Combining Static and Dynamic Myofascial Dry Cupping Therapy to Improve Local and Regional Symptoms in Individuals with Low Back Pain: A Case Series.

Introduction: Chronic low back pain is a common musculoskeletal healthcare presentation with an expense of over $100 billion annually. The clinical effect of myofascial cupping on pain and function is not clear, especially when different cupping techniques are combined. The purpose of this case series was to explore changes in pain and function following local static and distal dynamic myofascial dry cupping treatments in patients with chronic low back pain. Case Descriptions: Three adults from the general population received three ten-minute treatment sessions, 48 hours between each session, of static dry cupping to the low back followed by dynamic myofascial cupping of the quadriceps and hamstring musculature. Outcome measures were taken at two different time points within one-week per participant. Subjective measures included the numeric pain rating scale and the Oswestry Disability Index, objective measures included passive straight leg raise measurements, and pressure pain threshold. Results and Discussion: Local static combined with distal dynamic myofascial cupping reduced pain, pain sensitivity and perceived disability, and improved hamstring muscle extensibility in all three participants. These encouraging results support the initiation of a larger controlled trial aimed at investigating the efficacy of combined dry cupping interventions to treat musculoskeletal dysfunction and pain. Level of Evidence: 4 (case series).

Novice Inter-Rater Reliability on the Selective Functional Movement Assessment (SFMA) After a 4-Hour Training Session.

Background: The Selective Functional Movement Assessment (SFMA) is a whole-body movement classification system that identifies non-optimal movement performance requiring further assessment. There needs to be more evidence specifying the training time required to obtain SFMA reliability for entry-level health care practitioners. Purpose: The primary intent of this study was to determine SFMA inter-rater reliability between two third-year physical therapy students following an in-person three-hour training and one-hour follow-up training with a certified SFMA physical therapist. The secondary purpose was to compare rater scores of the composite criterion 50-point checklist and rater categorization using the top-tier movements in real-time assessments of healthy participants. Study Design: Inter-rater reliability study. Methods: Two novice raters received training on assessing movement using the SFMA. Participants included non-pregnant healthy adults screened for general exercise, participants were excluded for history of orthopedic surgery within the prior six months. Three independent raters, including two novice and one SFMA-certified rater, individually assessed the top-tier movements in separate rooms in real-time. Participants were randomly assigned a start location, and raters were blinded to each other's criterion 50-point checklist and categorical scoring. Statistical analysis included a paired t-test, a repeated measures ANOVA, and a two-way, mixed absolute agreement ICC. Results: Twenty-five participants (23.4 years ± 1.9; 72% female) completed the SFMA top-tier movements. Significant differences were identified with novice raters identifying fewer non-optimal movement patterns than the certified clinician. The intraclass correlation coefficient (ICC2,1) was moderate (0.60, p<0.001) for all three raters on the 50-point criterion checklist scoring. Conclusion: Third year physical therapy students were able to demonstrate moderate inter-rater reliability assessing healthy individuals using the 50-point criterion checklist. Variation between novice raters may reflect the amount of previous exposure assessing movement and suggests that some may require more time learning and practicing in order to identify non-optimal movement patterns that may require further assessment. Level of Evidence: 3b©The Author(s).

The efficacy of manual therapy on HRV in those with long-standing neck pain: a systematic review.

OBJECTIVES: Long-standing neck pain (LNP) is a clinical condition frequently encountered in the physical therapy clinic. LNP is a complex, multifactorial condition affecting multiple body systems including the autonomic nervous system (ANS). Traditionally, research on the impact of physical therapy on LNP has focused on self-report measures and pain scales. Heart rate variability (HRV) is an objective measure of the ANS, allowing for quantification of effects of treatment. This systematic review is intended to evaluate if manual therapy acutely affects heart rate variability in adults with long-standing neck pain. METHODS: Pubmed, Medline, CINAHL, Google Scholar, Web of Science, and Cochrane library were used to retrieve the randomized controlled trials for this review between the years 2010-2021. Search terms included: chronic neck pain, neck pain, cervical pain, manual therapy, mobilization, manipulation, osteopathy, osteopathic or chiropractic. Heart rate variability, HRV, heart rate variation, effects, outcomes, benefits, impacts or effectiveness. RESULTS: Of 139 articles located and screened, three full-text articles were selected for full qualitative synthesis, with a combined population of 112 subjects, 91 of which were female, with an average age of 33.7 ± 6.8 years for all subjects. MT techniques in three studies were statistically significant in improving HRV in people with LNP; however, techniques were differed across studies, while one study showed no benefit. The studies were found to be of high quality with PEDro scores ≥6. CONCLUSIONS: Although no clear cause and effect relationship can be established between improvement in HRV with manual therapy, results supported the use of MT for an acute reduction in HRV. No one particular method of MT has proven superior, MT has been found to produce a statistically significant change in HRV. These HRV changes are consistent with decreased sympathetic tone and subjective pain.

Combined Neurocognitive and Exercise Tolerance Testing Improves Objectivity of Buffalo Concussion Treadmill Test.

CONTEXT: The Buffalo Concussion Treadmill Test (BCTT) is a standard assessment of exercise tolerance utilized for exercise prescription following concussion and to inform decisions regarding return to play. One limitation of the BCTT is that interpretation of test results is dependent on individuals' self-report of symptom exacerbation with exertion. Symptoms following concussion are significantly underreported or unreported. Combining objective neurocognitive assessment with exercise tolerance testing may enable clinicians to objectively identify those requiring further assessment or rehabilitation before return to play. The purpose of this study was to investigate how performance on a neurocognitive assessment battery is affected by provocative exercise testing. DESIGN: Prospective cohort study, pretest/posttest. METHODS: A total of 30 participants included 13 women (43.3%), age 23.4 (1.93) years, height 173.56 (10) cm, weight 77.35 (16.3) kg, and 11 (36.7%) with history of concussion. All participants completed a neurocognitive assessment battery, including the Stroop Test and standardized assessments of working memory, attention, and information processing speed/accuracy in single-task (seated position) and dual-task conditions (walking on a treadmill at 2.0 miles per hour). The neurocognitive assessment battery was performed at baseline and after the standard BCTT test protocol. RESULTS: BCTT: Average percentage of heart rate maximum (%HRmax) = 93.97% (4.8%); average maximum rating of perceived exertion = 18.6 (1.5). Time-based performance in single-task and dual-task conditions significantly improved from baseline (P < .05) following maximal exercise testing on the BCTT for the following neurocognitive assessments: concentration-reverse digits, Stroop congruent, and Stroop incongruent. CONCLUSIONS: Healthy participants demonstrated improvements across multiple domains of neurocognitive performance following the exercise tolerance testing on the BCTT. Understanding normal responses in neurocognitive performance for healthy individuals following exercise tolerance testing may allow clinicians to more objectively monitor the trajectory of recovery following sports-related concussion.

Predictors of Success in the National Physical Therapy Examination for Hispanic Doctor of Physical Therapy Students.

INTRODUCTION: Hispanic/Latino students often underachieve in higher education programs in the health professions and have shown lower first-time pass rates on the National Physical Therapy Examination than their White peers. A plausible explanation for this difference is the lack of English proficiency. The purpose of this study was to determine predictive academic variables for passing licensure examination on the first attempt for Hispanic/Latino Doctor of Physical Therapy (DPT) students. REVIEW OF THE LITERATURE: Numerous studies have been conducted to determine the factors that predict success on the National Physical Therapy Examination; however, there is a scarcity of literature on the predictors of success for Hispanic/Latino DPT students, particularly on the influence of English proficiency. SUBJECTS: A nonprobability convenience sample of 67 Hispanic students from a single DPT program was used. METHODS: A retrospective, predictive, correlational study was conducted. Data collection was performed by secondary analysis of student academic profiles. Predictor variables included proficiency in the English language; undergraduate grade point average; verbal, quantitative, and written skills; and first-year and third-year grade point average while enrolled in the physical therapist education program. RESULTS: The first-time pass rate was 59.7% (n = 40). Results showed that students who passed and those who did not pass on their first attempt differed in first-year and third-year program grade point average with large effect sizes of d = 1.13 and d = 1.48, respectively; however, third-year grade point average was the only significant independent predictor of success. English proficiency and preadmission variables did not predict first-time success. DISCUSSION AND CONCLUSION: The results suggest first-year and third-year grade point average may be used to identify at-risk students. Use of these variables is encouraged to monitor the progression of students. The study highlighted the need to identify additional predictors of performance.

Reliability and Validity of Inertial Sensor Assisted Reaction Time Measurement Tools among Healthy Young Adults.

The assessment of movement reaction time (RT) as a sideline assessment is a valuable biomarker for mild TBI or concussion. However, such assessments require controlled laboratory environments, which may not be feasible for sideline testing during a game. Body-worn wearable devices are advantageous as being cost-effective, easy to don and use, wirelessly transmit data, and ensure unhindered movement performance. This study aimed to develop a Drop-stick Test System (DTS) with a wireless inertial sensor and confirm its reliability for different standing conditions (Foam versus No Foam) and task types (Single versus Dual), and postures (Standing versus sitting). Fourteen healthy young participants (seven females, seven males; age 24.7 ± 2.6 years) participated in this study. The participants were asked to catch a falling stick attached to the sensor during a drop test. Reaction Times (RTs) were calculated from data for each trial from DTS and laboratory camera system (gold standard). Intraclass correlation coefficients (ICC 3,k) were computed to determine inter-instrument reliability. The RT measurements from participants using the camera system and sensor-based DTS showed moderate to good inter-instrument reliability with an overall ICC of 0.82 (95% CI 0.78-0.85). Bland-Altman plots and 95% levels of agreement revealed a bias where the DTS underestimated RT by approximately 50 ms.

Heart Rate Variability as a Reliable Biomarker Following Concussion: A Critically Appraised Topic.

CLINICAL SCENARIO: Recent systematic reviews show conflicting information regarding the effect of concussion on cardiac autonomic function. Controlled aerobic exercise is the most popular intervention for those recovering from a concussion. There is a gap in the literature supporting the utility of objective metrics during exertional return to play protocols and rehabilitation. CLINICAL QUESTION: Can heart rate variability (HRV) during physical exertion be a reliable biomarker over time for those who suffered a sport-related concussion? SUMMARY OF KEY FINDINGS: A literature search produced 3 studies relevant to the clinical question. One, a prospective-matched control group cohort study, reported disturbances in HRV during physical exertion in those with a history of concussion, and identified persistent HRV dysfunction after resolution of subjective complaints, return to play, and with multiple concussive events. Second, a cross-sectional cohort study found an HRV difference in those with and without a history of concussion and in HRV related to age and sex. Finally, the prospective longitudinal case-control cohort study did not find sex or age differences in HRV and concluded that, although postconcussion HRV improved as time passed, resting HRV was not as clinically meaningful as HRV during exertional activities. CLINICAL BOTTOM LINE: There is emerging evidence to support the use of HRV as an observable biomarker, over time, of autonomic function during physical exertion following a sport-related concussion. However, the meaningfulness of HRV data is not fully understood and the utility seems individualized to the level of athlete, age, and sex and, therefore, cannot be generalizable. In order to be more clinically meaningful and to assist with current clinical decision making regarding RTP, a preinjury baseline assessment would be beneficial as an individualized reference for baseline comparison. STRENGTH OF RECOMMENDATION: Although HRV is not fully understood, currently, there is grade B evidence to support the use of individualized baseline exertional HRV data as comparative objective metric to assess the autonomic nervous system function, over time, following a concussive event.

Test-Retest Reliability of Postural Control Assessment on Biodex BioSway™.

Background: Recent protocols for posturographic assessment of postural control and balance have included head shake test conditions to challenge the vestibular contributions of postural control in an effort to increase the diagnostic accuracy of identifying individuals with impaired balance. However, evidence is limited regarding the test-retest reliability of such assessment protocols. Purpose: The purpose of this study was twofold: to determine the test-retest reliability of postural control assessment on the Biodex Biosway™, an accessible and field expedient tool for posturographic assessment, and to determine the test-retest reliability of the Head Shake Sensory Interaction and Balance Test (HS-SIB), an adaptation of the modified Clinical Test of Sensory Interaction and Balance (mCTSIB) which adds two head shake conditions to challenge the vestibular contributions to postural control. Study Design. This was a correlational time series cohort study completed in a biomechanics laboratory. Methods: The sample consisted of nineteen healthy adults (10 females, 9 males). Sway Index, Equilibrium Score, and the area of the ellipse enclosing 95% of the anterior-posterior (AP) and medial-lateral (ML) center of gravity (COG) displacement (AREA95) are the 3 summary variables. Standard Error of Measurement (SEM) and Minimum Detectable Change (MDC) are also reported. Results: Test-retest reliability was generally poor with limited exceptions. Moderate to good reliability was observed for the more challenging stance conditions (ICC range 0.58-0.81), including those with head shake. Conclusions: Field-expedient systems, such as the Biodex BioSway™, may offer reliable posturographic testing where gold-standard methods are not available. Clinicians should be aware that less demanding test conditions have limited reliability; however, test-retest reliability of this assessment tool is improved with more challenged stance conditions and the inclusion of a head shake task.

The Effect of Whole-Body Fatigue on King-Devick Test and Balance.

Purpose: Fatigue may mimic suboptimal brain functioning seen after a concussion and lead to false-positive King-Devick (K-D) scores and decreased balance. The purpose of this study was to investigate if whole-body fatigue has an effect on K-D scores or postural sway. Method: A total of 38 healthy participants (20 females; age = 23.5 ± 2.63 y; height = 170 ± 0.1 cm; mass = 75.2 ± 10.3 kg) volunteered for the study. Participants completed the King-Devick (K-D) test and the modified Clinical Test of Sensory Interaction of Balance (mCTSIB) on the Biodex BioSwayTM Portable Balance System prior to and immediately following the completion of a fatigue protocol on a Concept2 Rower. Results: Half of the participants demonstrated a positive K-D test post-fatigue. Balance scores were poorer post-fatigue. No difference was found between participants based on history of concussion. Among the participants that had a positive post-fatigue K-D test, 71% had also a worse composite sway index score (χ2 = 6.3, p = .02). Conclusions: Whole-body fatigue may negatively impact a person's ability to perform the K-D test and balance assessments. It is recommended that the athlete is allowed a period of time to accommodate for the acute effects of fatigue before administering these assessments following a suspected concussion.

Item-level and Composite-level Interrater Reliability of Functional Movement Screen™ Scores Following Condensed Training in Novice Raters.

BACKGROUND: The Functional Movement Screen™ (FMS™) is a clinical instrument designed to use movement behaviors to screen individuals for injury risk. Current rater certification programs focus on extensive, individualized training, which may not be appropriate in all screening contexts. PURPOSE: The purpose of this research was to examine the effect of a two-hour FMSTM training seminar on measures of reliability between previously untrained scorers. STUDY DESIGN: Repeated measures, descriptive cohort study. METHODS: Four novice raters completed a two-hour training course administered by an FMS™-certified, licensed physical therapist. The novices and the instructor then scored a group of 16 individuals on the seven FMS™ component tests on two separate occasions. Interrater reliability was assessed for FMS™ component scores using Fleiss' kappa and Krippendorff's α. Interrater reliability for the FMS™ composite score was assessed using a two-way ICC for agreement (a priori significance level=0.05). RESULTS: Reliability ranged from fair to almost perfect (kappa) for Deep Squat (0.61 Day 1, 0.79 Day 2), Shoulder Mobility (0.90 Day 1, 1.00 Day 2), Active Straight Leg Raise (0.53 Day 1, 0.69 Day 2), and Trunk Stability Push Up (0.48 Day 1, 0.49 Day 2) on both testing occurrences (p<0.05). Reliability (kappa) was fair for Inline Lunge (0.24 Day 1, 0.39 Day 2), and poor for Hurdle Step (Day 1 -0.01, Day 2 no result) and Rotary Stability (Day 1 -0.03, Day 2 -0.01). Results for Krippendorff's α were similar, with unacceptable interrater reliability for Hurdle Step (Day 1 -0.01, Day 2 1.00), Inline Lunge (Day 1 0.31, Day 2 0.39), and Rotary Stability (Day 1 -0.02, Day 2 -0.01). Interrater composite score reliability (ICC) was good (0.79 Day 1, 0.84 Day 2; both p<0.05). CONCLUSIONS: Findings suggest that a brief training seminar may be sufficient to ensure acceptable reliability in many, but not all, of the FMS™ component tests and composite score. LEVELS OF EVIDENCE: Level 2b.

The role of pre-season health characteristics as injury risk factors in female adolescent soccer players.

[Purpose] Determine if female adolescent soccer players with a history of concussion, impaired K-D scores, and pre-season subjective complaints of neck pain, dizziness, and headache were predisposed to additional risk of musculoskeletal or concussive injury during 10-weeks of competitive play. [Participants and Methods] Twenty-three female high school soccer athletes provided concussion history and reported pre-season subjective complaints. K-D testing was performed pre and postseason. During the 10-week season, all injuries, preventing participation in practice or game, were recorded. [Results] Six reported a history of concussion. Of those six, three injuries were reported, including two concussions and a hamstring strain. Baseline K-D scores were worse in athletes that had two or more pre-season subjective factors compared to those that did not have any. Moderate positive correlations were found between a history of concussion and the number of injuries and a history of concussion and K-D post-test scores. [Conclusion] Findings indicate that pre-season subjective factors of neck pain, dizziness and headache, history of concussion, and K-D potentially increased injury risk. Combining pre-season metrics both at baseline and during the course of the season may assist in better injury risk screening in-season or indicate suboptimal function due to cumulative effects.

Proposing a new algorithm for premanipulative testing in physical therapy practice.

In the field of physical therapy, there is debate as to the clinical utility of premanipulative vascular assessments. Cervical artery dysfunction (CAD) risk assessment involves a multi-system approach to differentiate between spontaneous versus mechanical events. The purposes of this inductive analysis of the literature are to discuss the link between cervical spine manipulation (CSM) and CAD, to examine the literature on premanipulative vascular tests, and to suggest an optimal sequence of premanipulative testing based on the differentiation of a spontaneous versus mechanical vascular event. Knowing what premanipulative vascular tests assess and the associated clinical application facilitates an evidence-informed decision for clinical application of vascular assessment before CSM.

Validity of Postural Sway Assessment on the Biodex BioSway™ Compared With the NeuroCom Smart Equitest.

CONTEXT: Current tools for sideline assessment of balance following a concussion may not be sufficiently sensitive to identify impairments, which may place athletes at risk for future injury. Quantitative field-expedient balance assessments are becoming increasingly accessible in sports medicine and may improve sensitivity to enable clinicians to more readily detect these subtle deficits. OBJECTIVE: To determine the validity of the postural sway assessment on the Biodex BioSway™ compared with the gold standard NeuroCom Smart Equitest System. DESIGN: Cross-sectional cohort study. SETTING: Clinical research laboratory. PARTICIPANTS: Forty-nine healthy adults (29 females: 24.34 [2.45] y, height 163.65 [7.57] cm, mass 63.64 [7.94] kg; 20 males: 26.00 [3.70] y, height 180.11 [7.16] cm, mass 82.97 [12.78] kg). INTERVENTION(S): The participants completed the modified clinical test of sensory interaction in balance on the Biodex BioSway™ with 2 additional conditions (head shake and firm surface; head shake and foam surface) and the Sensory Organization Test and Head Shake Sensory Organization Test on the NeuroCom Smart Equitest. MAIN OUTCOME MEASURES: Interclass correlation coefficient and Bland-Altman limits of agreement for Sway Index, equilibrium ratio, and area of 95% confidence ellipse. RESULTS: Fair-good reliability (interclass correlation coefficient = .48-.65) was demonstrated for the stance conditions with eyes open on a firm surface. The Head Shake Sensory Interaction and Balance Test condition on a firm surface resulted in fair reliability (interclass correlation coefficient = .50-.59). The authors observed large ranges for limits of agreement across outcome measures, indicating that the systems should not be used interchangeably. CONCLUSIONS: The authors observed fair reliability between BioSway™ and NeuroCom, with better agreement between systems with the assessment of postural sway on firm/static surfaces. However, the agreement of these systems may improve by incorporating methods that mitigate the floor effect in an athletic population (eg, including a head shake condition). BioSway™ may provide a surrogate field-expedient measurement tool.

SCORING PERFORMANCE VARIATIONS BETWEEN THE Y-BALANCE TEST, A MODIFIED Y-BALANCE TEST, AND THE MODIFIED STAR EXCURSION BALANCE TEST.

BACKGROUND: The Modified Star Excursion Balance Test (MSEBT) and the Y-Balance Test- Lower Quarter (YBT-LQ) are utilized to assess dynamic postural stability. These assessments cannot be used interchangeably secondary to kinematic variations and performance differences. A Modified Y-Balance Test-Lower Quarter (MYBT-LQ) was developed to determine if a modification allows performance scores to be directly compared to the MSEBT. PURPOSE: The purpose of this research was to determine if reach distances were similar for young, healthy individuals between three different balance tests: the YBT-LQ, the MYBT-LQ, and the MSEBT. STUDY DESIGN: Repeated measures, descriptive cohort study. METHODS: Twenty-eight participants (17 males, 11 females) were recruited from a convenience sample of young, healthy adults. Participants completed all testing within a single session and performed three trials in each direction, on each leg, for all balance tests. Scoring performance was calculated for each balance test using the average normalized reach distance in the anterior, posterolateral, and posteromedial directions. A one-way ANOVA was used to compare between-subject posteromedial and posterolateral scores, while anterior scores were analyzed using a Kruskal Wallis test. The intraclass correlation coefficient (ICC) was used to determine within-subject participant performance reliability. RESULTS: Analyses indicated significant differences in the posterolateral and posteromedial reach directions between the YBT-LQ and MSEBT and between the MYBT-LQ and MSEBT, while no significant difference was found between the YBT-LQ and MYBT-LQ in any direction. No anterior reach differences were noted between any of the tests. Within-subject ICCs showed a very strong level of agreement between right and left anterior and right posteromedial reaches between all three tests, while only the YBT-LQ and MYBT-LQ demonstrated very strong agreement in all directions. CONCLUSION: Reach performance on the MSEBT differed from the performance on the YBT-LQ and MYBT-LQ in the anterior, posteromedial and posterolateral directions in this population. These findings further support the difference in motor control strategies used during these tests. LEVELS OF EVIDENCE: 2c.

Fascial manipulation vs. standard physical therapy practice for low back pain diagnoses: A pragmatic study.

BACKGROUND: Connective tissue mobility alters motor unit recruitment, but the restoration of fascial mobility allows for optimal motor function. The Fascial Manipulation® (FM®) method is a multiplanar approach that assesses and treats the mobility of deep fascia in specific anatomical locations where motor units converge. OBJECTIVES: To assess the effects of FM® vs. standard physical therapy treatment (SPT) in patients with low back pain (LBP). DESIGN: Six-months controlled clinical trial. METHOD: 102 participants with LBP received SPT or FM®. Numeric Pain Rating Scale (NPRS), 15- point Global Rating of Change (GROC), and Oswestry Disability Index (ODI) were used to monitor progress. RESULTS: The FM® group had a significantly lower ODI (p < 0.009) and NPS scores (p < 0.0001) and significantly higher GROC scores (p < 0.003) once their means were adjusted for initial scores. When comparing the SPT to FM®, the final ODI decreased by at least 1 category in 48.9% of the SPT cases, while in 36.2% of the cases was no change. ODI minimal clinical importance difference (MCID) change of 10% decrease in scores occurred in 70.2% of the SPT group compared to 96% of the FM® group (p = 0.003). ODI MCID change of 50% decrease in scores occurred in 40% of the SPT group compared to 64.6% of the FM® group (p = 0.02) 44.7% of the participants in the SPT group had final GROC values above +5 at discharge, compared to 92% of the participants from the FM® group (p = 0.0001). The FM® subjects had almost three times the change in NPRS compared to SPT counterparts (-4.3 ±â€¯2.2 to -1.5  ± 2.4, p=0.0001). CONCLUSIONS: FM® appears to improve NPRS, GROC, and ODI more than SPT. FM® may provide an effective treatment technique for LBP.

A commentary review of the cost effectiveness of manual therapies for neck and low back pain.

BACKGROUND & PURPOSE: Neck and low back pain (NLBP) are global health problems, which diminish quality of life and consume vast economic resources. Cost effectiveness in healthcare is the minimal amount spent to obtain acceptable outcomes. Studies on manual therapies often fail to identify which manual therapy intervention or combinations with other interventions is the most cost effective. The purpose of this commentary is to sample the dialogue within the literature on the cost effectiveness of evidence-based manual therapies with a particular focus on the neck and low back regions. METHODS: This commentary identifies and presents the available literature on the cost effectiveness of manual therapies for NLBP. Key words searched were neck and low back pain, cost effectiveness, and manual therapy to select evidence-based articles. Eight articles were identified and presented for discussion. RESULTS: The lack of homogeneity, in the available literature, makes difficult any valid comparison among the various cost effectiveness studies. DISCUSSION: Potential outcome bias in each study is dependent upon the lens through which it is evaluated. If evaluated from a societal perspective, the conclusion slants toward "adequate" interventions in an effort to decrease costs rather than toward the most efficacious interventions with the best outcomes. When cost data are assessed according to a healthcare (or individual) perspective, greater value is placed on quality of life, the patient's beliefs, and the "willingness to pay."