***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 
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    ***EXAMPLES*** 
    Input: & NA ; The  placebo effect of transcutaneous electrical stimulation was studied in 93 patients in a double‐blind cross‐over trial using a genuine stimulator and a placebo machine . Placebo analgesic effects occurred in 32 % of trials , as compared with 48 % for actual stimulation . The placebo  effect of the transcutaneous electrical stimulator is similar to the placebo effect that is noted in other double‐blind studies in which medicationms are used BACKGROUND AND PURPOSE The prescriptive validity of a treatment-oriented extension-mobilization category for patients with low back syndrome ( LBS ) was examined . SUBJECTS Of a total of 39 patients with LBS referred for physical therapy , 24 patients ( 14 male , 10 female ) , aged 14 to 50 years ( means = 31.3 , SD = 11.6 ) , were classified as having signs and symptoms indicating treatment with an extension-mobilization approach .  The remaining subjects were dismissed from the study . Patients in the extension-mobilization category were r and omly assigned to either an experimental ( treatment ) group ( n = 14 ) or a comparison group ( n = 10 ) . METHODS The experimental and comparison group subjects were treated with either mobilization and extension ( a treatment matched to the category ) or a flexion exercise regimen ( an unmatched treatment ) . Outcome was assessed with a modified Oswestry Low Back Pain Question naire administered initially and at 3 and 5 days after initiation of treatment . Data were analyzed with a 2 x 3 ( treatment group x treatment period ) analysis of variance . RESULTS The subjects ' rate of improvement , as indicated by the Oswestry question naire scores , was dependent on the treatment group to which they were assigned . Subjects treated with extension and mobilization positively responded at a faster rate than did those treated with a flexion-oriented program . CONCLUSION AND DISCUSSION This study illustrates that a priori classification of selected patients with LBS into a treatment category of extension and mobilization and subsequently treating the patients accordingly with specified interventions can be an effective approach to conservative management of selected patients Therapeutic trials often attempt to “ blind ” patient and investigator to the true nature of treatments received , reducing the influences of conscious or subconscious prejudices . In drug trials , this is accomplished with placebo tablets , but blinding in trials of physical treatments is more problematic . This issue arose in a clinical trial of transcutaneous electrical nerve stimulation ( TENS ) for patients with chronic low back pain . Several study design features were incorporated to promote blinding : use of sham TENS units visually identical with real units , exclusion of potential subjects with previous TENS experience , avoidance of a crossover design and use of identical visit frequency , instructions and modifications in electrode placement . Subjects were asked not to discuss treatments with the clinicians who performed outcome assessment s. Both patients and clinicians were asked to guess actual treatment assignments at the trial 's end . Every patient in the true TENS group believed the unit was functioning properly , but the degree of certainty varied . In the sham TENS group , 84 % also believed they had functioning units , but their certainty was significantly less than in the active treatment group . Differences in patient perceptions did not affect compliance , as the two groups had similar dropout rates , appointment compliance , days of TENS use and daily duration of TENS use . Clinicians guessed treatments correctly 61 % of the time ( as opposed to 50 % expected by chance ) , again suggesting partial success in blinding . These efforts at blinding may partly explain the negative trial results for TENS efficacy . We conclude that complete blinding is difficult to achieve because of sensory difference in treatment and unintended communication between patient and examiner . Nonetheless , trials of physical treatments can achieve partial blinding with the techniques described here , and the success of blinding can be assessed with simple questions at study completion OBJECTIVES To determine the efficacy of a complementary analgesic modality , percutaneous electrical nerve stimulation ( PENS ) , for the treatment of chronic low back pain ( CLBP ) in community-dwelling older adults . DESIGN R and omized , controlled clinical trial . SETTING University of Pittsburgh Pain Evaluation and Treatment Institute . PARTICIPANTS Thirty-four English speaking , community-dwelling adults aged 65 and older with CLBP of at least moderate intensity experienced every day or almost every day . INTERVENTION Subjects were r and omized to receive twice-weekly PENS and physical therapy ( PT ) or sham PENS and physical therapy for 6 weeks . MEASUREMENTS At baseline , immediately after the 6-week intervention period , and 3 months later , the primary outcome measures pain intensity and pain-related disability were assessed . The secondary outcome measures physical performance ( timed chair rise , functional reach , gait speed , static and isoinertial lifting ) , psychosocial factors ( mood , sleep , and life control ) , and cognitive function ( measures of attention , concentration , and mental flexibility ) were also collected . RESULTS Subjects r and omized to PENS plus PT displayed significant reductions in pain intensity measures from pre- to posttreatment ( P < .001 ) , but the sham PENS plus PT group did not ( P = .94 ) . These pain reduction effects were maintained at 3-month follow-up . Similarly , significant reductions in pain-related disability were observed at posttreatment ( P = .002 ) for the PENS plus PT group and were maintained at follow-up , but the sham PENS plus PT group did not show reductions in pain-related disability ( P = .81 ) . Of the secondary outcome measures , psychosocial function , timed chair rise , and isoinertial lifting endurance also improved significantly at posttreatment for the PENS plus PT group , and their improvement was sustained at 3-month follow-up , but the sham PENS plus PT did not display significant changes on these measures after treatment . CONCLUSION This preliminary study suggests that PENS may be a promising treatment modality for community-dwelling older adults with CLBP , as demonstrated by reduction in pain intensity and self-reported disability , and improvement in mood , life control , and physical performance . Larger studies with longer duration of follow-up are needed to vali date these findings and support the use of PENS in clinical practice OBJECTIVE To investigate to what extent a single 60-minute session of transcutaneous electrical nerve stimulation ( TENS ) would modify chronic clinical pain , acute experimental pain , and the flexion reflex evoked in chronic low back pain patients . STUDY DESIGN Thirty young subjects with chronic low back pain were r and omly allocated to two groups , receiving either TENS or placebo stimulation to the lumbosacral region for 60 minutes . The flexion reflex was elicited by an electrical stimulation applied to the subject 's right sole and recorded electromyographically from the biceps femoris and the tibialis anterior muscles . MAIN OUTCOME MEASURES Subjective sensation of low back pain and the electrically induced pain were measured by two separate visual analog scales , termed VAS(LBP ) and VAS(FR ) , respectively . Data obtained before , during , and 60 minutes after TENS and placebo stimulations were analyzed using repeated measures ANOVA . RESULTS The VAS(LBP ) score was significantly reduced to 63.1 % of the prestimulation value after TENS ( p<.001 ) , but the reduction was negligible after placebo stimulation ( to 96.7 % , p = .786 ) . In contrast , no significant change was found in the VASFR score ( p = .666 ) and the flexion reflex area ( p = .062 ) during and after stimulation within each group and between the two groups ( p = .133 for VASFR and p = .215 for flexion reflex area ) . CONCLUSIONS The same TENS protocol had different degrees of antinociceptive influence on chronic and acute pain in chronic low back pain patients BACKGROUND Electrical stimulation of peripheral nerves produces acute analgesic effects . This r and omized , sham-controlled , crossover study was design ed to evaluate the effect of differing duration s of electrical stimulation on the analgesic response to percutaneous electrical nerve stimulation in 75 consenting patients with low back pain . METHODS All patients received electrical stimulation for four different time intervals ( 0 , 15 , 30 , and 45 min ) in a r and om sequence over the course of an 11-week study period . All active percutaneous electrical nerve stimulation treatments were administered using alternating frequencies of 15 and 30 Hz three times per week for 2 consecutive weeks . The pre study assessment s included the health status survey short form question naire and 10-cm visual analog scale scores for pain , physical activity , and quality of sleep , with 0 being the best and 10 being the worst . The pain scoring was repeated 5 - 10 min after each 60-min study session and 24 h after the last treatment session with each of the four methods . The daily oral analgesic requirements were assessed during each of the four treatment blocks . At the end of each 2-week treatment block , the question naire was repeated . RESULTS Electrical stimulation using percutaneously placed needles produced short-term improvements in the visual analog scale pain , physical activity , and quality of sleep scores , and a reduction in the oral analgesic requirements . The 30-min and 45-min duration s of electrical stimulation produced similar hypoalgesic effects ( 48+/-21 % and 46+/-19 % , respectively ) and were significantly more effective than either 15 min ( 21+/-17 % ) or 0 min ( 10+/-11 % ) . The 30- and 45-min treatments were also more effective in improving physical activity and sleep scores over the course of the 2-week treatment period . In contrast to the sham treatment ( 0 min ) , the health status survey short form revealed that electrical stimulation for 15 to 45 min three times per week for 2 weeks improved patient function . CONCLUSION The recommended duration of electrical stimulation with percutaneous electrical nerve stimulation therapy is 30 min & NA ; It has recently been shown that ice massage of the web between the thumb and index finger produces significantly greater relief of dental pain than a placebo control procedure . These results indicate that ice massage may be comparable to transcutaneous electrical stimulation ( TES ) and acupuncture , and may be mediated by similar neural mechanisms . The purpose of this study was to examine the relative effectiveness of ice massage and TES for the relief of  low‐back pain . Patients suffering chronic low‐back pain were treated with both ice massage and TES . The order of treatments was balanced , and changes in the intensity of pain were measured with the McGill Pain Question naire ( MPQ ) . The results show that both methods are equally effective : based on the Pain Rating Index of the MPQ , 67–69 % of patients obtained pain relief greater than 33 % with each method . The results indicate that ice massage is an effective therapeutic tool , and appears to be more effective than TES for some patients . It may also serve as an additional sensory‐modulation method to alternate with TES to overcome adaptation effects . Evidence that cold signals are transmitted to the spinal cord exclusively by A‐delta fibers and not by C fibers suggests that ice massage provides a potential method for differentiating among the multiple feedback systems that mediate analgesia produced by different forms of intense sensory input A prospect i ve , r and omized , double-blind , placebo-controlled clinical trial was performed to investigate the efficacy of electrical muscle stimulation when combined with a therapist-guided , st and ardized exercise therapy program in the treatment of nonacute low back pain .  Eighty patients with low back pain of at least 6 weeks ' duration were r and omized into the following 2 groups : st and ardized exercise therapy with functional electrical muscle stimulation or st and ardized exercise therapy with placebo electrical stimulation . Subjects were evaluated at baseline , 2 months , and 6 months with a st and ardized back pain question naire and objective measurements of lumbar spine function .  Exercise therapy was continued for 6 months , but electrical stimulation was discontinued at the 2-month interval . Of the 80 patients initially enrolled , 42 discontinued or withdrew before completing the entire study protocol . At the 2-month follow-up interval , subjects in the treatment group had statistically significantly improved lumbar spine function compared with the control subjects . This effect continued during the last 4 months of the study after electrical stimulation had been discontinued . This suggests that electrical muscle stimulation can be an effective adjunctive treatment modality for nonacute low back pain . The effects of this combined therapy seem to last beyond the duration of electrical stimulation treatment Patients with acute or chronic low back pain were treated in a double-blind study that compared transcutaneous electrical nerve stimulation at intense levels and gentle , mechanically administered massage . Transcutaneous electrical nerve stimulation produced significantly greater pain relief , based on two measures of the McGill Pain Question naire , and significant improvement in straight leg raising . There were no significant differences between the two groups in backflexion scores . Pain-relief scores and range-of-motion scores were significantly correlated . The results indicate that pain-relief scores provide valuable information and can easily be obtained from patients for whom pain is a major symptom STUDY DESIGN A r and omized trial design ed to compare interferential therapy with motorized lumbar traction and massage management for low back pain in a primary care setting . OBJECTIVE To measure and compare the outcome of interferential therapy and management by motorized lumbar traction and massage . SUMMARY OF BACKGROUND DATA Management of low back pain by interferential therapy and motorized lumbar traction and massage is common in Germany . No reports of previous r and omized trials for the outcome from interferential therapy were found . METHODS Consenting patients were r and omly assigned into one of two groups . A pretreatment interview was performed by the patient using a computer-based question naire . It also incorporated the Oswestry Disability Index and a pain visual 
    Output:
    
However , in the other RCT , no statistically significant differences between treatment and control groups were shown for multiple outcome measures .
There is inconsistent evidence to support the use of TENS as a single treatment in the management of chronic LBP .