Notes: The two subgroups of WAD are based on a cluster analysis. The variables above the dotted line (ie, PPT, CPT, and HPT) were used to identify subgroups in the WAD group; the possible ranges concerning the thresholds are PPT 0–600 kPa, CPT 10°C–32°C, and HPT 32°C–50°C. For each instrument, the maximum value is given in brackets. For abbreviations, please see the Methods section. To the right is given the result of the statistical evaluation (Kruskal Wallis test) and post hoc tests if applicable. Abbreviations: WAD, whiplash-associated disorder; CON, control; PPT, pressurepain threshold; CPT, cold pain threshold; HPT, heat pain threshold; PRi, pain regions index; HADS-D, hospital anxiety and depression scale-depression; HADS-A, hospital anxiety and depression scale-anxiety ASi, anxiety sensitivity index; PASS, pain anxiety symptoms scale; PCS, pain catastrophizing scale; Rum, rumination; Magn, magnification; Helpl, helplessness; FABQ, fear-avoidance beliefs questionnaire; PSEQ, pain self- efficacy questionnaire; GSES, general self-efficacy scale; PDI, pain disability index; QOL, quality of life; PF, physical functioning; RP, role – physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role – emotional; MH, mental health; S, significant; NS, nonsignificant; NA, not applicable.
Abstract: Mechanical hyperalgesia defined as decreased pressurepain thresholds (PPTs) is commonly associated with pain. In this narrative review, we report the current state of the art within topographical pressure sensitivity maps. Such maps are based on multiple PPT assess- ments. The PPTs are assessed by an a priori defined grid with special focus on both spatial and temporal summation issues. The grid covers the muscle or the body region of interest using absolute or relative values determined from anatomical landmarks or anthropometric values. The collected PPTs are interpolated by Shepard or Franke and Nielson interpolation methods to create topographical pressure sensitivity maps. This new imaging technique has proven to be valuable in various disciplines including exercise physiology, neurology, physical therapy, occupational medicine, oncology, orthopedics, and sport sciences. The reviewed papers have targeted different body regions like the scalp, low back, neck–shoulder, and upper and lower extremities. The maps have delineated spatial heterogeneity in the pressurepain sensitivity underlining the different extents of pressurepain hyperalgesia in both experimentally induced and disease-associated pain conditions. Furthermore, various intervention studies have proven the utility of topographical pressurepain sensitivity maps. Topographical pressurepain sen- sitivity maps have contributed to revealing the efficacy of therapeutic, ergonomic, or training interventions that aim at reducing pain.
High velocity low amplitude (HVLA) thrust manipulation and mobilisation are commonly used by manual therapists to relieve spinal pain and improve mobility. The aim of this controlled, single blinded study was to investigate the effect of manipulation and mobilisation on pressure- pain thresholds (PPT) in the thoracic spine in an asymptomatic population. Subjects (N=96) were screened for tender thoracic segments, and PPT measurements were made using an electronic pressure algometer immediately before and after treatment intervention. Subjects were randomly allocated into three intervention groups, and received either a single high velocity extension thrust, thirty seconds of extension mobilisation, or thirty seconds of sham treatment (control) consisting of ‘laser acupuncture’. Within-group pre and post-intervention PPT values were analysed using dependent t-tests, revealing significant changes in the mobilisation (p<0.01) and manipulation (p=0.04) groups, but not the sham treatment group (p=0.88). Analysis of mean group changes with a one-way ANOVA and post-hoc analysis revealed a significant difference between the mobilisation and control group (p=0.01), but no significant difference between the manipulation and control group (p=0.67). Pre-post effect sizes in the mobilisation group were medium to large (d=0.72), small to medium for
Prushansky et al.  established that differences between around 20%-25% are required to indicate a true clinical difference in PPT, at least in the cervical spine. In the current study, differences in mechanical sensitiv- ity over the second metacarpal and the tibialis anterior muscle were superior to this value. In fact, current results were highly surprising as we showed that pianists with neck pain exhibit lower PPT levels over non-symp- tomatic points and normal over symptomatic areas. The presence of pressurepain hypersensitivity in distant pain-free areas indicates sensitization of the central ner- vous system in pianists suffering from neck pain; how- ever, the absence of pressure hyper-sensitivity over the symptomatic areas makes this assumption inconclusive. This was an unexpected finding as previous studies have found the presence of lower PPT over the cervical spine in patients with insidious neck pain  or whiplash- associated neck pain . Nevertheless, as central sensiti- zation is a dynamic condition influenced by multiple factors including the activity of peripheral nociceptive inputs,  it may be that different factors are involved in our results. The existence of sensitization
PPT, as a measure of deep mechanical pain sensitivity, was measured using an algometer (FDIX, Wagner Instruments, USA) with a 1 cm 2 rubber probe. The alg- ometer was validated and standardised against a Kistler Force Plate prior to use in this study (Pearson’s r = 0.99, p = .01). For measurement, the algometer was placed perpendicular to the skin and pressure was increased at a rate of 500 g/cm 2 per second, monitored real-time on the digital algometer display by the assessor. The partici- pant was asked to say “Yes” when the sensation of pres- sure first changed to pain, at which point the algometer was removed and the maximum pressure recorded. Single measurements at each site were taken following a standard pattern, repeated three times to obtain three measurements per site. This validated approach allowed sufficient rest time between measures at each site [34, 35]. We used a cut-off point of 10 kg/cm 2 for the forehead and scapula , and 12.5 kg/cm 2 for the lumbar and gastro- cnemius sites as this was the upper limit of the algometer. If the cut-off was reached, the cut-off value was used as the measurement for that site and the algometer removed. The average of the second and third measures was used for analysis . An increase in PPT represents a decrease in sensitivity.
Abstract: The aim of this study was to investigate the differences in cold pain threshold (CTh), pressurepain threshold (PPT), cold pain tolerance (CPTo) tests, and the level of self-efficacy when self-efficacy for diagnostic sensory testing was manipulated by verbal persuasion before a testing situation in persons with neck pain and in healthy controls. A randomized experimen- tal design was used. Twenty-one healthy volunteers and 22 individuals with either traumatic or nontraumatic chronic neck pain were recruited to participate in the study. The intervention consisted of two experimental verbal persuasion conditions: Increase self-efficacy and Decrease self-efficacy. The PPT was measured using a pressure algometer, the CTh was measured using a thermo test system, and CPTo was measured by submerging the participant’s hand in ice water up to the elbow joint. On three occasions, the participants reported their self-efficacy level in performing the sensory tests. In the chronic neck pain group, there were no differences in pain threshold or tolerance. There was a difference in the self-efficacy level after verbal persuasion between the experimental conditions. In the healthy control group, the CThs increased follow- ing the condition that aimed to increase self-efficacy. No other differences were observed in the healthy controls. A short verbal persuasion in the form of manipulative instructions seems to have a marginal effect on the individual’s self-efficacy levels in the chronic neck pain group and a slight influence on the results of sensory testing in healthy controls.
included 7 boys with FETTH, we could not compare pressurepain hypersen- sitivity between genders. Future stud- ies should analyze gender differences in these sensitization mechanisms. Fi- nally, another limitation of this study is that we can speculate on the mecha- nisms (peripheral or central) that are responsible for the increased mechan- ical pain sensitivity only over periph- eral nerves. Additional studies are re- quired to deﬁne the potential role of nerve tissue hypersensitivity in the perpetuation of central sensitization in children with tension-type headache.
extended position has been described as most efficient position for the elbow for measuring grip strength in patients with LE. 35 Maximum grip strength of the uninvolved side was also measured in the same position at baseline. Handle position of the dynamometer was selected by the patients based on their comfort level and what they could squeeze most effectively. The unit of measurement was kilograms (kgs). Pressurepain threshold (PPT) and pain levels were secondary outcome measures. PPT was measured using Tracker Freedom® Wireless algometry device. It consisted of a force gauge attached to a round 1cm 2 rubber tip which is screwed on to the rod. The pressure exerted on the rod was transmitted to the body and recorded by a computer. For this test, the patient was seated with their shoulder in neutral rotation and their elbow extended beside their body. Then the most palpably tender site around the lateral epicondyle that reproduced the patient’s pain and its corresponding point on the unaffected side were identified gently and marked to ensure that same site was used for repeated measures. The tip of algometer was applied perpendicular to the skin over the marked points, with pressure increasing at rate of 5N/sec (50kPa/sec). 36 The patients were instructed to say ‘stop’ or press the hand switch (held in untested hand) the instant sensation changed from comfortable pressure to slightly unpleasant pain 36 and device was removed from the skin. The unit of measurement was Newton/cm 2 . Intra-observer reliability of PPT has been shown to be excellent (ICC range 0.91-0.96) in LE population. 12 Both the devices were wireless and connected to the Tracker Manual software with the help of USB receiver connection. They were calibrated by the examiner before beginning the first test for each patient.
We examined whether a nocebo hyperalgesia to pressurepain could be induced by social observational learning in a female general population sample. There was no interac- tion between condition and ointment application. However, main effects for condition and ointment application on the pain ratings were observed. Planned comparisons revealed that, within the NC, participants reported more pain with as compared to without ointment, so a nocebo effect for the NC was observed. Unexpectedly, pain ratings in the CC with ointment were higher than without, so a pain increase after ointment application was observed in the CC too. Due to the unexpected pain increase with ointment in the CC, no interaction was observed. The pain ratings with ointment were higher in the NC than in the CC, indicating that the observation of the model had an additional effect on pain perception. Contrary to our hypothesis, in the NC, no cor- relation between the nocebo response and empathy, pain catastrophizing, hypochondriacal concerns, or the amount of bodily symptoms was observed. In contrast, in the CC,
maximum tolerable pressure level was reached (painpressure tolerance prior to CPT [PTo1]). Second, the subject then sub- merged the nondominant hand in the bath, maintaining the water level 1–2 cm above the wrist, spreading the fingers, and allowing water freely to circulate around the hand. The time to pain registration (cold pressor test pain threshold [CPP]) and time to pain tolerance (cold pressor test pain tolerance [CPTo]) were registered. Third, immediately after withdrawal of the hand from the bath, a second pressure algometry test at the dominant index finger was made (painpressure tolerance immediately after CPT [PTo2]). The difference in pressurepain thresholds was calculated as ∆ PTo = PTo2 - PTo1.
At the beginning of the experimental session, anthropo- metric measurements (height weight, skinfolds) were taken. A pressurepain test measurement procedure was then administered using a pressure algometer (Somedic AB, Farsta, Sweden, probe size of 1 cm 2 surface area) ap- plied at the bellies of the upper trapezius (UT), anterior deltoid (AD), and biceps brachii (BIC) muscle sites to identify PPT. Muscle sites were identified and marked prior to administering the pain tests to ensure that PPT was applied at the same place before and after the fa- tiguing task. In a seated position, the participant rested their right arm on a table with their shoulder flexed 90° and a straight elbow. Pressure was applied manually at a generally constant rate of 40 kPa/s . To allow for re- turn to baseline sensation but minimize fatigue recovery during the post-fatigue measurements , PPT trials were performed sequentially in the following order UT, AD, and lastly BIC, with 30-s rest in between each trial to the same muscle. This sequence was performed three times, resulting in three trials for each muscle. The par- ticipant was instructed to indicate when the sensation of pressure only changed to one of pressure and pain by pressing a button connected to the pressure algometer held in the opposite hand while keeping their eyes closed. With proper instructions, the pressure algometer technique to assess PPT has previously shown strong intra- observer , and strong test-retest reliability [16, 35].
of sex on DNIC is inconsistent. Some authors failed to ﬁ nd differences of DNIC between female and male healthy subjects (Baad-Hansen et al 2005; Bud et al 2005). Staud and colleagues (2003) observed a gender-speciﬁ c lack of DNIC upon thermal “wind-up”, ie, women yielded less reduction of temporal summation of repeated heat pain stimuli when the contralateral hand was immersed into hot water. Ge and colleagues (2004) used repeated injections of hypertonic saline into the trapezoid muscle as counterirritant and found that the temporal development of inhibition of phasic pressurepain differed between men and women. In both sexes DNIC diminished over time, but men exhibited longer-lasting DNIC than women. This study is particularly interesting as it shows that repeated ongoing pain states appear to reduce the recruit- ment of descending inhibition, especially in women. Based on these evidences it is possible that age and sex impact on neuronal plasticity of inhibitory pain systems leading to a generally greater risk for chronic pain in older women. The sample size of our study was, however, too small to statisti- cally estimate any variance of DNIC due to age or sex.
In an attempt to expand the research about the brain mechanisms of pain processing in recent years, studies have been conducted with the aid of refined neuroimag- ing techniques and paradigms of experimental pain in patients with musculoskeletal pain syndromes, such as fibromyalgia and complex regional pain [11, 16, 19–26]. These studies, performed using functional magnetic res- onance imaging (fMRI), demonstrated that adult patients with fibromyalgia (FM), a subclassification of IMP syn- dromes, tolerate a smaller amount of pressure (pain) and showed differences in brain activation patterns in cortical and subcortical areas related to pain, especially in the cortex of the cingulate, insula, S1 and S2, as well as brain volume changes, when compared to healthy controls, i.e. without complaints of chronic pain [11, 27, 28]. Studies with fMRI in adults that evaluated the aging effect on the brain showed changes in the pattern of gray and white matter in accordance with the age of patients with fibromyalgia, as well as a strong correlation between smaller amount of gray and white matter with greater sen- sitivity to pain . Lebel et al. suggest that changes resulting from chronic pain occurring at a time of intense development and neuroplasticity may modify the pain
(8 a.m.) by laboratory sessions, which were procedurally equal and designed to assess three domains, namely cortisol, atten- tion, and pain. At the beginning and end of each laboratory session, participants provided a saliva sample for later deter- mination of cortisol levels. Further, two attention-related tests (dot-probe task and eye-tracking paradigm with emotional facial stimuli), which allowed to check for in ﬂ uences of sleep on attentional measures, and a laboratory pain testing to examine effects of sleep on pain were implemented. Pain testing consisted of the assessment of pressurepain thresholds (PPTs), followed by the assessment of temporal summation of pain (TSP) and conditioned pain modulation (CPM). After the experimental pain test, participants completed the Situational Catastrophizing Questionnaire (SCQ; state version of pain catastrophizing) 21 to assess catastrophizing thoughts in rela- tion to the just experienced pain. At the end of the evening sessions, a portable PSG device was installed and a questionnaire to assess subjective sleep parameters (evening and morning protocols) was handed out. 22 At the beginning of the morning sessions, the PSG device was detached and a further laboratory session followed. Additional question- naires about sleep (Pittsburgh Sleep Quality Index (PSQI)) 23 and pain (Pain Catastrophizing Scale (PCS); trait version of pain catastrophizing) 24 as well as clinical pain (German Pain Questionnaire (DSF); assessment of pain intensity and pain duration in the sample of chronic pain patients) 25 were com- pleted at the end of the ﬁ rst morning session.
Mechanical pressurepain sensitivity of the thumb has been advocated as a good choice of a 'neutral' site for testing general pain sensitivity – i.e. a site at which general pain sensitivity can be assessed, unaffected by any local- ized tissue pain such as e.g. low-back pain [3,11]. Clauw et al.  reported a moderate correlation (ρ = 0.38-0.52) between pressurepain detection and tolerance thresholds of the thumb and physical function and pain in LBP suf- ferers. Pain sensitivity of the thumb and thenar muscles have also been used as an indicator of general pain sensi- tivity in reports of hyperalgesia in relation to vulvodynia , the peri-menstrual period  and myofacial jaw pain . Giesecke et al.  used mechanical pressure of the thumb in a study of chronic LBP and fibromyalgia to demonstrate increased pain sensitivity compared to pain-free controls.
On the first day, the bodyweight of the subject was mea- sured with the use of a digital scale. The subjects were asked to fast for at least 3 hours before each session. In each of the 10 sessions at baseline (BL), after a 10 min rest, a resting whole saliva sample was collected using the drain- ing method . The collection of saliva samples took place in a quiet room. The subjects were seated upright in a chair with the head slightly bent forward, and instructed to drool into a plastic cup for 10 min . The subjects were then asked to rate spontaneous pain (if any) on a 0- 10 numerical rating scale (NRS, 0 = no pain, 10 = most im- aginable pain). Then, pressurepain thresholds (PPT) and pressurepain tolerance levels (PPTol) of the left masseter and temporalis muscles were measured . Systolic and diastolic blood pressure (BP) and heart rate (HR) were also measured with the use of a digital blood pressure monitor (UA-767plus; A&D Medical, Abingdon, UK).
Despite various adjustments to the amplitude- modulated frequency (AMF) often used in clinical prac- tice to treat different injury or disease stages, studies have indicated that AMF does not influence hypoalgesia in healthy individuals [13,14], which suggests that the main parameter that should be adjusted is the carrier frequency of the current to affect the pain inhibitory mechanisms . A 2 kHz carrier frequency is often used to strengthen the muscles, and a 4 kHz frequency is used to produce analgesia. However, this conduct is based on therapists’ personal observations, equipment manuals  and not on controlled studies. Only one study  has compared the effect of the carrier fre- quencies of the interferential current on the pressurepain threshold in healthy individuals. This study demon- strated that a 1 kHz frequency provides a higher hypoalgesic response compared with 8 kHz or 10 kHz during and after IFC stimulation. However, the evidence on the use of IFC alone for decreasing pain remains in- sufficient. In addition, chronic low back pain appears to be linked to central sensitisation and a deficiency in the activation of the central pain inhibition mechanisms. Thus, these patients could possibly benefit from the use of IFC to relieve their symptoms. For these reasons, we decided to conduct a prospective randomized controlled study to assess the effects of IFC on pain at rest and dur- ing movement, and the disability in patients with chronic low back pain. This study also aims to assess if the use of IFC would reactivate the innate mechanism of
However, the Gorecki et al., (2011) review was limited because they were unable to evaluate PU descriptors for Category 1 PUs (the most prevalent PU Category) . A problem with research in this field is that there is a pau- city of research about pain associated with Category 1 PUs. Only one patient from the combined review sample had a Category 1 PU, the majority of patients had mul- tiple PUs of mixed categories. Furthermore, the system- atic review of patients’ experiences of pain and pressure ulceration highlighted that pain at skin sites was experi- enced by patients prior to PU development but was often not recognised as important by their health care professionals [3,6]. Patients felt that they were respon- sible for communicating pain and that their care pro- vider was responsible for attending to it, but patients’ views and concerns did not always prompt action and many healthcare professionals dismissed patients’ re- ports of pain at pressure areas [6,12].
After dropping 19 patients, the remaining patients showed significant reduction of Visual Analogue Scale Score in flupirtine and diclofenac as compared to control (p<0.0001). Pain relief was 69.8% for control and 90.2% and 90.5% for flupirtine and diclofenac, respectively. Side effects did not show any significant differences among the groups. Hence, oral flupirtine was proved to be equally effective as diclofenac. 11 Up till now, four triptans and flupirtine have been approved for the treatment of pedriatic acute migraine and TTH. 12 The efficacy of flupirtine maleate 100 mg thrice daily was compared to tramadol hydrochloriode 50 mg thrice daily in postoperative pain management for a period of 5 days by taking 113 volunteer patients. Out of them, 104 met the inclusion criteria and were further divided into two treatment groups. One group received flupirtine maleate orally whereas the other received tramadol hydrochloride orally. Significant reduction in pain score was found in the flupirtine group having equal efficacy to tramadol group but much less adverse effects were seen (7.4%). Hence, oral administration of both tramadol and flupirtine was found to be helpful in avoiding the adverse effects of opioids and NSAIDs. 13 In a rat model of prostate bone metastasis, both morphine (ED₅₀ = 0.74 mg/kg) and flupirtine (ED₅₀ = 3.32 mg/kg) caused dose-related anti- hyperalgesia at doses that did not cause sedation. Synergism was noted between flupirtine and morphine and addition of flupirtine to morphine improved morphine anti-hyperalgesia and reversed cancer-induced heat hyperalgesia. Hence, flupirtine in combination with low dose morphine was proved to manage pain caused by tumors growing in bone. 14 In another study, the analgesic efficacy of flupirtine MR 400 mg OD was found
had their pain worsened by vibration (Hollins et al., 2011). This correlational evidence is the basis for the current study: the application of vibration during pain will be manipulated to determine if its effect on pain depends on the context of pain at the time it is applied. If so, the direction of pain modulation could depend not on the parameters of the vibratory stimulus, but the timing of its application in relation to how pain intensity is changing. This problem will be tested by applying a vibratory stimulus only when pain is increasing or decreasing to measure its effects during different pain contexts. One alternative explanation of the previous results is that subjects who sensitize more rapidly to repetitive stimuli process pain differently in some central mechanism (e.g. at the spinal cord or early cortical levels) which alters the effect of vibration.