Quantitative Sensory Testing In Patients Research Articles

Quantitative sensory testing in patients with migraine: a systematic review and meta-analysis.

Quantitative sensory testing (QST) is widely used to assess somatosensory function by application of controlled stimuli across a variety of modalities. The aim of the present meta-analysis is to synthesize QST results across a wide array of studies of patients with migraine to identify the QST parameters that are reliably different between patients with migraine and healthy controls. In addition, we aimed to determine whether such differences vary according to stimulus location. A comprehensive literature search (up to January 2017) was conducted, which included studies comparing QST parameters between patients with migraine and healthy controls. For each QST modality, we calculated up to 3 meta-analyses for combined (combined data from multiple testing locations), local (head and neck), and nonlocal (outside the head or neck) locations. A total of 65 studies were included in the meta-analyses. Lower heat and pressure pain thresholds were observed in patients with migraine compared with healthy controls in the combined locations. Importantly, lower pressure pain threshold in patients with migraine was found in local areas but not in nonlocal areas. In addition, patients with migraine had higher pain ratings to cold suprathreshold stimuli for combined and nonlocal areas, and higher pain ratings to electrical suprathreshold stimuli for nonlocal areas. This meta-analysis indicates that the alterations in nociceptive processing of patients with migraine may be modality, measure, and location specific. These results provide researchers and clinicians the evidence to choose QST parameters optimally suited for differentiating patients with migraine and healthy controls.

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.

Subtle Sensory Abnormalities Detected by Quantitative Sensory Testing in Patients with Trigeminal Neuralgia

Background: Trigeminal neuralgia (TN) is characterized by paroxysmal pain attacks affecting the somatosensory distributions of the trigeminal nerve. It is thought to be associated with a neurovascular conflict most frequently, but pathomechanisms have not been fully elucidated. In general, no sensory deficit is found in routine clinical examination. There is limited data available, however, showing subtle subclinical sensory deficits upon extensive testing. Objective: We used quantitative sensory testing (QST) to detect abnormalities in sensory processing in patients with TN by comparing the affected and non-affected nerve branches with their contralateral counterparts and by comparing the results of the patients with those of controls. Study Design: Observational study. Setting: University Hospital, Departments of Neurosurgery, Institute for Cognitive and Clinical Neuroscience. Methods: QST was conducted on 48 patients with idiopathic TN and 27 controls matched for age and gender using the standardized protocol of the German Neuropathic Pain Network. Stimulations were performed bilaterally in the distribution of the trigeminal branches. The patients had no prior invasive treatment, and medications at the time of examination were noted. Results: In patients with TN deficits in warm and cold sensory detection thresholds in the affected and also the non-affected nerve branches were found. Tactile sensation thresholds were elevated in the involved nerve branches compared to the contralateral side. Limitations: More data are needed on the correlation of such findings with the length of history of TN and with changes of the morphology of the trigeminal nerve. Conclusions: QST shows subtle sensory abnormalities in patients with TN despite not being detected in routine clinical examination. Our data may provide a basis for further research on the development of TN and also on improvement after treatment. Key words: Quantitative sensory testing, trigeminal neuralgia, facial pain, neuropathic pain, microvascular decompression, cranial nerve

18. Laser evoked potentials and quantitative sensory testing in patients affected by multiple sclerosis: Clinical, neurophysiological and psychophysiological correlates

Pain is a common finding in patients affected by Multiple Sclerosis (MS). Many different types of pain can afflict MS patients, including neuropathic, nociceptive, or mixed pain. TSA-II-Thermotest (QST) and Laser evoked potentials (LEPs) are psychophysical and neurophysiological tests commonly used to explore pain. The study aims to determine psychophysical and neurophysiological correlates in MS patients. 16 MS patients (5 men, 11 women, mean age 59 years, mean EDSS 7) where clinically and neurophysiologically tested. 5 patients presented neuropathic central pain (according to NeuPSIG 2011 guidelines), 8 patients presented nociceptive or mixed pain, and 3 patients were pain-free. For QST, the dorsum of both hands and feet were examined; for LEPs, the dominant hand and both feet were tested. Results were collected and compared to age and sex matched controls. Pin-prick was altered in 37.5%, LEPs were abnormal in 57.8% and QST was pathological in 85.9% of examined sites. We detected a significant correlation between pain and clinical examination (0.022), pain and altered QST (0.042), while LEP abnormalities correlated well with the presence of neuropathic pain (0.012). Our results suggest that LEPs are more specific than QST to differentiate neuropathic from nociceptive pain.

Methods to measure peripheral and central sensitization using quantitative sensory testing: A focus on individuals with low back pain

Quantitative sensory testing can be used to assess peripheral and central sensitization; important factors that contribute to the individual’s experience of pain and disability. Many studies use quantitative sensory testing in patients with low back pain to detect alterations in pain sensitivity, however, because investigators employ different protocols, interpretation of findings across studies can become problematic. The purpose of this article is to propose a standardized method of testing peripheral and central pain sensitization in patients with low back pain. Video clips are provided to demonstrate correct procedures for measuring the response to experimental pain using mechanical, thermal and pressure modalities. As nurse researchers and clinicians increase utilization of quantitative sensory testing to examine pain phenotypes, it is anticipated that more personalized methods for monitoring the trajectory of low back pain and response to treatment will improve outcomes for this patient population.

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.

EHMTI-0156. Quantitative sensory testing in patients with headache attributed by idiopathic intracranial hypertension – a case-control study

Background In patients with idiopathic intracranial hypertension (IIH) headache often persist as a disabling symptom even after intracranial pressure (ICP) has normalized. Yet very little is known about the mechanisms of chronification. Aim To explore pain perception in patients with IIH in a controlled design at time of diagnosis and after 3 months of treatment. Materials and methods We explored pain perception in patients with newly diagnosed IIH by Quantitative Sensory Testing (QST) measuring cephalic and extra-cephalic supra-threshold pain ratings and pain thresholds for pressure and electrical stimulation. QST was performed at diagnosis and after one and three months. ICP was measured at baseline and at the 3-month follow-up. QST measurements from sex-matched controls were used for comparisons. Headache was assessed by monthly standardized interviews and headache diaries. Results At baseline IIH patients (n = 28) showed no consistent abnormalities in pain sensitivity or thresholds (p > 0.09 for all comparisons to healthy controls (n = 28). Although headache improved markedly and ICP normalized in 52%, there was no consistent change in pain sensitivity from baseline to follow-up (p > 0.09 for all variables). Patients with (54%) and without persistent chronic headache (46%) 3 months after diagnosis showed no different pain perception either at baseline or at the 3-month follow-up. Conclusions Although headache persisted as a chronic symptom in half of the patients we found no evidence of increased central pain sensitivity suggesting that headache chronification in IIH is caused by mechanisms other than central sensitization.

A Solid Methodological Step Forward for Quantitative Sensory Testing in Patients With Chronic Neck Pain

A Solid Methodological Step Forward for Quantitative Sensory Testing in Patients With Chronic Neck Pain

Multi-modal Quantitative Sensory Testing in Patients with Unilateral Chronic Neck Pain: An Exploratory Study

ObjectivesThe main objective of this study was to evaluate the pattern of altered pain processing in patients with chronic idiopathic neck pain, with particular emphasis on the interaction between pain sensitivity and modulation.MethodsThis cross-sectional study systematically evaluates patients with unilateral chronic idiopathic neck pain using a comprehensive, multi-modal quantitative sensory testing [QST] protocol. Only patients with unilateral idiopathic neck pain present without radicular symptoms for more than six months were invited to participate. The QST measurements consists of pressure pain threshold testing, thermal threshold testing, electrical pain threshold testing, wind-up response testing using electrical stimulation, and measurement of descending inhibitory modulation using the Conditioned Pain Modulation paradigm. For a control group, we randomly selected age- and gender-matched control values from our center database consisting of reference values of 118 pain-free healthy volunteers.Re...

Reliability of Static and Dynamic Quantitative Sensory Testing in Patients With Painful Chronic Pancreatitis

Quantitative sensory testing (QST) has proven to be an important instrument to characterize mechanisms underlying somatic and neuropathic pain disorders. However, its reliability has not previously been established in patients with visceral pain. We investigated the test-retest reliability of static and dynamic QST in patients with visceral pain due to chronic pancreatitis. Sixty-two patients (38 men, 53 [11] y) with painful chronic pancreatitis were included. Static QST comprised sensory thresholds for pressure and electrical stimulation performed in the ventral and dorsal T10 dermatomes (sharing spinal innervation with the pancreas, ie, pancreatic viscerotomes) and in 4 heterologous regions (control areas). Dynamic QST comprised conditioned pain modulation. Measurements were obtained from 2 subsequent test sessions separated by 1 week. The reliability of static QST was generally high, with the best test-retest performance seen for pressure pain thresholds (intraclass correlation coefficients [ICC], 0.74) and electrical sensation thresholds (ICC, 0.66). In contrast, the reliability of dynamic QST was poor (ICC, 0.01). For static QST measures, the reliability was higher for pain thresholds compared with suprapain thresholds (P < 0.01). No differences between assessments in the pancreatic viscerotomes compared with heterologous regions were seen (P = 0.6). Sensory thresholds in the pancreatic viscerotomes and control areas were reproducible over time. In contrast, dynamic QST measurements reflecting active central modulation of pain processing state (ie, conditioned pain modulation) were not stable over time and showed considerable variability. These factors should be taken into consideration in case QST is used to follow disease mechanisms, drug effects, or effects of pain intervention.

Temporal Summation in Patients With Irritable Bowel Syndrome (IBS) Compared to Healthy Controls (HC)

INTRODUCTION: A recent study demonstrated a significant correlation between somatic hyperalgesia and increased permeability in patients with irritable bowel syndrome (Pain 2009;146:41-46). In order to determine the importance of this association, we performed quantitative sensory testing in patients with moderately active inflammatory bowel disease (IBD) as a model disease with increased permeability. METHODS: Healthy controls and patients with confirmed Crohn's disease or ulcerative colitis were invited. Patients completed the SIBDQ as a validated health status measure for IBD patients. Pain thresholds were determined over the dominant hand and the four abdominal quadrants for pressure and heat application. Threshold and tolerance for ischemic and cold pain were assessed and rated during regular hand exercises with a blood pressure tourniquet inflated to 200 mmHg and during ice water immersion of the dominant hand, respectively. RESULTS: Fifty controls (37±2 years) and 10 IBD patients (36±4 years; SIBD score: 39.9±1.9) were recruited. Pain thresholds for pressure (5.8±0.2 vs. 5.7±0.4 kg/cm2) or heat (44.3±0.4 vs. 43.4±0.4o C; controls vs. IBD) over the dominant did not differ. Pressure thresholds were significantly lower over the abdomen, but did not differ between the groups (figure). In contrast, heat pain thresholds were similar between forearm and abdominal wall and did not differ between the groups. The results for ischemic pain (threshold: 60.0±7.5 vs. 65.2±14.3 s; tolerance: 117.3±8.6 vs. 134.6±14.0 s) or cold pain (threshold: 15.2±4.2 vs. 13.6±4.8 s; tolerance: 51.8±8.3 vs, 68.4±23.3 s) were comparable for both groups. CONCLUSION: We did not find differences in experimental pain in response to several different stimulus modalities between controls and IBD patients, arguing against an importance of increased intestinal permeability in the development of hyperalgesia.

Intestinal Inflammation and Somatic Pain

INTRODUCTION: A recent study demonstrated a significant correlation between somatic hyperalgesia and increased permeability in patients with irritable bowel syndrome (Pain 2009;146:41-46). In order to determine the importance of this association, we performed quantitative sensory testing in patients with moderately active inflammatory bowel disease (IBD) as a model disease with increased permeability. METHODS: Healthy controls and patients with confirmed Crohn's disease or ulcerative colitis were invited. Patients completed the SIBDQ as a validated health status measure for IBD patients. Pain thresholds were determined over the dominant hand and the four abdominal quadrants for pressure and heat application. Threshold and tolerance for ischemic and cold pain were assessed and rated during regular hand exercises with a blood pressure tourniquet inflated to 200 mmHg and during ice water immersion of the dominant hand, respectively. RESULTS: Fifty controls (37±2 years) and 10 IBD patients (36±4 years; SIBD score: 39.9±1.9) were recruited. Pain thresholds for pressure (5.8±0.2 vs. 5.7±0.4 kg/cm2) or heat (44.3±0.4 vs. 43.4±0.4o C; controls vs. IBD) over the dominant did not differ. Pressure thresholds were significantly lower over the abdomen, but did not differ between the groups (figure). In contrast, heat pain thresholds were similar between forearm and abdominal wall and did not differ between the groups. The results for ischemic pain (threshold: 60.0±7.5 vs. 65.2±14.3 s; tolerance: 117.3±8.6 vs. 134.6±14.0 s) or cold pain (threshold: 15.2±4.2 vs. 13.6±4.8 s; tolerance: 51.8±8.3 vs, 68.4±23.3 s) were comparable for both groups. CONCLUSION: We did not find differences in experimental pain in response to several different stimulus modalities between controls and IBD patients, arguing against an importance of increased intestinal permeability in the development of hyperalgesia.

Association between preoperative magnetic resonance imaging, pain intensity and quantitative sensory testing in patients awaiting lumbar diskectomy

Magnetic resonance imaging (MRI) offers important information regarding the morphology, location and size of a herniated disc, which influences the decision to offer lumbar diskectomy (LD). This study aims to examine the association between clinical neurophysiologic indices including pain intensity and quantitative sensory testing (QST), and the degree of lumbar nerve root compromise depicted on magnetic resonance (MR) in patients awaiting LD. With institutional ethical approval, 16 patients (American Society of Anaesthesiologists Grades I-II, 18-65 years) with radicular pain for greater than 3 months undergoing elective LD were studied. Preoperative pain was assessed using (i) a visual analogue scale measuring pain intensity at rest and with movement and (ii) by quantifying pain sensory thresholds (St), pain perception thresholds (PPt), and pain tolerance threshold (PTt) using QST. MR images were independently graded by two radiologists blinded to the clinical data using the Pfirrmann grading system. Statistical analyses using Student's t-tests and Pearson's correlation were preformed where appropriate. This study showed that: (i) findings on MR imaging corresponded with the symptomatic side and distribution of the pain; (ii) the degree of nerve root compromise, detected on MRI correlated with increased pain intensity at rest; and (iii) QST identified a trend towards higher St, PPt and PTt in patients with higher Pfirrmann grades. The Pfirrmann grading system of nerve root compromise may be clinically useful preoperatively as a method of identifying individuals who would benefit most from LD. However, additional studies with greater patient numbers and longer follow-up are required to definitively confirm the findings of this study.

Test–retest and interobserver reliability of quantitative sensory testing according to the protocol of the German Research Network on Neuropathic Pain (DFNS): A multi-centre study

Quantitative sensory testing (QST) is an instrument to assess positive and negative sensory signs, helping to identify mechanisms underlying pathologic pain conditions. In this study, we evaluated the test–retest reliability (TR-R) and the interobserver reliability (IO-R) of QST in patients with sensory disturbances of different etiologies. In 4 centres, 60 patients (37 male and 23 female, 56.4±1.9years) with lesions or diseases of the somatosensory system were included. QST comprised 13 parameters including detection and pain thresholds for thermal and mechanical stimuli. QST was performed in the clinically most affected test area and a less or unaffected control area in a morning and an afternoon session on 2 consecutive days by examiner pairs (4 QSTs/patient). For both, TR-R and IO-R, there were high correlations (r=0.80–0.93) at the affected test area, except for wind-up ratio (TR-R: r=0.67; IO-R: r=0.56) and paradoxical heat sensations (TR-R: r=0.35; IO-R: r=0.44). Mean IO-R (r=0.83, 31% unexplained variance) was slightly lower than TR-R (r=0.86, 26% unexplained variance, P<.05); the difference in variance amounted to 5%. There were no differences between study centres. In a subgroup with an unaffected control area (n=43), reliabilities were significantly better in the test area (TR-R: r=0.86; IO-R: r=0.83) than in the control area (TR-R: r=0.79; IO-R: r=0.71, each P<.01), suggesting that disease-related systematic variance enhances reliability of QST. We conclude that standardized QST performed by trained examiners is a valuable diagnostic instrument with good test–retest and interobserver reliability within 2days. With standardized training, observer bias is much lower than random variance.Quantitative sensory testing performed by trained examiners is a valuable diagnostic instrument with good interobserver and test–retest reliability for use in patients with sensory disturbances of different etiologies to help identify mechanisms of neuropathic and non-neuropathic pain.

Neurological complications in Fabry disease

In Fabry disease, deficiency of α-galactosidase A results in the accumulation of glycosphingolipids in body fluids and tissues including corneas, blood vessels, kidneys and also structures of the central and peripheral nervous system. Many patients show cardiovascular and cerebrovascular dysfunction. Cerebrovascular dysfunction is particularly associated with a high risk of strokes and of mortality even at a young age. The prevalence and severity of cerebrovascular complications increase with patients'age. Clinical data as well as histologic and neurophysiologic studies showed predominantly small fiber dysfunction in patients with Fabry disease. We recently performed quantitative sensory testing in patients with Fabry disease and found reduced cold and heat-pain detection thresholds, while nerve conduction velocities were only mildly reduced. From our findings, we concluded that small fiber dysfunction is more prominent than large fiber dysfunction in Fabry patients. Clinically, small fiber dysfunction contributes to recurrent episodes of burning and lancinating pain and paresthesias in the distal extremities. Such episodes can be typically triggered by changes of the environmental temperature, particularly by warming. Moreover, dysfunction of small thinly-myelinated and unmyelianated nerve fibers accounts for altered sympathetic and parasympathetic modulation. Sympathetic dysfunction explains the hypohidrosis and a subsequent poor exercise and heat tolerance. Enzyme replacement therapy (ERT) with recombinant human α-galactosidase A is available. We could demonstrate improvement of small fiber neuropathy and neuropathic pain after 18-23 months of ERT, which probably resulted from glycosphingolipid clearing from perineurial cells, axons and Schwann cells or from blood vessels supplying the nerves.

Assessment of Trigeminal Nerve Functions by Quantitative Sensory Testing in Patients and Healthy Volunteers

Orofacial sensory dysfunction plays an important role in oral and maxillofacial surgery. Quantitative sensory testing (QST) is a psychophysical approach to evaluate thermal and mechanical somatosensation. The present human study 1) collected normative QST data in extraoral and intraoral regions, 2) analyzed effects of age, gender, and anatomical sites on QST, and 3) applied QST in 11 patients with iatrogenic inferior alveolar nerve lesions. Sixty (30 male and 30 female) healthy volunteers were tested bilaterally in the innervation areas of infraorbital, mental, and lingual nerves. Ten patients with sensory disturbances in innervation areas of the mental nerve were investigated at 1, 4, and 8 weeks after surgery. Another patient with a complete sensory loss after surgery was repetitively tested within 453 days after primary surgery (dental implant) and subsequent surgical reconstruction of the inferior alveolar nerve by autologous graft. Older subjects were significantly less sensitive than younger subjects for thermal parameters. Thermal detection thresholds in infraorbital and mental regions showed higher sensitivity in women. Sensitivity to thermal stimulation was higher in the infraorbital region than in the mental and lingual regions. QST monitored somatosensory deficits and recovery of inferior alveolar nerve functions in all patients. Age, gender, and anatomic region affect various QST parameters. QST might be useful in the diagnosis of inferior alveolar nerve disorders in patients. In dentistry, the monitoring of afferent nerve fiber functions by QST might support decisions on further interventions.

Randomized controlled pilot study: Quantitative sensory testing in patients with back pain before and after Gua Sha massage

Question Permanent nociceptive influx may lead to functional changes in the nervous system, i.e. hyperalgesia and allodynia occur. These processes are suspected to contribute substantially to the ongoing pain process. Reflex therapies, like the Gua Sha, a traditional Chinese massage technique preferentially used in the treatment of back pain, are supposed to affect the transmission and processing of sensory information on receptor and spinal level [1] . If so one could assume that the Gua Sha massage should not only decrease the pain level itself, but also change sensory thresholds in the affected areas. In order to test this, we applied the Gua Sha massage in patients with chronic back pain and evaluated sensory threshold changes. Methods Thirty patients with chronic back pain (mean age 50.3±10.1 years) were randomized to treatment group (TG) or waiting list control group (WLC). At T1 all patients rated their pain on a 0–10 VAS scale. Baseline sensory testing was then conducted, followed by Gua Sha massage for the TG. Seven days later (T2) sensory testing was repeated and the WLC received Gua Sha. Testing included determination of mechanical detection threshold (MDT), pressure pain threshold (PPT) and vibration detection threshold (VDT) as described in the Quantitative Sensory Testing procedure (QST) by Rolke et al. [2] at the site of maximal pain, 10 cm next to the pain maximum and two control areas. In accordance to the QST procedure MDT and PPT scores were logarithmized. For further analysis, differences between T1 and T2 were compared between TG and WLC. Results First results show a significant decrease in mean pain ratings for the TG compared with the WLC ( p p Conclusions GuaSha not only decreased pain intensity for 35% on average compared with 4.6% increase in the WLC. TG also showed increased MDT and PPT at 10 cm next to the pain maximum. Together with the steady thresholds in both control areas this can be interpreted as the result of functional changes in the sensitized area. It appears that Gua Sha reduced allodynia in the pain surrounding area.

Quantitative sensory testing in patients with chronic neck pain before and after the application of the acupressure pad—A randomized, controlled pilot study

In the treatment of chronic neck pain alternative and complementary therapies receive increasing attention. One device based on the principles of Traditional Chinese Medicine is the Acupressure Pad. The pad with more than 1000 plastic needles is applied by the patient on the painful part of the body. Its supposed mode of action is thought to be similar to acupuncture or acupressure. It is likely that the pad yields its analgesic effect through direct mechanical stimulation of nociceptors which might affect the transmission and processing of sensory information on the spinal level, which likely will induce measureable changes in mechanical pain and perception thresholds. Therefore we investigated whether a 2-week application of the pad leads to changes in neck pain and sensory thresholds. Methods In total 40 patients (mean age 46.6±11.6 years) suffering from chronic neck pain for longer than 3 months participated in the study and were randomized to either treatment or waiting list control group. On day 1 actual pain rating was recorded on a 0–10 visual analog scale (VAS) followed by different methods of quantitative sensory testing (QST): mechanical detection threshold with von Frey filaments (MDT), vibration detection threshold (VDT) and pressure pain threshold (PPT) at the point of maximal pain, 10 cm next to the pain maximum and two control areas (hand, foot). The treatment group then received detailed information about the application of the acupressure pad. A daily application of at least 30 min over a period of 14 days was recommended. Fourteen days later the recording of VAS rating and QST measurement were repeated. Results Analysis of the change in recorded pain ratings showed a significant group difference (p=0.008) with a decrease in pain only for the treatment group (−31%). PPT significantly increased at pain maximum (p=0.011) and 10 cm close to the pain maximum (p=0.039), but not at the control areas. No such effects were found for VDT and MDT. Conclusion The present data suggest that an effect of the acupressure pad application is not only seen in VAS ratings but also in PPT. The elevated PPT after treatment supports the idea of a direct influence on transmission and processing of sensory information on the spinal level by reflex therapies such as the acupressure pad.

Quantitative sensory testing in patients with polyneuropathy and healthy individuals

Elderly individuals and patients with polyneuropathy often feel heat pain or burning sensation on quantitative sensory testing (QST) of warm perception distally in the lower limbs. We therefore studied heat pain threshold (HPT), warm perception threshold (WPT) and the difference between heat pain and warm perception thresholds in 48 patients with symptoms and signs of polyneuropathy matched according to age and gender with 48 healthy persons. QST (using method of limits) was performed on the distal calf and the dorsal foot. Particularly in the neuropathy group several individuals (58%) had an unpleasant feeling, often burning, when the thresholds according to the WPT algorithm were recorded. Difference between heat pain and warm perception thresholds in the lower calf of the patients was 3.9 +/- 3.5 and 5.8 +/- 3.4 degrees C in the controls (P = 0.012), and on the foot 3.8 +/- 2.8 vs 5.3 +/- 3.6 degrees C (P = 0.02). When performing QST it is important to assess also quality features of warm perception, such as burning and heat pain sensation.

Dysfunction in Multiple Primary Afferent Fiber Subtypes Revealed By Quantitative Sensory Testing in Patients with Chronic Vincristine-Induced Pain

Vincristine is one of the frontline chemotherapy drugs for the treatment of numerous lymphoid neoplasias. The main dose-limiting complication of vincristine is the development of painful peripheral neuropathy. Although clinical reports have appeared in the literature detailing the symptoms of vincristine neuropathy, quantitative sensory testing data that might yield insight to dysfunction in subsets of primary afferents are lacking. In this report, pain descriptors and anatomical distributions of sensory abnormalities were collected in each patient. Touch detection threshold, sharpness detection threshold, the thresholds for the detection of skin warming, heat pain, skin cooling, and the perception of cooling-induced pain were measured in patients with chronic vincristine-induced pain in each area of sensory abnormality and in skin perceived as outside the affected areas. Elevated touch detection thresholds were observed both within and outside areas affected by pain and sensory abnormality. Elevated sharpness and warm detection thresholds were noted only in areas affected by pain. These data suggest that chronic vincristine-induced pain is associated with dysfunction in Aβ, Aδ, and C caliber primary afferent fibers. Deficits in Aβ fibers appear to precede and presage deficits in the other fiber types, whereas deficits in Aδ- and C-fiber function appear to be specifically associated with the generation of pain.