Machine Learning Based Linking of Patient Reported Outcome Measures to WHO International Classification of Functioning, Disability, and Health Activity/Participation Categories

BACKGROUND

In the primary and secondary medical health sector, patient reported outcome measures (PROMs) are widely used to assess a patient's disease-related functional health state. However, the World Health Organization (WHO), in its recently adopted resolution on "strengthening rehabilitation in all health systems", encourages that all health sectors, not only the rehabilitation sector, classify a patient's functioning and health state according to the International Classification of Functioning, Disability and Health (ICF).

AIM

This research sought to optimize machine learning (ML) methods that fully and automatically link information collected from PROMs in persons with unspecific chronic low back pain (cLBP) to limitations in activities and restrictions in participation that are listed in the WHO core set categories for LBP. The study also aimed to identify the minimal set of PROMs necessary for linking without compromising performance.

METHODS

A total of 806 patients with cLBP completed a comprehensive set of validated PROMs and were interviewed by clinical psychologists who assessed patients' performance in activity limitations and restrictions in participation according to the ICF brief core set for low back pain (LBP). The information collected was then utilized to further develop random forest (RF) methods that classified the presence or absence of a problem within each of the activity participation ICF categories of the ICF core set for LBP. Further analyses identified those PROM items relevant to the linking process and validated the respective linking performance that utilized a minimal subset of items.

RESULTS

Compared to a recently developed ML linking method, receiver operating characteristic curve (ROC-AUC) values for the novel RF methods showed overall improved performance, with AUC values ranging from 0.73 for the ICF category d850 to 0.81 for the ICF category d540. Variable importance measurements revealed that minimal subsets of either 24 or 15 important PROM variables (out of 80 items included in full set of PROMs) would show similar linking performance.

CONCLUSIONS

Findings suggest that our optimized ML based methods more accurately predict the presence or absence of limitations and restrictions listed in ICF core categories for cLBP. In addition, this accurate performance would not suffer if the list of PROM items was reduced to a minimum of 15 out of 80 items assessed.

The Back Muscle Surface Electromyography-Based Fatigue Index: A Digital Biomarker of Human Neuromuscular Aging?

As part of our quest for digital biomarkers of neuromuscular aging, and encouraged by recent findings in healthy volunteers, this study investigated if the instantaneous median frequency (IMDF) derived from back muscle surface electromyographic (SEMG) data monitored during cyclic back extensions could reliably differentiate between younger and older individuals with cLBP. A total of 243 persons with cLBP participated in three experimental sessions: at baseline, one to two days after the first session, and then again approximately six weeks later. During each session, the study participants performed a series of three isometric maximal voluntary contractions (MVC) of back extensors using a dynamometer. These were followed by an isometric back extension at 80% MVC, and—after a break—25 slow cyclic back extensions at 50% MVC. SEMG data were recorded bilaterally at L5 (multifidus), L2 (longissimus dorsi), and L1 (iliocostalis lumborum). Linear mixed-effects models found the IMDF-SEMG time-course changes more rapidly in younger than in older individuals, and more prominently in male participants. The absolute and relative reliabilities of the SEMG time–frequency representations were well compared between older and younger participants. The results indicated an overall good relative reliability, but variable absolute reliability levels. IMDF-SEMG estimates derived from cyclic back extensions proved to be successful in reliably detecting differences in back muscle function in younger vs. older persons with cLBP. These findings encourage further research, with a focus on assessing whether an IMDF-SEMG-based index could be utilized as a tool to achieve the preclinical detection of back muscle aging, and possibly predict the development of back muscle sarcopenia.

Do the WHO-ICF personal factors "age" and "sex" impact limited activity and restricted participation category profiles differently between younger and older women and men in multimodal chronic back pain rehabilitation?

PURPOSE

To investigate if the International Classification of Functioning and Health (ICF) context factors "age" and "sex" would impact the disablement and respective improvement with rehabilitation defined with the ICF core set for chronic low back pain (cLBP). Furthermore, associations between limitations/restrictions and measures of body function or quality of life were of interest.

MATERIALS AND METHODS

One thousand five hundred and twelve employed cLBP patients who completed 6 months of outpatient rehabilitation and for whom complete assessments were available before and after rehabilitation. Rehabilitation comprised of progressive resistance training, psychological counseling, and educational sessions. Main outcome measures were the ICF-activity/participation core categories automatically predicted from random forests and utilizing information from the Roland Morris Disability Questionnaire and Pain Disability Index.

RESULTS

Generalized linear-mixed models revealed that upon completion of rehabilitation the presence of a limitation within the ICF activity "walking" significantly decreased with significant between-group differences. The category "doing housework" demonstrated gender-specific differences, and both gender- and age-specific differences were observed for work-related participation categories. There were no meaningful associations between ICF limitation/restriction categories and body function measures (point-biserial/Spearman's correlations).

CONCLUSIONS

The personal factors "age" and "sex" impact some ICF limitation/restriction categories in cLBP; appropriately addressing these personal features could further improve phase III rehabilitation outcome.Implications for rehabilitationConsistent with calls to explore the age and sex/gender influence on health and disease, little is known how these factors affect the disablement of individuals with chronic back pain.The factors "age" and "sex" drive differences in some categories within the ICF activity/restriction categories.If age- and gender-specific features in activities and participation are not appropriately addressed through interventions, rehabilitation outcome may remain suboptimal in cLBP.

Perceived psychosocial stressors and coping resources in chronic low back pain patients as classified by the avoidance-endurance model

Objectives

The Avoidance-Endurance Model distinguishes between subgroups of low back pain (LBP) patients with three maladaptive styles of coping with pain: fear-avoidance (FAR), distress-endurance (DER), eustress-endurance (EER), and one adaptive coping style (AR). This study aimed to compare the quantity of patients' perceived psychosocial stressors and coping resources across these subgroups.

Materials and methods

This cross-sectional study was conducted at an outpatient rehabilitation center for patients with chronic musculoskeletal pain. One hundred and thirty-seven patients (69 women/68 men) with chronic LBP were assessed using the following: a demographic checklist, the visual analogue scale, Avoidance-Endurance Questionnaire, Roland-Morris Disability Questionnaire, Pain Disability Index, and 36-Item Short Form. Subsequently, patients participated in semi-structured interviews led by clinical psychologists, which were intended to identify their perception of stressors and coping resources. The quantity of psychosocial stressors and coping resources were analyzed using deductive and inductive content analyses and then compared between subgroups using chi-square-tests.

Results

FARs experienced significantly higher levels of “mental suffering” (p = <0.001) and “other workplace problems” compared to ARs and EERs (p = <0.001). DERs reported significantly higher levels of “mental suffering” (p = <0.001), “job stress” (p = 0.022), and “familial losses” (p = 0.029) compared to ARs, whereas the AR group demonstrated significantly more “coping resources” (p = 0.001) compared to FARs.

Conclusion

AEM-subgroups differed in the quantity of perceived psychosocial stressors and coping resources with AR, who demonstrated a lower risk for pain chronicity and reported the highest quantity of resources. The variability across subgroups may imply differences in patientś needs regarding therapeutic interventions and suggests that a resource-centered approach to cope with stress and pain may be beneficial.

Changes in the International Classification of Functioning, Disability, and Health Components "Activity/Participation" as Predicted Through Patient-Reported Outcomes Along With Comprehensive Back Pain Rehabilitation

OBJECTIVES

The World Health Organization (WHO) recommended the International Classification of Functioning, Disability and Health (ICF) but its use in clinical practice is sparse. This study investigated the limitations and restrictions in the most relevant brief ICF core set categories for chronic low back pain (cLBP) as automatically predicted from routinely measured outcomes using a novel, validated mapping algorithm.

MATERIALS AND METHODS

Of 2718 cLBP patients recruited, data from 1541 (64% females) were available from before and at the end of 6 months comprehensive outpatient rehabilitation. Assessments included the Roland Morris Disability Questionnaire (RMDQ) and Pain Disability Index (PDI) questionnaires, the percentage of patients with predicted limitations and restrictions in important activity and participation ICF categories, bodily functional measurements, pain intensity, and anxiety/depression (EQ-5D).

RESULTS

At baseline, both the RMDQ and the PDI measures were within the third of the lowest disability scores whilst 80% of the patients had limitations with "maintaining a body position" and 30% with "walking" ICF categories. Intervention-associated gains in the maximum isometric lumbar extension and flexion strength and the lumbar range of motion were significant overall, but improvements in patients' ICF limitations/restrictions varied. Anxiety/depression, lumbar range of motion, and extension strength all had a significant impact on the majority of the ICF categories, whereas flexion strength had none.

DISCUSSION

The rate of patients with predicted limitations/restrictions in activity/participation ICF core categories for cLBP partly mirrored disability levels and the impact of the body function scores on these limitations/restrictions in ICF categories was varied. Thus, assessing problems in the ICF activity/participation core categories is of relevance to clinical practice for both treatment goal setting and intervention planning. This may be achieved by computer-generated mapping without additional time burden.

In-depth analysis of life values and their corresponding inhibitors and facilitators in chronic low back pain patients: A mixed-method approach

BACKGROUND

The struggle with pain often interferes with the ability of chronic low back pain (CLBP) patients to pursue important life values due to psychological inflexibility.

OBJECTIVE

This research examined life values, related inhibitors and facilitators relevant to personalized therapy planning.

METHODS

Two hundred and forty-four CLBP patients completed the Chronic Pain Values Inventory (CPVI). Of these, 68 patients were interviewed to assess inhibitors and facilitators related to life values. Mixed-effects models quantitatively examined differences in the values, structuring content analysis served to qualitatively analyze the interviews.

RESULTS

Participants rated the value "family" as being of highest importance and success. The largest discrepancy between importance and success was found for "health". Content analyses revealed a broad range of inhibitors and facilitators related to the examined life values with the highest number of inhibitors related to "work". Facilitators were also found to be of relevance to all life values, but to a lower extent than inhibitors.

CONCLUSIONS

The perceived importance and success of life values and their related inhibitors and facilitators may differentially affect CLBP patients. Considering such individual aspects is therefore of utmost importance to improve patient care, as they enable treatment goals and the therapeutic strategies to be adapted accordingly.

Cardiopulmonary response to high-altitude mountaineering in lung transplant recipients-The Jebel Toubkal experience

OBJECTIVES

Only a small proportion of lung transplant recipients achieve a physical status comparable to healthy individuals in the long term. It is reasonable to hypothesize that the necessary cardiopulmonary adaptation required for strenuous physical exercise may be impaired. Exposure to high altitude provides an optimal platform to study the physiological cardiopulmonary adaptation in lung transplant recipients under aerobic conditions. To gain a deeper understanding, 14 healthy lung transplant recipients and healthcare professionals climbed the highest peak in North Africa (Mount Jebel Toubkal; 4167 m) in September 2019.

METHODS

Monitoring included daily assessment of vital signs, repeated transthoracic echocardiography, pulmonary function tests, and capillary blood sampling throughout the expedition.

RESULTS

Eleven out of fourteen lung transplant recipients reached the summit. All recipients showed a stable lung function and vital parameters and physiological adaptation of blood gases. Similar results were found in healthy controls. Lung transplant recipients showed worse results in the 6-minute walk test at low and high altitude compared to controls (day 1: 662 m vs. 725 m, p < 0.001, day 5: 656 m vs. 700 m, p = 0.033) and a lack of contractile adaptation of right ventricular function with increasing altitude as measured by tricuspid plane systolic excursion on echocardiography (day 2: 22 mm vs. 24 mm, p = 0.202, day 5: 23 mm vs. 26 mm, p = 0.035).

CONCLUSIONS

Strenuous exercise in healthy lung transplant recipients is safe. However, the poorer cardiopulmonary performance in the 6-minute walk test and the lack of right ventricular cardiac adaptation may indicate underlying autonomic dysregulation.

Mapping patient reported outcome measures for low back pain to the International Classification of Functioning, Disability and Health using random forests

BACKGROUND

There is need for feasible and efficient concepts to document patients functioning impairment according to the International Classification of Functioning, Disability and Health (ICF) without imposing additional burden to clinical practice.

AIM

The aim of this study was to develop and validate an automatic linking approach that translates information derived from patient reported outcome measures (PROMs) into the ICF.

DESIGN

Proof-of-concept study.

SETTING

Participants completed both the Roland-Morris disability questionnaire and the Pain Disability Index and were interviewed using the activity and participation component of the ICF brief core set for low back pain.

POPULATION

A total of 244 patients with light to moderate chronic low back pain (cLBP); additionally, 19 patients with higher levels of pain were recruited and assessed for validation purposes.

METHODS

Based on information extracted from the PROMs and considering the factors age and gender, random forest models that predicted the presence or absence of an impairment at the specific ICF category were computed and validated.

RESULTS

Accuracy of the models was found to be acceptable for the most relevant ICF brief core set categories for low back pain if applied at the population level.

CONCLUSIONS

The presented approach can be assumed valid if applied at large on population level. The results are of relevance for the further development of automatic linking programs that would allow the ICF-based classification of functioning properties within the International Classification of Diseases (ICD-11) for any health condition.

CLINICAL REHABILITATION IMPACT

The presented approach eases the documentation of patients' functioning impairment according to the standardized ICF.

Age-specific differences in the time-frequency representation of surface electromyographic data recorded during a submaximal cyclic back extension exercise: a promising biomarker to detect early signs of sarcopenia

PURPOSE

Motivated by the goal of developing new methods to detect early signs of sarcopenia, we investigated if surface electromyographic (SEMG) data recorded during the performance of cyclic, submaximal back extensions are marked by age-specific differences in their time and frequency characteristics. Furthermore, day-to-day retest reliability of the EMG measures was examined.

METHODS

A total of 86 healthy volunteers used a back dynamometer to perform a series of three maximal voluntary contractions (MVC) consisting of isometric back extensions, followed by an isometric back extension at 80% MVC, and finally 25 slow cyclic back extensions at 50% MVC. SEMG data was recorded bilaterally at L1, L2, and L5 from the iliocostalis lumborum, longissimus, and multifidus muscles, respectively. Tests were repeated two days and six weeks later. A linear mixed-effects model with fixed effects "age, sex, test number" and the random effect "person" was performed to investigate age-specific differences in both the initial value and the time-course (as defined by the slope of the regression line) of the root mean square (RMS-SEMG) values and instantaneous median frequency (IMDF-SEMG) values calculated separately for the shortening and lengthening phases of the exercise cycles. Generalizability Theory was used to examine reliability of the EMG measures.

RESULTS

Back extensor strength was comparable in younger and older adults. The initial value of RMS-SEMG and IMDF-SEMG as well as the RMS-SEMG time-course did not significantly differ between the two age groups. Conversely, the IMDF-SEMG time-course showed more rapid changes in younger than in older individuals. Absolute and relative reliability of the SEMG time-frequency representations were comparable in older and younger individuals with good to excellent relative reliability but variable absolute reliability levels.

CONCLUSIONS

The IMDF-SEMG time-course derived from submaximal, cyclic back extension exercises performed at moderate effort showed significant differences in younger vs. older adults even though back extension strength was found to be comparable in the two age groups. We conclude that the SEMG method proposed in this study has great potential to be used as a biomarker to detect early signs of sarcopenic back muscle function.

Myostatin and other musculoskeletal markers in lung transplant recipients

Recipients of lung transplantation (LuTx) may experience impaired muscle function and bone metabolism even after rehabilitation. We investigated the potential use of musculoskeletal markers in identifying the impairment of muscle function and bone function in these patients. Biochemical parameters, bodily functions, and lung function of 37 LuTx recipients were evaluated at the time of their discharge from the hospital stay and about 6 months later. The biomarkers were also assessed in 30 healthy age and gender distribution-matched controls. Compared to controls, the negative muscle regulator myostatin was elevated in LuTx recipients at baseline and follow-up, whereas its opponent follistatin only showed a group-specific difference at follow-up. LuTx recipients had reduced serum levels of sclerostin and increased levels of dickkopf 1 and periostin. Lung function and physical function were improved during follow-up. The change in lung function was correlated with the change in chair-rising time and the 6-min walking test. At follow-up, all musculoskeletal markers of LuTx recipients differed from those of controls, thus reflecting their still reduced lung function and bodily functions. Among the tested biomarkers, myostatin, sclerostin, dickkopf 1, and periostin were useful to detect impaired musculoskeletal function in LuTx recipients. Myostatin may serve as a target of treatment in the future.

Rheumatoid arthritis in remission : Decreased myostatin and increased serum levels of periostin

Background

Chronic inflammation of rheumatoid arthritis (RA) is associated with disturbances in muscle and bone metabolism.

Aim

The purpose of this study was to investigate whether endocrine regulators of myogenesis and bone metabolism in patients with rheumatoid arthritis (RA) in remission differed from unaffected healthy controls. An additional point was whether these were associated with patients’ health-related functioning or particular bodily functions of the International Classification of Functioning, Disability and Health (ICF).

Methods

Bone turnover and the markers for muscle, i.e. myostatin (MSTN), follistatin (FSTN), growth differentiation factor (GDF-15) and for bone, i.e. sclerostin (SOST), dickkopf 1 (Dkk1), periostin (PSTN) metabolism were determined in 24 female RA patients and matched healthy controls. The chair rising test (CRT), timed up and go test (TUG), 6 min walking test, maximum hand grip and back extensor strength tests were used to assess patients’ health-related functions. Additionally, bone mineral density of the lumbar spine and the hip region was measured.

Results

For the bone turnover markers no differences were observed between patients and controls. In contrast, the markers MSTN and Dkk1 were significantly lower and FSTN and PSTN significantly higher in patients than controls. Patients performed worse in the CRT and TUG. Some correlations reflected associations between these endocrine factors and physical function.

Conclusion

Anti-inflammatory therapy may be responsible for the positive effect on endocrine factors influencing myogenesis. Elevation of PSTN probably reflects the increased risk of fragility fractures in RA patients.

Predictors of an unfavorable outcome 1.5 and 12 years after a first, uncomplicated lumbar disc surgery

PURPOSE

To identify predictors of both intermediate and long-term unfavorable outcomes after first time, uncomplicated lumbar disc surgery.

METHODS

Patients (n = 120) who had undergone lumbar disc surgery were followed up 1.5 and 12 years thereafter. Baseline assessments were carried out 5-8 days after surgery. Clinical outcome was assessed in both follow-ups using the Low Back Pain Rating Scale. Statistical analysis included binary logistic and linear regression.

RESULTS

Unfavorable outcomes were found in 50.5 % (1.5 years) and 52.6 % (12 years) of patients available for follow-up examination. Low pre-operative physical activity and severe pain in the first week after surgery were predictive of an unfavorable post-operative outcome at both follow-ups.

CONCLUSIONS

Identified predictors suggest that particular emphasis should put on comprehensive post-operative care at large and encouragement to adapt a physically active lifestyle in particular in rehabilitation concepts after first time uncomplicated lumbar disc surgery.

Age and gender related neuromuscular pattern during trunk flexion-extension in chronic low back pain patients

BACKGROUND

The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from standing has repeatedly been recommended to objectively assess muscle function in chronic low back pain patients. However, literature addressing older patients is sparse. This cross sectional study sought to examine differences in neuromuscular activation between age groups (>60 versus 40-60 versus <40 years) and sexes during a standardized trunk flexion-extension task.

METHODS

A total of 216 patients (62 older, 84 middle-aged, 70 younger) performed maximum trunk extensions followed by trunk flexion extension testing thereby holding static positions at standing, half, and full trunk flexion. The lumbar extensor muscle activity and 3d-accelerometric signals intended to monitor hip and trunk position angles were recorded from the L5 (multifidus) and T4 (semispinalis thoracis) levels. Permutation ANOVA with bootstrapped confidence intervals were performed to examine for age and gender related differences. Ridge-regressions investigated the impact of physical-functional and psychological variables to the half flexion relaxation ratio (i.e. muscle activity at the half divided by that in maximum flexion position).

RESULTS

Maximum back extension torque was slightly but significantly higher in youngest compared to oldest patients if male and females were pooled. Normalized RMS-SEMG revealed highest lumbar extensor muscle activity at standing in the oldest and the female groups. Patients over 60 years showed lowest activity changes from standing to half (increments) and from half to the maximum flexion position (decrements) leading to a significantly lower half flexion relaxation ratio compared to the youngest patients. These oldest patients demonstrated the highest hip and lowest lumbothoracic changes of position angles. Females had higher regional hip and gross trunk ranges of movement compared to males. Lumbothoracic flexion and the muscle activity at standing had a significant impact on the half flexion relaxation ratio.

CONCLUSIONS

The neuromuscular activation pattern and the kinematics in this trunk flexion-extension task involving static half flexion position changed according to age and sex. The test has a good potential to discriminate between impaired and unimpaired neuromuscular regulation of back extensors in cLBP patients, thereby allowing the design of more individualized exercise programs.

Age and gender related neuromuscular changes in trunk flexion-extension

BACKGROUND

The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from a standing position and task specific spine ranges of motion objectively assess muscle function in healthy young and middle age individuals. However, literature on neuromuscular activation and associated spine and hip kinematics in older individuals is sparse. This cross sectional study sought to examine the sex and age (<40 versus >60 years) related differences in the neuromuscular activation profiles of the lumbar extensors and the related spine and hip kinematics from healthy individuals during a standardized trunk flexion-extension task.

METHODS

Twenty five older (13 females, 60-90 years) and 24 younger (12 females, 18-40 years) healthy individuals performed trunk flexion-extension testing by holding static positions at half-flexion way and full range of motion between standing and maximum trunk flexion. The associated lumbar extensor muscle activity was derived from measurements at standing, half, and maximum flexion positions. The range of motion at the hip and lumbar spine was recorded using 3d accelerometers attached to the skin overlying the multifidus and semispinalis thoracis muscles lateral to the L5 and T4 spinous processes, respectively. Statistical calculations were performed using a permutation ANOVA with bootstrap confidence intervals.

RESULTS

The muscle activity in the half related to the maximum flexion position (half flexion relaxation ratio) was significantly smaller in older males when compared with younger males. Moreover, measurements revealed smaller activity changes from standing to the half and from half to the maximum flexion position in older compared to younger individuals. Older males displayed smaller gross trunk range of motion from standing to maximum flexion than any other group.

CONCLUSIONS

Gender and normal aging significantly affect both the activation patterns of the lumbar extensor muscles and the kinematics of the trunk during a standardized trunk flexion-extension task. Measurement results from healthy young and middle age individuals should not be used for the assessment of individuals older than 60 years of age.

The potential use of spectral electromyographic fatigue as a screening and outcome monitoring tool of sarcopenic back muscle alterations

Background

To examine whether or not median frequency surface electromyographic (MF-EMG) back muscle fatigue monitoring would be able to identify alterations in back muscle function in elderly muscles, if a protocol was used that allowed optimum standardization of the processes underlying electromyographic fatigue, and whether these tests were reliable from day to day.

Methods

A total of 42 older (21 females; 67 (±10.5) years old) and 44 younger persons (19 females; 33 (±10) years) performed maximum isometric back extensions which were followed by one 30 s lasting 80% submaximum extension. Participants were seated on a dynamometer with their trunks 30° anteflexed, and they repeated all tests after 1-2 days and 6 weeks. SEMG was recorded bilaterally from the L1 (iliocostalis lumborum), L2 (longissimus), and L5 (multifidus) recording sites. Outcome variables included maximum back extension torque, initial MF-EMG (IMF-EMG), MF-EMG slope declines, and individual MF-EMG muscular imbalance scores. Two-factorial ANOVAs served to examine the age and gender-specific effects, and models from Generalizability Theory (G-Theory) were used for assessing retest-reliability.

Results

Maximum back extension moment was non-significantly smaller in elders. IMF-EMG was overall higher in elders, with significant differences at the L5 recordings sites. In the elderly, MF-EMG fatigue declines were significantly smaller in L5, in the recording with the most negative slope, or if the slope of all electrodes was considered. Retest reliability was unanimous in young and older persons. ICC-type measurements from G-Theory of both the IMF and the fatigue slopes ranged from 0.7 to 0.85. Absolute SEM values were found clinically acceptable for the IMF-EMG, but relatively high for the fatigue slope declines.

Conclusions

The MF-EMG fatigue method is able to elucidate alterations of aging back muscles. This method, thus, might be suggested as a potential biomarker to objectively identify persons at risk for sarcopenia. Considering the clinical relevance of the IMF-EMG relative to the MF-EMG slope declines, spectral EMG may also be used as an outcome monitoring tool in elderly populations.

Reliability of isometric trunk moment measurements in healthy persons over 50 years of age

OBJECTIVE

To determine the short- and long-term test-retest reliability of maximum isometric trunk moment measurements in healthy volunteers over 50 years of age, to compare these results with those from volunteers younger than 50 years, and to test whether volunteers' anticipatory emotional state affects the precision of these measurements.

METHODS

Forty-two older persons (21 females; age range 50-90 years) and 44 younger persons (19 females; age range 18-49 years) performed maximum isometric trunk extensions, flexions, and rotations using dynamometers (DAVID, Fi, David Health Solutions Ltd, Helsinki, Finland). They repeated the tests after 1-2 days (short-term) and at 6 weeks (long-term). Retest-reliability was evaluated for age- and gender-specific subgroups, with assessment of intraclass correlation coefficient (ICC2,1) , standard error of measurement, smallest real difference, and smallest real difference, in percent.

RESULTS

For the elderly group, smallest real difference, in percent values varied up to 33% and were similar to those obtained from young volunteers. Precision of the trunk rotation tests was lower than that of trunk flexion or extension. Retest agreement exceeded 0.75 (ICC2,1) for all tests, with no relevant differences observed between gender- and age-specific subgroups. Neither participants' motivation nor their anticipatory emotions correlated with the individual coefficients of variation of the trunk muscle moment measurements.

CONCLUSION

Isometric maximum trunk extension and flexion moment measurements taken from healthy persons > 50 years old are as reliable as those from persons < 50 years old, and can be expected to enable an acceptable level of detection of expected changes in muscle strength parameters as a result of planned exercise interventions.

A systematic review on the effectiveness of medical training therapy for subacute and chronic low back pain

Medical training therapy (MTT) to improve muscular strength and endurance follows evidence based guidelines and is increasingly recommended to patients suffering from subacute and chronic back pain (LBP). This study investigated whether MTT was effective in reducing pain and improving function in patients with subacute or chronic LBP. Data sources were MEDLINE, EMBASE, CINAHL, Pedro, Cochrane Central Register of Controlled Trials. We included RCTs that examined exercise or MTT in adult patients with LBP compared to placebo, no intervention or other interventions. Study outcomes had to include at least one of the following: pain intensity; functional status, absenteeism. Two independent reviewers performed quality assessment. Visual analogue scale ratings ranging from 0-10 MTT quantified the MTT aspects of the intervention. Studies with rating scores >7.5 were included. We identified only 2 studies that examined the effectiveness of MTT. Both trials, one was of high quality, found MTT to decrease pain and improve function significantly better than therapy of uncertain effectiveness. There is moderate evidence that would support the effectiveness of MTT in the treatment chronic LBP. Future high quality RCT will have to clarify whether MTT is effective and would be superior to other forms of therapeutic exercise.

ICF Core Sets for osteoarthritis

OBJECTIVE

To report on the results of the consensus process integrating evidence from preliminary studies to develop the first version of a Comprehensive ICF Core Set and a Brief ICF Core Set for osteoarthritis.

METHODS

A formal decision-making and consensus process integrating evidence gathered from preliminary studies was followed. Preliminary studies included a Delphi exercise, a systematic review, and an empirical data collection. After training in the ICF and based on these preliminary studies relevant ICF categories were identified in a formal consensus process by international experts from different backgrounds.

RESULTS

The preliminary studies identified a set of 388 ICF categories at the second, third, and fourth ICF levels with 144 categories on body functions, 49 on body structures; 165 on activities and participation, and 43 on environmental factors. Seventeen experts from 7 different countries attended the consensus conference on osteoarthritis. Altogether 55 second-level categories were included in the Comprehensive ICF Core Set with 13 categories from the component body functions, 6 from body structures, 19 from activities and participation, and 17 from environmental factors. The Brief ICF Core Set included a total of 13 second-level categories (3 on body functions, 3 on body structures, 3 on activities and participation, and 4 on environmental factors).

CONCLUSION

A formal consensus process integrating evidence and expert opinion based on the ICF framework and classification led to the definition of ICF Core Sets for osteoarthritis. Both the Comprehensive ICF Core Set and the Brief ICF Core Set were defined.

Cross-cultural adaption of the manniche questionnaire for german-speaking low back pain patients

OBJECTIVE

To develop and validate a cross-cultural version of the Manniche Low Back Pain Rating Scale (MRS) for use in German-speaking low back pain patients.

BACKGROUND

Clinical intervention research in back pain would be enormously facilitated if a small number of relevant, patient-centred questionnaires became internationally used. MRS seems to be particularly suitable for cross-cultural adaptation due to its coverage of multidimensional back pain-specific health domains.

METHODS

MRS was translated and back-translated, pretested and reviewed by a committee. The German version was tested in 126 patients with low back pain from all countries of German-speaking Europe. Reliability (subsample n = 20), dimensionality and construct validity was assessed. Single-dimensionality, higher correlations of MRS with the physical scales compared with the mental scales of the MOS SF-36, a moderate to good correlation with the Roland Morris Questionnaire and a low correlation with the Finger Floor Distance were hypothesized.

RESULTS

Spearman's Rho for test-retest reliability was 0.98 (p < 0.001); Cronbach's alpha 0.95. Factor analysis revealed only 1 factor with an Eigenvalue >1 [3.25]. MRS was strongly correlated with the Roland Morris Questionnaire (r = 0.91), and slightly correlated with the Finger Floor Distance (r = 0.23). Correlations of MRS with domains of the SF-36 "Physical Functioning", "Role Physical" and "Bodily Pain" were higher (r -0.66 to -0.72) than with "Role Emotional", "Mental Health" and "Social Functioning" (r -0.34 to -0.61).

CONCLUSION

The German version of the MRS seems to be reliable, uni-dimensional and construct valid for the assessment of functional status in German-speaking low back pain patients.

Reliability of pelvic floor muscle strength measurement in elderly incontinent women

Pelvic floor muscles (PFM) play an important role in maintaining urinary continence with increasing age. Therefore, their contractile properties need to be evaluated. The aim of the study was to examine the reliability and correlation of simple techniques to measure PFM strength in elderly women with urinary incontinence. An interview was used to evaluate the ability to stop the urinary stream during micturition and to calculate the incontinence index. A pad test was applied to objectively evaluate the severity of the disease. Functional testing included a digital examination to measure the force and duration of one contraction, a perineometer measurement (Peritron) to assess maximal contraction force and contraction force of 5 s, and a cone-retention test (Femcon) while walking for 1 min and during Valsalva's manoeuvre. This procedure was performed on three separate occasions within one week. The 37 participating women with a mean age of 62+/-8 (mean+/-SD) years had a severity index of 4.4+/-2.6 and a urine loss of 9.5+/-13.6 mg during the pad test. Sixteen women were able to completely stop the urinary stream during micturition. The digital examination showed no intratester variability. The perineometer measurement showed that the absolute difference in maximal contraction force and mean contraction force within 5 s was less than 5.3 mm Hg and 4.5 mm Hg, respectively, with a probability of 0.95. While walking and during Valsalva's manoeuvre, 19 and 20 women, respectively, held the same cone in place on all three occasions. The maximal contraction force and mean force during the 5-s contraction correlated well with the ability to stop the urinary stream and the digital examination but only weakly with the cone-retention tests. The reliability of PFM strength measurement is highest in the digital examination, followed by perineometer measurements, and then by vaginal cone tests. As PFM function is easy to assess, it should be routinely done in the assessment of urinary incontinence in elderly women.

Effectiveness of exercise therapy in patients with internal derangement of the temporomandibular joint

This study intended in evaluating the effectiveness of exercise therapy in patients with craniomandibular disorders (CMD). Twenty consecutive patients suffering from CMD with anterior disc displacement without reduction consulting a CMD service were included in the study if they met following criteria: (i) pain in the temporomandibular region, (ii) reduced incisal edge clearance (<35 mm), (iii) magnet resonance imaging confirmed anterior disc displacement without reduction and (iv) evidence of postural dysfunction. All patients were assigned to a waiting list, serving as a no-treatment control period, according to a before-after trial. The treatment consisted of active and passive jaw movement exercises, correction of body posture and relaxation techniques. A total of 18 patients completed the study, no adverse effects occurred. Following main outcome measures were evaluated: (1) pain at rest (2) pain at stress (3) impairment (4) mouth opening at base-line, before and after treatment and at 6 month follow-up. As a result of treatment pain, impairment and mouth opening improved significantly more than during control period (paired samples t-test P < 0.05). After treatment four patients had no pain at all (chi-square: P < 0.05) and only seven patients revealed an impaired incisal edge clearance after treatment. (chi-square Test, P < 0.001). At follow up, seven patients had no pain and experienced no impairment. Exercise therapy seems to be useful in the treatment of anterior disc displacement without reduction.

The effect of calisthenic home exercises on postmenopausal fractures--a long-term observational study

OBJECTIVES

To evaluate the long-term effects of calisthenic home exercises on the incidence of fractures in postmenopausal women.

DESIGN

Controlled long-term observational study.

METHODS

Postmenopausal women between 45 and 75 years of age who had been randomly assigned to an exercise or control group in the course of a previous study conducted 5-10 years ago, were invited for follow-up. The number of fractures before and during the observation time were recorded by means of a questionnaire. Vertebral deformities due to fractures were diagnosed by X-rays at entry and at follow-up. Walking speed, muscle strength, static posturography, and maximum oxygen uptake were measured in addition.

RESULTS

After an average follow-up time of 7.6+/-1.1 years, 73 women of the exercise group and 64 subjects of the control group were investigated. Thirty-three per cent (n=24) of the exercise group reported to have exercised continuously at least three times a week for 20 min. No intergroup differences between the compliant and non-compliant exercisers and the control group were seen in the number of fractures. However, the incidence of fracture was lowest in women with a baseline bone mass less than one standard deviation (SD) below the mean for young adults (high BMC) and highest in those with more than 2.5 SD below the mean for young adults (low BMC) (P<0.001, odds ratio 2.9 [95% CI, 1.59-5.39]).

CONCLUSION

This long-term follow-up did not produce any evidence that prescription of a calisthenic home exercise program may prevent fractures in postmenopausal women aged between 61+/-6.4 and 68+/-6.5 years.

[Evaluating rehabilitation progress by measuring thigh circumference]

QUESTION

Thigh girth measurements have been widely used to quantify rehabilitation progress following knee surgery, but the correlation between thigh girth and other functional measures has not been investigated. This study intended to investigate whether such a correlation exists.

METHODS

15 women with bilateral osteoarthrosis of the knee participated in this study. Isokinetic knee extensor strength, thigh girth and body mass were measured immediately before, then at six weeks and six months following cementless total knee arthroplasty.

RESULTS

The involved side showed clear pre-operative isokinetic knee extensor strength deficits, and slight reductions in thigh girth. Post-operatively, mean strength deficits were reduced, whereas differences in mean thigh girth became lager. Although thigh girth changes correlated well with body mass, they did not correlate with knee extensor strength.

CONCLUSION

Changes in thigh girth are mainly due to changes in body mass. Thigh girth measurement is of no use for the quantification of the rehabilitation progress in total knee arthroplasty.

Relationship between craniomandibular disorders and poor posture

The purpose of this research was to show that a relationship between craniomandibular disorders (CMD) and postural abnormalities has been repeatedly postulated, but still remains unproven. This study was intended to test this hypothesis. Twenty-five CMD patients (mean age 28.2 years) were compared with 25 gender and age matched controls (mean age 28.3 years) in a controlled, investigator-blinded trial. Twelve postural and ten muscle function parameters were examined. Measurements were separated into three subgroups, consisting of those variables associated with the cervical region, the trunk in the frontal plane, and the trunk in the sagittal plane. Within these subgroups, there was significantly more dysfunction in the patients, compared to control subjects (Mann-Whitney U test p < 0.001, p < 0.05, p < 0.01). Postural and muscle function abnormalities appeared to be more common in the CMD group. Since there is evidence of the mutual influence of posture and the craniomandibular system, control of body posture in CMD patients is recommended, especially if they do not respond to splint therapy. Whether poor posture is the reason or the result of CMD cannot be distinguished by the data presented here.

Aerobic capacity in adult dermatomyositis/polymyositis patients and healthy controls

OBJECTIVE

Assessment of myositis patients has relied on symptoms, strength testing, and serum muscle enzyme activity. Recently, functional assessments and evaluation of strength by dynamometry and of disease activity by magnetic resonance imaging have also been added. Aerobic testing in selected patients has been considered useful.

DESIGN

Case-control study.

SETTING

University Hospital, Vienna, Austria.

PATIENTS

Twenty-two subjects (8 outpatients with chronic dermatomyositis and 3 outpatients with chronic polymyositis, and 11 healthy controls) participated, allowing the identification of 11 case-control pairs matched by age (+/-3 years) and gender (mean age, 48+/-14 yrs; ratio of women to men, 18/4).

MAIN OUTCOME MEASURES

Target parameters were peak oxygen uptake (peak VO2) to estimate aerobic exercise capacity and peak isometric torque for muscle strength. Creatine phosphokinase (CPK) was measured to assess elevation of muscle enzymes.

RESULTS

The mean peak VO2 in patients with dermatomyositis/polymyositis was 15.3 mL/min/kg (SD = 5.8) and in the healthy controls 28.7 mL/min/kg (SD = 7.8). Cardiorespiratory capacity expressed as peak VO2 was thus significantly reduced at 53% (p = .0001) of the control value. Muscle strength expressed as peak isometric torque was significantly lower (p = .01) in patients (mean 148+/-73 Nm) when compared to the control group (mean 261+/-99 Nm). In myositis patients peak VO2 and peak isometric torque correlate well with each other (r = .7631; p = .0001), but not at all with serum CPK levels (r = .056; p = .869).

CONCLUSION

Peak VO2 is significantly diminished in patients with dermatomyositis/polymyositis, compared with age- and sex-matched controls. Serum CPK did not significantly correlate with VO2. Aerobic exercise testing may be a useful assessment parameter in selected patients with dermatomyositis/ polymyositis.

Cross-cultural adaptation of the Roland-Morris questionnaire for German-speaking patients with low back pain

STUDY DESIGN

Cross-cultural adaptation and cross-sectional psychometric testing.

OBJECTIVES

To develop and validate a cross-cultural version of the Roland-Morris Questionnaire for use in German-speaking patients with low back pain.

SUMMARY OF THE BACKGROUND DATA

Clinical research related to the management of back pain would be facilitated enormously if a small number of patient-oriented questionnaires became widely used. If the transposition of a questionnaire from its original cultural context is done by simple translation, it is unlikely to be successful because of language and cultural differences. Therefore, a simple direct translation of a questionnaire from one language to another does not permit its use in clinical trials.

METHODS

The instrument was translated and back-translated, pretested, and reviewed by a committee. The German version of the Roland-Morris Questionnaire was tested in 125 patients with low back pain. The study was conducted at the spa resort at Senftenberg, Austria, which is visited by patients from all countries of German-speaking Europe. Reliability and concurrent construct validity were assessed with Pearson's correlation coefficient on the Roland-Morris Questionnaire scores compared with the scales of the Medical Outcome Study Short Form-36 questionnaire.

RESULTS

Pearson's correlation coefficient for test-retest reliability of the German version was r = 0.82 (P = 0.0001), and Cronbach's alpha was 0.81. The concurrent validity was r = 0.81 (Roland-Morris Questionnaire/pain rating; P = 0.0001), r = 0.48 (Roland-Morris Questionnaire/forward bending; P = 0.0001), and r = -0.47 (Roland-Morris Questionnaire/lateral bending; P = 0.0001). Correlation between the functional scales of the Medical Outcome Study Short Form-36 questionnaire and the Roland-Morris Questionnaire sum scores ranged from r = -0.29 (emotional limitations; P = 0.0011) to r = -0.71 (physical limitations; P = 0.0001).

CONCLUSION

Because the German version of the Roland-Morris Questionnaire seems to be reliable and valid for the assessment of the functional status in German-speaking patients with low back pain, the use of this translated instrument can be recommended in future clinical trials.

Benefit of 6 months long-term physical training in polymyositis/dermatomyositis patients

OBJECTIVE

The benefit of long-term physical training in patients with chronic polymyositis or dermatomyositis (PM/DM) was studied prospectively.

METHODS

Eight patients with chronic PM/DM participated in a training programme for 6 months. A group of five PM/DM patients without any physical training was observed for control purposes.

RESULTS

While there was no significant change in serum creatine phosphokinase (CPK) levels, the 'activities of daily living (ADL)' score improved significantly (P < 0.03), peak isometric torque (PIT) generated by muscle groups in the lower extremities rose significantly (P < 0.03) and there was a statistically highly significant increase in peak oxygen uptake (VO2max) relative to body weight (P < 0.02) due to the long-term training. The patients improved their aerobic capacity by 28%, which is clinically significant. In the untrained patients, no improvement in these target parameters was observed.

CONCLUSION

In clinically stable DM/PM patients, long-term physical training can safely be performed and is recommended as part of a comprehensive rehabilitation management, particularly in view of the cardiopulmonary risk in these patients.

EMG fatigue patterns accompanying isometric fatiguing knee-extensions are different in mono- and bi-articular muscles

OBJECTIVES AND METHODS

Isometric, fatiguing knee-extensions at 30%, 50% and 70% maximum voluntary contraction (MVC) were performed by 18 healthy human subjects. Surface electromyographic (SEMG) activity was recorded from the mono-articular vastus medialis (VM) and vastus lateralis (VL) muscles, and the bi-articular rectus femoris muscle (RF). To make the bi-articular muscle work under (1) constant and (2) similar working conditions as the two mono-articulars do, the hip was fixed in a flexed position. The root mean square (RMS) SEMG recorded during fatigue was standardized to the respective values of MVC. The mean coefficients of regression of the RMS and median frequency (MF) changes were then analyzed by multivariate analysis of variance.

RESULTS

The load effect upon the muscle fatigue changes, as measured by increase in RMS EMG, differed between the bi-articular muscle and the two mono-articulars, in that the parameter dropped with maximum load for the bi-articular, whilst it remained stable or even increased for the mono-articulars. This might suggest that the mono- and bi-articular muscles have different roles in fatigue tasks where the bi-articulars function purely as mono-articulars. By contrast, such a clear dichotomy between the bi-articular RF and the two mono-articulars, VM and VL, was lacking for the fatigue parameter of MF.

CONCLUSIONS

As these findings were confined to the changes in RMS EMG, different neuronal coding mechanisms for the mono- and bi-articular muscles in the central nervous system may be inferred.

Cortical DC potential shifts accompanying the central processing of visually presented analogue and digital time displays

According to studies in brain-lesioned patients, the cortical substrate subserving the reading of digitally presented time displays seems to differ from that of reading analogue displays. While the right hemisphere has been assumed to be important for reading analogue displays, reading digital displays is attributed to the left hemisphere. This study attempts to localize the cortical substrate of reading analogue versus digital time displays in the intact human brain using scalp-recorded event-related slow negative DC potential shifts. In the arithmetic tasks, subjects had to judge whether or not the time conveyed by the last out of three tachistoscopically presented (analogue or digital) slides was the exact difference between the time conveyed by the first and the second slide. In the control condition, subjects only had to attend to (analogue or digital) time displays. With analogue slides, frontolateral recording sites revealed a right hemispheric preponderance of DC shifts measured in the interval between the second and third slide. Anterior temporal recording sites revealed a right hemispheric preponderance only when calculations were performed. By contrast, there was no hemispheric lateralization with digital slides. The arithmetic versus control manipulation modulated waveforms, but did not influence hemispheric laterality.