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.

Reproducibility of the 6-minute walk test in lung transplant recipients.

PURPOSE: There is reason to believe that the favorable measurement properties of the 6­minute walk test (6MWT) reported for retest reliability and its capability to detect a true change in healthy individuals or persons with chronic respiratory disease may not apply to lung transplant recipients (LuTXr). We therefore investigated retest reliability of the 6MWT and, in addition, made an attempt to explore whether the 6MWT was sensitive enough to detect important changes that occur with postacute rehabilitation in LuTXr after first time LuTX. METHODS: Immediately before postacute rehabilitation, 50 LuTXr completed 6MWT testing twice, separated by 1-2 workdays (retest reliability), and were reassessed after completion of rehabilitation 2 months later (sensitivity to changes). Body function measures and health-related quality of life (HRQoL) assessments were collected at baseline. RESULTS: Baseline retest 6­minute walk distance (6MWD) and the age-related predicted walking distance (6MWD%pred) scores significantly increased before postacute rehabilitation. The intraclass coefficient of correlation ICC of the 6MWD was 0.93 (95% confidence interval, CI: 0.88-0.96) and its smallest real difference (SRD) 79 m (95% CI: 52;107). Receiver operating curve analyses revealed the rehabilitation associated changes in 6MWD/6MWD%pred to exceed the SRD/SRD% values in a highly accurate way. CONCLUSION: The 6MWT overall represents a reliable functional performance tool in LuTXr that is sensitive to detect changes in physical performance as a result of medical postacute rehabilitation.

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 patients 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.

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.

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.

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.

Correction to: Age- and sex-specific effects in paravertebral surface electromyographic back extensor muscle fatigue in chronic low back pain.

Unfortunately, the author names in the author group section were incorrectly captured in the published online paper.

Overactivity in Chronic Pain, the Role of Pain-related Endurance and Neuromuscular Activity: An Interdisciplinary, Narrative Review.

OBJECTIVES: Decades of research have convincingly shown that fear of pain and pain-related avoidance behavior are important precursors of disability in daily life. Reduced activity as a consequence of avoidance, however, cannot be blamed for chronic disability in all patients. A contrasting behavior, pain-related dysfunctional endurance in a task and overactivity has to be considered. Currently, there is a need to better understand the psychological determinants of overactivity, dysfunctional endurance, and neurobiomechanical consequences. METHODS: This is a narrative review. RESULTS: The first part of this review elucidates research on self-reported overactivity, showing associations with higher levels of pain and disability, especially in spinal load positions, for example, lifting, bending, or spending too long a time in specific positions. In addition, measures of habitual endurance-related pain responses, based on the avoidance-endurance model, are related to objective assessments of physical activity and, again, especially in positions known to cause high spinal load (part 2). The final part reveals findings from neuromuscular research on motor control indicating the possibility that, in particular, overactivity and dysfunctional endurance may result in a number of dysfunctional adaptations with repetitive strain injuries of muscles, ligaments, and vertebral segments as precursors of pain. DISCUSSION: This narrative review brings together different research lines on overactivity, pain-related endurance, and supposed neuromuscular consequences. Clinicians should distinguish between patients who rest and escape from pain at low levels of pain, but who have high levels of fear of pain and those who predominantly persist in activities despite severely increasing pain until a break will be enforced by intolerable pain levels.

Age- and sex-specific effects in paravertebral surface electromyographic back extensor muscle fatigue in chronic low back pain.

The impact of aging on the back muscles is not well understood, yet may hold clues to both normal aging and chronic low back pain (cLBP). This study sought to investigate whether the median frequency (MF) surface electromyographic (SEMG) back muscle fatigue method-a proxy for glycolytic muscle metabolism-would be able to detect age- and sex-specific differences in neuromuscular and muscle metabolic functions in individuals with cLBP in a reliable way, and whether it would be as sensitive as when used on healthy individuals. With participants seated on a dynamometer (20° trunk anteflexion), paraspinal SEMG activity was recorded bilaterally from the multifidus (L5), longissimus (L2), and iliolumbalis (L1) muscles during isometric, sustained back extensions loaded at 80% of maximum from 117 younger (58 females) and 112 older (56 female) cLBP individuals. Tests were repeated after 1-2 days and 6 weeks. Median frequency, the SEMG variable indicating neuromuscular fatigue, was analyzed. Maximum back extensor strength was comparable between younger and older participants. Significantly less MF-SEMG back muscle fatigue was observed in older as compared to younger, and in older female as compared to older male cLBP individuals. Relative reliability was excellent, but absolute reliability appeared large for this SEMG-fatigue measure. Findings suggest that cLBP likely does not mask the age-specific diagnostic potential of the MF-SEMG back extensor fatigue method. Thus, this method possesses a great potential to be further developed into a valuable biomarker capable of detecting back muscle function at risk of sarcopenia at very early stages.

The impact of age and gender on the ICF-based assessment of chronic low back pain.

PURPOSE: To evaluate the impact of age and gender on the international classification of functioning, disability and health (ICF)-based assessment for chronic low back pain. METHODS: Two hundred forty-four chronic low back pain patients (52% female) with a mean age of 49 years (SD =17.64) were interviewed with the comprehensive ICF core set for activities and participation, and environmental factors. After conducting explorative factor analysis, the impact of age and gender on the different factors was analyzed using analyzes of variances. RESULTS: Results revealed that older patients experienced more limitations within "self-care and mobility" and "walking" but less problems with "transportation" compared to younger patients. Older or middle-aged low back pain patients further perceived more facilitation through "architecture and products for communication", "health services", and "social services and products for mobility" than younger patients. Regarding gender differences, women reported more restriction in "housework" than men. An interaction effect between age and gender was found for "social activities and recreation" with young male patients reporting the highest impairment. CONCLUSIONS: The study demonstrated that the comprehensive ICF core set classification for chronic low back pain is influenced by age and gender. This impact is relevant for ICF-based assessments in clinical practice, and should be considered in intervention planning for rehabilitative programs. Implications for rehabilitation It is important to consider age and gender differences when classifying with the ICF. The intervention planning based on the ICF should focus on improvement of bodily functioning and mobility in older patients, facilitation of household activities in women, consideration of work-life balance and recreation (e.g., through mindfulness based stress reduction), and reduction of dissatisfaction with rehabilitation in younger patients. It is important to offer patients the opportunity to participate in intervention planning based on the ICF. For intervention planning professionals should bear in mind the resource-oriented approach of the ICF (e.g., facilitation through environmental factors), and a collaboration with other professionals.

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.

Impairments in Postural Control and Retest Reliability of Dynamic Posturographic Measures After Lung Transplantation.

OBJECTIVES: The aims of the study were to classify impairments in postural control using computerized posturography in lung transplant recipients undergoing subacute rehabilitation and to examine the retest reliability of these measures. METHODS: In a prospective repeated-measures study, 50 lung transplant recipients underwent clinical and quantitative posturographic testing (SMART EquiTest), which included the sensory organization test, motor control test, and limits of stability test. Testing was repeated after 1 to 2 days and upon completion of rehabilitation, 2 mos later. Main outcome measures were the following: sensory organization test-composite score, motor control test-latency and amplitude scaling, limits of stability test-movement velocity, and endpoint excursion/maximum excursion. RESULTS: At the beginning of rehabilitation, the mean sensory organization test-composite score and limits of stability test, but not the motor control test scores, were below normative reference values and and did not return to normal after rehabilitation. Intraclass correlation coefficients(2,1) yielded excellent relative reliability for all posturographic tests. The smallest detectable differences observed for the sensory organization test and limits of stability test exceeded the mean changes observed upon completion of rehabilitation. CONCLUSIONS: Impairments in sensory and anticipatory postural control were insufficiently restored after subacute lung transplantation rehabilitation. The little sensitivity of the sensory organization test-composite score or limits of stability test scores to detect a minimal change in performance due to rehabilitation limits the clinical applicability of these tests as objective outcome measures in lung transplantation rehabilitation.

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.

Long-Term Course of Shoulders After Ultrasound Therapy for Calcific Tendinitis: Results of the 10-Year Follow-Up of a Randomized Controlled Trial.

OBJECTIVE: The aim of the study was to follow both the structure- and function-related long-term course of shoulders that had been treated with therapeutic ultrasound for symptomatic calcific tendinitis. DESIGN: This is a long-term follow-up of 45 shoulders (37 patients) that had been treated for symptomatic calcific tendinitis with either a series of ultrasound or sham ultrasound 10 yrs ago. The main outcome variables were presence of calcium deposits and subacromial impingement on standardized x-ray imaging, shoulder symptoms (Binder score), and function (Constant score). RESULTS: At 10 yrs, a similar proportion of calcium deposits had resolved in 78% of the originally ultrasound treated compared with 83% of sham-treated shoulders, whereas at 9 mos, significantly more calcium deposits had been resolved in the ultrasound group (P = 0.045). Relative to baseline, shoulder symptoms and function had significantly improved at both the 10-yr and 9-mo follow-up examinations with no significant differences between groups. Regular sports performance at baseline predicted a favorable long-term outcome. CONCLUSIONS: Symptomatic calcific tendinitis of the shoulder has a good likelihood to completely resolve in the long term. Treating the calcium deposit effectively, however, may not be causal to the recovery from symptoms and function in calcific tendinitis.