***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The aim of the multicentre study * entitled ` Description and Documentation of Painful States in Spinal Cord Injury Patients ' , in addition to the description and documentation of chronic pain and stressful dysaesthesiae in SCI patients , was the search for correlations between these symptoms and medical and psychosocial variables . To this end , the sample was selected to be as representative as possible . All patients referred for in-patient or out-patient treatment at the centres taking part were enrolled in the study in order of presentation , providing they gave consent and met the inclusion criteria . Psychosocial , medical and demographic data were elicited by a st and ardized battery of questions and a st and ardized physical examination , as were any chronic pain/dysaesthesiae ( P/D ) present in any localization . Among 901 patients , 34 % had no chronic pain or dysaesthesiae , 50 % had pain only , 11 % had painful dysaesthesiae and 5 % , non-painful but chronic and distressing dysaesthesiae . The intensity of P/D was noted as seven or more on a 10 cm visual analogue scale by 61 % of the patients affected and was experienced as rather or very distressing in 75 % of cases . Most ( 86 % ) P/D were located below the spinal lesion or in the transition zone . There were significant correlations between the presence of P/D and age on question ing and at onset of the paraplegia/tetraplegia , problems with rectal paralysis , expectations of life as a paraplegic/tetraplegic , and subjective assessment of changes in working life . Highly significant correlations were found with subjective distress result ing of paraplegia/tetraplegia as such , depressed mood and psychosomatic disturbances of wellbeing . Overall , among the selected variables of our study , we found that correlations between P/D and psychosocial variables were more frequent and closer than those between P/D and medical variables UNLABELLED Pain is a serious consequence of spinal cord injury ( SCI ) . Our aim was to investigate the temporal aspects of different types of pain following traumatic SCI and to determine possible predictors of neuropathic pain . Prospect i ve data on 90 patients were collected at 1 , 6 , and 12 months after traumatic SCI . The patients completed question naires on pain severity , descriptors , and impact and underwent clinical examination with bedside sensory testing .  Eighty-eight patients completed the 12-month follow-up . Approximately 80 % of patients reported any type of pain at all 3 time points . Neuropathic pain related to SCI increased over time , and musculoskeletal pain decreased slightly , with both being present in 59 % of patients at 12 months ; other neuropathic pain not related to SCI and visceral pain were present in 1 to 3 % . At-level neuropathic pain present at 1 month resolved in 45 % and below-level pain resolved in 33 % . Early ( 1 month ) sensory hypersensitivity ( particularly cold-evoked dysesthesia ) was a predictor for the development of below-level , but not at-level , SCI pain at 12 months . In conclusion , the present study demonstrates phenotypical differences between at-level and below-level SCI pain , which is important for future studies aim ing to uncover underlying pain mechanisms . PERSPECTIVE The finding that early sensory hypersensitivity predicts later onset of below-level central neuropathic pain may help to identify patients at risk of developing neuropathic pain conditions after traumatic spinal cord injury . Information about onset of pain may help to identify different phenotypes in neuropathic pain conditions & NA ; Central mechanisms related to referred muscle pain and temporal summation of muscular nociceptive activity are facilitated in fibromyalgia syndrome ( FMS ) patients . The present study assessed the effects of an NMDA‐antagonist ( ketamine ) on these central mechanisms . FMS patients received either i.v . placebo or ketamine ( 0.3 mg/kg , Ketalar ® ) given over 30 min on two separate occasions . Habitual pain intensity was assessed on a visual analogue scale ( VAS ) . Initially , 29 FMS patients received ketamine or isotonic saline to determine which patients were ketamine responders ( > 50 % decrease in pain intensity at rest by active drug on two consecutive VAS assessment s ) . Fifteen out of 17 ketamine‐responders were included in the second part of the study . Before and after ketamine or placebo , experimental local and referred pain was induced by intramuscular ( i.m . ) infusion of hypertonic saline ( 0.7 ml , 5 % ) into the tibialis anterior ( TA ) muscle . The saline‐induced pain intensity was assessed on an electronic VAS , and the distribution of pain drawn by the subject . In addition , the pain threshold ( PT ) to i.m . electrical stimulation was determined for single stimulus and five repeated ( 2 Hz , temporal summation ) stimuli . The pressure PT of the TA muscle was determined , and the pressure PT and pressure pain tolerance threshold were determined at three bilaterally located tenderpoints ( knee , epicondyle , and mid upper trapezius ) . VAS scores of pain at rest were progressively reduced during ketamine infusion compared with placebo infusion . Pain intensity ( area under the VAS curve ) to the post‐drug infusion of hypertonic saline was reduced by ketamine ( −18.4±0.3 % of pre‐drug VAS area ) compared with placebo ( 29.9±18.8 % , P<0.02 ) . Local and referred pain areas were reduced by ketamine ( −12.0±14.6 % of pre‐drug pain areas ) compared with placebo ( 126.3±83.2 % , P<0.03 ) . Ketamine had no significant effect on the PT to single i.m . electrical stimulation . However , the span between the PT to single and repeated i.m . stimuli was significantly decreased by the ketamine ( −42.3±15.0 % of pre‐drug PT ) compared with placebo ( 50.5±49.2 % , P<0.03 ) indicating a predominant effect on temporal summation . Mean pressure pain tolerance from the three paired tenderpoints was increased by ketamine ( 16.6±6.2 % of pre‐drug thresholds ) compared with placebo ( −2.3±4.9 % , P<0.009 ) . The pressure PT at the TA muscle was increased after ketamine ( 42.4±9.2 % of pre‐drug PT ) compared with placebo ( 7.0±6.6 % , P<0.011 ) . The present study showed that mechanisms involved in referred pain , temporal summation , muscular hyperalgesia , and muscle pain at rest were attenuated by the NMDA‐antagonist in FMS patients . It suggested a link between central hyperexcitability and the mechanisms for facilitated referred pain and temporal summation in a sub‐group of the fibromyalgia syndrome patients . Whether this is specific for FMS patients or a general phenomena in painful musculoskeletal disorders is not known Objectives : In chronic pain patients , impaired conditioned pain modulation ( CPM ) and exercise-induced hypoalgesia ( EIH ) have been reported . No studies have compared CPM and EIH in chronic musculoskeletal pain patients with high pain sensitivity ( HPS ) and low pain sensitivity ( LPS ) . Material s and Methods : On 2 days , manual pressure pain thresholds ( PPTs ) were recorded at the legs , arm , and shoulder in 61 chronic pain patients and they performed the cold pressor test , 2 exercise conditions ( bicycling and isometric contraction ) , and a control condition in a r and omized and counterbalanced order .  PPTs , pain tolerance , pain tolerance limit , and temporal summation of pain were assessed with cuff algometry before and after the tests . On the basis of a median split of the average PPTs for women and men , respectively , low ( LPS ; N=30 ) and high ( HPS ; N=31 ) pain-sensitivity groups were created . Results : At baseline , cuff PPT and pain tolerance were decreased and temporal summation of pain was increased in the HPS group ( P<0.02 ) . Cuff PPT increased and pain tolerance limit decreased after the cold pressor test and exercises in LPS ( P<0.001 ) . Temporal summation of pain was increased after bicycling in HPS ( P<0.005 ) . Pain tolerance increased after the cold pressor test and exercise in both groups ( P<0.001 ) . Discussion : CPM and EIH were partly impaired in chronic pain patients with high versus less pain sensitivity , suggesting that the CPM and EIH responses depend on the degree of pain sensitivity . This has clinical implication s as clinicians should evaluate pain sensitivity when considering treatment options utilizing the descending modulatory pain control OBJECTIVE . : To assess pain sensitivity and spreading hyperalgesia in lateral epicondylalgia ( LE ) . SUBJECTS . : Twenty-two women with LE , and 38 controls were included . OUTCOME MEASURES . : Computerized cuff pressure algometry was used for assessment of pressure-pain threshold and tolerance . The stimulus was applied using a single ( stimulation-area : 241 cm(2 ) ) or double-chambered ( stimulation-area : 482 cm(2 ) ) tourniquet on the arm and leg . Spatial summation was expressed as the ratio between pressure-pain thresholds to single and double cuff-chamber stimulation . During 10-minute constant pressure stimulation at intensity relative to the individual pain threshold , the pain intensity was continuously recorded using an electronic visual analogue scale ( VAS ) , and from this the degree of temporal summation was estimated . For LE , a Doppler ultrasound examination of the elbow was made to identify inflammation . RESULTS . : In LE compared with controls the pressure-pain threshold and tolerance were on average reduced by respectively 31 % ( nonsignificant ) and 18 % ( nonsignificant ) on the lower arm and by 32 % ( P < 0.05 ) and 22 % ( P < 0.05 ) on the lower leg ( spreading sensitization ) . Within the LE group , pressure-pain thresholds were on average reduced by 20 % ( P < 0.05 ) and pain tolerance by 10 % ( nonsignificant ) on the painful compared with the asymptomatic side . Spatial summation ( P < 0.01 ) and temporal summation ( P < 0.05 ) was facilitated in LE compared with controls . In LE patients without signs of peripheral inflammation assessed by Doppler ultrasound , temporal summation was significantly stronger than in patients with ongoing inflammation ( P < 0.01 ) . CONCLUSION . : Patients with LE may be subgrouped based on pain hypersensitivity and Doppler ultrasound into clinical ly meaningful subgroups with varying duration of symptoms and different degrees of central sensitization . These groups may require different pain management strategies OBJECTIVE To examine possible deficiencies in endogenous pain modulating mechanisms in fibromyalgia patients compared with matched pain-free control subjects . DESIGN /SUBJECTS/ METHODOLOGY : Pain reduction was investigated in 25 female patients with fibromyalgia and 26 age-matched healthy women using the diffuse noxious inhibitory controls ( DNIC ) paradigm . Tonic thermal stimuli at painful and nonpainful intensities , tailored to individual heat pain thresholds , were employed to induce pain inhibition . The anticipated effect was assessed by measuring the electrical pain threshold and detection threshold , using a double staircase method . Only nontender control points were stimulated ( thermode on the foot , electrodes on the inner forearm ) . RESULTS The patients with fibromyalgia had significantly lower heat pain thresholds than the healthy subjects , but similar electrical detection and pain thresholds . The repeatedly applied electrical stimuli result ed in a degree of perceptual adaptation that was similar between the two groups . However , concurrent tonic thermal stimuli , at both painful and nonpainful levels , significantly increased the electrical pain threshold in the healthy subjects but not in the fibromyalgia patients . The electrical detection threshold was not affected in either group . CONCLUSIONS Pain modulation , produced by a concurrent tonic stimulus in healthy persons , was not seen in the fibromyalgia group . The patients either had deficient pain modulation or were unable to tolerate a tonic stimulus intense enough to engage a modulatory process . It remains to be established whether the pain reduction found in the healthy subjects was the conventional DNIC effect , another effect ( e.g. , distraction ) , or a combination of both & NA ; We have previously shown that fibromyalgia ( FMS ) patients have enhanced temporal summation ( windup ) and prolonged decay of heat‐induced second pain in comparison to control subjects , consistent with central sensitization . It has been hypothesized that sensory abnormalities of FMS patients are related to deficient pain modulatory mechanisms . Therefore , we conducted several analyses to further characterize enhanced windup in FMS patients and to determine whether it can be central ly modulated by placebo , naloxone , or fentanyl . Pre‐drug baseline ratings of FMS and normal control ( NC ) groups were compared with determine whether FMS had higher pain sensitivity in response to several types of thermal tests used to predominantly activate A‐delta heat , C heat , or cold nociceptors . Our results confirmed and extended our earlier study in showing that FMS patients had larger magnitudes of heat tap as well as cold tap‐induced windup when compared with age‐ and sex‐matched NC subjects . The groups differed less in their ratings of sensory tests that rely predominantly on A‐delta‐nociceptive afferent input . Heat and cold‐induced windup were attenuated by saline placebo injections and by fentanyl ( 0.75 and 1.5 & mgr;g/kg ) . However , naloxone 
    Output:
    
The results indicate that circumferential limb compression in patients most likely becomes painful at ∼10 - 18 kPa and can become unbearable even below 25 kPa .
In addition , the increase of pain with time tends to be significantly higher , and the adaptation to pain significantly lower , than in healthy subjects .
The results of this review provide guidance to design ers of wearable robotics for population s with chronic pain regarding rates and magnitudes of tissue compression that may be unacceptable to users