 4 patients who had not previously undergone QST testing consented to QST testing. Nine patients completed testing at both steady state and following a VOE. Thermal testing was well tolerated by all participants (n=1 not offered due to equipment unavailability). Mechanical pain testing/windup was partially omitted (n=1) by patient request. The median Gracely Box Scale (0-20) score following QST was 0.5 (IQR 0-4, range 0-6) for pain unpleasantness and was 0 (IQR 0-6, range 0-8) for pain intensity.Conclusions: Quantitative Sensory Testing is well accepted, feasible and well tolerated in patients with SCD at the end of a Vasoocclusive Episode.Acknowledgments: 1- ASH Clinical Research Training Institute 2- Sickle Cell Disease Association of America 3- *PedsQL™ contact information and permission to use: Mapi Research Trust, Lyon, France. E-mail: PROinformation@mapi-trust.org – Internet: www.Mapi-trust.org and http://www.pedsql.org/index.html DisclosuresNo relevant conflicts of interest to declare.

A Randomized, Controlled Investigation of Motor Cortex Transcranial Magnetic Stimulation (TMS) Effects on Quantitative Sensory Measures in Healthy Adults

There is emerging evidence that transcranial magnetic stimulation (TMS) can produce analgesic effects in clinical samples and in healthy adults undergoing experimentally induced pain; and the field of minimally invasive brain stimulation for the management of pain is expanding rapidly. Although motor cortex is the most widely used cortical target for TMS in the management of neuropathic pain, few studies have systematically investigated the analgesic effects of a full range of device parameters to provide initial hints about what stimulation intensities and frequencies are most helpful (or even potentially harmful) to patients. Further, there is considerable inconsistency between studies with respect to laboratory pain measurement procedures, TMS treatment parameters, sophistication of the sham methods, and sample sizes. This study used a sham-controlled, within-subject, cross-over design to examine the effects of 5 different TMS treatment parameters across several quantitative sensory measures in a sample of healthy adult volunteers. Sixty-five participants underwent quantitative sensory testing procedures pre and post-40-minutes of real and sham motor cortex TMS. TMS was delivered at 1 Hz 80% resting motor threshold (rMT), 1 Hz 100% rMT, 10 Hz 80% rMT, 10 Hz 100% rMT, or 50 Hz triplets at 90% of active motor threshold (intermittent theta-burst). The mean painfulness rating of real TMS stimulation itself was 3.0 (SE=0.36) out of 10 and was significantly greater than zero [t(64)=8.17, P<0.0001]. The sham TMS methods used permitted matching between real and sham TMS-induced scalp sensations and participants were successfully blinded to condition (real versus sham). Findings suggest that the effects of motor cortex TMS on quantitative sensory tests in healthy adults vary across different treatment parameters with the smallest observed effect for intermittent theta-burst stimulation (Cohen's d=0.03) and the largest for 10 Hz 100% rMT (d=0.34). Overall, TMS was associated with statistically significant effects on warm and cool sensory thresholds, cold pain thresholds, suprathreshold stimulus unpleasantness ratings, and wind-up pain. With respect to device parameter effects, higher frequency stimulation seems to be associated with the most analgesic and antisensitivity effects with the exception of intermittent theta-burst stimulation. The present findings support several clinical research findings suggesting that higher TMS frequencies tend to be associated with the most clinical benefit in patients with chronic pain.

Supra-threshold scaling, temporal summation, and after-sensation: relationships to each other and anxiety/fear

This study investigated the relationship of thermal pain testing from three types of quantitative sensory testing (ie, supra-threshold stimulus response scaling, temporal summation, and after-sensation) at three anatomical sites (ie, upper extremity, lower extremity, and trunk). Pain ratings from these procedures were also compared with common psychological measures previously shown to be related to experimental pain responses and consistent with fear-avoidance models of pain. Results indicated that supra-threshold stimulus response scaling, temporal summation, and after-sensation, were significantly related to each other. The site of stimulation was also an important factor, with the trunk site showing the highest sensitivity in all three quantitative sensory testing procedures. Supra-threshold response measures were highly related to measures of fear of pain and anxiety sensitivity for all stimulation sites. For temporal summation and after-sensation, only the trunk site was significantly related to anxiety sensitivity, and fear of pain, respectively. Results suggest the importance of considering site of stimulation when designing and comparing studies. Furthermore, psychological influence on quantitative sensory testing is also of importance when designing and comparing studies. Although there was some variation by site of stimulation, fear of pain and anxiety sensitivity had consistent influences on pain ratings.

Effects of Upper Extremity Neural Mobilization on Thermal Pain Sensitivity: A Sham-Controlled Study in Asymptomatic Participants

A single-blinded, quasi-experimental, within- and between-sessions assessment. To investigate potential mechanisms of neural mobilization (NM), using tensioning techniques in comparison to sham NM on a group of asymptomatic volunteers between the ages of 18 and 50. NM utilizing tensioning techniques is used by physical therapists in the treatment of patients with cervical and/or upper extremity symptoms. The underlying mechanisms of potential benefits associated with NM tensioning techniques are unknown. Participants (n = 62) received either a NM or sham NM intervention 2 to 3 times a week for a total of 9 sessions, followed by a 1-week period of no intervention to assess carryover effects. A-delta (first pain response) and C-fiber (temporal summation) mediated pain perceptions were tested via thermal quantitative sensory testing procedures. Elbow extension range of motion (ROM) and sensory descriptor ratings were obtained during a neurodynamic test for the median nerve. Data were analyzed with repeated-measures analysis of variance (ANOVA). No group differences were seen for A-delta mediated pain perception at either immediate or carryover times. Group differences were identified for immediate C-fiber mediated pain perception (P = .032), in which hypoalgesia occurred for the NM group but not the sham NM group. This hypoalgesic effect was not maintained at carryover (P = .104). Group differences were also identified for the 3-week and carryover periods for elbow extension ROM (P = .004), and for the participant sensory descriptor ratings (P = .018), in which increased ROM and decreased sensory descriptor ratings were identified in participants in the NM group but not the sham NM group. This study provides preliminary evidence that mechanistic effects of tensioning NM differ from sham NM for asymptomatic participants. Specifically, NM resulted in immediate, but not sustained, C-fiber mediated hypoalgesia. Also, NM was associated with increased elbow ROM and a reduction in sensory descriptor ratings at 3-week and carryover assessment times. These differences provide potentially important information on the mechanistic effects of NM, as well as the description of a sham NM for use in future clinical trials.