Tonic cuff pressure pain sensitivity in chronic pain patients and its relation to self-reported physical activity.

OBJECTIVES: Physical inactivity is a global health concern and a significant problem among chronic pain patients. They often experience pain flare-ups when they try to increase their physical activity level. Most research on the relationship between pain sensitivity and physical activity has been on healthy participants. Data on chronic pain patients are lacking. Using cuff pressure algometry, this study investigated tonic cuff pressure pain sensitivity and its associations to self-reported physical activity and other patient-reported outcomes in chronic pain patients. METHODS: Chronic pain patients (n=78) were compared to healthy controls (n=98). Multivariate data analysis was used to investigate the associations between tonic cuff pressure pain sensitivity, physical activity, and other patient-reported outcome measures. RESULTS: The three most important variables for group discrimination were perceived health status (EQVAS: p(corr)=-0.85, i.e., lower in patients), depression (HADS-D: p(corr)=0.81, i.e., higher in patients), and the tonic cuff pressure pain sensitivity variable maximum pain intensity (VAS-peak-arm: p(corr)=0.75, i.e., higher in patients). In patients, the most important predictors for high VAS-peak-arm were female sex (p(corr)=-0.75), higher number of painful regions (p(corr)=0.72), higher pain intensity (p(corr)=0.55), followed by lower level of self-reported physical activity (p(corr)=-0.39). VAS-peak-arm in patients correlated negatively with self-reported physical activity (rho=-0.28, p=0.018). CONCLUSIONS: Physical activity may be the most important patient-changeable variable correlating to pain sensitivity. This study highlights the importance of more research to further understand how increased physical activity may decrease pain sensitivity in chronic pain patients.

Patients' Expectations Before Initiation of Intrathecal Baclofen Treatment: A Longitudinal Study with 1-Year Follow-Up.

OBJECTIVE: To investigate patients' expectations, met/unmet expectations and satisfaction with intrathecal baclofen treatment in relation to effect on spasticity, pain intensity, sleep quality, occupational performance, well-being and self-efficacy. DESIGN: A prospective longitudinal study with follow-up at 1 year. PATIENTS: Consecutive patients, age ≥ 18 years with a disabling spasticity of cerebral or spinal origin selected for intrathecal baclofen treatment at 2 university hospitals in Sweden were included. From August 2016 to June 2019, 35 patients began intrathecal baclofen treatment; 29 patients were included and completed the study. METHODS: Baseline and 1-year follow-up included assessment of spasticity by physiotherapists, a semi-structured interview regarding occupational performance using the Canadian Occupational Performance Measure and a questionnaire. RESULTS: Overall satisfaction with treatment and satisfaction with occupational performance were reported as moderate. Important variables that explained satisfaction with occupational performance were improvements in performance, expectations and performance before treatment. Patients had higher expectations compared with the 1-year outcomes regarding occupational performance, spasticity, pain intensity and sleep quality, although improvements were reported. CONCLUSION: A thorough discussion of goal setting with intrathecal baclofen treatment before implantation is necessary to give patients individual and realistic expectations.

Pain Tolerance in Chronic Pain Patients Seems to be More Associated with Physical Activity than with Depression and Anxiety.

OBJECTIVE: To explore the associations between habitual self-reported physical activity, pain sensitivity and patient-reported outcomes (including pain intensity) in patients with chronic pain. DESIGN: Cross-sectional, experimental study. SUBJECTS: Patients (n = 78), age range 18-65 years, with different chronic pain conditions (> 3 months) were compared with age- and sex-matched healthy controls (n = 98). METHODS: Multivariate correlations between self-reported physical activity, pressure pain sensitivity, and patient-reported outcome measures were assessed. RESULTS: Lower perceived health status (p < 0.001, Cohen's d = 2.34), higher levels of depression (p < 0.001, Cohen's d = 1.77), and lower pain tolerance threshold (p < 0.001, Cohen's d = 1.66) were the most prominent variables discriminating patients from controls. In patients, bivariate and multivariate analyses showed that higher pressure pain tolerance was associated with male sex, lower pain intensity and fewer painful regions, higher self-efficacy and more self-reported physical activity, but not with lower levels of anxiety and depression. CONCLUSION: Pain tolerance thresholds, as well as degree of depression and perceived health status discriminated between patients and controls, and there was an association between pain tolerance thresholds and level of self-reported physical activity in patients. This study highlights the importance of further research into how increased physical activity may improve pain sensitivity in patients with chronic pain.

Dosing Patterns In Treatment of Disabling Spasticity With Intrathecal Baclofen.

PURPOSE: The aim of this study was to describe and analyze dosing patterns for patients with ITB treatment over time and to identify possible subgroups demonstrating diversity in patterns. DESIGN: A retrospective design. METHODS: For 81 patients from six different hospitals, baclofen doses from the first 2 years of treatment were identified using medical records. Line graphs of each patient's doses were analyzed and grouped based on similarities in dosing pattern. FINDINGS: The analyses of the dosing patterns resulted in four different subgroups classified as stable, slow increase, rapid increase, and fluctuating. CONCLUSION: The results highlight the clinical challenge of predicting dose development over time. CLINICAL RELEVANCE TO REHABILITATION NURSING: This study provides rehabilitation healthcare professionals with a better understanding of intrathecal baclofen dose development. Illustrations of the four subgroups can be used as an educational tool for patients, family, and caregivers.

Experiences from intrathecal baclofen treatment based on medical records and patient- and proxy-reported outcome: a multicentre study.

PURPOSE: To investigate patient satisfaction with intrathecal baclofen treatment, complications from the treatment, and the impact of general expectations on treatment outcome in relation to satisfaction. METHODS: A multicentre study with cross-sectional design. Data were collected through questionnaires and patient records. Patients were recruited from six outpatient intrathecal baclofen clinics in Sweden. Eighty-three patients who had been treated with intrathecal baclofen for 1-4 years were included. For patients unable to communicate, data were collected through a proxy. The Patient Global Impression of Change was used to measure patients' general satisfaction with change from intrathecal baclofen treatment. The Life Orientation Test - revised, was used to measure general expectations/optimism. RESULTS: General satisfaction with intrathecal baclofen treatment was high; 51/77 patients reported "much improved" or "very much improved." There was no relationship between the two main outcomes (general satisfaction and general expectations/optimism) (rs = 0.12, p = 0.382). The two groups; those who could and those who could not communicate, did differ regarding personal characteristics and should be evaluated as such. CONCLUSIONS: Most patients/proxies reported a high level of satisfaction with intrathecal baclofen treatment. The reported satisfaction with intrathecal baclofen treatment was not dependent on general expectations. Implications for Rehabilitation Patients with intrathecal baclofen treatment report low levels of health and quality of life at the same time as they are highly satisfied with their treatment. Intrathecal baclofen should be equally offered to both optimistic and less optimistic patients. Patients who are able to/not able to communicate, differs in characteristics and should be informed and followed up in different ways in daily clinical practice.

Cuff Pressure Pain Detection Is Associated with Both Sex and Physical Activity Level in Nonathletic Healthy Subjects.

PURPOSE: The aim of this study was to evaluate pressure pain sensitivity on leg and arm in 98 healthy persons (50 women) using cuff algometry. Furthermore, associations with sex and physical activity level were investigated. METHOD: Normal physical activity level was defined as Godin Leisure-Time Exercise Questionnaire (GLTEQ) score ≤ 45 and high activity level as GLTEQ > 45. A pneumatic double-chamber cuff was placed around the arm or leg where a single chamber was inflated. The cuff inflation rate (1 kPa/s) was constant, and pain intensity was registered continuously on a 10 cm electronic visual analogue scale (VAS). The pain detection threshold (PDT) was defined as when the pressure was perceived as painful, and pain tolerance (PTT) was when the subject terminated the cuff inflation. For PTT, the corresponding VAS score was recorded (VAS-PTT). The protocol was repeated with two chambers inflated. RESULT: Only single cuff results are given. For women compared with men, the PDT was lower when assessed in the arm ( P = 0.002), PTTs were lower in the arm and leg ( P < 0.001), and the VAS-PTT was higher in the arm and leg ( P < 0.033). Highly active participants compared with less active had higher PDT ( P = 0.027) in the leg. Women showed facilitated spatial summation ( P < 0.014) in the arm and leg and a steeper VAS slope (i.e., the slope of the VAS pressure curve between PDT and PPT) in the arm and leg ( P < 0.003). CONCLUSION: This study indicates that reduced pressure pain sensitivity is associated both with male sex and physical activity level.

Single-point but not tonic cuff pressure pain sensitivity is associated with level of physical fitness--a study of non-athletic healthy subjects.

Exercise is often used for pain rehabilitation but the link between physical activity level and pain sensitivity is still not fully understood. Pressure pain sensitivity to cuff algometry and conditioned pain modulation (CPM) were evaluated in highly active men (n=22), normally active men (n=26), highly active women (n=27) and normally active women (n=23) based on the Godin Leisure-Time Exercise Questionnaire. Cuff pressure pain sensitivity was assessed at the arm and lower leg. The subjects scored the pain intensity on an electronic Visual Analogue Scale (VAS) during ten minutes with 25 kPa constant cuff pressure and two minutes with zero pressure. The maximal VAS score and area under the VAS-curve were extracted. Pressure pain thresholds (PPT) were recorded by manual pressure algometry on the ipsilateral tibialis anterior muscle before, during and after the tonic arm stimulation. Tonic cuff stimulation of the arm and leg resulted in higher VAS peak scores in women compared with men (p<0.04). In all groups the PPTs were reduced during and after the cuff stimulation compared with baseline (p=0.001). PPT were higher in men compared with women (p=0.03) and higher in highly physical active compared with normal active (p=0.048). Besides the well-known gender difference in pressure pain sensitivity this study demonstrates that a high physical fitness degree in non-athletic subjects is associated with increased pressure pain thresholds but does not affect cuff pressure pain sensitivity in healthy people.

Use of an adjustable hand plate in studying the perceived horizontal plane during simulated flight.

BACKGROUND: Quantitative data on spatial orientation would be valuable not only in assessing the fidelity of flight simulators, but also in evaluation of spatial orientation training. In this study a manual indicator was used for recording the subjective horizontal plane during simulated flight. METHODS: In a six-degrees-of-freedom hexapod hydraulic motion platform simulator, simulating an F-16 aircraft, seven fixed-wing student pilots were passively exposed to two flight sequences. The first consisted in a number of coordinated turns with visual contact with the landscape below. The visually presented roll tilt was up to a maximum 670. The second was a takeoff with a cabin pitch up of 100, whereupon external visual references were lost. The subjects continuously indicated, with the left hand on an adjustable plate, what they perceived as horizontal in roll and pitch. There were two test occasions separated by a 3-d course on spatial disorientation. RESULTS: Responses to changes in simulated roll were, in general, instantaneous. The indicated roll tilt was approximately 30% of the visually presented roll. There was a considerable interindividual variability. However, for the roll response there was a correlation between the two occasions. The amplitude of the response to the pitch up of the cabin was approximately 75%; the response decayed much more slowly than the stimulus. DISCUSSION: With a manual indicator for recording the subjective horizontal plane, individual characteristics in the response to visual tilt stimuli may be detected, suggesting a potential for evaluation of simulation algorithms or training programs.

Widespread pain hypersensitivity and facilitated temporal summation of deep tissue pain in whiplash associated disorder: an explorative study of women.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: The results indicated widespread hyperalgesia in chronic whiplash associated disorder and facilitated temporal summation outside the primary pain area, suggesting involvement of central sensitization.

Biochemical alterations in the trapezius muscle of patients with chronic whiplash associated disorders (WAD)--a microdialysis study.

The mechanisms behind the development of chronic trapezius myalgia in patients with whiplash associated disorders (WAD) appear to involve both peripheral and central components, but the specific contribution of alterations in muscle is not clear. Female patients with WAD and involvement of trapezius (N=22) and female controls (N=20; CON) were studied during an experiment compromised of rest (baseline), 20min repetitive low-force exercise and 120min recovery. Their interstitial concentrations of serotonin (5-HT), glutamate, lactate, pyruvate, potassium, interleukin-6 (IL-6), and blood flow were determined in the trapezius muscle using a microdialysis technique. Pressure pain thresholds (PPT) over trapezius and tibialis anterior muscles were also assessed. In WAD, we found signs of generalized hypersensitivity according to PPT. The WAD group had significantly higher interstitial [IL-6] and [5-HT] in the trapezius than the CON. [Pyruvate] was overall significantly lower in WAD, and with lactate it showed another time-pattern throughout the test. In the multivariate regression analysis of pain intensity [5-HT] was the strongest regressor and positively correlated with pain intensity in WAD. In addition, blood flow, [pyruvate], and [potassium] influenced the pain intensity in a complex time dependent way. These findings may indicate that peripheral nociceptive processes are activated in WAD with generalized hypersensitivity for pressure and they are not identical with those reported in chronic work-related trapezius myalgia, which could indicate different pain mechanisms.

Managing chronic whiplash associated pain with a combination of low-dose opioid (remifentanil) and NMDA-antagonist (ketamine).

The aim was to investigate the efficacy of a combination of low-dose remifentanil (REMI) and ketamine (KET) compared to the single drugs and placebo (P) on whiplash associated pain (WAD) in a double-blind, randomized, placebo-controlled, cross-over study. Twenty patients with chronic (>1 year) WAD were included. Four different drug combinations were tested in four sessions: placebo/placebo (P/P), placebo/remifentanil (P/REMI), ketamine/placebo (KET/P) and ketamine/remifentanil (KET/REMI). Target concentrations were 1 and 2ng/ml (stepwise) for remifentanil and 100ng/ml for ketamine. Habitual pain intensity was assessed on a visual analogue scale (VAS). Experimental pain was assessed with electrical stimulation (single and repeated) of tibialis anterior (TA) muscle, pressure pain algometry applied over infraspinatus (IS) and TA muscles and VAS scores after intramuscular hypertonic saline infusion in TA. KET/REMI significantly reduced habitual pain. KET/REMI infused at low REMI target concentration (1ng/ml) significantly elevated electrical intramuscular pain thresholds (single and repeated). Pain thresholds to electrical stimulation were similarly increased by both P/REMI and KET/REMI at 2ng/ml target concentration. Pressure pain thresholds were increased by both KET/REMI and P/REMI. VAS-scores after intramuscular saline were also similarly decreased by both REMI combinations. Seven out of 20 subjects were non-responders (<50% pain relief). No correlation was found between effects on spontaneous pain and experimental pain. KET/REMI showed an analgesic effect on habitual pain. Experimental pain was attenuated by both combinations containing the opioid, however, KET seemed to enhance the effect of REMI on electrical pain thresholds when a low REMI target concentration was used.

The responses to pharmacological challenges and experimental pain in patients with chronic whiplash-associated pain.

OBJECTIVES: This study evaluates the analgesic responses to intravenous administration of morphine, lidocaine, and ketamine and their relations to duration of chronic pain after whiplash trauma. In addition, experimental muscle pain sensitivity and its correlation to pain duration and pharmacological responses were assessed. METHODS: Thirty-three patients with diagnosed whiplash-associated disorder grade II in the chronic stage, according to the Quebec classification, were included. The pharmacological evaluation was performed in a randomized, double-blind, cross-over design and consisted of a 30-minute period of intravenous administration of morphine (0.3 mg/kg), lidocaine (5 mg/kg), ketamine (0.3 mg/kg), or placebo (isotonic saline). Intensity ratings of habitual pain on a visual analogue scale were taken before, during, and after the infusion. The patients were classified as nonresponders, placebo-responders, or responders (minimum 50% decrease of pain intensity) of the drugs. Pressure pain thresholds and intramuscular and cutaneous electrical stimulation pain thresholds were measured. The pain intensity during experimental muscle pain by intramuscular hypertonic saline was also recorded. Experimental pain assessments were performed on the lower legs outside the habitual painful area. RESULTS: Thirty patients completed the study; 2 were placebo responders and 10 were nonresponders. Of 18 responders, there were 15 morphine responders, 11 lidocaine responders, and 14 ketamine responders. In the patients with whiplash-associated disorder duration less than 2 years, 7 responded to morphine, 5 to lidocaine, and 8 to ketamine. In the patients with pain duration longer than 2 years, 8 responded to morphine, 6 to lidocaine, and 6 to ketamine. Thus, no pattern with respect to pain duration was found. Seventeen patients participated in the experimental pain assessment, and no significant differences in the variables of the intramuscular and cutaneous stimulation and intramuscular-induced pain with respect to response to the pharmacological challenges or whiplash-associated disorder duration existed. DISCUSSION: The pharmacological challenges identified subgroups of patients with chronic whiplash-associated disorder that might be considered before instituting therapeutic interventions or research. However, the pattern of responses to the pharmacological challenges did not show any clear relationships with pain duration or the experimental pain tests.