Quantitative Sensory Testing Values Research Articles

Profiling migraine patients according to clinical and psychophysical characteristics: clinical validity of distinct migraine clusters

AimsInvestigate if different clinical and psychophysical bedside tools can differentiate between district migraine phenotypes in ictal/perictal (cohort 1) and interictal (cohort 2) phases.MethodThis observational study included two independent samples in which patients were subgrouped into distinct clusters using standardized bedside assessment tools (headache frequency, disability, cervical active range of motion, pressure pain threshold in different areas): (A) cohort 1—ictal/perictal migraine patients were subgrouped, based on previous studies, into two clusters, i.e., Cluster-1.1 No Psychophysical Impairments (NPI) and Cluster-1.2 Increased Pain Sensitivity and Cervical Musculoskeletal Dysfunction (IPS-CMD); (B) cohort 2—interictal migraine patients were subgrouped into three clusters, i.e., Cluster-2.1 NPI, Cluster-2.2 IPS, and Cluster-2.3 IPS-CMD. Clinical characteristics (multiple questionnaires), somatosensory function (comprehensive quantitative sensory testing (QST)), and cervical musculoskeletal impairments (cervical musculoskeletal assessment) were assessed and compared across headache clusters and a group of 56 healthy controls matched for sex and age.ResultsCohort 1: A total of 156 subjects were included. Cluster-1.2 (IPS-CMD) had higher headache intensity (p = 0.048), worse headache-related (p = 0.003) and neck-related disability (p = 0.005), worse quality of life (p = 0.003), and higher symptoms related to sensitization (p = 0.001) and psychological burden (p = 0.005) vs. Cluster-1.1(NPI). Furthermore, Cluster-1.2 (IPS-CMD) had (1) reduced cervical active and passive range of motion (p < 0.023), reduced functionality of deep cervical flexors (p < 0.001), and reduced values in all QST(p < 0.001) vs. controls, and (2) reduced active mobility in flexion, left/right lateral flexion (p < 0.045), and reduced values in QST (p < 0.001) vs. Cluster-1.1 (NPI). Cohort 2: A total of 154 subjects were included. Cluster-2.3 (IPS-CMD) had (1) longer disease duration (p = 0.006), higher headache frequency (p = 0.006), disability (p < 0.001), and psychological burden (p = 0.027) vs. Cluster-2.2 (IPS) and (2) higher headache-related disability (p = 0.010), neck-related disability (p = 0.009), and higher symptoms of sensitization (p = 0.018) vs. Cluster-2.1 (NPI). Cluster-2.3(IPS-CMD) had reduced cervical active and passive range of motion (p < 0.034), and reduced functionality of deep cervical flexors (p < 0.001), vs. controls, Custer-2.1 (NPI), and Cluster-2.2 (IPS). Cluster-2.2 (IPS) and 2.3 (IPS-CMD) had reduced QST values vs. controls (p < 0.001) and Cluster-2.1 (p < 0.039).ConclusionA battery of patient-related outcome measures (PROMs) and quantitative bedside tools can separate migraine clusters with different clinical characteristics, somatosensory functions, and cervical musculoskeletal impairments. This confirms the existence of distinct migraine phenotypes and emphasizes the importance of migraine phases of which the characteristics are assessed. This may have implications for responders and non-responders to anti-migraine medications.

Feasibility and reliability of a quantitative sensory testing protocol in youth with acute musculoskeletal pain postsurgery or postinjury.

Quantitative sensory testing (QST) is increasingly used in pediatric chronic pain; however, assessment in youth with acute musculoskeletal (MSK) pain is limited. This study evaluated the feasibility, reliability, and sources of variability of a brief QST protocol in 2 clinical samples of youth with acute MSK pain. Participants were 277 youth (M age = 14.5 years, SD = 2.0, range = 11-18 years, 59% female, 81% non-Hispanic) across 3 geographic study sites who completed a QST protocol assessing pressure and thermal pain sensitivity, temporal summation of pain, and conditioned pain modulation 8 weeks after MSK surgery (n = 100) or within 4 weeks after an acute MSK injury (n = 177). High feasibility was demonstrated by protocol completion rates ranging from 97.5% to 100% for each task, with 95.3% of youth completing all tasks. Reliability was high, with reliability coefficients of >0.97 for 7 out of 8 QST parameters and minimal influence of examiner or participating site effects. Younger youth had lower pressure and heat pain thresholds (11-12 vs 13-18 years, d = -0.80 to -0.56) and cold pain tolerance (d = -0.33). Hispanic youth had higher pressure and heat pain thresholds (d = 0.37-0.45) and pain ratings for cold pain tolerance (d = 0.54) compared with non-Hispanic youth. No significant differences were observed in QST values by sex or personal contextual factors at the time of assessment (momentary pain, menstrual period, use of pain medications). Overall findings demonstrate feasibility of a brief QST protocol with youth with diverse acute MSK pain and data provide initial support for the reliability of this QST protocol for multisite research studies.

Designing and Development of Diabetic Exercise Mat and its Effect on Sensory Motor Dysfunction in Chronic Diabetic Individuals

Background: Diabetic neuropathy (DN) is one of the most common late complications of diabetic individual. Diabetic peripheral neuropathy causes peripheral sensory loss and motor deterioration. Objectives: The objectives of the study were to find the effect of conventional exercises on designed mat for sensory and motor dysfunction in chronic diabetic individuals. Materials and Methods: An experimental study was carried out using simple random sampling method during 1 year in Krishna Hospital. A total of 44 subjects were allocated into Groups A and B to receive conventional physiotherapy and exercise on designed mat, respectively. Protocol was conducted for 3 days per week for 6 weeks. Pre- and post-design was used for assessing the study. Results: Subjects were assessed for quantitative sensory testing (QST) and manual muscle testing (MMT). Between the groups, the QST values were for Groups A 4.40 ± 0.66 and B 3.59 ± 1.18 along with P = 0.0071. MMT ankle dorsiflexion values were for Groups A 4.27 ± 0.55 and B 3.90 ± 0.61 along with P &lt;0.044, ankle plantar flexion values were for Groups A 4.31 ± 0.47 and B 3.95 ± 0.65 along with P = 0.04. Wrist flexion values were for Groups A 4.18 ± 0.50 and B 4.50 ± 0.51 along with P = 0.04. Wrist extension values were for Groups A 3.90 ± 0.61 and B 4.50 ± 0.59 with P = 0.002. Conclusion: This study concluded that both conventional exercises and exercise on designed mat showed significant improvement on QST and MMT. Thus, the study provided the evidence to support that exercises on designed mat are found to be more effective than conventional exercises.

Observing Altered Nociceptive Detection Thresholds in Patients With Persistent Spinal Pain Syndrome Type 2 With a Dorsal Root Ganglion Stimulator

ObjectivesThere is a lack of clinically relevant measures for quantification of maladaptive mechanisms of the nociceptive system leading to chronic pain. Recently, we developed a method that tracks nociceptive detection thresholds (NDTs) using intraepidermal electrical stimulation. In this study, we explored the feasibility of using this NDT method in patients with persistent spinal pain syndrome type 2 (PSPS-T2) and its potential to enable observation of altered nociceptive processing induced by dorsal root ganglion (DRG) stimulation. In addition, we compared NDTs with quantitative sensory testing (QST) measurements and numeric rating scale (NRS). Materials and MethodsA total of 12 patients with PSPS-T2 (seven men; 60.4 ± 12.3 years) experiencing chronic unilateral lower limb pain treated with DRG stimulation were included in the study. Both the NDT method and electrical and pressure QST methods were performed twice in the L5 dermatome on both the affected and the unaffected foot, once with the DRG stimulator turned off and, subsequently, once with the DRG stimulator turned on. ResultsThe NDT method can be applied to patients with PSPS-T2. With the DRG stimulator turned off, NDTs on the affected side were significantly higher than on the unaffected side. This difference was no longer present once the DRG stimulator was turned on. Furthermore, DRG stimulation affected QST (electrical and pressure) values and NRS scores. Finally, NDTs showed larger contrasts between the sides than QST measures. ConclusionsThe NDT method permitted observation of altered nociceptive function. The effect of DRG stimulation also was reflected in QST outcomes and NRS scores. The larger contrast between the sides for NDTs suggests that the NDT method might be valuable for future quantification of nociceptive dysfunction in chronic pain.

Quantitative sensory testing of mandibular somatosensory function following orthognathic surgery-A pilot study in Chinese with class III malocclusion.

Somatosensory changes after sagittal split ramus osteotomy (SSRO) have not been fully studied in Chinese patients by the latest technologies. To provide a comprehensive analysis of somatosensory function at the lower lip and chin at different time points following SSRO in a Chinese population. A total of 22 patients (18-27years; nine men) with skeletal III malocclusion and scheduled for SSRO were recruited. Quantitative sensory testing (QST) was performed at pre-operation (baseline), 1week (1W), 1, 3 and 6months (1M, 3M, 6M) post-operatively. Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT), mechanical pain threshold (MPT), pressure pain threshold (PPT) and two-point discrimination threshold (2PD) were tested at the lower lip and chin. Except for PPT at both test sides at 1W and 1M, all QST values indicated a significantly reduced sensitivity (p<.05). All values had returned to baseline values at 3M with exception of HPT at the right chin which, however, had recovered at 6M (p>.05). Somatosensory function at the lower lip and chin appears to be fully recovered in the majority of young Chinese adults 6months after SSRO for skeletal class III malocclusion.

Establishing abdominal QST reference values for healthy adults and adolescents

Debilitating abdominal and pelvic pain conditions are highly prevalent in adults and adolescents. Assessing sensory functioning among people with painful conditions is important in understanding the disease. Reference values for Quantitative Sensory Testing (QST), used to assess sensory perception, are well established for other regions but not the abdomen. The aim of this study was to establish QST reference values for the abdomen in a diverse group of males and female adults and adolescents. In this cross-sectional study, 181 healthy, pain-free males and females from age 12-50 years completed a comprehensive QST battery in upper and lower abdomen and a control site. The QST battery consisted of: Dynamic Mechanical Touch (DMT), Light Touch Detection (LTD), Sharp Prick Detection (SPD), Pressure Pain Threshold (PPT), Temporal Summation of Pain (TSP), Cool and Warmth Detection Thresholds (CDT, WDT), and Cold and Heat Pain Thresholds (CPT, HPT). Participants also answered pain-related questionnaires including the Pain Catastrophizing Scale, 36-Item Short Form Survey, Pain Sensitivity Questionnaire (PSQ). Mean and standard deviation values were calculated for each QST sub-test and separated by age, sex, and body site (upper and lower abdomen, and control site). Results of RMANOVAs indicated that pain sensitivity differed by site and modality, with no consistent pattern indicating one area was generally more sensitive than others. There were also effects of sex with males experienced less sensitivity to pressure and cold pain than females. Self-reported pain sensitivity (PSQ) was associated with greater abdominal sensitivity to punctate, cold, and heat pain. This paper successfully established reference QST values for the upper and lower abdominal sites for healthy, pain-free male and female adolescents and adults which will be critical in understanding somatosensory nervous system function among patients with abdominal and pelvic pain. These data will be critical in understanding nociceptive processing in the abdominal region. Boston Center for Endometriosis/Marriott Family Foundation Investigator Grant Office of Faculty Developtment at Boston Children's Hospital.

Sickle Cell Pain: Intervention with Capsaicin Exposure (SPICE)

Sickle Cell Pain: Intervention with Capsaicin Exposure (SPICE)

Abstract D044: Age and sex effects on quantitative sensory testing values in healthy African American adults

Abstract Introduction: Only a few studies have reported quantitative sensory testing (QST) reference values for healthy African Americans, and those studies are limited in sample size and range of age of participants. The intent of our study was to fill a gap in the understanding of pain and somatosensory function in African Americans by generating QST values for healthy African American adults. In a large cohort of pain-free, healthy African American adults whose past pain experiences and current psychological status were known, our study aim was to determine thermal and mechanical QST values and compare those values at the anterior forearm by age and sex. We also determined the values for 5 other body sites and compared the values for differences by testing site location (upper body versus lower body). Methodology: In this cross-sectional study, 124 pain-free African American adults (age 18 to 69 years, 49% female) completed demographic and self-reported pain, fatigue and psychosocial measures. QST included obtaining thermal and mechanical responses and associated pain intensity levels. We applied the Benjamini-Hochberg procedure to adjust the p values to account for the multiple t tests. Results: We found thermal detection values at the anterior forearm were (29.2°C±1.6) for cool detection (CD) and (34.5°C±1.2) for warm detection (WD). At that site, pain thresholds were: cold pain threshold (CPTh) (26.3°C±5.0), heat pain threshold (HPTh) (37.8°C±3.6), and mechanical pain thresholds (MPTH) (16.7±22.2 grams of force, gF). There was a significant between sex difference for WD, with women being more sensitive (q=0.027). Lower body sites were less sensitive than upper body sites across all thermal modalities (q&amp;lt;0.003), but not for the mechanical modality. Mean pain intensity scores rated immediately after the CPTh and HPTh were 1.9 ± 1.3 to 2.2 ± 1.2 on the 0-10 pain intensity scale. Similarly, after the MPTh tests the mean pain intensity scores were 0.5 ± 0.5 to 0.8 ± 0.6. These scores did not differ significantly by sex or age group and clearly indicate that the participants reported pain threshold at an appropriately low perceptual intensity. Pain intensity values for past pain experiences and low ratings for fatigue, depression and anxiety indicated that these factors were unlikely contributors to their pain threshold reports. Conclusion: The QST values from this protocol at the anterior forearm indicate that healthy African American adults had average thermal pain thresholds within 6°C of the temperature of adaptation and average MPTh under 20 gF. Differences in responses to thermal and mechanical stimuli for upper verses lower body were consistent with prior research. These findings add to the body of literature confirming that African American adults indeed have lower pain thresholds than those reported for White adults. These QST values can be used as controls for African Americans with cancer to understand the neuropathic pain syndromes associated with tumor progression and cancer treatments. Citation Format: Keesha L. Powell-Roach, Starja Q. Booker, Yingwei Yao, Marie L. Suarez, Miriam O. Ezenwa, Roger B. Fillingim, Zaijie J. Wang, Robert E. Molokie, Diana J. Wilkie. Age and sex effects on quantitative sensory testing values in healthy African American adults [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D044.

Pain and small-fiber affection in hereditary neuropathy with liability to pressure palsies (HNPP).

Background and aims Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal - dominant hereditary neuropathy caused by a deficiency in the peripheral protein PMP-22, due to deletion on chromosome 17p11,2 or in some rare cases point mutations in the PMP-22 gene. The clinical picture is characterized by recurrent mononeuropathies in nerves which frequently may be exposed to pressure, such as the median, ulnar, radial and peroneal nerves or also a more general neuropathy. Although pain is reported to be an unusual clinical symptom, there have been reports of pain in a surprisingly high proportion of these patients. Since pain may be explained by mechanisms in afferent small unmyelinated C- nerve fibers, an assessment of the function of small nerve fibers has been requested. The purpose of the present study was to investigate the presence of pain and the possible affection of afferent small nerve-fibers, A-δ and C-fibers, by quantitative sensory testing (QST)-assessment of thermal thresholds, as well as quantitative sudomotor axon reflex (QSART), a quantitative, validated assessment of efferent postganglionic sumodotor function. QST values were compared to values of age- and sex matched healthy subjects. Methods The 19 patients were investigated clinically, with an emphasis on pain characteristics, with nerve conduction studies (NCS) of major nerves in upper- and lower extremity, small fiber testing (QST, measurement of thermal thresholds) and with QSART. Results A total of 10 patients reported numbness in some extremity, suggesting entrapment of individual nerves as well as a general neuropathy, as verified by NCS in nine patients. A total of 15 patients had findings compatible with a general polyneuropathy. A total of eight patients reported pain, seven patients with pain in the feet, described as burning, aching, shooting and six with severe pathological QST values, mainly cold detection, but also four patients with elevated thresholds to warmth. Four of the patients had signs of a severe sensory neuropathy on NCS, with no sural findings. One patient had only pain in the arms, with only minor changes on NCS and with normal QST-values. Cold detection thresholds (CD) were significantly elevated (reduced sensibility) on the dorsum of the foot (mean of two feet), in patients [26.0 °C (19.7-28.0)] as compared with healthy subjects [28.6 °C (27.4-29.6) p = 0.000]. There were also significantly elevated warmth detection thresholds (WD) in feet in patients 39.5 °C (36.4-42.9) compared to healthy subjects [37.7 °C (36.1-39.4) p = 0.048]. However, there were no significant differences in QST values between patients with and without pain. Conclusions Of a total of 19 patients with verified HNPP, eight patients (42.1%) suffered from neuropathic pain, mainly in both feet. Implications Due to the high percentage of pain in HNPP, it is important not to disregard this diagnosis in a patient presenting with pain. Since there are no significant differences in QST values in patients with and without pain, routine QST studies in HNPP do not seem necessary.

Thermal and mechanical quantitative sensory testing values among healthy African American adults.

PurposeOnly a few studies have reported quantitative sensory testing (QST) reference values for healthy African Americans, and those studies are limited in sample size and age of participants. The study purpose was to characterize QST values in healthy, pain-free African American adults and older adults whose prior pain experiences and psychological status were also measured. We examined the QST values for differences by sex, age, and body test site.Patients and methodsA cross-sectional sample of 124 pain-free African American adults (age 18–69 years, 49% female) completed demographic and self-reported pain, fatigue and psychosocial measures. QST was performed to obtain thermal and mechanical responses and associated pain intensity levels.ResultsWe found thermal detection values at the anterior forearm were (29.2 °C±1.6) for cool detection (CD) and (34.5 °C±1.2) for warm detection (WD). At that site the sample had cold pain threshold (CPTh) (26.3 °C±5.0), heat pain threshold (HPTh) (37.8 °C±3.6), and mechanical pain thresholds (MPTH) (16.7±22.2 grams of force, gF). There was a significant between sex difference for WD, with women being more sensitive (q=0.027). Lower body sites were less sensitive than upper body sites across all thermal modalities (q<0.003), but not for the mechanical modality.ConclusionThe QST values from this protocol at the anterior forearm indicate that the healthy African American adults had average thermal pain thresholds close to the temperature of adaptation and average MPTh under 20 gF. Differences in responses to thermal and mechanical stimuli for upper verses lower body were consistent with prior research.

Trigeminal Neuropathy After Mandibular Fractures: Epidemiology and Neurophysiologic Diagnosis.

To study the trigeminal nerve neuropathy prevalence after mandibular fractures and follow nerve recovery and to examine associations with clinical features. The files of 304 patients treated for 424 mandibular fractures in Hadassah Medical Center between 2001 and 2008 were analyzed. Twenty-five patients with paresthesia were examined by electro-diagnostic conduction test (quantitative sensory testing). The most common fracture sites were the symphysis (28.5%) and condyle (21.4%). A strong correlation between fracture severity and treatment modality was found. Nerve damage occurred in 13.4% of nondisplaced fractures and in 65.3% of >5 mm displaced fractures. Patients who were treated by open reduction internal fixation demonstrated the biggest difference in quantitative sensory testing values between the affected and nonaffected sides. C nerve fibers were the most damaged and least regenerated. There was correlation between damage perception and objective test results. There is a correlation between fracture type and displacement severity on neurologic deficit and prognosis. The objective neurosensory damage was manifested by higher nerve excitation threshold on the injured side. Patients should be informed on the prognosis of neurologic deficit according to fracture type.

Do We Measure What Patients Feel?: An Analysis of Correspondence Between Somatosensory Modalities Upon Quantitative Sensory Testing and Self-reported Pain Experience.

Hyperalgesia and allodynia are typical signs of neuropathic pain. Quantitative sensory testing (QST) is a validated tool to clinically assess these phenomena. However, whether QST reveals findings that are reported by the patients is unclear. The aim of this study was therefore to investigate the association between self-reported symptoms assessed with the painDETECT questionnaire (PDQ) with results of validated QST. PDQ and QST data of 96 patients with chronic neuropathic pain were analyzed. Questions upon presence of painful light touch, painful cold or heat, light pressure triggering pain, and numbness upon PDQ were compared with findings of dynamic mechanical allodynia, increased sensitivity to heat, cold, or pressure pain as well as loss of detection upon QST, respectively. Self-reported pain symptoms upon PDQ showed only a small to moderate concordance with corresponding signs assessed upon QST, whereat the highest, but still only moderate association between self-reported symptoms and measured signs could be obtained for self-reported presence of painful light touch and dynamic mechanical allodynia upon QST. However, the positive and negative likelihood ratio to predict QST values with PDQ scores did not reach convincing values. Results demonstrate that self-reported PDQ symptoms cannot predict abnormal QST values. The poor predictive power of the PDQ may depend on several factors based on possibility of comparison between PDQ and QST and also on methodical issues. Both, symptoms (questionnaires) and signs address complementary aspects of the pain experience and should be considered for diagnosis and treatment of neuropathic pain.

Altered somatosensory profile according to quantitative sensory testing in patients with degenerative lumbar spine disorders scheduled for surgery

BackgroundSomatosensory profiling in affected and non-affected body regions can strengthen our insight regarding the underlying pain mechanisms, which can be valuable in treatment decision making and to improve outcomes, in patients with degenerative lumbar spine disorders pre-surgery. The aim was to describe somatosensory profiles in patients with degenerative lumbar spine disorders, to identify the proportion with altered somatosensory profile, and to analyze demographic characteristics, self-reported function, pain, and health pre- and 3 months post-surgery.MethodsIn this prospective cohort study in a Spine Clinic, 105 patients scheduled for surgery for spinal stenosis, disc herniation, degenerative disc disease, or spondylolisthesis were consecutively recruited. Exclusion criteria were; indication for acute surgery or previous surgery at the same spinal level or severe grade of pathology. Quantitative sensory testing (QST) and self-reported function, pain, and health was measured pre- and 3 months post-surgery. The somatosensory profile included cold detection threshold, warmth detection threshold, cold pain threshold, heat pain threshold and pressure pain threshold in affected and non-affected body regions.ResultsOn a group level, the patients’ somatosensory profiles were within the 95% confidence interval (CI) from normative reference data means. On an individual level, an altered somatosensory profile was defined as having two or more body regions (including a non-affected region) with QST values outside of normal ranges for reference data. The 23 patients (22%) with altered somatosensory profiles, with mostly loss of function, were older (P = 0.031), more often female (P = 0.005), had higher back and leg pain (P = 0.016, 0.020), lower mental health component summary score (SF-36 MCS) (P = 0.004) and larger pain distribution (P = 0.047), compared to others in the cohort. Post-surgery there was a tendency to worse pain, function and health in the group with altered somatosensory profile pre-surgery.ConclusionsOn a group level, patients with degenerative lumbar spine disorders scheduled for surgery were within normal range for the QST measurements compared to reference values. On an individual level, an altered somatosensory profile outside of normal range in both affected and non-affected body regions occurred in 22% of patients, which may indicate disturbed somatosensory function. Those patients had mostly loss of sensory function and had worse self-reported outcome pre-surgery, compared to the rest of the cohort. Future prospective studies are needed to further examine whether these dimensions can be useful in predicting post-surgery outcome and guide need of additional treatments.

Thermal Perception as a Key Factor for Assessing Effects of Trigeminal Nerve Injury.

To conduct a functional examination using multimodal exploration of a sample of patients with iatrogenic trigeminal nerve injury to understand the underlying mechanisms of neuropathic pain following trigeminal nerve injury. Subjective and objective symptoms and responses to thermal and electrical quantitative sensory testing (QST) were evaluated in 85 patients with unilateral trigeminal nerve injury. Objective symptoms were measured by seven clinical sensory tests. Thermal QST included cold detection threshold (CDT), warm detection threshold (WDT), and heat pain threshold (HPT). Electrical current perception threshold was performed with electrical stimuli of 2,000, 250, and 5 Hz. The time since injury was included as a possible independent variable. The data were analyzed using chi-square test, independent t test, Mann Whitney U test, one-way analysis of variance (ANOVA), and Kruskal-Wallis test. Further analyses with Pearson correlation analysis, Spearman rank correlation analysis, and cluster analysis were applied. Unlike objective symptoms, thermal and electrical QST values and subjective symptoms did not improve in patients with an old injury. Thermal QST, particularly WDT, showed the highest positive correlation with subjective symptoms in all tests. Cluster analysis of the thermal QST values identified three subgroups: cluster 1, which was characterized by prominent cold and warm hypoesthesia; cluster 2, which presented elevated WDT; and cluster 3, which showed the smallest thermal differences for all thermal variables but had the highest proportion of neuropathic pain. These findings have demonstrated that thermal QST is a suitable tool for evaluating and characterizing the sensory effects of trigeminal nerve injury. Three subgroups with different thermosensory profiles showed that the less the damage, the more neuropathic pain occurs. The loss of warm perception in particular might play a pivotal role in the chronicity and severity of subjective sensory symptoms.

(180) Quantitative sensory testing: a population based study of adolescents with and without chronic pain

Quantitative sensory testing (QST) has emerged as a modality for examining responses to somatosensory stimuli. However, little data is available in pediatric populations to understand whether youth demonstrate a differential response to QST when they have chronic pain. Data on QST may extend our understanding of the pathophysiology underlying the persistence of pediatric pain. Using a population-based sample, this study compared QST values in adolescents with and without chronic pain. We hypothesized that adolescents with chronic pain would have altered QST compared to adolescents without chronic pain. We conducted secondary data analyses using a population-based sample of 1038 adolescents recruited from the first year of high school in two Scandinavian municipalities. Adolescents reported on chronic pain characteristics and underwent a QST protocol (pressure- and heat-pain threshold and tolerance, cold pressor endurance). Adolescents 16-19 years old (males=51.4%) were included and classified either as not having chronic pain (n=741) or as having chronic pain (weekly pain lasting ≥3months; n=197). T tests examined group differences on QST variables. As hypothesized, adolescents with persistent pain had lower shoulder pressure pain threshold (M=767kPa, SD=223 vs M=785kPa, SD=210) and tolerance (M=266kPa, SD=130 vs M=289kPa, SD=132) compared to healthy adolescents (p’s=0.05). However, mean heat-pain threshold and tolerance were not different between groups. There was a trend for groups to differ in rates of reaching the max tolerance time (106 seconds) for the cold pressor endurance task (45.2% of adolescents with chronic pain vs 51.2% of adolescents without chronic pain, p=0.08). Our findings identified several differences in pain sensitivity on QST between adolescents with and without chronic pain. However, a strong pattern of differences between groups across modalities was not supported. Future research is needed in clinical pain samples and with other modalities and anatomical locations in order to better understand adolescent responses to experimental pain protocols. Quantitative sensory testing (QST) has emerged as a modality for examining responses to somatosensory stimuli. However, little data is available in pediatric populations to understand whether youth demonstrate a differential response to QST when they have chronic pain. Data on QST may extend our understanding of the pathophysiology underlying the persistence of pediatric pain. Using a population-based sample, this study compared QST values in adolescents with and without chronic pain. We hypothesized that adolescents with chronic pain would have altered QST compared to adolescents without chronic pain. We conducted secondary data analyses using a population-based sample of 1038 adolescents recruited from the first year of high school in two Scandinavian municipalities. Adolescents reported on chronic pain characteristics and underwent a QST protocol (pressure- and heat-pain threshold and tolerance, cold pressor endurance). Adolescents 16-19 years old (males=51.4%) were included and classified either as not having chronic pain (n=741) or as having chronic pain (weekly pain lasting ≥3months; n=197). T tests examined group differences on QST variables. As hypothesized, adolescents with persistent pain had lower shoulder pressure pain threshold (M=767kPa, SD=223 vs M=785kPa, SD=210) and tolerance (M=266kPa, SD=130 vs M=289kPa, SD=132) compared to healthy adolescents (p’s=0.05). However, mean heat-pain threshold and tolerance were not different between groups. There was a trend for groups to differ in rates of reaching the max tolerance time (106 seconds) for the cold pressor endurance task (45.2% of adolescents with chronic pain vs 51.2% of adolescents without chronic pain, p=0.08). Our findings identified several differences in pain sensitivity on QST between adolescents with and without chronic pain. However, a strong pattern of differences between groups across modalities was not supported. Future research is needed in clinical pain samples and with other modalities and anatomical locations in order to better understand adolescent responses to experimental pain protocols.

SAT0194 Evaluation of Systemic Sclerosis Patients by Quantitative Sensory Testing for the Presence of Neuropathy

BackgroundNeuropathy is a common feature of collagen tissue disorders. Although development of digital ulcerations may be associated with presence of neuropathy, percentage of systemic sclerosis (SSc) patients with documented neuropathy...

Quantitative sensory abnormalities in post-surgical cutaneous nerve injuries

Quantitative sensory testing (QST) is a psychophysical approach measuring evoked responses to standardized mechanical and thermal stimuli, whether painful or non-painful. QST may be of benefit in assessing pain mechanisms in various pathological states. Here we chose to characterize QST responses in a cohort of 10 patients with post-surgical cutaneous nerve injuries (scar neuromas) and persistent pain following surgery or injury. We included patients who had greater than 80% pain relief following subcutaneous injection of 0.5% bupivacaine. We characterized thermal (cold and warmth) detection and pain thresholds, mechanical detection and pain thresholds, mechanical pain sensitivity for pinprick stimuli, dynamic mechanical allodynia, and wind-up ratio. Prior to conducting QST at the scar neuroma, all procedures were conducted at a contralateral or non-painful control area. Comparisons between the site of pain and control were made using paired t-tests and Wilcoxon signed-rank significance tests. All statistical analysis was conducted in SAS 9.1. We found mechanical detection thresholds to be significantly higher (p < 0.05) at the painful site, and pain ratings to be significantly higher in response to a 512 mN pin (p < 0.05) at the painful site. This suggests diminished mechanical detection but increased sensitivity to pain caused by pressure in the painful area. These results provide the first QST data for painful scar neuromas. Further work to verify these results in a larger cohort would be of benefit. We are currently characterizing the QST response to a therapeutic intervention and furthermore determining whether QST values predict and track therapeutic responsiveness.