Enhanced Therapeutic Alliance Modulates Pain Intensity and Muscle Pain Sensitivity in Patients With Chronic Low Back Pain- Fuentes 2013

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Enhanced Therapeutic AllianceModulates Pain Intensity and Muscle

Pain Sensitivity in PatientsWith Chronic Low Back Pain:An Experimental Controlled StudyJorge Fuentes, Susan Armijo-Olivo, Martha Funabashi, Maxi Miciak, Bruce Dick,Sharon Warren, Saifee Rashiq, David J. Magee, Douglas P. Gross

Background. Physical therapy influences chronic pain by means of the specificingredient of an intervention as well as contextual factors including the setting and

therapeutic alliance (TA) between provider and patient.Objective. The purpose of this study was to compare the effect of enhanced

versus limited TA on pain intensity and muscle pain sensitivity in patients withchronic low back pain (CLBP) receiving either active or sham interferential currenttherapy (IFC).

Design. An experimental controlled study with repeated measures was con-ducted. Participants were randomly divided into 4 groups: (1) AL (n30), whichincluded the application of active IFC combined with a limited TA; (2) SL (n29),

which received sham IFC combined with a limited TA; (3) AE (n29), which receivedactive IFC combined with an enhanced TA; and (4) SE (n29), which received shamIFC combined with an enhanced TA.

Methods. One hundred seventeen individuals with CLBP received a single sessionof active or sham IFC. Measurements included pain intensity as assessed with anumerical rating scale (PI-NRS) and muscle pain sensitivity as assessed via pressurepain threshold (PPT).

Results. Mean differences on the PI-NRS were 1.83 cm (95% CI14.320.3),1.03 cm (95% CI6.612.7), 3.13 cm (95% CI27.233.3), and 2.22 cm (95%CI18.925.0) for the AL, SL, AE, and SE groups, respectively. Mean differences onPPTs were 1.2 kg (95% CI0.71.6), 0.3 kg (95% CI0.20.8), 2.0 kg (95% CI1.62.5), and 1.7 kg (95% CI1.32.1), for the AL, SL, AE, and SE groups, respectively.

Limitations. The study protocol aimed to test the immediate effect of the TAwithin a clinical laboratory setting.

Conclusions. The context in which physical therapy interventions are offeredhas the potential to dramatically improve therapeutic effects. Enhanced TA combined

with active IFC appears to lead to clinically meaningful improvements in outcomeswhen treating patients with CLBP.

J. Fuentes, PT, MScRS, PhD,Department of Physical Therapy,Faculty of Rehabilitation Medicine,University of Alberta, 3-48 CorbettHall, Edmonton, Alberta, CanadaT6G 2G4, and Department ofPhysical Therapy, Catholic Univer-sity of Maule,Talca, Chile.Addressall correspondence to Mr Fuentesat: [email protected].

S. Armijo-Olivo, PT, MSc, PhD,Faculty of Rehabilitation Medi-cine, University of Alberta.

M. Funabashi, PT, MSc, Faculty ofRehabilitation Medicine, Univer-sity of Alberta.

M. Miciak, PT, Faculty of Rehabil-itation Medicine, University of

Alberta.

B. Dick, PhD, Department of Anes-thesiology and Pain Medicine,University of Alberta.

S. Warren, PhD, Faculty of Reha-bilitation Medicine, University of

Alberta.

S. Rashiq, MSc(Epid), Departmentof Anesthesiology and Pain Medi-

cine, University of Alberta.

D.J. Magee, PT, PhD, Departmentof Physical Therapy, University of

Alberta.

D.P. Gross, PT, PhD, Departmentof Physical Therapy, University of

Alberta.

[Fuentes J, Armijo-Olivo S, Fun-abashi M, et al. Enhanced thera-peutic alliance modulates painintensity and muscle pain sensi-tivity in patients with chroniclow back pain: an experimentalcontrolled study. Phys Ther.

2014;94:477489.]

2014 American Physical TherapyAssociation

Published Ahead of Print:December 5, 2013

Accepted: November 26, 2013Submitted: April 2, 2013

Research Report

Post a Rapid Response tothis article at:ptjournal.apta.org

April 2014 Volume 94 Number 4 Physical Therapy f 477


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Nonspecific low back pain

(LBP) is defined as pain, mus-cle tension, or stiffness local-

ized below the costal margin of theback and above the inferior gluteal

folds, with or without leg pain (sci-atica).1 When LBP persists for 12weeks or more, the condition isdescribed as chronic (CLBP).2 Thiscondition is a highly prevalent prob-lem that represents a challenge forhealth care providers and society.35

Patients with CLBP are commonlytreated by physical therapists, yetthe mechanisms by which physi-cal therapy interventions influencechronic pain are complex. Variablesassociated with the clinician, pati-

ent, and setting may influence clini-cal outcomes in addition to the spe-cific physical interventions. Thesefactors make up the context andcan be described as nonspecific orcontextual.6 When contextual fac-tors positively influence clinical out-comes, they are known as contex-tual, nonspecific, or placebo effects.The placebo effect is thus the posi-tive psychosocial and neurobiologi-cal effect that the treatment context

has on clinical outcomes.7,8 Althoughin clinical practice both specificand nonspecific effects may worktogether, the quantification of the

placebo effect, or contextual factorsthat surround a therapy, has not tra-ditionally been a primary focus ofinvestigation in the physical therapyliterature. However, a comprehen-

sive analysis of all factors that poten-tially could influence physical thera-pys clinical efficacy is needed,especially in the management ofchronic pain.9

Among the diverse contextual fac-tors, the therapeutic alliance (TA) isfundamental to the therapeutic pro-cess and the placebo effect. The TAcan be defined as the working rap-port or positive social connectionbetween the patient and the thera-

pist.10 More specifically, during reha-bilitation, TA relies on a complexinterplay of technical skill, commu-nicative competence, and the reflec-tive capacity of the therapist torespond to the patient in the momentof therapy.11(p873) The TA is morethan the communication between thepatient and the therapist. For example,the TA involves the sense of collabo-ration, warmth, and support that arecritical aspects of this construct.12

The TA has been correlated with treat-ment adherence and positive out-comes in several disciplines, includingmedicine, psychotherapy, and physi-cal rehabilitation.1320 Although anidentifiable practitioner effect hasbeen documented in LBP and neckpain intervention trials,21 this phenom-enon has not been systematicallyinvestigated in treatments aimed atmodifying musculoskeletal pain. In

physical rehabilitation, a positive TAhas been correlated with improvedpain, reduced disability, and highertreatment satisfaction.20 Recently, theTA was found to be more stronglyassociated with disability and functioncompared with pain outcomes inCLBP.22 Experimental manipulation ofthe TA construct is needed to confirma causal effect during physical therapyintervention for musculoskeletal con-ditions. To date, no randomized con-

trolled study has adequately tested therole of TA in physical therapy clinicaloutcomes for CLBP.

In physical therapy, the application

of electrophysical agents is com-monly associated with therapeuticprocedures involving application oftechnologically impressive equip-ment. Because the placebo responseis influenced by the invasiveness ofthe procedure and the way the treat-ment is applied (ie, therapeuticdevice versus pill),2325 it is plausiblethat electrophysical agents may bemore prone to the influence of pla-cebo effects. The protocol of thisstudy was based on a previous study

that explored the active and placeboeffects of interferential current ther-apy (IFC) in experimentally con-trolled conditions.26 The results ofthe study suggested that IFC hassome clinical efficacy but that thetherapeutic context in which IFC

was applied influenced muscle painsensitivity.26 Therefore, the currentstudy attempted to confirm this find-ing in patients with chronic painfulconditions.

The aim of this study was to comparethe effect of an enhanced TA versusa limited TA on pain intensity andmuscle pain sensitivity in patients

with CLBP receiving either activeor sham IFC. Also, the use of IFCallowed us to apply an adequatesham intervention needed for 2 ofthe groups included in this study.

Method

The report of this trial followed theguidelines established for the CON-SORT statement.27

Study DesignThis was a double-blind, placebo-controlled experimental study withrepeated measures. Participants wererandomly divided into 4 groups:(1) AL (n30), which receivedactive IFC combined with a limitedTA; (2) SL (n29), which received

Available WithThis Article atptjournal.apta.org

eFigure:Carbon RubberElectrodes Placed Over Lumbarand Sacral Areas

eTable:Pair-wise ComparisonsAmong Groups for ExpectationsDifference and Therapeutic

Alliance

Avideoshowing the limited andenhanced clinician-patientinteractions used in the study.

Discussion Podcastwith PauloFerreira and author JorgeFuentes. Moderated by StevenGeorge.

Modulating Pain Intensity and Muscle Pain Sensitivity in Chronic Low Back Pain

478 f Physical Therapy Volume 94 Number 4 April 2014
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sham IFC combined with a limitedTA; (3) AE (n29), which receivedactive IFC combined with anenhanced TA; and (4) SE (n29),

which received sham IFC combinedwith an enhanced TA (Fig. 1).

All patients acknowledged theirunderstanding and willingness toparticipate by providing signed con-sent, but the consent disclosure

omitted certain descriptors andinformation about the methods toprotect the studys scientific validity.For example, neither the word pla-cebo nor the word sham wasmentioned. Also, to avoid biasingtheir opinions of interactions withthe treating therapist, participants

were not told about the different lev-els of TA associated with the treat-ments. Participants were informed

that the study was aimed at deter-mining the difference in effective-ness between the standard electro-therapy treatment for LBP (ie, activeIFC) and a new treatment based on asubthreshold level of electrical stim-ulation (ie, sham IFC).

RandomizationA randomization sequence stratifiedby sex was computer-generated by

Patients Meeting the InclusionCriteria

Randomization

Active IFC PlusLimited

TherapeuticAlliance (n=30)

ShamIFC PlusLimited


Active IFC PlusEnhanced


ShamIFC PlusEnhanced


PretreatmentAssessment of PainIntensity (PI-NRS)

Assessment of Disability (ODI)Assessment of Expectations (CEQ)

IFC TreatmentActive orSham

PosttreatmentAssessment of PainIntensity (PI-NRS)Assessment of Therapeutic Alliance

(PRES)

Figure 1.Flowchart and schematic sequence of the study procedure. IFCinterferential current therapy, PI-NRSpain intensity numericalrating scale, ODIOswestry Disability Index, CEQCredibility Expectancy Questionnaire, PRESPain Rehabilitation ExpectationsScale.




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a research assistant not involved inthe study. This assistant distributedthe results of the sequence into con-secutively numbered, opaque, andsealed envelopes. Participants were

allocated to the treatment groups bya physical therapist who opened thenext available envelope prior to eachtreatment session.

SettingThe study was conducted in thesports physical therapy laboratoryof the Faculty of Rehabilitation Med-icine at the University of Alberta,Edmonton, Canada. This laboratoryis located within an academic build-ing on the university campus. The

laboratory is also used for treatingvarsity and professional athletes.

Participants and RecruitmentVolunteers with CLBP were recruitedfrom the local community by a widelycirculated poster advertisement. Inclu-sion criteria were nonspecific LBP ofat least 3 months duration, resulting ina mild to moderate level of disability(Oswestry Disability Index 60%); apain intensity score between 3 and 8

points on a numerical rating scale (PI-NRS) ranging from 0 (no pain) to 10(worst possible pain); and agebetween 18 and 65 years. Exclusioncriteria were any contraindications tothe use of electrotherapy, neurologicalproblems (central or peripheral, suchas sciatica), concomitant physical ther-apy or chiropractic treatment, and pre-

vious experience with electrotherapy.Participants were asked to refrainfrom taking pain medications the day

of the treatment session.

All patients acknowledged theirunderstanding and willingness toparticipate by providing writteninformed consent, and each partici-pant was reimbursed CAD$20 forparticipating in the study.

InterventionBoth the AL and AE groups includedthe application of active IFC. The

intensity of the current was at sen-sory level.26,28 The frequency wasset at an amplitude-modulated fre-quency of 0 Hz.26,28 The participantsassigned to the SL and SE groups

received sham IFC treatment. Thisintervention was delivered using thesame equipment and the same elec-trode arrangement as per the activeIFC groups, except that the lead

wires of the equipment were discon-nected from the output channel jack.Thus, the participants received nocurrent output.

Output channel jacks were coveredduring the procedure, and the equip-ment screen displayed the same

visual and output signals as in theactive treatment groups. Thus, nei-ther the participant nor the assessor

was able to distinguish betweenactive and sham treatments.

The intensity of the current for treat-ment application was a strong butcomfortable sensory level, produc-ing a pins-and-needleslike sensa-tion without visible muscletwitches.26,28,29 During sham appli-

cation, the investigators instructionswere: Today, I am going to apply anew treatment called therapeuticsubthreshold current . . . as the levelof stimulation is subthreshold, youmight not be able to feel it beneaththe electrodes.

In order to create the same levelof positive treatment expectations,all participants received a similarinstructional set (verbal suggestions)

about the effectiveness of the inter-vention (ie, The intervention youare going to receive is an effectivepain-relieving treatment). Therefore,expectations were not manipulatedin an attempt to control the effect ofexpectations among groups.

AL group. In this group, a single30-minute session of active IFC wasapplied. The limited interactionincluded about 5 minutes during

which the therapist introduced her-self and explained the purpose of thetreatment. In addition, participants

were told that this was a scientificstudy in which the therapist had

been instructed not to converse withparticipants.30 After setting up thetreatment parameters, the therapistleft the room and returned 15 and 30minutes into the treatment to bepresent when the tester arrived toconduct outcome assessment.

SL group. In this group, the sameprotocol as described for the ALgroup was applied. The difference

was that a sham IFC intervention wasadministered.

AE group. In this group, a single30-minute session of active IFC wasapplied. During the first 10 minutes,each participant was questionedabout his or her symptoms and life-style and about the cause of his orher condition. The therapeutic inter-action was enhanced through verbalbehaviors, including active listening(ie, repeating the patients words,asking for clarifications), tone of

voice, nonverbal behaviors (ie, eyecontact, physical touch), and empa-thy (such as saying, I can under-stand how difficult LBP must befor you.). This intervention modelaimed to create an optimal patient-clinician relationship.30,31 The thera-pist then stayed in the room duringthe entire treatment and during themeasurement of outcomes. Duringthis time, verbal interaction betweenthe therapist and participant was

encouraged. Finally, at the end of thesession, few words of encourage-ment were given.

SE group. In this group, the sameprotocol as described for the AEgroup was applied. The difference

was that a sham IFC intervention wasused.

These treatment protocols wereadapted from a previous trial explor-




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ing the components of placeboeffect in acupuncture for irritablebowel syndrome.30

Therapists and Training Methods

Three female physical therapistsadministered the experimental treat-ments. Their average clinical experi-ence in the management of muscu-loskeletal disorders was 11.3 years.The therapists were formally trainedin methods of patient-clinician inter-actions by a clinical psychologist toensure they were able to createthe 2 different therapeutic contexts(ie, limited TA and enhanced TA).The therapists were instructed inadvance on the scripts for their inter-

actions by means of a training man-ual and by role playing with simu-lated patients.30Avideoshowing thelimited and enhanced clinician-patient interactions used in the studyis available online at ptjournal.apta.org.

Adherence to TreatmentProtocolsTherapist adherence was based onhow closely the therapists followed

the experimental protocol.30,32,33Therapist adherence was assessed by

videotaping all treatment sessions,of which 28 (20%) were randomlyselected for evaluation. Tworesearch assistants not involved withthe study separately rated each ses-sion regarding treatment fidelity.

ProcedureAt the beginning of the study, thetreatment procedure was explained

with a standard information sheet.Baseline measurements were thenconducted. Level of disability, painintensity, pressure pain thresholds(PPTs), and expectations of painrelief were assessed. Next, the IFCtreatment was applied. After com-pleting IFC treatment, pain intensityand expectations of pain relief wereassessed again. Also, participantscompleted a measure of TA and aglobal rating scale (GRS).

All measurements under the 4 treat-ment conditions were made by thesame trained investigator ( J.F.) who

was blind to the treatment appliedand to the statistical analysis. Partic-

ipants were blind to intervention sta-tus. To determine whether the activeand sham IFC treatments were per-ceived differently, the difference inexpectations of pain relief scoresat baseline among the 4 treatments

was calculated. In addition, after thesession ended, participants wereasked to guess the type of treatmentreceived (ie, active IFC or sham IFC).

Outcome MeasuresPain intensity. The PI-NRS is aself-report measure of pain inten-sity.34 The PI-NRS has been shownto be a reliable and valid measure ofpain severity in CLBP.35,36 The mini-mal clinically important difference(MCID) for LBP has been reported torange from 1.5 to 3.2 points.3741

Measurements of pain intensity (PI-NRS) were taken before treatment(ie, at baseline) and immediately fol-lowing the end of the intervention.

Pressure pain sensitivity. Pres-sure pain sensitivity is the most com-monly used method for quantitativeanalysis of local muscle pain and ten-derness in pain research.26,29,4244

Pressure pain sensitivity was evalu-ated via PPT, or the minimum pres-sure that induces pain or discom-fort.45 This evaluation was doneusing a calibrated mechanical algom-eter (Wagner Instruments, Green-

wich, Connecticut). Measurements

of PPT have been shown to havegood or excellent interrater (intra-class correlation coefficient [ICC].74.90)46 and intrarater reliability(ICC.75.99).4751 In addition, good

values of sensitivity (0.77 0.88) andspecificity (0.87 0.94) for condi-tions such as myofascial pain andfibromyalgia have been reported.52,53

The minimum important difference(MID) has been reported to be1.10 kg/cm2/s.26,54

Before conducting the PPT assess-ment, participants were instructedin the application of the algometerand given a demonstration. A trainedphysical therapist assessor ( J.F.)

measured the PPTs by applyingthe algometer at a constant rate offorce of 1 kg/cm2/s. The algometer

was applied perpendicularly overthe right erector spinae muscle,landmarked 4 cm to the right ofthe spinous process of L4 forreproducibility (eFigure, availableat ptjournal.apta.org). The forcerecorded was the minimum amountof pressure that evoked the first sen-sation of pain.55,56 Participants wereasked to say stop as soon as they

felt a clear sensation of pain, distinctfrom pressure or discomfort.

Measurements of PPT were takenon 4 different occasions during theexperimental procedure: M1 (10minutes before treatment), M2 (time0 or start of treatment), M3 (15 min-utes into treatment), and M4 (at 30minutes or end of treatment). Oneach occasion, 2 consecutive PPTmeasurements performed 60 sec-

onds apart were collected and aver-aged for analysis.

TA. The TA between the therapistand the patient was measured usingthe working alliance subscale of thePain Rehabilitation ExpectationsScale (PRES). The PRES is a self-report, clinical intervention-specificassessment tool developed to mea-sure proxy efficacy, motivation/ex-pectations, and working alliance for

rehabilitation interventions in patientswith LBP.57 Preliminary psychomet-ric results validated the factorialstructure of the PRES.57 In addition,high values of internal consistencyfor each subscale (proxy efficacy,.93; motivation/expectations,.95; and working alliance,.96)have been reported.57

Level of expectations. Partici-pants were asked to rate their expec-


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tations of pain relief using the Cred-ibility and Expectancy Questionnaire(CEQ). The CEQ comprises 6 items(2 sets) and 2 factors (ie, credibilityand expectancy). Items 1 to 3 mea-sure credibility, and items 4 to 6appraise expectancy.58 The CEQ isconsidered to be a valid and reliabletool59 to measure the expectancyconstruct. Expectations were assessed

before treatment (ie, at baseline) andimmediately after the intervention

was completed.

GRS. Clinical significance andwhether changes experienced weremeaningful from the participantsperspective were assessed using theGRS. Patients respond by estimatingthe degree of change in pain experi-enced on a 15-point Likert scale(7a very great deal worse,

0

about the same, and

7

avery great deal better).60 Changesof1 to 3 represent small changes,changes of4 to 5 represent mod-erate changes, and changes of6 to7 represent large changes.60

Data AnalysisA 2-way repeated-measures multivar-iate analysis of variance (MANOVA)

was used as the main test to evaluatethe differences in PI-NRS and PPTs

among treatment groups. In addi-tion, a MANOVA test was used toevaluate differences in TA and differ-ences in expectancies (before-aftertreatment) among groups after theinterventions. Furthermore, a corre-lation between TA and differencesin expectancies (before-after treat-ment) was conducted to determinethe relationship between these vari-

ables using the Kendall tau correla-tion coefficient. In order to deter-mine whether different therapists(ie, therapist effect) influenced the

way that participants responded tothe treatments, a 2-way MANOVA

was performed. A Bonferroni posthoc test was used to determine sig-nificance between pair-wise compar-isons. An a priori sample size of 116participants (ie, 29 per group) wascalculated for a 4-group MANOVA,

with repeated measures to detect achange of 2 points on the PI-NRSwith a power of 0.80, .05, and amoderate effect size of 0.75 usingestablished statistical guidelines.61

Calculation of effect size (Cohend)62

was conducted to determine themagnitude of the therapeutic effectand whether changes in outcomes

were clinically meaningful. In addi-tion, the calculation of MID has been

commonly reported in studies aimedat evaluating the magnitude of imme-diate analgesic effects (ie, shortfollow-up) for an intervention inacute LBP63 and CLBP.6466 There-fore, the MIDs for PPT and PI-NRS

were calculated from the GRS fol-lowing the guidelines established byGuyatt et al.60

SPSS version 17.0 (SPSS Inc, Chicago,Illinois) was used to perform the sta-tistical analysis. The level of signifi-cance was set at .05. The analyst

was blinded to treatment allocation.

Role of the Funding SourceMr Fuentes is supported by the Uni-

versity of Alberta through the Disser-tation Fellowship Award. This proj-ect was funded by the PhysiotherapyFoundation of Canada (PFC) through

the Ortho Canada Research Awardand the Department of PhysicalTherapy, University of Alberta,through the Thesis Research Operat-ing Grant Program.

ResultsParticipants

A total of 117 participants with CLBPwere enrolled. The mean age was30 years (SD6.8, range1965).Complete data were available on all

Table 1.Baseline Variables for the 4 Treatment Groupsa

Characteristic

Group

PAL (n30) SL (n29) AE (n29) SE (n29)

Age (y) 30.5 (10.26) 30.3 (11.22) 29.7 (11.33) 29.8 (10.78) .991

Height (cm) 170.9 (9.53) 168.2 (10.11) 169.1 (9.41) 169.4 (10.13) .769

Weight (kg) 69.6 (18.64) 66.6 (11.99) 67.1 (13.28) 65.3 (18.64) .695

Sex, n (%)

Female 18 (60%) 17 (58.6%) 19 (65.5%) 17 (58.6%)

Male 12 (40%) 12 (41.4%) 10 (34.5%) 12 (41.4%)

PI-NRS 4.01 (0.91) 4.09 (0.10) 4.03 (0.92) 4.10 (0.12) .986

CEQ baseline score 15.6 (2.69) 15.2 (4.51) 15 (2.73) 16 (4.80) .898

Pain duration (mo) 45.3 (56.76) 51.1 (38.19) 51.21 (38.30) 47.28 (87.29) .974

a Data are presented as mean (SD) unless otherwise specified. Significant differences at P.05. The AL group received active interferential current therapy(IFC) combined with a limited therapeutic alliance (TA), the SL group received sham IFC combined with a limited TA, the AE group received active IFCcombined with an enhanced TA, and the SE group received sham IFC combined with an enhanced TA. PI-NRSpain intensity numerical rating scale,CEQCredibility Expectancy Questionnaire.




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data points for all participants. Base-line characteristics were not signifi-cantly different among the groups on

any variable (Tab. 1).

Differences (Pretreatment-Posttreatment) in Pain Intensityand PPTStatistically significant differences

were observed among groups onthe mean change (pretreatment-posttreatment) of PPTs and painintensity scores (P.05). Results ofthe multiple comparisons amonggroups using the Bonferroni post

hoc test for PPTs and pain intensityare displayed in Table 2.

Pain intensity. Mean differenceson the PI-NPR were 1.83 cm (95%confidence interval [95% CI]14.320.3), 1.03 cm (95% CI6.612.7),3.13 cm (95% CI27.233.3), and2.22 cm (95% CI18.925.0) for the

AL, SL, AE, and SE groups, respec-tively. Percentages of pain reduction

were 45.6%, 24.5%, 77.4%, and54.5% for the AL, SL, AE, andSE groups, respectively (Tab. 3). Sig-nificant differences (P.01) were

found between the SL group and theAL, AE, and SE groups (Fig. 2). Thelarger group differences occurred

between the SL group and the 2enhanced groups (AE, SE). Whencompared with the SL group, the dif-ferences were 23 mm (deemed clin-ically meaningful) and 11.9 mm forthe AE and SE groups, respectively.

Muscle pain sensitivity. Mean dif-ferences in PPTs were 1.25 kg (95%CI0.71.6), 0.39 kg (95% CI0.20.8), 2.09 kg (95% CI1.62.5), and1.75 kg (95% CI1.32.1), for the

Table 2.Pair-Wise Comparisons for Muscle Pain Sensitivity (PPT) and Pain Intensitya

Measure

Group

(I)

Comparison Group

(J)

Mean Difference

(IJ) SE Pb

95% CI for Differenceb

Lower Boundary Upper Boundary

PPT AL SL 0.816 0.308 .05 0.010 1.642

AE 0.856* 0.308 .03 1.682 0.030

SE 0.525 0.308 .54 1.351 0.301

SL AL 0.816 0.308 .05 1.642 0.010

AE 1.672* 0.310 .00 2.505 0.839

SE 1.341* 0.310 .00 2.174 0.508

AE AL 0.856* 0.308 .30 0.030 1.682

SL 1.672* 0.310 .00 0.839 2.505

SE 0.331 0.310 1.00 0.502 1.164

SE AL 0.525 0.308 .30 0.301 1.351

SL 1.341* 0.310 .00 0.508 2.174

AE 0.331 0.310 1.00 1.164 0.502

Pain AL SL 7.623* 2.166 .00 1.806 13.440

AE 12.949* 2.166 .00 18.766 7.132

SE 4.673 2.166 .19 10.491 1.144

SL AL 7.623* 2.166 .00 13.440 1.806

AE 20.572* 2.184 .00 26.439 14.706

SE 12.297* 2.184 .00 18.163 6.430

AE AL 12.949* 2.166 .00 7.132 18.766

SL 20.572* 2.184 .00 14.706 26.439

SE 8.276* 2.184 .00 2.410 14.142

SE AL 4.673 2.166 .19 1.144 10.491

SL 12.297* 2.184 .00 6.430 18.163

AE 8.276* 2.184 .00 14.142 2.410

a Based on estimated marginal means. The AL group received active interferential current therapy (IFC) combined with a limited therapeutic alliance (TA),the SL group received sham IFC combined with a limited TA, the AE group received active IFC combined with an enhanced TA, and the SE group receivedsham IFC combined with an enhanced TA. SEstandard error, 95% CI95% confidence interval, PPTpressure pain threshold. Asterisk indicates the meandifference is significant at the .05 level.b Bonferroni adjustment for multiple comparisons.




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AL, SL, AE, and SE groups, respec-tively. Percentages of increasedpain thresholds were 32.6%, 10.5%,51.5%, and 40.0% for the AL, SL, AE,and SE groups, respectively (Tab. 3).Significant differences (P.05) werefound between the SL group and the

AE and SE groups (Fig. 3). Largergroup differences occurred betweenthe SL group and the 2 enhancedgroups (AE, SE). When compared

with the SL group, the differenceswere 1.7 kg and 1.4 kg for the AE and

SE groups, respectively (both clini-cally meaningful).

Differences in TA and PatientsExpectationsMean (SD) scores for TA (PRES)assessed at the end of the treatment

were 30.7 (6.0), 42.5 (2.7), 34.4(4.5), and 42.8 (1.81) points for the

SL, SE, AL, and AE groups, respec-tively. There were significant differ-ences in TA among groups (P.05).

All of the groups differed witheach other except for the com-parison between the AE and SEgroups(eTable, availableat ptjournal.apta.org).

Mean differences (pretreatment-posttreatment) in expectation scores(CEQ) were 0.9, 2.9, 2.1, and 5.8

points for the SL, SE, AL, and AEgroups, respectively. There were sta-tistically significant differences inmean differences of CEQ scoresamong groups. Specifically, there

were significant differences betweenthe AL and AE groups and betweenthe SL and AE groups (eTable).

The Kendall tau correlation coeffi-cients indicated that there was a

Table 3.Mean Differences (Baseline and Posttreatment) in Muscle Pain Sensitivity and Pain Intensity Scores for the 4 Treatment Groupsa

Outcome Measure

Group

AL (n30) SL (n29) AE (n29) SE (n29)

Pain intensity (PI-NRS), cm

Baseline 4.01 (0.91) 4.09 (1.0) 4.03 (0.92) 4.10 (1.29)

Posttreatment 2.18 (1.17) 3.06 (1.27) 0.89 (0.98) 1.88 (1.44)

Difference 1.83 (0.85) 1.03 (0.65) 3.13 (0.97)* 2.22 (0.75)*

% of change (pain reduction) 45.6 24.5 77.4 54.5

Muscle pain sensitivity (PPT), kg/cm2/s

Baseline 3.89 (1.8) 3.76 (1.8) 4.11 (1.8) 4.5 (2.3)

Posttreatment 5.15 (2.6) 4.16 (1.6) 6.21 (2.6) 6.3 (2.8)

Difference 1.25 (1.3)* 0.39 (0.9) 2.09 (1.1)* 1.75 (1.3)*

% of change (increased PPT) 32.6 10.5 51.5 40.0

a Data are presented as mean (SD). The AL group received active interferential current therapy (IFC) combined with a limited therapeutic alliance (TA), theSL group received sham IFC combined with a limited TA, the AE group received active IFC combined with an enhanced TA, and the SE group received sham

IFC combined with an enhanced TA. PI-NRSpain intensity numerical rating scale, PPTpain pressure threshold. Asterisk indicates findings were clinicallyimportant according to indexes based on distribution (ie, minimally important difference, standard error of measurement) reported in the literature.

Figure 2.Between-group differences for pain intensity scores. Results are shown as mean standard error of measurement. The AL group received active interferential currenttherapy (IFC) combined with a limited therapeutic alliance (TA), the SL group receivedsham IFC combined with a limited TA, the AE group received active IFC combined withan enhanced TA, and the SE group received sham IFC combined with an enhanced TA.PI-NRSpain intensity numerical rating scale. Asterisk indicates significant at P.01.


http://ptjournal.apta.org/content/94/4/477/suppl/DC1http://ptjournal.apta.org/content/94/4/477/suppl/DC1http://ptjournal.apta.org/content/94/4/477/suppl/DC1http://ptjournal.apta.org/content/94/4/477/suppl/DC1http://ptjournal.apta.org/content/94/4/477/suppl/DC1


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very little association between TAand differences in expectancies(pretreatment-posttreatment) (.24). Based on the coefficient of vari-ation, it could be said that only 4% of

the variance of expectancies wasaccounted for by the TA. Therefore,although expectations increased forthe enhanced groups, it appears thatthis was not the main reason for theobserved improvement.

Therapist EffectNo significant difference wasobserved among therapists (P.18)or for the interaction between ther-apists and groups (P.10) for eitherpain or PPT outcomes. In addition,

TA scores among therapists were notdifferent (P.53). In other words,therapists were similar in providingthe treatment and did not have aninfluence in the way that patientsresponded to different treatments.

Clinical ImportancePain intensity. Group differencesbetween pretreatment and posttreat-ment measurements for the AEgroup (3.13 cm) and the SE group

(2.22 cm) exceeded suggestedvalues for the MCID.3841 Clinicallyimportant effect sizes (Cohen d)

were found between the AE and SLgroups (d2.51), SE and SL groups(d1.73), and AL and SL groups(d0.89). In the same way, largeeffect sizes were calculated betweenthe AE and AL groups (d1.36) andthe AE and SE groups (d1.0).

Muscle pain sensitivity. Differ-

ences for the AL group (1.2 kg/cm

2

/s),AE group (2.0 kg/cm2/s), and SEgroup (1.7 kg/cm2/s) reached val-ues deemed to be clinically mean-ingful.26,54 In the same way, clini-cally important effect sizes (Cohend) were found between the AE andSL groups (d0.93) and the SE andSL groups (d0.94). A moderateeffect size (d0.48) was calculatedbetween the AL and SL groups.

GRS. The average change in GRSratings reported by the participants

was 4, 2, 5, and 4 points for the AL,

SL, AE, and SE groups, respectively.Ninety percent of the participants inthe AE group perceived the changeas moderate (ie, 45 points),

whereas this change was reported infewer than 5% of the participantsin the SL group. The average painintensity considered meaningful forparticipants was calculated to be 12mm. The average PPT consideredminimally important for participants

was calculated to be 1.05 kg/cm2/s.

Blinding AssessmentDifferences in expectations at base-line among the 4 treatment groups

were not significant (P.90, Tab. 1).When participants were asked at theend of the session to guess the typeof treatment (ie, active or sham IFC),87% (n25) of participants in theSL group and 97% (n28) of the par-ticipants in the SE group thoughtthey had been treated with an active

intervention. In other words, only8% (n5) of all participants in bothsham IFC groups (n58) correctly

guessed that they had not receivedan active treatment.

These findings suggest that the blind-ing procedures were adequate andthat both active and sham treatments

were perceived equally by the par-ticipants. No one in the activegroups (AL, AE) thought that theyhad received a sham intervention.

Adherence to Treatment

ProtocolsEvaluation of videotaped interac-tions indicated that 86% of the ses-sions evaluated were rated as adher-ent to the protocol. Reliability ofthese ratings between the raters wasconsidered excellent (ICC.95, 95%CI0.80.9, P.01).

Adverse EffectsTwo participants (one woman inthe AL group and one man in the SL

Figure 3.Between-group differences for pressure pain threshold (PPT) measurements at baselineand posttreatment. Results are shown as mean standard error of measurement. The

AL group received active interferential current therapy (IFC) combined with a limitedtherapeutic alliance (TA), the SL group received sham IFC combined with a limited TA,the AE group received active IFC combined with an enhanced TA, and the SE groupreceived sham IFC combined with an enhanced TA. Asterisk indicates significant atP.05.




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group) reported an increase in theirpain with no apparent reason afterreceiving the IFC treatment. Noother adverse effects were reported.

DiscussionThis study examined the impact ofTA on clinical physical therapy out-comes in patients with nonspecificCLBP. The most striking result wasthe meaningful effect of enhancedTA when applied with active IFCon pain modulation. Thus, factorsrelated to the therapist (ie, TA)appeared to be as important as thetherapy (ie, IFC) in pain modulation,and their interaction may producesubstantive clinical benefits.

Our results are in line with thefindings of a recent study30 thatconfirmed a supportive patient-practitioner relationship is a potentcomponent of placebo effects inthe management of irritable bowelsyndrome. In that study, the magni-tude of the effect for an augmentedinteraction (ie, 45 minutes duration,including supportive, warm, activelistening behaviors) between the

practitioner and the patient was notonly statistically but also clinicallyimportant compared with limitedinteraction (ie, 5 minutes) or a wait-ing list control group. Althoughmethodological differences are pres-ent between the studies, similaritiessuch as the intervention protocoland the use of subjective outcomemeasures make the comparisonsbetween these 2 studies worthconsidering.

In physical therapy, it is conceivablethat the patients perceived differ-ences in treatment responsivenessare likely related to the therapistsinterpersonal skills rather than theappropriateness of the treatment.This notion may have some supportconsidering the nature of therapeu-tic interventions in which featuressuch as touch, care, and attentionplay a relevant role. The results of

recent systematic reviews and meta-analyses about common nonpharma-cological interventions used by phys-ical therapists to treat patients withCLBP have shown similar and mod-

est short-term benefit, but little long-term benefit.67,68 In clinical settings,it is possible that treatments appliedin a neutral or business-like man-ner (ie, limited contextual factors)may translate into less-than-optimalclinical outcomes.

In this study, therapists in theenhanced groups communicated(verbally and nonverbally) not onlyto translate information but also toengage with patients in meaningful

ways. They communicated in orderto convey broader concepts suchas empathy, warmth, caring, encour-agement, and support. These are

widely accepted as critical aspects ofTA.12

There is a difference between inter-acting and engaging and betweenconnecting and meaningfully con-necting. All require communication,but engaging and meaningfully con-

necting enhance the relationship.Thus, in this study, the interactionbetween patient and therapist wasbased on more than just improvedtherapist communication.

Magnitude of the EffectThe results of this study showed aclear dose-response effect. The larg-est beneficial effect was seen withthe AE group, and the smallest effect

was observed in the SL group. The

magnitude of the effect in the AEgroup was larger than we had antic-ipated. On average, participants inthe AE group had decreased painintensity by 3.1 points on the PI-NRS.In addition, they increased theirPPTs by 2.09 kg/cm2/s. These valuesgreatly exceeded what is considereda clinically meaningful difference forthese outcomes.26,54

Clinical outcomes for participants inthe SL group showed the smallesteffect and are not considered clini-cally meaningful. Interestingly, thesham IFC with an enhanced TA (SE

group) demonstrated better resultsthan the active IFC with a limited TA(AL group). Although this difference

was not statistically different, thequestion of whether a sham applica-tion (ie, no active ingredient) in anenhanced TA is better than an activeintervention (ie, active ingredientincluded) in a limited TA would be

worthwhile exploring further.

The large effect sizes (Cohen d) inpain intensity shown in this study for

the enhanced groups (AE, d3.2;SE, d1.6) are in agreement withthe results of previous meta-analysesstudying the mechanisms of placeboanalgesia.69,70 In these studies, themanipulation of expectations throughinstructional sets or conditioningprotocols also was able to producelarge placebo effects (d0.95,70

d1.0069). Thus, placebo effectsappear to be larger when expecta-tions and TA are experimentally

manipulated, and these seem to beequally effective mechanisms to pro-duce significant placebo responses.

Analysis of clinical importance fromthe patients perspective showedthat most participants rated theirreduction in pain after the treatmentas being clinically meaningful. Thus,average GRS scores were 5, 4, and 4points for the AE, SE, and AL groups,respectively. These scores con-

trasted with the perception ofchange in pain rated in the partici-pants in the SL group, where theaverage GRS score was 2 points, rep-resenting a small change.

MechanismsPersonal characteristics of clinicianscan influence treatment outcomeseither positively or negatively. Somepotential behavioral styles may favoror inhibit placebo responses. For




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example, the clinician, by listening,sending appropriate messages, andphysically contacting the patient dur-ing the clinical examination, mayinduce a strong placebo effect,

whereas inappropriate comments mayexacerbate symptoms.71 Other thera-peutic variables that enhance placeboresponses include the amount of timethe clinician spends with patients anda warm, empathic interaction.30,32

In this study, physical therapists inthe enhanced groups were presentfor the whole treatment session, andthey used behaviors such as activelistening, empathy, and words ofencouragement. Interaction between

practitioner and patient has beenconsidered central in determiningoutcome in back pain and neckpain.72,73 The therapists in this study

were skilled clinicians, empatheticand open to answering questions dur-ing the interaction with the partici-pants while delivering the treatments.In addition, the enhanced communica-tion skills and the concerned opti-mism exhibited about the patient bythe physical therapist during the treat-

ment session could potentially explainthese results. Finally, available datasuggest that the placebo-associatedimprovement is strongly influenced bythe patients awareness of the proce-dure and depends on the invasive-ness of the procedure; elaborate rit-uals can produce effects that aregreater than a simple pill inges-tion.24,74 Thus, the application oftechnologically impressive equip-ment such as an IFC machine may

have resulted in a highly evocativeand therapeutically potent agent forthe patients in our study.

Therapist EffectsIn this study, we did not find sig-nificant differences among the ther-apists or interaction between ther-apists and groups on clinicaloutcomes, which demonstrated thatindividual differences (ie, personal-ity) among therapists did not influ-

ence the placebo response. Thisfinding suggests that when differenttherapists adhere to a highly scriptedand standardized treatment proto-col, their personality attributes may

not have an influence on the waypatients respond to treatments. Thisfinding also suggests that therapists

who do not have great innate skillsat building TA may achieve goodresults by following protocols.

Strengths and Limitations ofthe StudyTo our knowledge, this is the firstexperimental controlled study aimedat exploring the effects of manipulat-ing the TA in physical therapy treat-

ment of chronic pain. The testingprotocol was standardized to mini-mize bias, but this standardizationmade the environment somewhatdifferent from routine clinical prac-tice. Our study had high internal

validity, as shown by adequate ran-domization, concealed allocation,baseline comparability among groups,and evidence of effective blindingof the research team and partici-pants. Experienced clinicians deliv-

ered the interventions in accordancewith a highly standardized study pro-tocol designed to deliver differenttherapeutic contexts.

Although the results of this study areencouraging, any inference from thisstudy needs to be tempered due tosome limitations. First, the positiveeffects shown in the enhancedgroups (ie, AE, SE) could have beendue to the possibility that patients in

these groups were more willing toplease the therapist compared withthe patients in the limited groups(ie, social desirability bias). Althoughthis may be possible when reportingpain scores, we believe that in a lesssubjective outcome such as PPT, par-ticipants will not respond in thesame socially desirable manner. Sec-ond, because we did not include ano treatment control group, theresults of this study might warrant

close scrutiny. It is possible that par-ticipants in the enhanced groups hada reduction in their pain due to nat-ural variability in pain levels alone.However, this confounder (pain vari-

ability) would have equally affectedall groups and thus would not accountfor the differences in the analgesiceffect observed across groups. Third,in order to have a relatively homoge-neous LBP sample, this study includeda young and moderated disabled LBPpopulation (average age30 years,average Oswestry Disability Indexscore22 points). Patients with moresevere symptoms may have a morecomplex clinical presentation, andfuture research should explore the

effect of TA in an older and moreseverely disabled population. Fourth,our study protocol aimed to test theimmediate effect of the TA. Therefore,there is a need to determine whetherthese reported benefits could be sus-tained in the longer term. Futureresearch is needed to overcome theselimitations and expand the analysis ofthe existing evidence regarding theeffects of TA as another therapeuticagent within clinical practice.

Implications for PracticeOur results call for a more in-depthconsideration of contextual factors

when delivering physical therapy.The results of this study suggest thatmaximizing TA during therapy isaccompanied by significant thera-peutic benefits. The effect ofaccepted interventions (ie, IFC) canbe improved when clinicians inter-act positively with their patients.

Physical therapists should consideroptimizing the psychosocial contextin the clinical management ofchronic pain conditions. In other

words, the TA may be considered asanother therapeutic agent. There-fore, physical therapists awarenessof this factor when delivering theirinterventions could lead to betteroutcomes.




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ConclusionThe context in which physical ther-apy interventions are offered has thepotential to dramatically improvetherapeutic effects. Enhanced TA

combined with active IFC appearsto lead to clinically meaningfulimprovements in outcomes whentreating patients with CLBP. Ourresults support efforts to fosterenhanced alliance between patientsand providers when deliveringphysical therapy interventions forchronic pain. Factors other thanthe specific ingredient of a treatmentmay have a large role in achievingpositive clinical outcomes, andexploring them is central to physical

therapist practice.

Dr Fuentes, Dr Armijo-Olivo, Dr Dick, DrRashiq, Dr Warren, Dr Magee, and Dr Grossprovided concept/idea/research design. DrFuentes, Dr Armijo-Olivo, Dr Gross, and DrMagee provided writing. Dr Fuentes, Dr

Armijo-Olivo, Ms Funabashi, and Ms Miciakprovided data collection. Dr Armijo-Olivoand Dr Fuentes provided data analysis. DrFuentes and Dr Gross provided projectmanagement. Dr Fuentes, Dr Gross, andDr Magee provided fund procurement. DrMagee and Dr Gross provided facilities/equipment. Dr Armijo-Olivo, Dr Dick, DrRashiq, Dr Warren, Dr Magee, Dr Gross,Ms Funabashi, and Ms Miciak provided con-sultation (including review of manuscriptbefore submission).

The University of Alberta Health ResearchEthics Committee approved the study.

Dr Fuentes is supported by the University ofAlberta through the Dissertation FellowshipAward. This project was funded by thePhysiotherapy Foundation of Canada (PFC)through the Ortho Canada Research Awardand the Department of Physical Therapy,

University of Alberta, through the ThesisResearch Operating Grant Program.

DOI: 10.2522/ptj.20130118

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Enhanced Therapeutic Alliance Modulates Pain Intensity and Muscle Pain Sensitivity in Patients With Chronic Low Back Pain- Fuentes 2013