Article

Cluster Analysis of an International Pressure Pain Threshold Database Identifies 4 Meaningful Subgroups of Adults With Mechanical Neck Pain

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Abstract

To determine Pressure Pain Detection Threshold (PPDT) related phenotypes of individuals with musculoskeletal neck pain (MNP) that may be identifiable in clinical practice. This report describes a secondary analysis of 5 independent, international MNP databases of PPDT values taken at both a local and distal region (total N=1176). Minor systematic differences in mean PPDT values across cohorts necessitated z-transformation prior to analysis, and each cohort was split into male and female genders. Latent Profile Analysis (LPA) using the k-means approach was undertaken to identify the most parsimonious set of PPDT-based phenotypes that were both statistically and clinically meaningful. LPA revealed 4 distinct clusters named according to PPDT levels at the local and distal zones: Low-Low PPDT (67%), Mod-Mod (25%), Mod-High (4%) and High-High (4%). Secondary predictor variables were evaluated for intra- and cross-cluster significance. Low-Low cluster was most affected, as indicated by pain intensity, disability, and catastrophization scores all significantly above the cohort- and gender-specific mean, and active range of motion scores significantly below the mean. The results suggest that there is a large proportion of people with neck pain that present with signs indicating dysfunction beyond the local tissues. Ongoing exploration of these presentations may lead to more informed management and improved outcomes.

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... Measurement of the pressure pain threshold (PPT) is of increasing value in clinical practice [5] and is commonly used to assess local and widespread pressure pain hyperalgesia in NSNP [5,6]. Assessing the mechanical sensitivity of deep structures by using PPT may help to discriminate between people with and without neck pain [7] and to classify clinically meaningful subgroups of NSNP patients [5]. ...
... Measurement of the pressure pain threshold (PPT) is of increasing value in clinical practice [5] and is commonly used to assess local and widespread pressure pain hyperalgesia in NSNP [5,6]. Assessing the mechanical sensitivity of deep structures by using PPT may help to discriminate between people with and without neck pain [7] and to classify clinically meaningful subgroups of NSNP patients [5]. ...
... Measurement of the pressure pain threshold (PPT) is of increasing value in clinical practice [5] and is commonly used to assess local and widespread pressure pain hyperalgesia in NSNP [5,6]. Assessing the mechanical sensitivity of deep structures by using PPT may help to discriminate between people with and without neck pain [7] and to classify clinically meaningful subgroups of NSNP patients [5]. It may also provide prognostic value for the chronicity of neck pain occurring after trauma [8] and help stratify responders versus non-responders to a given intervention [9]. ...
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Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.
... In contrast, CS does not seem to be a typical feature of CINP. On a group-level, several studies have reported no evidence for widespread hyperalgesia and no decreased efficacy of CPM in patients with CINP compared to healthy pain-free controls (Coppieters et al., 2017a;Scott et al., 2005;Malfliet et al., 2015), although in subgroups and hence on an individual level, widespread hyperalgesia has been observed in individuals with CINP as well (Castaldo et al., 2018(Castaldo et al., , 2019Lopez-de-Uralde-Villanueva et al., 2016;Malfliet et al., 2015;Pina-Pozo et al., 2019;Walton et al., 2017). And, more recently, a meta-analysis revealed moderate-quality evidence of mechanical widespread hyperalgesia in patients with non-traumatic neck pain compared to pain-free controls (Xie et al., 2020). ...
... And, more recently, a meta-analysis revealed moderate-quality evidence of mechanical widespread hyperalgesia in patients with non-traumatic neck pain compared to pain-free controls (Xie et al., 2020). Thus, it is clear that interindividual differences in pain sensitivity are present in both chronic neck pain conditions (Walton et al., 2017;Castaldo et al., 2018), which may be best conceptualized as a continuum with CWAD on a further end of the spectrum compared to CINP. It is clear though that a better understanding of these sensory signs is needed, as signs of CS, as assessed with quantitative sensory testing (QST), are also present in various other chronic musculoskeletal pain disorders, and are generally associated with more (widespread) pain and disability, and poorer treatment responses (Nijs et al., 2019;Jull et al., 2007;Gerhardt et al., 2016;Uddin and MacDermid, 2016;Staud et al., 2012). ...
... chronic neck pain populations, with increasing severity of symptoms and alterations in pain processing. The idea of a continuum is in accordance with other research investigating patients with CINP and CWAD (Malfliet et al., 2015;Walton et al, 2017;Castaldo et al., 2019Castaldo et al., , 2018. ...
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Background Chronic neck pain is a leading cause of disability worldwide, affecting the lives of millions of people. Research investigating functional brain alterations in relation to somatosensory function is necessary to better understand mechanisms underlying pain development and maintenance in individuals with chronic neck pain, yet remains scarce. This case-control study aimed to examine resting-state functional connectivity alterations and associations with pain outcomes, self-reported central sensitization-related symptoms and quantitative sensory testing (QST) measures in patients with chronic non-traumatic (idiopathic/CINP) neck pain and chronic traumatic (whiplash associated/CWAD) neck pain compared to pain-free controls. Methods Resting-state functional magnetic resonance images were acquired in 107 female participants (38 CINP, 37 CWAD, 32 healthy controls). After data pre-processing, seed-to-seed analyses were conducted focusing on resting-state functional connectivity involving pre-defined regions of interest that have previously been observed to be structurally or functionally altered and/or associated with pain-related measures in this patient population. Results Findings demonstrate enhanced left amygdala functional coupling during rest with the left frontal operculum in women with CINP and CWAD compared to controls. This increased resting-state functional connectivity was associated with more self-reported symptoms related to central sensitization and decreased efficacy of conditioned pain modulation. Furthermore, enhanced connectivity between the left amygdala and left frontal orbital cortex, and between the left pallidum and the left frontal operculum was observed only in patients with CWAD compared to healthy controls. In patients, additional associations between local hyperalgesia and enhanced connectivity between the left superior parietal cortex and the left and right precentral gyrus were found. Conclusions In line with our hypotheses, patients with CWAD showed the most pronounced alterations in resting-state functional connectivity, encompassing subcortical limbic (amygdala) and basal ganglia (pallidum), and ventral frontal regions (frontal operculum, orbitofrontal cortex) when compared to CINP and controls. Findings are generally in line with the idea of a continuum, in absence of significant group differences across CINP and CWAD. Enhanced amygdala-frontal operculum functional connectivity was the most robust and only connectivity pair in the cluster that was associated with QST (i.e., dynamic QST; endogenous pain inhibition), and that was observed in both patient groups. In addition, independent of group differences, enhanced resting-state functional connectivity between superior parietal cortex (involved in attention) and primary motor cortex was associated with static QST (i.e., greater local hyperalgesia). Taken together, our findings show a key role for enhanced amygdala-ventral frontal circuitry in chronic neck pain, and its association with diminished endogenous pain inhibition further emphasizes the link between cognitive-affective and sensory modulations of pain in women with chronic non-traumatic and traumatic neck pain.
... Also, studies of chronic neck pain reported such a negative association between PPT and catastrophizing [41,42]. Partly in contrast, Walton et al. [43] analysed the phenotypes of individuals with neck pain in five international registers and found the association between PPTs and pain characteristics, including catastrophizing, to be conflicting [43]. ...
... Also, studies of chronic neck pain reported such a negative association between PPT and catastrophizing [41,42]. Partly in contrast, Walton et al. [43] analysed the phenotypes of individuals with neck pain in five international registers and found the association between PPTs and pain characteristics, including catastrophizing, to be conflicting [43]. ...
Article
Background and aims Psychological traits such as pain catastrophizing may play a role in the development of chronic pelvic pain (CPP). Pain catastrophizing is the tendency to amplify negative cognitive and emotional pain processes. The Pain Catastrophizing Scale (PCS) assesses elements of pain catastrophizing divided into three subgroups of factors (rumination, helplessness and magnification). Previous studies have shown associations between CPP and increased pain sensitivity, widespread generalized hyperalgesia, and decreased pain thresholds, but the relation between pain catastrophizing and specific pain thresholds has not yet been widely examined in this patient group. The aims of this study were (a) to determine if catastrophizing is increased in women with CPP compared with pain-free women, (b) to assess the importance of pain catastrophizing, psychological distress variables, and subjective pain sensitivity for pain thresholds of heat, cold and pressure in these two groups, and (c) to determine whether psychological variables or pain thresholds best contribute to the differentiation between CPP and controls. Methods Thirty-seven women with chronic pelvic pain who underwent diagnostic laparoscopy on the suspicion of endometriosis participated along with 55 healthy and pain-free controls. All underwent quantitative sensory testing on six locations on the body to determine heat (HPT), cold (CPT) and pressure (PPT) pain thresholds. The PCS, the Pain Sensitivity Questionnaire (PSQ), the Hospital Anxiety Depression Scale, (HADS) demographics and clinical data were collected prospectively. Principal component analysis and orthogonal partial least square regressions were used to assess the associations between PCS scores and pain thresholds. Results The women with CPP scored significantly higher on PCS than the healthy controls. PCS-helplessness, PCS-rumination and HADS-depression were significantly associated with pain thresholds for the whole group. In the CPP group, PCS-rumination, body mass index and PSQ were significant regressors for HPT and CPT. The PCS and the HADS subscales were strongly intercorrelated in women with CPP and were stronger regressors of group membership than the three pain thresholds. In the group of healthy control women, no relationships were found to be significant. The psychological variables were somewhat stronger significant regressors than pain thresholds (also significant) for group membership. Conclusions Women with CPP have significantly higher pain catastrophizing scores than women without CPP. The pain catastrophizing rumination factor is significantly associated with pain thresholds of heat and cold in CPP women. PCS and HADS are strongly intercorrelated and PSQ correlates positively with these variables. It seems that the psychological variables are important for group differentiation. Implications The results clearly indicate the need for a multimodal assessment (bio-psycho-social) of CPP patients including psychological symptoms such as catastrophizing, anxiety and depression. The registration of semi-objective pain thresholds captures both specific pain sensitivity information (mechanical pressure, cold or heat) and the degree of wide spread pain hypersensitivity. There is a need for future larger studies investigating whether certain profiles in the clinical presentations (including pain thresholds and psychological variables) are associated with outcomes after different types of interventions.
... [4][5][6] Recent efforts to optimize treatment decisions have explored the potential value of diagnostic, prognostic, or theranostic subgroups. [7][8][9] To date, subgroups have been determined using scores on self-report tools, 7 results of quantitative sensory testing 8 or presence of restricted range of motion (ROM) in defined planes of cervical motion (sagittal/frontal/horizontal). 9 Active cervical mobility (ROM) has been traditionally viewed as a useful clinical metric for identifying dysfunction and evaluating outcomes of treatment. ...
... [4][5][6] Recent efforts to optimize treatment decisions have explored the potential value of diagnostic, prognostic, or theranostic subgroups. [7][8][9] To date, subgroups have been determined using scores on self-report tools, 7 results of quantitative sensory testing 8 or presence of restricted range of motion (ROM) in defined planes of cervical motion (sagittal/frontal/horizontal). 9 Active cervical mobility (ROM) has been traditionally viewed as a useful clinical metric for identifying dysfunction and evaluating outcomes of treatment. ...
Article
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Introduction: Chronic neck pain results in considerable personal, clinical, and societal burden. It consistently ranks among the top three pain-related reasons for seeking healthcare. Despite its prevalence, neck pain is difficult to both assess and treat. Quantitative approaches are required since diagnostic imaging techniques rarely provide information on movement-related neck pain, and most common clinical assessment tools are limited to single plane motion measurement. Methods: In this study, the ability of an inertial measurement unit to document the cervical motion characteristics of 28 people with chronic neck pain and 23 healthy controls was assessed. A total of six circumduction metrics and one neck circumduction trajectory model were proposed as identification metrics. Results: Five metrics demonstrated significant differences between the two groups. The neck circumduction trajectory model successfully distinguished between the two groups. Discussion: The evaluation of the proposed metrics provides proof of concept that novel metrics can be captured with relative ease in the clinical setting using an inexpensive wearable sensor headband. The derivation of the proposed model may open new lines of inquiry into the clinical utility of assessing the multiplanar movement of cervical circumduction. The results obtained from this study also provide additional insight for the development of a sensitive, quantifiable and real-world neck evaluation strategies.
... Quantitative sensory testing (QST) assists in the interpretation of pain types and-mechanisms underlying clinical pain presentations [5,[12][13][14]. It allows the assessment of function of all somatosensory modalities according to the different sensory nerve fibers (Aβ, Aδ and C fibers) and the documentation of a loss of function (hypoesthesia) or gain of function (hyperalgesia, allodynia) [13,15,16]. ...
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Background The clinical presentation of neck-arm pain is heterogeneous with varying underlying pain types (nociceptive/neuropathic/mixed) and pain mechanisms (peripheral/central sensitization). A mechanism-based clinical framework for spinally referred pain has been proposed, which classifies into (1) somatic pain, (2) neural mechanosensitivity, (3) radicular pain, (4) radiculopathy and mixed pain presentations. This study aims to (i) investigate the application of the clinical framework in patients with neck-arm pain, (ii) determine their somatosensory, clinical and psychosocial profile and (iii) observe their clinical course over time. Method We describe a study protocol. Patients with unilateral neck-arm pain (n = 180) will undergo a clinical examination, after which they will be classified into subgroups according to the proposed clinical framework. Standardized quantitative sensory testing (QST) measurements will be taken in their main pain area and contralateral side. Participants will have to complete questionnaires to assess function (Neck Disability Index), psychosocial factors (Tampa Scale of Kinesiophobia, Pain Catastrophizing Scale, Depression, anxiety and stress scale), neuropathic pain (Douleur Neuropathique 4 Questions, Pain DETECT Questionnaire) and central sensitization features (Central Sensitization Inventory). Follow-ups at three, six and 12 months include the baseline questionnaires. The differences of QST data and questionnaire outcomes between and within groups will be analyzed using (M)AN(C)OVA and/or regression models. Repeated measurement analysis of variance or a linear mixed model will be used to calculate the differences between three, six, and 12 months outcomes. Multiple regression models will be used to analyze potential predictors for the clinical course. Conclusion The rationale for this study is to assess the usability and utility of the proposed clinical framework as well as to identify possible differing somatosensory and psychosocial phenotypes between the subgroups. This could increase our knowledge of the underlying pain mechanisms. The longitudinal analysis may help to assess possible predictors for pain persistency.
... C hronic non-specific neck pain (NSNP) accounts for 33.6 millions of years lived with disability in the last three decades, 1 and is among the highest economic burden of disease in the European Union. 2 Around 70% of the population worldwide will suffer at least one neck pain event during their lives, and 14% will eventually develop chronic NSNP. 3,4 Frequent related symptoms are local pressure pain hyperalgesia, 5 and restricted cervical range-of-movement (ROM). 6 Pain in the neck has been also associated with restricted maximal mouth opening in individuals without temporomandibular problems, due to central excitatory effects resulting from persistent nociceptive input. ...
Article
Study design: A randomized, single-blinded (the outcome assessor was unaware of participants' allocation group) controlled clinical trial. Objective: To investigate the effects of myofascial release therapy (MRT) over the suboccipital muscles, compared with self-MRT using a novel device, the INYBI tool, on pain-related outcomes, active cervical mobility, and vertical mouth opening, in adults with chronic non-specific neck pain (NSNP). Summary of background data: MRT is used to manage chronic musculoskeletal pain conditions, with purported positive effects. The efficacy of self-MRT, compared to MRT, has been scarcely evaluated. Methods: Fifty-eight participants (mean age of 34.6 ± 4.7 years; range 21-40 years; 77.6% females, 22.4% males) with persistent NSNP agreed to participate, and were equally distributed into an INYBI (n = 29) or a control group (n = 29). Both groups underwent a single 5-minutes intervention session. For participants in the control group, MRT of the suboccipital muscles was performed using the suboccipital muscle inhibition technique, while those in the INYBI group underwent a self-MRT intervention using the INYBI device. Primary measurements were taken of pain intensity (Visual Analogue Scale), local pressure pain sensitivity, as assessed with an algometer, and active cervical range-of-movement. Secondary outcomes included pain-free vertical mouth opening. Outcomes were collected at baseline, immediately after intervention and 45 minutes later. Results: The ANOVAs demonstrated no significant between-groups effect for any variable (all, p > 0.05). In the within-groups comparison, all participants significantly improved pain-related outcomes, and showed similar positive changes for mouth opening. Cervical range-of-movement- mainly increased after intervention for participants in the control group. Conclusion: Both, MRT and self-MRT using the INYBI, are equally effective to enhance self-reported pain intensity, and local pressure pain sensitivity in chronic NSNP patients. For cervical mobility, MRT appears to be slighlty superior, compared to the INYBI, to achieve improvements in this population. Level of evidence: 2.
... The number of people suffering from skeletal muscle problems is constantly increasing, often due to work activities that lead us to assume the wrong position for a prolonged period of time. The symptoms that are perceived by the subject can be various: stiffness, pain in the cervical area and muscles associated with it, tingling along the upper limbs, loss of strength, brachialgia, headaches and dizziness [4][5][6]. ...
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In manual therapy, high velocity low amplitude (HVLA) cervical manipulation techniques are frequently used, but often the physiological and biomechanical effects that can be obtained are not completely clear. The techniques are mostly used for the treatment of biomechanical joint dysfunction, but little is yet known about the possibility of using them in order to achieve better performance on healthy subjects. The objective of the study is to describe how cervical manipulation can impact on a musculoskeletal disorder. A systematic search was carried out on the Pubmed electronic database from the beginning of January to March 2020. Two independent reviewers conducted the screening process through the PRISMA diagram to determine the eligibility of the articles. The inclusion criteria covered randomized controlled trial (RCT) manuscripts published in peer-reviewed journals with individuals of all ages from 2005 to 2020. The included intervention was thrust manipulation or HVLA directed towards the cervical spine region. After reviewing the literature, 21 of 74 articles were considered useful and relevant to the research question. The results of the research show that HVLA techniques, on subjects with musculoskeletal disorders, are able to influence pain modulation, mobility and strength both in the treated area and at a distance. Cervical manipulations are effective in management of cervicalgia, epicondylalgia, temporomandibular joint disorders and shoulder pain. With regard to results on strength in healthy subjects, given the divergent opinions of the authors, we cannot yet state that manipulation can significantly influence this parameter. Cervical manipulations can also have risks for the patient if applied when not appropriate but the frequency of complications due to vertebral manipulation are very low. However, the manipulation techniques might be limited by low patients tolerance or the presence of contraindications. In addition, the optimal number of manipulations to be performed and the long-term benefits produced are unknown.
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bstract Objective: Chronic mechanical neck pain is associated with musculoskeletal tissue alterations. Active trigger points in the trapezius and levator scapulae muscles are common in patients with chronic mechanical neck pain. In this study, we com- pared the effect of dry needling (DN) combined with manual therapy (MT) to sham dry needling (SDN) combined with MT on pain, pain pressure threshold, cervical range of motion and neck disability in patients with chronic mechanical neck pain. Methods: A randomised, single-blind clinical trial was carried out involving 101 participants with chronic mechanical neck pain, divided into an intervention group (DN+MT, n=47) and a control group (SDN+MT, n=54). Participants received two treatment sessions. The intervention group received MT in conjunction with DN of the most mechano-sensitive myofascial trigger point (MTrP). The control group received MT plus SDN. Outcomes measures were: pain intensity (numeric pain rating scale, NPRS), pressure pain threshold (PPT), cervical range of motion (ROM) and neck disability (neck disability index, NDI). Results: This study found that between-group differences in pain intensity were statistically significant (P<0.01). Pain decreased after the first intervention in the DN+MTgroup (3.47±0.25 points on the NPRS) and even more so after the second intervention (4.76±0.24 points on the NPRS). After 4weeks, pain intensity differed from baseline by 4.89±0.27 points on the NPRS. Statistically significant differences (P<0.001) in PPT were also found between the intervention group and the control group. After the first intervention, a significant increase in PPT within the DN+MTgroup (3.09±0.8 kg/ cm2) was observed. Cervical ROM also showed highly statistically significant differences. After 4weeks, a statistically significant reduction (P<0.001) in NDI was observed between the two groups. Conclusion: Our results show that DN+MT is efficacious and significantly better than SDN+MT at reducing pain intensity, PPT, neck disability and cervical ROM in patients with chronic mechanical neck pain.
Article
Objective Evidence suggests altered pronociceptive and antinociceptive mechanisms in many chronic pain conditions. Knowledge about these mechanisms in nonspecific chronic neck pain (NSNP) would improve understanding of the causes and the design of more effective treatments. Pressure pain threshold (PPT) is often used to assess presence of altered nociceptive processing in NSNP; however, its usefulness to detect this is yet to be established. The purpose of this study was to determine the functional status of temporal summation of second pain (TSSP) and conditioned pain modulation (CPM) in NSNP and to characterize the association of both measures with PPT and clinical features of NSNP. Methods Thirty-two participants with NSNP (mean [SD] age = 44 [11] y; 27 female) and 32 age and sex matched healthy controls were recruited. TSSP was assessed using an electrical stimulus at the dorsum of the hand, and CPM was evaluated with the Cold Pressor Test. PPT was assessed bilaterally at the neck and tibialis anterior muscles. Results Participants with NSNP showed greater TSPP (mean difference = 0.23; 95% CI = 0.46-0.01; Cohen d = 0.51) and lower CPM (mean difference = 19.44; 95% CI = 10.42-28.46; Cohen d = 1.09). Pooled data from all participants showed lower PPTs at the neck than the tibialis anterior. However, PPT measures did not differ between groups at either location. PPT measures were not correlated with CPM and TSP. Conclusion NSNP is associated with enhanced pronociceptive and impaired antinociceptive mechanisms, which may explain long-lasting pain and failure of some treatments to resolve symptoms. However, due to the observational nature of this study, a clear cause-effect relationship cannot be established. Normal PPT values in the clinic should not be interpreted as absence of altered nociceptive processing. Impact This study fills in some gaps in knowledge. Changes in central nociceptive processing may explain persistent and recurrent symptoms in NSNP and failure of treatments to obtain long-lasting relief. Further research is required to ascertain if TSSP and CPM assessment in the clinic may help predict physical therapy treatment outcome. Whether symptomatic relief with physical therapy is mediated by an improvement in TSSP and CPM should also be explored. PPTs were unaltered in participants with NSNP despite evidence of impairment in the central pain modulatory systems. Normal PPTs should not be interpreted as evidence of unaltered central pain-related processing.
Article
Objective: Chronic mechanical neck pain is associated with musculoskeletal tissue alterations. Active trigger points in the trapezius and levator scapulae muscles are common in patients with chronic mechanical neck pain. In this study, we compared the effect of dry needling (DN) combined with manual therapy (MT) to sham dry needling (SDN) combined with MT on pain, pain pressure threshold, cervical range of motion and neck disability in patients with chronic mechanical neck pain. Methods: A randomised, single-blind clinical trial was carried out involving 101 participants with chronic mechanical neck pain, divided into an intervention group (DN+MT, n=47) and a control group (SDN+MT, n=54). Participants received two treatment sessions. The intervention group received MT in conjunction with DN of the most mechano-sensitive myofascial trigger point (MTrP). The control group received MT plus SDN. Outcomes measures were: pain intensity (numeric pain rating scale, NPRS), pressure pain threshold (PPT), cervical range of motion (ROM) and neck disability (neck disability index, NDI). Results: This study found that between-group differences in pain intensity were statistically significant (P<0.01). Pain decreased after the first intervention in the DN+MT group (3.47±0.25 points on the NPRS) and even more so after the second intervention (4.76±0.24 points on the NPRS). After 4 weeks, pain intensity differed from baseline by 4.89±0.27 points on the NPRS. Statistically significant differences (P<0.001) in PPT were also found between the intervention group and the control group. After the first intervention, a significant increase in PPT within the DN+MT group (3.09±0.8 kg/cm2) was observed. Cervical ROM also showed highly statistically significant differences. After 4 weeks, a statistically significant reduction (P<0.001) in NDI was observed between the two groups. Conclusion: Our results show that DN+MT is efficacious and significantly better than SDN+MT at reducing pain intensity, PPT, neck disability and cervical ROM in patients with chronic mechanical neck pain. Level of evidence: 1b.
Article
Objective: The purpose of the current randomized clinical trial was to examine the effects of cervical thrust manipulation or sham manipulation on cervicocephalic kinaesthetic sense, pain, pain-related disability, and pressure pain sensitivity in patients with mechanical neck pain. Methods: Fifty-four individuals with neck pain were randomly assigned to receive either a cervical manipulation (right or left) or a sham manipulation. Immediate outcomes included cervical kinesthetic sense as assessed by joint position sense error (JPSE) and pressure pain thresholds (PPTs). At 1 week, neck pain intensity (numerical pain rate scale) and neck pain-related disability (Neck Disability Index [NDI]) outcomes were also collected. Results: The mixed-model analysis of covariance revealed a significant group × time interaction in favor of the cervical thrust manipulation group for the JPSE on rotation and extension. There was also a significant interaction for changes in PPTs at C5 to C6 and tibialis anterior. At the 1-week follow-up, a significant interaction existed for neck-related disability but not for neck pain at rest, worst pain, or lowest pain experienced the preceding week. Conclusions: Our results suggest that cervical spine thrust manipulation improves JPSE, PPT and NDI in participants with chronic mechanical neck pain. Furthermore, changes in JPSE and NDI were large and surpass published minimal detectable changes for these outcome measures. In addition, the effect sizes of PPTs were medium; however, only C5 to C6 zygapophyseal joint exceeded the minimal detectable change. In contrast, cervical thrust manipulation did not improve neck pain intensity at 1 week after the intervention.
Article
Background: Impaired proprioception, increased pain sensitivity, higher levels of anxiety and catastrophizing are present in adults with chronic idiopathic neck pain. Despite the high prevalence of neck pain, studies in adolescents are scarce. Objectives: The main aim was to compare pressure pain thresholds (PPTs) and joint repositioning error (JRE) between adolescents with chronic idiopathic neck pain and adolescents without neck pain. Secondary aims were to compare these groups for catastrophizing and anxiety and to investigate the association between PPTs, JRE and psychosocial variables and pain characteristics. Methods: 80 adolescents (40 with and 40 without chronic neck pain) were assessed for: neck repositioning error, neck, upper trapezius and tibialis anterior PPTs, anxiety and catastrophizing. Neck pain was characterized in terms of intensity, frequency, duration and associated disability. MANCOVA was used for between group comparisons and Pearson and Spearman coefficients for correlational analysis. Results: Adolescents with neck pain showed higher levels of catastrophizing (p < 0.001) and anxiety (trait: p < 0.001; state: p = 0.028), lower PPTs (p < 0.001) and higher JRE (p < 0.001) than asymptomatic controls. Pain intensity, frequency and duration were moderately correlated with anxiety, and disability was moderately correlated with anxiety (r between 0.43 and 0.50, p < 0.05) and catastrophizing (r = 0.40, p < 0.05). Conclusions: This study suggests that functional changes and maladaptive cognitive processes are present in adolescents with neck pain aged 16-18 years old. These findings need to be replicated in future studies.
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Chronic whiplash-associated disorders (WAD) incur both costs and suffering. Treatments that can relieve chronic WAD are therefore needed. Exercise therapy (ET) has been shown to provide pain relief. Another often used treatment for chronic pain in Scandinavia is basic body awareness therapy (BAT). We compared the effectiveness of 10 weeks of twice-weekly, 90-min sessions of either ET or BAT in a randomized comparative trial. We recruited 113 patients suffering from chronic WAD grades I-III and several years' duration of symptoms in a primary health care setting. 57 were allocated to ET and 56 to BAT. Primary outcome measures were Neck Disability Index and SF-36 v.2. From baseline to post-treatment, the BAT group increased their physical functioning (median 5, IQR = 15) more than the ET group (median = 0, IQR = 15), p = 0.032, effect size -0.54. Three months after the end of treatment, the BAT group had less bodily pain (m = 17.5, 95% CI 6.9-17.6) than the ET group (m = 4.9, 95% CI -0.1 to 9.8), p = 0.044, effect size -0.4. The BAT group had also increased their social functioning (m = 13.3, 95% CI 6.6-19.9) more than the ET group (m = 3.5, 95% CI -3 to 9.9), p = 0.037, effect size -0.41. No statistically significant differences between groups were found for the change of other outcomes. No serious adverse effects were found in either groups. The present trial indicates that BAT led to greater improvements than ET for the patients with chronic WAD. Implications for Rehabilation Chronic whiplash-associated disorders are disabling and incur great costs to society often through inability to work. Exercise therapy (ET) may alleviate symptoms of chronic WAD. Basic body awareness therapy (BAT) is often a component of multimodal pain rehabilitation programs. In this randomized comparative trial, BAT increased physical functioning and led to greater pain reduction and social functioning 3 months after the end of treatment.
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In Study 1, the Pain Catastrophizing Scale (PCS) was administered to 425 undergraduates. Analyses yielded a three component solution comprising (a) rumination, (b) magnification, and (c) helplessness. In Study 2, 30 undergraduate participants were classified as catastrophizers (n = 15) or noncatastrophizers (n = 15) on the basis of their PCS scores and participated in an cold pressor procedure. Catastrophizers reported significantly more negative pain-related thoughts, greater emotional distress, and greater pain intensity than noncatastrophizers. Study 3 examined the relation between PCS scores, negative pain-related thoughts, and distress in 28 individuals undergoing an aversive electrodiagnostic medical procedure. Catastrophizers reported more negative pain-related thoughts, more emotional distress, and more pain than noncatastrophizers. Study 4 examined the relation between the PCS and measures of depression, trait anxiety, negative affectivity, and fear of pain. Analyses revealed moderate correlations among these measures, but only the PCS contributed significant unique variance to the prediction of pain intensity.
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Background: Despite increasing clinical and research use of the 11-item version of the Tampa Scale for Kinesiophobia (TSK-11) in people with neck pain, little is known about its measurement properties in this population. Objective: The purpose of this study was to rigorously evaluate the measurement properties of the TSK-11 when used in people with mechanical neck pain. Design: This study was a secondary analysis of 2 independent databases (N=235) of people with mechanical neck pain of primarily traumatic origin. Methods: The TSK-11 was subjected to Rasch analysis and subsequent evaluation of concurrent associations with the Neck Disability Index and a numeric rating scale for pain intensity. Results: The TSK-11 conformed well to the Rasch model for interval-level measurement, but less so for acute or nontraumatic etiologies. A transformation matrix suggested that small changes at the extremes of the scale are more meaningful than in the middle. Cross-sectional convergent validity testing suggested relationships of expected magnitude and direction compared with pain intensity and neck-related disability. The use of the linearly transformed TSK-11 led to potentially important differences in distribution of data compared with use of the raw scores. Limitations: The sample size was slightly smaller than desired for Rasch analysis. The 2 databases were similar in terms of symptom duration, but differed in pain intensity and age. Conclusions: The TSK-11 can be considered an interval-level measure when used in people with neck pain. It provides potentially important information regarding the nature of neck-related disability. Clinically important difference may not be consistent across the range of the scale.
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The measurement of subjective pain intensity continues to be important to both researchers and clinicians. Although several scales are currently used to assess the intensity construct, it remains unclear which of these provides the most precise, replicable, and predictively valid measure. Five criteria for judging intensity scales have been considered in previous research: (a) ease of administration of scoring; (b) relative rates of incorrect responding; (c) sensitivity as defined by the number of available response categories; (d) sensitivity as defined by statistical power; and (e) the magnitude of the relationship between each scale and a linear combination of pain intensity indices. In order to judge commonly used pain intensity measures, 75 chronic pain patients were asked to rate 4 kinds of pain (present, least, most, and average) using 6 scales. The utility and validity of the scales was judged using the criteria listed above. The results indicate that, for the present sample, the scales yield similar results in terms of the number of subjects who respond correctly to them and their predictive validity. However, when considering the remaining 3 criteria, the 101-point numerical rating scale appears to be the most practical index.
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The aim of this study was to investigate whether bilateral widespread pressure hypersensitivity exists in patients with unilateral carpal tunnel syndrome. A total of 20 females with carpal tunnel syndrome (aged 22-60 years), and 20 healthy matched females (aged 21-60 years old) were recruited. Pressure pain thresholds were assessed bilaterally over median, ulnar, and radial nerve trunks, the C5-C6 zygapophyseal joint, the carpal tunnel and the tibialis anterior muscle in a blinded design. The results showed that pressure pain threshold levels were significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the carpal tunnel, the C5-C6 zygapophyseal joint, and the tibialis anterior muscle in patients with unilateral carpal tunnel syndrome as compared to healthy controls (all, P < 0.001). Pressure pain threshold was negatively correlated to both hand pain intensity and duration of symptoms (all, P < 0.001). Our findings revealed bilateral widespread pressure hypersensitivity in subjects with carpal tunnel syndrome, which suggest that widespread central sensitization is involved in patients with unilateral carpal tunnel syndrome. The generalized decrease in pressure pain thresholds associated with pain intensity and duration of symptoms supports a role of the peripheral drive to initiate and maintain central sensitization. Nevertheless, both central and peripheral sensitization mechanisms are probably involved at the same time in carpal tunnel syndrome.
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To determine whether a newly developed disability scale for patients with neck pain demonstrated acceptable reliability and validity. Testing was conducted using three different samples of patients with neck pain (n = 162). Test-retest reliability of the scale was carried out on the same day with one sample (n = 39), and between-day reliability was carried out with another (n = 21). Differential item functioning with regard to the influence of gender and age was carried out with these two patient groups, as was construct validity. Responsiveness was measured using patients participating in a clinical trial involving patients with chronic neck pain (n = 102). Additionally, scale scores were compared with a wide range of physical measurements using the patients in the clinical trial. Short-term, between-day and postal questionnaire reliability coefficients were all extremely high. The Cronbach's alpha coefficient for internal consistency was 0.9 for the entire scale, and the coefficients for individual items were all greater than 0.88. Disability scale scores correlated strongly to pain scores as well as to doctor and patient global assessments, indicating good construct validity. Relative changes in disability scores demonstrated a moderately strong correlation to changes in pain scores after treatment. Scale scores correlated weakly to all physical measurements. The disability scale demonstrated excellent practicality and reliability. The scale accurately reflects patient perceptions regarding functional status and pain as well as doctor's global assessment and is responsive to change over long periods of time. We feel that this scale can be a valuable tool for the assessment of patients in future clinical trials and quality of care studies.
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Patients with sensory disturbances of painful and non-painful character show distinct changes in touch and/or pain sensitivity. The patterns of sensory changes were compared to those of human surrogate models of neuropathic pain to assess the underlying mechanisms. We investigated 30 consecutive in-patients with dysaesthesia of various origins (peripheral, spinal, and brainstem lesions) and 15 healthy subjects. Tactile thresholds were determined with calibrated von Frey hairs (1.1mm). Thresholds and stimulus-response functions for pricking pain were determined with a series of calibrated punctate mechanical stimulators (0.2mm). Allodynia was tested by light stroking with a brush, Q-tip, and cotton wisp. Perceptual wind-up was tested by trains of punctate stimuli at 0.2 or 1Hz. Intradermal injection of capsaicin (n=7) and A-fiber conduction blockade (n=8) served as human surrogate models for neurogenic hyperalgesia and partial nociceptive deafferentation, respectively. Patients without pain (18/30) showed a continuous distribution of threshold shifts in the dysaesthetic skin area with a low to moderate increase in pain threshold (by 1.52+/-0.45 log2 units). Patients with painful dysaesthesia presented as two separate groups (six patients each): one showing lowered pain thresholds (by -1.94+/-0.46 log2 units, hyperalgesia) and the other elevated pain thresholds (by 3.02+/-0.48 log2 units, hypoalgesia). The human surrogate model of neurogenic hyperalgesia revealed nearly identical leftward shifts in stimulus-response function for pricking pain as patients with spontaneous pain and hyperalgesia (by a factor of about 5 each). The sensory changes in the human surrogate model of deafferentation were similar to patients with hypoalgesia and spontaneous pain (rightward shift of the stimulus-response function with a decrease in slope). Perceptual wind-up did not differ between symptomatic and control areas. There was no exclusive association of any parameter obtained by quantitative sensory testing with a particular disease (of either peripheral or central origin). Our findings suggest that neuropathic pain is based on two distinct mechanisms: (I) central sensitization (neurogenic hyperalgesia; in patients with minor sensory impairment) and (II) partial nociceptive deafferentation (painful hypoalgesia; in patients with major sensory deficit). This distinction as previously postulated for postherpetic neuralgia, is obviously valid also for other conditions. Our findings emphasize the significance of a mechanism-based classification of neuropathic pain.
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This article describes the development and validation of the S-LANSS score, a self-report version of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale. The S-LANSS aims to identify pain of predominantly neuropathic origin, as distinct from nociceptive pain, without the need for clinical examination. Two hundred patients with chronic pain were asked to complete the S-LANSS unaided. A researcher then administered the S-LANSS scale and the Neuropathic Pain Scale (NPS) in interview format. An independent clinician determined the pain type (neuropathic versus nociceptive) and rated his or her certainty about diagnosis. The S-LANSS scale was also incorporated into a chronic pain questionnaire that was sent to 160 community patients and 150 newly referred patients waiting for pain clinic assessment. The S-LANSS scale correctly identified 75% of pain types when self-completed and 80% when used in interview format. Sensitivity for self-completed S-LANSS scores ranged from 74% to 78%, depending on the cutoff score. There were significant associations between NPS items and total score with S-LANSS score. In the postal survey, completed questionnaires were returned by 57% of patients (n = 174). Internal consistency and convergent validity of the survey S-LANSS scores were confirmed. The findings support the S-LANSS scale as a valid and reliable self-report instrument for identifying neuropathic pain and it is also acceptable for use in postal survey research. Establishing valid measures of symptoms and signs in neuropathic pain will allow standardized comparisons with other investigational measures. This might lead to new insights into the relationship between pathophysiologic mechanisms and clinical manifestations of pain.
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Increased excitability of the central nervous system generated by repetitive and sustained pericranial myofascial nociception may be responsible for transformation of episodic tension-type headache into chronic form. We aimed to compare mechanical and electrical (intramuscular and cutaneous) pain thresholds in trapezius and anterior tibial regions between 20 patients with chronic tension type headache and 20 healthy controls. Pain thresholds to three types of electrical stimulation (single pulse, 2 and 100 Hz) were significantly lower in patients than in controls in trapezius muscle (P < 0.02) and in skin overlying the trapezius muscle (P < 0.05), whilst electrical pain thresholds did not differ between groups in anterior tibial muscle and skin. Quantitative sensory testing revealed increased pain sensitivity in patients as assessed by pressure-controlled manual palpation (local tenderness score, LTS; P < 0.01) and by pressure algometry (mechanical pain thresholds; P < 0.05) in test areas over the trapezius muscle, but not the anterior tibial muscle. In summary, this study demonstrates lower pain thresholds in muscle and skin of the cephalic region but not in lower limb muscle and skin in patients with chronic tension-type headache than in healthy controls. Increased sensitivity in nociceptive pathways from cephalic region may be of importance in the pathophysiology of chronic tension type headache.
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Background In a cohort of well-characterized patients with different degrees of knee osteoarthritis (OA) and pain, the aims were to utilize mechanism-based quantitative sensory testing (QST) to (1) characterize subgroups of patients; (2) analyse the associations between clinical characteristics and QST; and (3) develop and apply a QST-based knee OA composite pain sensitivity index for patient classification.Methods Two hundred seventeen OA pain patients and 64 controls were included. Kellgren and Lawrence (KL) grading scores were obtained, and pressure pain thresholds (PPTs), temporal summation of pain to repeated painful pressure stimulation and conditioning pain modulation (CPM) were assessed. Associations between pain score/area/duration, radiological findings and QST-related parameters were analysed. A pain sensitivity index was developed and applied based on PPT, temporal summation and CPM. z-Score, as statistical tool, was calculated for statistically comparing the pain index of a single patient with a healthy control group.ResultsHigh knee pain associated with low KL grade showed particular signs of pain sensitization. Patients showed significant associations between clinical knee pain intensity/duration and lowering of knee PPTs (p < 0.01), facilitation of temporal summation (p < 0.01), reduction of CPM function (p < 0.01) and high pain sensitivity index (p < 0.01). The index classified 27–38% of the OA patients and 3% of the controls as highly sensitive with no association to KL. The index increased for high knee pain intensities and long pain duration.Conclusions Radiological scores, contrary to clinical pain intensity/duration, were poorly associated with QST parameters. The pain sensitivity index could classify OA patients with different degrees of OA and pain.
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Evidence suggests that brief physiotherapy programmes are as effective for acute whiplash-associated disorders as more comprehensive programmes; however, whether this also holds true for chronic whiplash-associated disorders is unknown. We aimed to estimate the effectiveness of a comprehensive exercise programme delivered by physiotherapists compared with advice in people with a chronic whiplash-associated disorder. PROMISE is a two group, pragmatic randomised controlled trial in patients with chronic (>3 months and <5 years) grade 1 or 2 whiplash-associated disorder. Participants were randomly assigned by a computer-generated randomisation schedule to receive either the comprehensive exercise programme (20 sessions) or advice (one session and telephone support). Sealed opaque envelopes were used to conceal allocation. The primary outcome was pain intensity measured on a 0-10 scale. Outcomes were measured at baseline, 14 weeks, 6 months, and 12 months by a masked assessor. Analysis was by intention to treat, and treatment effects were calculated with linear mixed models. The trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12609000825257. 172 participants were allocated to either the comprehensive exercise programme (n=86) or advice group (n=86); 157 (91%) were followed up at 14 weeks, 145 (84%) at 6 months, and 150 (87%) at 12 months. A comprehensive exercise programme was not more effective than advice alone for pain reduction in the participants. At 14 weeks the treatment effect on a 0-10 pain scale was 0·0 (95% CI -0·7 to 0·7), at 6 months 0·2 (-0·5 to 1·0), and at 12 months -0·1 (-0·8 to 0·6). CNS hyperexcitability and symptoms of post-traumatic stress did not modify the effect of treatment. We recorded no serious adverse events. We have shown that simple advice is equally as effective as a more intense and comprehensive physiotherapy exercise programme. The need to identify effective and affordable strategies to prevent and treat acute through to chronic whiplash associated disorders is an important health priority. Future avenues of research might include improving understanding of the mechanisms responsible for persistent pain and disability, investigating the effectiveness and timing of drugs, and study of content and delivery of education and advice. The National Health and Medical Research Council of Australia, Motor Accidents Authority of New South Wales, and Motor Accident Insurance Commission of Queensland.
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Two classification methods, latent class cluster analysis and cluster analysis, are used to identify groups of child behavioral adjustment underlying a sample of elementary school children aged 6 to 11 years. Behavioral rating information across 14 subscales was obtained from classroom teachers and used as input for analyses. Both the procedures and results were compared. The latent class cluster analysis uncovered three classes representing differing levels of children's behavioral adjustment (well adjusted, average adjustment, functionally impaired), whereas the cluster analysis uncovered seven groups of child behavior. Results show a high degree of overlap, and each procedure offers unique information toward classifying child behavior.
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The lack of efficacy of rehabilitative approaches to the management of chronic whiplash associated disorders (WAD) may be in part due to heterogeneity of the clinical presentation of this patient population. The aim of this study was to identify homogeneous subgroups of patients with chronic WAD based on symptoms of PTSD and sensory hypersensitivity and to compare the clinical presentation of these sub-groups. Successive k-means cluster analyses using 2, 3 and 4 cluster solutions were performed using data for 331 (221 female) patients with chronic (> 3 months) WAD. The 4 cluster solution was identified as the most clinically relevant yielding 4 distinct clusters: no to mild post-traumatic stress symptoms and no sensory hypersensitivity (nPnH), no to mild post-traumatic stress symptoms and sensory hypersensitivity (nPH), moderate to severe post-traumatic stress and no sensory hypersensitivity (PnH) and moderate to severe post-traumatic stress and sensory hypersensitivity (PH). The nPnH cluster was the largest cluster comprising 43.5% of the sample. The PH cluster had significantly worse disability, pain intensity, self report mental health status and cervical ROM in comparison to the nPnH and nPH clusters. These data provide further evidence of the heterogeneity of the chronic WAD population and the association of a more complex clinical presentation with higher disability and pain in this patient group.
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Objectives: To evaluate the properties of the Pain Catastrophizing Scale (PCS) from a Rasch paradigm. Methods: A secondary analysis of 235 patients with work-related pain conditions was performed using the Rasch methodology. Unidimensionality, item fit, location independence, differential item functioning, response option structure, and linearity were evaluated for the 13-item PCS score. Results: Two items (8 and 12) required rescoring to address disordered response thresholds. Significant misfit to the Rasch model was corrected through the use of testlets based on the original 3 factors of the PCS (rumination, magnification, and helplessness). After rescoring and creation of testlets, the scale showed good fit to the Rasch model (χ(2)=6.93, P=0.91) and could be logically considered an interval-level scale. No evidence of differential item functioning was found for sex or location of pain. The items in the scale covered the spectrum of catastrophizing levels reported by the sample. A transformation matrix is presented that allows simple conversion of ordinal to interval-level scores. Discussion: The results of this secondary analysis suggest that the PCS can be appropriately evaluated as an interval-level scale when the composite 13-item score is considered, as has been standard practice to date. Implications for clinical and research use are discussed.
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Widespread deep tissue pain hyperalgesia was evaluated in women with chronic whiplash associated disorder (n = 25) and controls (n = 10) using computerized cuff pressure algometry and hypertonic saline infusion. A pneumatic double-chamber cuff was placed around: (i) the arm and (ii) the leg. Cuff inflation rate was constant and the pain intensity was registered continuously on a visual analogue scale (VAS); thresholds of detection and tolerance were extracted. For assessment of spatial summation the protocol was repeated with a single-chamber cuff inflated around the leg. Temporal summation of pain was assessed from the leg with constant cuff pressure stimulation at 2 different pressure intensities for 10 min. Hypertonic saline was infused in the tibialis anterior muscle. Cuff pressure pain thresholds were lower in subjects with whiplash associated disorder compared with controls (p < 0.05). Tonic pressure stimulation evoked higher maximal VAS and larger areas under the VAS curve in subjects with whiplash associated disorder compared with controls (p < 0.05). The pain threshold and tolerance were higher during single cuff than double cuff stimulation. The area under the VAS curve after intramuscular saline infusion was larger in whiplash associated disorder (p < 0.05). The results indicated widespread hyperalgesia in chronic whiplash associated disorder and facilitated temporal summation outside the primary pain area, suggesting involvement of central sensitization.
Article
Sustained isometric muscle contraction (fatiguing contraction) recruits segmental and/or extrasegmental descending inhibition in healthy subjects but not in fibromyalgia (FM). We hypothesized that fatiguing contraction may shift descending pain modulation from inhibition towards facilitation and that the effect of descending pain modulation be dependent on peripheral muscle pain sensitivity. Pressure pain thresholds (PPT) were measured from 13 points bilaterally in the upper trapezius muscle and from the mid-point bilaterally in the tibialis anterior before-, immediately after-, and 20 min after fatiguing contraction of shoulder abduction in 22 FM patients and 22 matched healthy controls. Rate of fatigue, pain intensity, and the duration of fatiguing contraction were recorded. The duration of fatiguing contraction was significantly shorter in FM (132.4 ± 25.2 s) than healthy control groups (286.2 ± 24.1 s) (P < 0.05), pain intensity was significantly higher in FM (8.25 ± 0.8 cm) than in healthy controls (5.1 ± 0.65 cm) (P < 0.01), whereas both groups reported similar fatigue intensity (P > 0.05). Following the contraction, PPTs were increased significantly and heterogeneously in the upper trapezius over time, but not, in the tibialis anterior muscle in healthy controls. However, PPT were significantly decreased over time in the tibialis anterior (P < 0.05), but not, in the upper trapezius in FM. Descending pain modulation shifts from descending inhibition towards descending facilitation following muscle nociception in FM. Peripheral mechanical hyperalgesia and descending facilitation counterbalance the effect of descending inhibition in FM.
Article
One-year prospective study of 141 acute whiplash patients (WLP) and 40 acute ankle-injured controls. This study investigates a priori determined potential risk factors to develop a risk assessment tool, for which the expediency was examined. The whiplash-associated disorders (WAD) grading system that emerged from The Quebec Task-Force-on-Whiplash has been of limited value for predicting work-related recovery and for explaining biopsychosocial disability after whiplash and new predictive factors, for example, risk criteria that comprehensively differentiate acute WLP in a biopsychosocial manner are needed. Consecutively, 141 acute WLP and 40 ankle-injured recruited from emergency units were examined after 1 week, 1, 3, 6, and 12 months obtaining neck/head visual analog scale score, number of nonpainful complaints, epidemiological, social, psychological data and neurological examination, active neck mobility, and furthermore muscle tenderness and pain response, and strength and duration of neck muscles. Risk factors derived (reduced cervical range of motion, intense neck pain/headache, multiple nonpain complaints) were applied in a risk assessment score and divided into seven risk strata. A receiver operating characteristics curve for the Risk Assessment Score and 1-year work disability showed an area of 0.90. Risk strata and number of sick days showed a log-linear relationship. In stratum 1 full recovery was encountered, but for high-risk patients in stratum 6 only 50% and 7 only 20% had returned to work after 1 year (P < 5.4 × 10). Strength measures, psychophysical pain measurements, and psychological and social data (reported elsewhere) showed significant relation to risk strata. The Risk Assessment score is suggested as a valuable tool for grading WLP early after injury. It has reasonable screening power for encountering work disability and reflects the biopsychosocial nature of whiplash injuries.
Article
Longitudinal cohort study. To determine whether pressure pain threshold (PPT), tested at 2 standardized sites, could provide additional prognostic ability to predict short-term outcomes in people with acute whiplash, after controlling for age, sex, and baseline pain intensity. PPT may be a valuable assessment and prognostic indicator for people with whiplash-associated disorder. The extent to which PPT can predict short-term disability scores has yet to be explored in people with acute (of less than 30 days in duration) whiplash-associated disorder in a clinical setting. Eligible patients were recruited from community-based physiotherapy clinics in Canada. Baseline measurements included PPT, as well as pain intensity, age, and sex. Neck-related disability was collected with the Neck Disability Index 1 to 3 months after PPT testing. Multiple linear regression models were constructed to evaluate the unique contribution of PPT in the prediction of follow-up disability scores. A total of 45 subjects provided complete data. A regression model that included sex, baseline pain intensity, and PPT at the distal tibialis anterior site was the most parsimonious model for predicting short-term Neck Disability Index scores 1 to 3 months after PPT testing, explaining 38.6% of the variance in outcome. None of the other variables significantly improved the predictive power of the model. Sex, pain intensity, and PPT measured at a site distal to the injury were the most parsimonious set of predictors of short-term neck-related disability score, and represented promising additions to assessment of traumatic neck pain. Neither age nor PPT at the local site was able to explain significant variance beyond those 3 predictors. Limitations to interpretation are addressed.
Article
Increased sensitivity to pressure is commonly associated with painful musculoskeletal conditions, including whiplash-associated disorders (WADs). Pressure pain thresholds (PPTs) close to the site of presumed tissue damage are thought to represent the degree of peripheral nociceptive sensitization. PPTs over healthy tissue, away from the site of injury, are a marker of central nervous system hyperexcitability. There is uncertainty, however, as to what extent does the sensitization of the nociceptive system, whether peripheral or central, contribute to the ongoing, habitual pain experienced by people with WAD. One hundred patients with WAD were assessed within 4 weeks of their accident and followed after 3 months; 24-hour average neck pain score, PPTs at the cervical spine and tibialis anterior, demographic factors, and psychological measures were collected. Cervical PPT and neck pain score were significantly, but weakly correlated (r = -0.20 to -0.33). There was no significant correlation between tibialis anterior PPT and pain score at any time point (r = -0.01 to -0.21). Regression analyses indicated a strong influence of generalized psychological distress and fear avoidance on the relationship between PPT and pain report. The competing explanations for these findings are that either PPTs provide a poor marker of peripheral and central sensitivity or that these processes are only weakly related to the day-to-day pain experienced by patients with WAD. The latter explanation is supported by the confounding effect of psychological factors on pain score.
Article
Distinct developmental trajectories for neck disability and posttraumatic stress disorder (PTSD) symptoms after whiplash injury have recently been identified. This study aimed to identify baseline predictors of membership to these trajectories and to explore their dual development. In a prospective study, 155 individuals with whiplash were assessed at <1 month, 3, 6, and 12 months postinjury. Outcomes at each time point were assessed according to the Neck Disability Index and the Posttraumatic Stress Diagnostic Scale. Baseline predictor variables were age, gender, initial pain (based on a visual analogue scale [VAS]), pressure pain thresholds (PPT), cold pain thresholds (CPT), and sympathetic vasoconstrictor responses. Group-based trajectory analytical techniques were used to parameterise the optimal trajectories and to identify baseline predictors. A dual trajectory analysis was used to explore probabilities of conditional and joint trajectory group membership. CPT > or = 13° C (OR = 26.320, 95% CI = 4.981-139.09), initial pain level (VAS) (OR = 4.3, 95% CI = 4.98-139.1), and age (OR = 1.109, 95% CI = 1.043-1.180) predicted a chronic/severe disability trajectory. The same baseline factors also predicted chronic moderate/severe PTSD (CPT > or = 13° C, OR = 9.7, 95% CI = 2.22-42.44; initial pain level [VAS]: OR = 2.13, 95% CI = 1.43-3.17; age: OR = 1.07, 95% CI = 1.01-1.14). There was good correspondence of trajectory group for both disability and PTSD. These findings support the proposal of links between the development of chronic neck related disability and PTSD after whiplash injury. Developmental trajectories of disability and posttraumatic stress disorder (PTSD) after whiplash injury are mostly in synchrony, and similar factors predict their membership. This suggests links between the development of chronic neck pain-related disability and PTSD.
Article
Fibromyalgia (FM), a complex chronic pain disorder affecting a heterogeneous patient population, is an area of active basic and clinical research. Although diagnostic criteria for FM have been available for 2 decades, there remains no definitive diagnostic and no consensus regarding its etiology. Accumulating evidence suggests the underlying cause of FM pain results from abnormal pain processing particularly in the central nervous system rather than from dysfunction in peripheral tissues where pain is perceived. In this review, we examine recent studies investigating abnormalities in central pain processing as a component of FM in both preclinical models of generalized muscle hypersensitivity and clinical research in patients with FM. We focus our discussion on two areas where strong evidence exists for abnormalities in sensory signaling: the reduction of descending control, including suppression of descending inhibitory pathways and/or enhancement of descending facilitatory pathways, and changes in key neurotransmitters associated with central sensitization. Finally, we discuss currently available pharmacological treatments indicated for the management of pain in FM patients, based on their proposed mechanism of action and efficacy.
Article
Mechanical pain sensitivity is assessed in every patient with pain, either by palpation or by quantitative pressure algometry. Despite widespread use, no studies have formally addressed the usefulness of this practice for the identification of the source of pain. We tested the hypothesis that assessing mechanical pain sensitivity distinguishes damaged from healthy cervical zygapophysial (facet) joints. Thirty-three patients with chronic unilateral neck pain were studied. Pressure pain thresholds (PPTs) were assessed bilaterally at all cervical zygapophysial joints. The diagnosis of zygapophysial joint pain was made by selective nerve blocks. Primary analysis was the comparison of the PPT between symptomatic and contralateral asymptomatic joints. The secondary end points were as follows: differences in PPT between affected and asymptomatic joints of the same side of patients with zygapophysial joint pain; differences in PPT at the painful side between patients with and without zygapophysial joint pain; and sensitivity and specificity of PPT for 2 different cutoffs (difference in PPT between affected and contralateral side by 1 and 30 kPa, meaning that the test was considered positive if the difference in PPT between painful and contralateral side was negative by at least 1 and 30 kPa, respectively). The PPT of patients was also compared with the PPT of 12 pain-free subjects. Zygapophysial joint pain was present in 14 patients. In these cases, the difference in mean PPT between affected and contralateral side (primary analysis) was -6.2 kPa (95% confidence interval: -19.5 to 7.2, P = 0.34). In addition, the secondary analyses yielded no statistically significant differences. For the cutoff of 1 kPa, sensitivity and specificity of PPT were 67% and 16%, respectively, resulting in a positive likelihood ratio of 0.79 and a diagnostic confidence of 38%. When the cutoff of 30 kPa was considered, the sensitivity decreased to only 13%, whereas the specificity increased to 95%, resulting in a positive likelihood ratio of 2.53 and a diagnostic confidence of 67%. The PPT was significantly lower in patients than in pain-free subjects (P < 0.001). Assessing mechanical pain sensitivity is not diagnostic for cervical zygapophysial joint pain. The finding should stimulate further research into a diagnostic tool that is widely used in the clinical examination of patients with pain.
Article
To investigate if hypersensitivity is present in elders with pain. Chronic headache was used as a model of chronic pain and mechanical and thermal pain thresholds were measured. Ninety-three people with headache and 44 control individuals participated in the study. Headache patients completed a headache questionnaire. Pressure pain thresholds were measured over the forehead, upper neck, and at a remote site (tibialis anterior). Heat and cold pain thresholds were measured over the upper neck. In the headache group, 26 had headaches classifiable as migraine, 10 with tension-type, 24 with cervicogenic, and 33 headaches were unclassifiable. There were no significant differences between the headache groups and controls in pressure and cold pain thresholds (all P>0.05). Heat pain thresholds were significantly lower in the headache groups (all P<0.01) but there were no differences between headache types (all P>0.05). No strong relationships were found between any headache variables and pain thresholds. Central hyperexcitability does not seem to be a feature of elders with headache. This may be as a consequence of age-related changes in the sensory system but could also be related to the nature of the stimulus provided. Further research in this area is required to better understand pain processing in elders.
Article
The mechanisms underlying sensory hypersensitivity (SH) in acute whiplash associated disorders (WAD) are not well understood. We examined the extent of the relationships between the sensory measures of pressure pain threshold (PPT) and cold pain threshold (CPT), catastrophizing, pain and disability levels and gender in acute WAD. Thirty-seven subjects reporting neck pain following a motor vehicle accident were examined within five weeks post-injury. Measures of neck pain and disability (Neck Disability Index, NDI) and catastrophizing (Pain Catastrophizing Scale, PCS) were taken. CPT was assessed in the cervical spine and PPTs were assessed in the cervical spine (PPTcx) and at a remote site (PPTdistal). CPT and PCS were moderately correlated (r=0.46; p < 0.01); however there were no significant relationships between PPT (cervical and distal) and PCS. Both CPT (r=0.55, p < 0.01) and PPTcx (r=-0.42, p < 0.01) were significantly correlated with NDI but PPTdistal was not (r=-0.08, p=0.65). Finally, gender modulated the relationships between sensory measures, catastrophizing, and pain and disability levels. In conclusion, subjects with higher levels of catastrophizing presented with sensory hypersensitivity to cold stimuli in the acute phase of whiplash. Differences between genders are in accordance with the growing body of evidence suggesting that the relationships between some psychological factors and injury-related symptoms are modulated by gender.
Article
The aim of this study was to investigate whether generalized deep tissue hyperalgesia exists in patients with chronic unilateral lateral epicondylalgia (LE). A total of 26 LE patients (10 males and 16 females, aged 25 to 63 y) and 20 healthy comparable matched controls (aged 26 to 61 y) were recruited and pressure pain threshold (PPT) was assessed bilaterally over the median, ulnar, and radial nerve trunks, the lateral epicondyle, C5-C6 zygapophyseal joint, and the tibialis anterior muscle in a blind design. PPT was significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the lateral epicondyle, the C5-C6 zygapophyseal joint, and tibialis anterior muscle in patients with LE than healthy controls (all P<0.001). PPTs over those measured points was negatively related to current elbow pain intensity (all P<0.05). A more significant decrease in PPTs were present in females (all P<0.05). This revealed a widespread mechanical hypersensitivity in patients with LE, which suggest that central sensitization mechanisms are involved in patients with unilateral LE. The generalized decrease in PPT levels was associated with elbow pain intensity, supporting a role of peripheral sensitization mechanisms in the initiation or maintenance of central sensitization mechanisms. In addition, females may be more prone to the development of generalized mechanical hypersensitivity.
Article
In contrast to the increasing knowledge of the sensory dysfunction involved in chronic whiplash associated disorders, the use of comprehensive quantitative sensory testing in the acute stage of the condition is sparse. In this study, we sought to investigate the presence of sensory hypoesthesia in participants with acute whiplash injury. Fifty-two volunteers within 4 weeks after a motor vehicle accident and 31 healthy asymptomatic volunteers were recruited for this study. We classified our cohort into either a "high-risk" (n=17; signs associated with poor recovery including Neck Disability Index scores >30, cold and mechanical hyperalgesia, heightened brachial plexus provocation test responses) or "low-risk" group (without these signs). Detection thresholds to electrical, thermal, and vibration stimuli measured in lower cervical nerve root innervation zones and psychologic distress and posttraumatic stress symptoms were compared between the groups using multivariate analysis of covariance. Both the high-risk and low-risk groups exhibited significant elevation in sensory detection when compared with controls (P<0.05). There was no difference in detection thresholds between the 2 whiplash groups, except for electrical detection which was greater in the high-risk group (P>0.05). Both groups were psychologically distressed. Our findings demonstrate generalized hypoesthesia in acute whiplash associated disorders suggesting adaptive central nervous system processing mechanisms are involved, regardless of pain and disability. The elevated levels of psychologic distress seen in both groups may also play a role.
Article
Local sensitization to noxious stimuli has been previously described in acute whiplash injury and has been suggested to be a risk factor for chronic sequelae following acute whiplash injury. In this study, we prospectively examined the development of tender points and mechano-sensitivity in 157 acute whiplash injured patients, who fulfilled criteria for WAD grade 2 (n=153) or grade 3 (n=4) seen about 5 days after injury (4.8+/-2.3) and who subsequently had or had not recovered 1 year after a cervical sprain. Tender point scores and stimulus-response function for mechanical pressure were determined in injured and non-injured body regions at specific time-points after injury. Thirty-six of 157 WAD grade 2 patients (22.9%) had not recovered, defined as reduced work capacity after 1 year. Non-recovered patients had higher total tender point scores after 12 (p<0.05), 107 (p<0.05) and 384 days (p<0.05) relative to those who recovered. Tenderness was found in the neck region and in remote areas in non-recovered patients. The stimulus-response curves for recovered and non-recovered patients were similar after 12 days and 107 days after the injury, but non-recovered patients had steeper stimulus-response curves for the masseter (p<0.02) and trapezius muscles (p<0.04) after 384 days. This study shows early mechano-sensitization after an acute whiplash injury and the development of further sensitization in patients with long-term disability.
Article
Clinical, field, and experimental studies of response to potentially stressful life events give concordant findings: there is a general human tendency to undergo episodes of intrusive thinking and periods of avoidance. A scale of current subjective distress, related to a specific event, was based on a list of items composed of commonly reported experiences of intrusion and avoidance. Responses of 66 persons admitted to an outpatient clinic for the treatment of stress response syndromes indicated that the scale had a useful degree of significance and homogeneity. Empirical clusters supported the concept of subscores for intrusions and avoidance responses.
Article
Injuries to the cervical spine, especially those involving the soft tissues, represent a significant source of chronic disability. Methods of assessment for such disability, especially those targeted at activities of daily living which are most affected by neck pain, are few in number. A modification of the Oswestry Low Back Pain Index was conducted producing a 10-item scaled questionnaire entitled the Neck Disability Index (NDI). Face validity was ensured through peer-review and patient feedback sessions. Test-retest reliability was conducted on an initial sample of 17 consecutive "whiplash"-injured patients in an outpatient clinic, resulting in good statistical significance (Pearson's r = 0.89, p less than or equal to .05). The alpha coefficients were calculated from a pool of questionnaires completed by 52 such subjects resulting in a total index alpha of 0.80, with all items having individual alpha scores above 0.75. Concurrent validity was assessed in two ways. First, on a smaller subset of 10 patients who completed a course of conservative care, the percentage of change on NDI scores before and after treatment was compared to visual analogue scale scores of percent of perceived improvement in activity levels. These scores correlated at 0.60. Secondly, in a larger subset of 30 subjects, NDI scores were compared to scores on the McGill Pain Questionnaire, with similar moderately high correlations (0.69-0.70). While the sample size of some of the analyses is somewhat small, this study demonstrated that the NDI achieved a high degree of reliability and internal consistency.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Two studies are presented that investigated 'fear of movement/(re)injury' in chronic musculoskeletal pain and its relation to behavioral performance. The 1st study examines the relation among fear of movement/(re)injury (as measured with the Dutch version of the Tampa Scale for Kinesiophobia (TSK-DV)) (Kori et al. 1990), biographical variables (age, pain duration, gender, use of supportive equipment, compensation status), pain-related variables (pain intensity, pain cognitions, pain coping) and affective distress (fear and depression) in a group of 103 chronic low back pain (CLBP) patients. In the 2nd study, motoric, psychophysiologic and self-report measures of fear are taken from 33 CLBP patients who are exposed to a single and relatively simple movement. Generally, findings demonstrated that the fear of movement/(re)injury is related to gender and compensation status, and more closely to measures of catastrophizing and depression, but in a much lesser degree to pain coping and pain intensity. Furthermore, subjects who report a high degree of fear of movement/(re)injury show more fear and escape/avoidance when exposed to a simple movement. The discussion focuses on the clinical relevance of the construct of fear of movement/(re)injury and research questions that remain to be answered.
Article
Psychological distress is a feature of chronic whiplash-associated disorders, but little is known of psychological changes from soon after injury to either recovery or symptom persistence. This study prospectively measured psychological distress (General Health Questionnaire 28, GHQ-28), fear of movement/re-injury (TAMPA Scale of Kinesphobia, TSK), acute post-traumatic stress (Impact of Events Scale, IES) and general health and well being (Short Form 36, SF-36) in 76 whiplash subjects within 1 month of injury and then 2, 3 and 6 months post-injury. Subjects were classified at 6 months post-injury using scores on the Neck Disability Index: recovered (<8), mild pain and disability (10-28) or moderate/severe pain and disability (>30). All whiplash groups demonstrated psychological distress (GHQ-28, SF-36) to some extent at 1 month post-injury. Scores of the recovered group and those with persistent mild symptoms returned to levels regarded as normal by 2 months post-injury, parallelling a decrease in reported pain and disability. Scores on both these tests remained above threshold levels in those with ongoing moderate/severe symptoms. The moderate/severe and mild groups showed elevated TSK scores at 1 month post-injury. TSK scores decreased by 2 months in the group with residual mild symptoms and by 6 months in those with persistent moderate/severe symptoms. Elevated IES scores, indicative of a moderate post-traumatic stress reaction, were unique to the group with moderate/severe symptoms. The results of this study demonstrated that all those experiencing whiplash injury display initial psychological distress that decreased in those whose symptoms subside. Whiplash participants who reported persistent moderate/severe symptoms at 6 months continue to be psychologically distressed and are also characterised by a moderate post-traumatic stress reaction.
Article
To assess both regional (vulvar) and overall (generalized) pain sensitivity in women with vulvodynia to determine whether both are increased, suggestive of altered central pain processing. Seventeen patients (aged 18-60 years) with vulvodynia and 23 age-matched control subjects were included in this cross-sectional study. Pressure pain thresholds in the vulvar area were evaluated in 23 defined locations using a newly developed vulvodolorimeter. Peripheral pressure pain sensitivity was assessed by applying 1) continuously ascending pressures to 3 bilateral locations (thumb, deltoid, and shin), and 2) discrete pressure stimuli to the thumb using both an ascending and random sequence of varying pressures. Pain thresholds at all vulvar locations were lower in the women with vulvodynia than in pain-free control subjects. Similarly, peripheral pain thresholds were lower at the thumb in women with vulvodynia when obtained by discrete ascending or random staircase paradigms, as well as at the thumb, deltoid, and shin when tested by dolorimeter (P <.05). Findings were similar in both those with generalized vulvar dysesthesia and those with localized vestibulodynia. The quantitative results obtained with the vulvodolorimeter and with the more subjective cotton-tipped swab testing routinely used in diagnosis were strongly correlated. Women with vulvodynia displayed significantly increased pressure pain sensitivity in both the vulvar region and in peripheral body regions, suggesting a "central" component to the mechanisms mediating this disorder. Both the novel vulvodolorimeter and the thumb pressure stimulator may assist in future experimental tests of this and related hypotheses.
Article
To investigate sensory changes present in patients with chronic whiplash-associated disorders and chronic idiopathic neck pain using a variety of quantitative sensory tests to better understand the pain processing mechanisms underlying persistent symptoms. A case control study was used with 29 subjects with chronic whiplash-associated disorders, 20 subjects with chronic idiopathic neck pain, and 20 pain-free volunteers. Pressure pain thresholds were measured over the articular pillars of C2-C3, C5-C6, the median, radial, and ulnar nerve trunks in the arm and over a remote site, the muscle belly of tibialis anterior. Heat pain thresholds, cold pain thresholds, and von Frey hair sensibility were measured over the cervical spine, tibialis anterior, and deltoid insertion. Anxiety was measured with the Short-Form of the Spielberger State Anxiety Inventory. Pressure pain thresholds were decreased over cervical spine sites in both subject groups when compared with controls (P < 0.05). In the chronic whiplash-associated disorders group, pressure pain thresholds were also decreased over the tibialis anterior, median, and radial nerve trunks (P < 0.001). Heat pain thresholds were decreased and cold pain thresholds increased at all sites (P < 0.03). No differences in heat pain thresholds or cold pain thresholds were evident in the idiopathic neck pain group at any site compared with the control group (P > 0.27). No abnormalities in von Frey hair sensibility were evident in either neck pain group (P > 0.28). Both chronic whiplash-associated disorders and idiopathic neck pain groups were characterized by mechanical hyperalgesia over the cervical spine. Whiplash subjects showed additional widespread hypersensitivity to mechanical pressure and thermal stimuli, which was independent of state anxiety and may represent changes in central pain processing mechanisms. This may have implications for future treatment approaches.
Article
Hypersensitivity to a variety of stimuli has been shown in whiplash associated disorders and may be indicative of peripheral nerve involvement. This cross-sectional study utilised Quantitative sensory testing (QST) including vibration, thermal, electrical detection thresholds as an indirect measure of primary afferents that mediate innocuous and painful sensation. Pain thresholds and psychological distress (SCL-90-R) were also measured. Thirty-one subjects with chronic whiplash (>3 months, NDI: 49+/-17) and 31 controls participated. The whiplash group demonstrated elevated vibration, heat and electrical detection thresholds at most hand sites compared to controls (p<0.05). Electrical detection thresholds in the lower limb were no different from controls (p=0.83). Mechanical and cold pain thresholds were lower in the whiplash group (p<0.05) with no group difference in heat pain thresholds (p>0.1). SCL-90 scores were higher in the whiplash group but did not impact on any of the sensory measures. A combination of pain threshold and detection measures best predicted the whiplash group. Sensory hypoaesthesia and hypersensitivity co-exist in the chronic whiplash condition. These findings may indicate peripheral afferent nerve fibre involvement but could be a further manifestation of disordered central pain processing.
Article
Whiplash is a heterogeneous condition with some individuals showing features suggestive of neuropathic pain. This study investigated the presence of a neuropathic pain component in acute whiplash using the Self-reported Leeds Assessment of Neuropathic Signs and Symptoms' scale (S-LANSS) and evaluated relationships among S-LANSS responses, pain/disability, sensory characteristics (mechanical, thermal pain thresholds, and Brachial plexus provocation test (BPPT) responses) and psychological distress (General Health Questionnaire-28 (GHQ-28)). Participants were 85 people with acute whiplash (<4 weeks) (54 females, age 36.27+/-12.69 years). Thirty-four percent demonstrated a predominantly neuropathic pain component (S-LANSS>or=12). This group showed higher pain/disability, cold hyperalgesia, cervical mechanical hyperalgesia, and less elbow extension with the BPPT (p<0.03) when compared to the group with non-neuropathic pain (S-LANSS<or=12). Pressure pain thresholds (PPTs) at distant sites and psychological distress (GHQ-28) were not different between the groups (p>0.09). None of the S-LANSS items could discriminate those with cold hyperalgesia (p=0.06). A predominantly neuropathic pain component is related to a complex presentation of higher pain/disability and sensory hypersensitivity. The S-LANSS may be a useful tool and the BPPT a useful clinical test in the early assessment of whiplash.
Introduction to data mining
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