Sensory Testing In Patients Research Articles

Sex Differences in Pain and Quantitative Sensory Testing in Patients With Rheumatoid Arthritis.

Women with rheumatoid arthritis (RA) have higher pain and worse functional outcomes compared to men, even when treated with similar medications. The objective of this study was to identify sex differences in pain intensity, pain interference, and quantitative sensory tests (QST), which are independent of inflammation, in patients with RA. This study is a post hoc analysis of participants in the Central Pain in Rheumatoid Arthritis cohort. Pain intensity was assessed using a 0-10 numeric rating scale. Pain interference was measured using a Patient-Reported Outcomes Measurement Information System computerized adaptive test. QST included pressure pain detection thresholds, temporal summation, and conditioned pain modulation. Women and men were compared using multiple linear regression, adjusted for age, education, race, research site, depression, obesity, RA disease duration, swollen joint count, and C-reactive protein. Mean ± SD pain intensity was 5.32 ± 2.29 among women with RA, compared to 4.60 ± 2.23 among men with RA (adjusted difference 0.83 [95% confidence interval (95% CI) 0.14, 1.53]). Women with RA had lower pressure pain detection thresholds at the trapezius (adjusted difference -1.22 [95% CI -1.73, -0.72]), wrist (adjusted difference -0.57 [95% CI -1.07, -0.06]), and knee (adjusted difference -1.10 [95% CI -2.00, -0.21]). No statistically significant differences in pain interference, temporal summation, and conditioned pain modulation were observed. Women reported higher pain intensity and lower pressure pain detection thresholds (higher pain sensitivity) than men. However, pain interference, temporal summation, and conditioned pain modulation did not differ between men and women.

Altered central pain processing assessed by quantitative sensory testing in patients with failed back surgery syndrome

ObjectiveTo investigate the presence of altered central pain processing in patients with failed back surgery syndrome (FBSS) using quantitative sensory testing (QST). MethodsThis study included 34 patients with FBSS, 102 patients post-lumbar surgery without low back pain (LBP), and 102 healthy subjects. All subjects underwent both pressure pain threshold (PPT) and conditioned pain modulation (CPM) in both local and remote pain-free areas, as well as temporal summation (TS) in a remote pain-free area. All patient subjects were assessed using the Pain Catastrophizing Scale (PCS), Beck Anxiety Inventory (BAI), Beck Depression Index (BDI), Numeric rating pain scale (NRS) and Oswestry Disability Index (ODI). ResultsCompared with both control groups, FBSS patients showed a reduction in both PPT and CPM in both tested areas, along with increased TS in a pain-free area (P < 0.05). Furthermore, the patients with FBSS had a significantly higher prevalence of anxiety, depression and pain catastrophizing thoughts than the patient controls (P < 0.05). In the FBSS patients, there was a significant correlation between LBP at rest and both CPM and TS in the pain-free areas, and QST measurements were also associated with the ODI, PCS and BAI (P < 0.05). ConclusionThese findings support the existence of augmented central pain processing in patients with FBSS, which may be caused by dysfunction of endogenous pain facilitation and inhibition. This central amplification of pain may contribute to both LBP intensity and disability in FBSS patients. Therefore, treatment efforts should take into account functional alterations in the central nervous system of FBSS patients.

Neuroendocrine effects of a single bout of functional and core stabilization training in women with chronic nonspecific low back pain: A crossover study.

Exercise‐induced hypoalgesia (EIH) is characterized as the pain reduction after an exercise session and it seems to be related to the release of plasma β‐endorphin. In this sense, the core stabilization training (CT) has been suggested for patients with chronic nonspecific low back pain (CNSLBP), but it is unclear whether it induces EIH. Patients with CNSLBP have neuromotor dysfunctions that can affect the performance of functional tasks, thus, performing functional training (FT) could improve motor control and promote EIH, since functional training uses multi‐joint exercises that aim to improve the functionality of actions performed in daily life. EIH is usually assessed using quantitative sensory tests (QST) such as conditioned pain modulation, pressure pain threshold, and temporal summation. Thus, the sum of parameters from quantitative sensory tests and plasma β‐endorphin would make it possible to understand what the neuroendocrine effects of FT and CT session are. Our study compared the acute effect of CT and FT on the EIH and plasma β‐endorphin release, and correlated plasma β‐endorphin with quantitative sensory testing in patients with CNSLBP. Eighteen women performed two training sessions (CT and FT) with an interval of 48 h between sessions. EIH was assessed by QST and plasma β‐endorphin levels. Results showed that only FT significantly increased plasma β‐endorphin (FT p < 0.01; CT p = 0.45), which correlated with pain pressure threshold (PPT) and conditioned pain modulation (CPM). However, QST values were not different in women with CNSLBP after CT or FT protocols. Plasma β‐endorphin correlated with PPT and CPM, however, the same did not occur with a temporal summation.

Thermal grill illusion of pain in patients with chronic pain: a clinical marker of central sensitization?

The thermal grill illusion of pain (TGIP) is a paradoxical burning pain sensation elicited by the simultaneous application of innocuous cutaneous warm and cold stimuli with a thermode ("thermal grill") consisting of interlaced heated and cooled bars. Its neurophysiological mechanisms are unclear, but TGIP may have some mechanisms in common with pathological pain, including central sensitization in particular, through the involvement of N-methyl- d -aspartate receptors. However, few studies have investigated TGIP in patients with chronic pain and its clinical relevance is uncertain. We hypothesized that the TGIP would be increased in comparison with controls in patients with fibromyalgia or irritable bowel syndrome, which are regarded as typical "nociplastic" primary pain syndromes related to changes in central pain processing. We compared the sensations elicited by a large range of combinations of temperature differentials between the warm and cold bars of a thermal grill applied to the hand between patients with fibromyalgia (n = 30) or irritable bowel syndrome (n= 30) and controls (n = 30). The percentage of TGIP responses and the intensity and unpleasantness of TGIP were significantly greater in patients than controls. Furthermore, positive correlations were found between TGIP intensity and clinical pain intensity and between TGIP intensity and the cold pain threshold measured on the hand. These results are consistent with our working hypothesis of shared mechanisms between TGIP and clinical pain mechanisms in patients with nociplastic chronic pain syndromes and suggest that TGIP might represent a clinical marker of central sensitization in these patients.

Are Reports of Pain, Disability, Quality of Life, Psychological Factors, and Central Sensitization Related to Outcomes of Quantitative Sensory Testing in Patients Suffering From Chronic Whiplash Associated Disorders?

Chronic whiplash associated disorders (CWAD) are characterized by long-lasting symptoms of neck pain occurring after an acceleration-deceleration injury. Central sensitization (CS) has been suggested as the possible underlying mechanism for these symptoms, and is characterized by changes in the central nervous system. Besides CS, psychological factors are believed to play an important role in the experience of (chronic) pain. Investigatingthe relationships between self-reported pain, disability, quality of life, psychological factors, and symptoms of CS; and electrical-based quantitative sensory testing (QST) outcomesin CWAD patients. Secondly, to investigate the differences in QST between CWAD patients and pain-free controls. Seventy-two individuals with CWAD and 55 pain-free controls underwent electrical stimuli-based QST. Detection and pain thresholds (EPT), temporal summation (TS), and conditioned pain modulation were examined. Spearman correlation and linear mixed models analyses were performed to assess, respectively, the hypothesized associations and group differences in QST. The Pain Catastrophizing magnification subscale correlated with the left wrist EPT (r=-0.332; P=0.004), and the Pain Anxiety Symptom Scale-20 with the left wrist (r=-0.325; P=0.005) and ankle (r=-0.330; P=0.005) EPT. TS at the ankle correlated with the CS inventory (r=0.303; P=0.010), Short Form 36 pain subscale (r=-0.325; P=0.005), and Illness Perception Questionnaire revised consequences subscale (r=0.325; P=0.005). EPTs left (P=0.011) and right wrist (P=0.023) were lower in the CWAD group, but conditioned pain modulation and TS did not differ between groups. QST outcomes relate to psychological constructs, rather than to self-reported pain intensity and distribution. Local hyperalgesia was found in individuals with CWAD, but no differences in endogenous pain facilitation nor inhibition.

Quantitative sensory testing in patients with the muscle pain subtype of temporomandibular disorder: a systemic review and meta-analysis.

This meta-analysis aimed to evaluate quantitative sensory testing (QST) evidence for pain processing in patients with the muscle pain subtype of temporomandibular disorders (mTMD). A comprehensive systematic electronic search strategy was performed in online literature databases. All full-text observational studies published up to July 2021 with the aim of investigating pain sensitization in humans with mTMD using QST measures were eligible for inclusion. Meta-analysis of QST data was performed using a random effects model, which included results comparing patients with mTMD to healthy controls, and standard mean difference (SMD) results were analyzed. Twelve studies with 732 participants (371 patients with mTMD and 361 healthy controls) were analyzed following screening and quality appraisal. Compared with healthy controls, patients with mTMD had significantly lower pressure pain threshold (SMD - 1.10, 95% confidence interval [CI] - 1.52 to - 0.68) with high heterogeneity (Tau2 = 0.61, I2 = 86%), and significantly lower mechanical pain threshold (SMD - 0.64, 95% CI - 0.95 to - 0.32) with no heterogeneity (Tau2 = 0.00, I2 = 0%). No difference was observed in the cold pain threshold (SMD 0.16, 95% CI - 0.13 to 0.45), heat pain threshold (SMD - 0.13, 95% CI - 0.40 to 0.15), and wind-up ratio (SMD 0.63, 95% CI - 0.11 to 1.38) between patients with mTMD and healthy controls. Other QST parameters were also discussed. The study results suggest that the pain processing of deep tissues is likely sensitized in mTMD and calls for more QST studies with standard procedures to reduce inter-study heterogeneity. The major findings of this meta-analysis support using PPT to examine the pain processing in patients with mTMD in clinical scenario.

Profiling thermal pain using quantitative sensory testing in patients with trigeminal nerve injury.

To investigate the thermal pain phenotypes using QST in patients with unilateral trigeminal nerve injury and to explore whether these different thermal pain phenotypes are associated with clinical and psychophysical characteristics. This retrospective study included 84 patients diagnosed with posttraumatic trigeminal neuropathy involving inferior alveolar nerve (IAN) and lingual nerve (LN). Data on clinical characteristics, subjective symptoms including hypoesthesia, dysesthesia, and allodynia, and objective signs using thermal QST were collected and explored. Three heat (heat hypoalgesia, heat hyperalgesia, and within normal range) and cold pain phenotypes (cold hypoalgesia, cold hyperalgesia, and within normal ranges) were identified, respectively. Thermal hypoalgesia was more frequently observed than thermal hyperalgesia. Heat hypoalgesia regardless of cold pain abnormalities appears to be associated with subjective negative symptoms, while thermal hyperalgesia seems to have little relationship with negative and positive symptoms. Thermal pain phenotypes were associated with loss of innocuous thermal sensation. Unlike heat pain phenotypes, cold pain phenotypes differed between IAN injury and LN injury. The thermal pain phenotypes identified in this study seem to be related to clinical and psychophysical findings differently. These results would be a good starting point for assessing posttraumatic trigeminal neuropathy and interpreting the thermal QST results.

Associations between physical performances, self-reported outcomes, and quantitative sensory testing in patients with chronic pain after knee osteoarthritis and total knee arthroplasty

Associations between physical performances, self-reported outcomes, and quantitative sensory testing in patients with chronic pain after knee osteoarthritis and total knee arthroplasty

Erratum to: Quantitative Sensory Testing in Patients with Multisomatoform Disorder with Chronic Pain as the Leading Bodily Symptom-a Matched Case-Control Study.

OBJECTIVE Chronic pain is a debilitating condition of multifactorial origin, often without physical findings to explain the presenting symptoms. Of the possible etiologies of persisting painful symptoms, somatoform disorders and functional somatic syndromes (FSS) are among the most challenging, with a prevalence of 8-20%. Many different somatoform disorders and FSS have overlapping symptoms, with pain being the most prevalent one. The concept of multisomatoform disorder (MSD) has been developed to acknowledge that fact. We hypothesized that the concept of MSD will be reflected in a distinct sensory profile of patients compared with healthy controls and possibly provide insight into the type and pathophysiology of the pain commonly experienced by patients. DESIGN We performed comprehensive quantitative sensory testing (QST) in 151 patients and 149 matched controls. RESULTS There were significant differences in the sensory profiles of patients compared with controls. Patients with MSD showed a combination of tactile and thermal hypesthesia combined with mechanical and cold hyperalgesia. This was true for measurements at test and control sites, with the exception of vibration detection threshold and mechanical pain threshold. Among the observed changes, a marked sensory loss of function, as evidenced by an increase in cold detection threshold, and a marked gain of function, as evidenced by a decrease of pressure pain threshold, were most notable. There was no evidence of concurrent medication influencing QST results. CONCLUSIONS The observed somatosensory profile of patients with MSD resembles that of patients suffering from neuropathic pain with evidence of central sensitization.

Quantitative Sensory Testing in Patients with Multisomatoform Disorder with Chronic Pain as the Leading Bodily Symptom-a Matched Case-Control Study.

Chronic pain is a debilitating condition of multifactorial origin, often without physical findings to explain the presenting symptoms. Of the possible etiologies of persisting painful symptoms, somatoform disorders and functional somatic syndromes (FSS) are among the most challenging, with a prevalence of 8-20%. Many different somatoform disorders and FSS have overlapping symptoms, with pain being the most prevalent one. The concept of multisomatoform disorder (MSD) has been developed to acknowledge that fact. We hypothesized that the concept of MSD will be reflected in a distinct sensory profile of patients compared with healthy controls and possibly provide insight into the type and pathophysiology of the pain commonly experienced by patients. We performed comprehensive quantitative sensory testing (QST) in 151 patients and 149 matched controls. There were significant differences in the sensory profiles of patients compared with controls. Patients with MSD showed a combination of tactile and thermal hypesthesia combined with mechanical and cold hyperalgesia. This was true for measurements at test and control sites, with the exception of vibration detection threshold and mechanical pain threshold. Among the observed changes, a marked sensory loss of function, as evidenced by an increase in cold detection threshold, and a marked gain of function, as evidenced by a decrease of pressure pain threshold, were most notable. There was no evidence of concurrent medication influencing QST results. The observed somatosensory profile of patients with MSD resembles that of patients suffering from neuropathic pain with evidence of central sensitization.

Itch sensitization? A systematic review of studies using quantitative sensory testing in patients with chronic itch.

As well established for patients with chronic pain, patients suffering from chronic itch also exhibit signs of peripheral and central sensitization. This has been linked to parallel neuroplastic sensitization processes. However, for chronic itch, sensitization has not yet been systematically assessed, studied, and hence validated. This review (Prospero CRD42016043002) summarizes and meta-analytically evaluates whether sensory aberrations including sensitization for itch occur in chronic itch. Databases PubMed, Embase, and Cochrane Library were searched for studies investigating somatosensory sensitivity assessment by quantitative sensory testing stimuli, including experimental cutaneous chemical pruritic provocations, in patients with chronic itch from skin/neurological conditions and compared with healthy controls. Outcomes were extracted for lesional and nonlesional skin, and risk of biases were assessed. Meta-analyses were performed when sufficient quantitative data were available. Of 4667 identified articles, 46 were included and 25 were eligible for meta-analyses. Patients (66% atopic dermatitis [AD]) were found more sensitive than the controls to histamine-evoked itch in lesional skin (standardized mean difference [SMD]: 0.66 confidence interval [CI]: 0.16-1.15), but not nonlesionally (SMD: -0.26 [CI: -0.58 to 0.06]). Cowhage did not evoke more itch in nonlesional skin of patients as compared to the controls (SMD: 0.38 [CI: -0.04 to 0.81]). For numerous other chemical provocations as well as for mechanical, thermal, and electrical stimulation paradigms, results were ambiguous or based on few studies. Patients with chronic itch are only robustly sensitized to various chemical pruritic stimuli when applied lesionally. More studies on somatosensory aberrations in chronic itch conditions other than AD are needed to establish whether sensitization is robustly present across chronic itch conditions.

(241) Gabapentin Efficacy in Chronic and Vaso-Occlusive Crises-Induced Acute Sickle Cell Disease Pain

Pain is the leading cause of hospitalization for patients with sickle cell disease (SCD). Currently, opioids are the main therapy for both chronic “steady state” SCD pain and acute pain that results from vaso-occlusive crises. However, opioids are often ineffective at fully alleviating pain, are associated with unwanted side effects, and do not target the underlying pain mechanism. Thus, new pain therapies are desperately needed for those suffering from SCD pain. Recent quantitative sensory testing in patients and electrophysiological studies in mouse models have identified a neuropathic component of SCD pain; SCD patients and mice exhibit robust mechanical and cold hypersensitivity that is further exacerbated following a vaso-occlusive event. As a result, we tested the analgesic effects of gabapentin, one of the first line therapies for neuropathic pain, in male and female transgenic SCD mice. A single dose of gabapentin (30 mg/kg) alleviated steady state mechanical hypersensitivity in the hindpaw but had no effect on steady state cold hypersensitivity, deep muscle pain, or facial mechanical hypersensitivity. In a separate experiment, gabapentin was administered daily for 4 weeks to model neuropathic pain patient therapy. This chronic administration did not alleviate steady state mechanical hypersensitivity, cold hypersensitivity, or deep muscle pain in SCD mice. However, chronic gabapentin treatment did prevent hypoxia-induced exacerbation of mechanical hypersensitivity in SCD mice. Notably, a single dose of gabapentin administered shortly after hypoxia treatment alleviated ischemia-induced mechanical hypersensitivity to a greater extent than chronic gabapentin treatment. Finally, the effects of gabapentin on spontaneous pain-like behaviors and spontaneous neuronal activity were assessed using conditioned place preference and ex vivo skin nerve recordings respectively. Collectively, these data demonstrate that the drivers of acute vaso-occlusive crisis pain and chronic mechanical hypersensitivity may be caused by different factors, the former of which may be alleviated by gabapentin treatment.

Quantitative sensory testing in patients with sensitive skin

Quantitative sensory testing in patients with sensitive skin

Children and adolescents with sickle cell disease have worse cold and mechanical hypersensitivity during acute painful events.

Sickle cell disease (SCD) pain associates with cold temperature and touch. Patients and murine models with SCD have baseline thermal and mechanical pain. In SCD mice, the baseline hypersensitivity is exacerbated by experimental vaso-occlusive crises. We hypothesized that patients with SCD will similarly experience increased hypersensitivity to thermal and mechanical stimuli during acute painful events compared with baseline health. We conducted a prospective study of 24 patients with SCD aged 7 to 19 years. Patients underwent quantitative sensory testing to thermal (cold/heat) and mechanical stimuli on the thenar eminence of the nondominant hand (glabrous skin) and the lateral dorsum of the foot (hairy skin) during baseline health and within 48 hours of hospitalization for acute pain. Primary outcomes were changes in: (1) cold pain threshold (°C), (2) heat pain threshold (°C), and (3) mechanical pain threshold (g). Median age was 10.5 (interquartile range [IQR] 9-14.8) years, 67% were females, and 92% were on hydroxyurea. Patients with SCD had increased cold pain sensitivity in the hand during hospitalization compared with baseline (25.2°C [IQR 18.4-27.5°C] vs 21.3°C [IQR 4.9-26.2°C]; P = 0.011) and increased mechanical pain sensitivity in the foot during hospitalization (0.32 g [IQR 0.09-1.1 g] vs 1.7 g [IQR 0.4-8.3 g]; P = 0.003). There were no differences in heat pain sensitivity. The increased cold (P = 0.02) and mechanical (P = 0.0016) pain sensitivity during hospitalization persisted after adjusting for age, sex, hydroxyurea use, opioid consumption, and numeric pain score. Thus, cold and mechanical pain is significantly worse during an acute SCD painful event as compared to baseline health in patients with SCD.

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.

High sensitivity of contact-heat evoked potentials in “snake-eye” appearance myelopathy

ObjectiveTo evaluate the sensitivity of dermatomal contact-heat evoked potentials (dCHEPs) compared to dermatomal somatosensory evoked potentials (dSSEPs) and clinical sensory testing in patients with focal central cord myelopathy, referred to as “snake-eye” appearance myelopathy (SEAM). Methods33 patients with SEAM in neuroimaging underwent electrophysiological (dCHEPs, dSSEPs) and clinical testing of sensory function (light touch [LT] and pin prick [PP]) at segments above, at and below to the spinal cord lesion. ResultsIn total, 151 dermatomes were tested (39 above, 112 at/below lesion). The sensitivity of dCHEPs (97.0%) was significantly higher compared to dSSEPs (23.3%, p<0.001), PP (66.7%, p=0.003) and LT (69.7%, p=0.006), respectively. The sensitivity of dCHEPs was highest when applied one to two segments caudally to the level of spinal cord lesion in MRI. ConclusionsdCHEPs are highly sensitive and superior to dSSEPs and clinical sensory testing in the diagnosis of SEAM. SignificancedCHEPs may complement the diagnosis in focal central cord myelopathies where clinical testing of sensory function and dSSEPs are less sensitive to provide conclusive findings.