Leif Sandsjö

Abstract A sample of 156 users of upper-limb prostheses from three fitting centers in Sweden and the United Kingdom participated in a survey that focused on user satisfaction. The survey was conducted via postal questionnaire. It included questions to record ...

A study on the assessment of hearing and hearing disorders in rock/jazz musicians concluded that 74% of the musicians had some kind of disorder. The main hearing disorders found were pure-tone hearing loss, tinnitus (an acoustic sensation of sounds), hyperacusis (a hypersensitivity to low or moderate sound levels), and distortion (music sounds out of tune). Affected musicians often were able to give the exact time of the first appearance of the hearing disorders, which often was associated with a period of excessive sound exposure, high workload, or some form of emotional stress. The aim of this study was to explore associations between psychosocial work conditions, mental load, and hearing disorders in rock/jazz musicians. A total of 139 (43 women and 96 men) voluntarily participating rock/jazz musicians answered a questionnaire on psychosocial work conditions and mental load. The data were correlated to hearing and sex. The median age was 35 years in the women and 37 years in the ...

We evaluated the clinical effects of a myofeedback-based teletreatment service in terms of pain, pain-related disability and work ability. We also investigated the time investment/savings of this treatment with respect to conventional care. Sixty-five women with neck and shoulder pain at work participated in the study. Thirty-three took part in the teletreatment and 32 participated in a control group which

We investigated the potential prognostic factors for clinically relevant improvements in pain intensity and pain-related disability after myofeedback-based teletreatment. Sixty-five female computer users, 56 female patients with whiplash-associated disorders and 18 female patients with non-specific neck and shoulder pain participated in the study. They received myofeedback-based teletreatment or usual treatment. Questionnaires concerning prognostic factors, pain and disability were completed before the start of the intervention (baseline) and at follow-ups at the end of the intervention, and after 3 and 6 months. Logistic regression analyses were performed in order to investigate prognostic factors for clinically relevant improvement. In the intervention group, improvement in pain intensity was predicted by baseline pain intensity. Baseline pain intensity and disability, and fear-avoidance and endurance related pain coping responses were prognostic factors for outcome in pain-relate...

We evaluated the clinical effects of a myofeedback-based teletreatment service in terms of pain, pain-related disability and work ability. We also investigated the time investment/savings of this treatment with respect to conventional care. Sixty-five women with neck and shoulder pain at work participated in the study. Thirty-three took part in the teletreatment and 32 participated in a control group which continued with conventional care. Questionnaires were completed before the start of the intervention (baseline) and at initial follow-up (T0) and 3 months (T3) after the intervention ended. A general linear model analysis for repeated measurements showed an improvement in terms of pain and work ability for both groups taken together, with no differences between them. Non-parametric tests showed an intervention effect in pain-related disability for both groups together and no differences between them when tested at baseline, T0 and T3. The time saved in relation to conventional car...

The current study investigated the associations between work-related perceived stress and surface electromyographic (sEMG) parameters (muscle activity and muscle rest) during standardized simulated computer work (typing, editing, precision, and Stroop tasks). It was part of the European case-control study, NEW (Neuromuscular assessment in the Elderly Worker). The present cross-sectional study was based on a questionnaire survey and sEMG measurements among Danish and Swedish female computer users aged 45 or older (n=49). The results show associations between work-related perceived stress and trapezius muscle activity and rest during standardized simulated computer work, and provide partial empirical support for the hypothesized pathway of stress induced muscle activity in the association between an adverse psychosocial work environment and musculoskeletal symptoms in the neck and shoulder.

Intermittent disturbances are common in ECG signals recorded with smart clothing: this is mainly because of displacement of the electrodes over the skin. We evaluated a novel adaptive method for spatio-temporal filtering for heartbeat detection in noisy multi-channel ECGs including short signal interruptions in single channels. Using multi-channel database recordings (12-channel ECGs from 10 healthy subjects), the results showed that multi-channel spatio-temporal filtering outperformed regular independent component analysis. We also recorded seven channels of ECG using a T-shirt with textile electrodes. Ten healthy subjects performed different sequences during a 10-min recording: resting, standing, flexing breast muscles, walking and pushups. Using adaptive multi-channel filtering, the sensitivity and precision was above 97% in nine subjects. Adaptive multi-channel spatio-temporal filtering can be used to detect heartbeats in ECGs with high noise levels. One application is heartbeat detection in noisy ECG recordings obtained by integrated textile electrodes in smart clothing.

Knowledge regarding the working mechanism of an intervention is essential for obtaining a better understanding of the intervention and contributes to optimize its outcome. This study aimed at investigating whether changes in cognitive-behavioral factors and muscle activation patterns after myofeedback training and ergonomic counseling were associated with outcome, in subjects with work-related musculoskeletal neck-shoulder complaints. Seventy-nine symptomatic subjects received either myofeedback with ergonomic counseling (Mfb/EC) or ergonomic counseling alone (EC). Outcome measures discomfort and disability, and process factors catastrophizing, pain control, fear-avoidance beliefs, and muscle activation patterns were assessed at baseline, after the interventions (T0), and at 3 months follow-up (T3). Mixed modeling techniques were used for analysis. Outcome in terms of discomfort and disability was generally comparable between both interventions. Catastrophizing was significantly reduced and fear-avoidance beliefs about work slightly increased after the interventions, but no consistent changes in muscle activation patterns were observed. Changes in discomfort were especially associated with changes in catastrophizing at T0 and T3, but R(2) was low (<0.14). Reduced catastrophizing at T0 and T3, and also reduced fear-avoidance beliefs about work at T3, were related to reduced disability (R(2) between 0.30 and 0.40). No differences between the two intervention groups were observed. Intervention effects were generally non-specific and findings suggested that cognitive-behavioral factors underlie the outcome of these interventions rather than changes in muscle activation patterns. Emphasizing these factors during therapy may increase the beneficial outcome of occupational interventions.

It has been suggested that treatments may be more effective when they are matched to patient characteristics. This study aimed at investigating potential prognostic factors for clinically relevant improvement in symptom intensity and symptom-related disability among employees with symptoms in the neck/shoulder area, receiving either ergonomics counseling or such counseling in combination with myofeedback training. A randomized controlled study was performed among female computer users aged 45 or older (n = 36). A clinical examination and a questionnaire survey were performed before inclusion in the study. Symptom intensity and disability was assessed using questionnaires before the start of the interventions (baseline) and at follow-ups directly after the end of the interventions (T0) and after 3 (T3) and 6 (T6) months. Logistic regression analyses were performed in order to assess prognostic factors for clinically relevant improvement in symptom intensity and disability. Improvement in symptom intensity was consistently predicted by symptom intensity at baseline. Diagnosis and stress-induced lack of muscular rest were prognostic factors for improvement in symptom intensity at short term follow-up. Baseline disability and passive coping consistently served as prognostic factors for outcome in disability. Few substantial differences were found between the interventions in terms of prognostic factors. Myofeedback training in combination with ergonomics counseling seem to be an especially beneficial tool for secondary prevention among employees with moderate levels of symptom intensity and symptom-related disability, who respond to work-related stress by increased/sustained muscle activation, and who tend to employ passive coping to deal with their neck/shoulder symptoms.

Unfavorable psychosocial working conditions are hypothesized to lead to perceived stress, which, in turn, can be related to an increased risk of development of neck/shoulder symptoms through increased and sustained muscle activation. The aim of the present study was to test this hypothesized process model among medical secretaries, a female-dominated profession characterized by a high amount of visual display unit use and a high prevalence of neck/shoulder symptoms. In this cross-sectional study, a questionnaire survey was conducted among medical secretaries (n = 200). The proposed process model was tested using a path model framework. The results indicate that high work demands were related to high perceived stress, which in turn was related to a high perceived muscle tension and neck/shoulder symptoms. Low influence at work was not related to perceived stress, but was directly related to a high perceived muscle tension. In general, these cross-sectional results lend tentative support for the hypothesis that adverse psychosocial work conditions (high work demands) may contribute to the development of neck/shoulder symptoms through the mechanism of stress-induced sustained muscular activation. This process model needs to be further tested in longitudinal studies.

Musculoskeletal disorders in the neck and shoulder area are a major occupational concern in the European countries especially among elderly females. The aim was to assess these disorders based on quantitative EMG indicators and functional tests. 252 female computer users (45-68 years) were recruited from four European countries in two contrast groups: (1) 88 neck/shoulder (NS) cases reporting trouble in the neck and/or shoulder region for more than 30 days during the last year, and (2) 164 NS-controls reporting such trouble for no more than 7 days. Questionnaires, functional/clinical tests, and physiological recordings were performed in workplace related field studies. The results showed no differences in anthropometrics but NS-cases reported more strained head positions and more eye problems than controls. The psychosocial working factors were similar, although, NS-controls had slightly better scores on working conditions, general health, and vitality compared to cases. The NS-cases had lower maximal voluntary contraction (MVC) during shoulder elevation (mean (SD) 310 (122) N) compared to the controls (364 (122) N). During 30% MVC electromyography (EMGrms) in the trapezius muscle was lower in NS-cases (194 (105) muV) than in controls (256 (169) muV), while no differences were found regarding endurance time. Estimated conduction velocity was not different between NS-cases and -controls. Four functional computer tests were performed equally well by NS-cases and -controls, and the corresponding EMG variables also did not differ. A major finding in this large-scale epidemiological study is the significantly lower MVC in NS-cases compared with NS-controls together with lower EMGrms value at 30% MVC, while computer tasks were performed at similar relative muscle activation. The study was unable to reveal quantitative EMG indicators and functional tests that could objectively assess disorders in NS-cases.

There is a lack of consistent and comprehensive questionnaire forms for the studies of factors associated with work-related musculoskeletal disorders at the European level. One of the results of the EU-funded project, neuromuscular assessment in the elderly worker (NEW), is a set of questionnaires for the screening of musculoskeletal status and the studies of factors that are believed to affect musculoskeletal health. The questionnaires have been used among elderly women (45+) in different occupations and organisations in Denmark, The Netherlands, Sweden and Switzerland. The aim of this short communication is to present the questionnaires used in the NEW study and to evaluate the appropriateness of pooling data gathered in each participating country into a common database. It is concluded that although differences exist among the study samples, these are not of such a magnitude or pattern that data from the four groups cannot be pooled. The questionnaires are available in Danish, Dutch, English, German and Swedish.

The electromyographic (EMG) activity patterns of 18 female supermarket employees reporting neck and shoulder pain were compared with those of 6 of their female colleagues reporting no pain when doing cash-register work. It was found that the EMG activity of the trapezius muscle tended to show a lack of low and high levels among pain subjects, and that the time the trapezius muscle was at rest was longer in the group reporting no pain. In the non-dominant side, the muscle rest time was significantly longer (P < 0.05) in the group reporting no pain, and this group also showed a larger EMG activity difference between the dominant and non-dominant sides, indicating a less static bilateral muscle activation. Self-reports of negative experiences (stressed, exhausted and tense) were somewhat higher in the group reporting pain, while positive experiences during work (concentrated, stimulated and happy) appeared to be similar in the two groups of supermarket employees.

The aim of the present study was to test a structural model of the relationship between the perceived quantitative (time pressure and unevenly distributed workload) and emotional work demands and self-reported musculoskeletal symptoms from the neck and shoulder region with felt stress (rested, relaxed, calm, tense, stressed, and pressured at the end of a normal workday) as a mediating variable. As part of the NEW (Neuromuscular assessment in the Elderly Worker) study, a European case-control study, the present cross-sectional study was based on a questionnaire survey among Danish, Dutch, Swedish and Swiss female computer users aged 45 or older (n =148). The hypothesized structural model was tested using structural equation modelling. The results indicate that perceived work demands influence neck/shoulder musculoskeletal symptoms through their effect on felt stress. The results further indicate complete mediation, which means that all of the effect of the perceived work demands on symptoms could be attributed to the stress mechanism. As regards the percentage of explained variance in the endogenous variables, 36% of the variation in felt stress was explained by the perceived work demands, and about 20% of the variation in musculoskeletal neck/shoulder symptoms was explained by the combination of the perceived work demands and the felt stress.

In recent decades, comprehensive rationalisations have been implemented in public dentistry in Sweden. How rationalisations affect working conditions, health and production from a long-term perspective has been poorly investigated. This study aims to analyse changes and associations in dentists' working conditions, health and productivity during a 5-year period. In 2003 and 2008, 65 dentists responded to questionnaires measuring work conditions and health. Treatment times for patients and productivity were tracked in electronic registers. Paired t-tests showed that the number of treated adult patients per dentist increased, and perceived physical working conditions improved while perceived work control and leadership deteriorated. Structural equation modelling showed that physical factors were important for health and productivity. When assessing risks in the work environment, there is a need to understand the interaction of effects on working conditions and health due to rationalisations so as to increase the sustainability of production systems. Dentistry in Sweden has undergone considerable change. Questionnaire surveys with dentists, undertaken in 2003 and 2008, found that the present rationalisations resulted in improved perceived physical working conditions. Aspects of the psychosocial working environment had deteriorated, however. This is a concern as health and workability are important for workplace efficiency.

Swedish dentistry has been exposed to frequent rationalisation initiatives during the last half century. Previous research has shown that rationalisation often results in increased risk of developing work-related musculoskeletal disorders, thus reducing sustainability in the production system. In this prospective study, we assessed mechanical exposures among Swedish dentists in relation to specific rationalisations of clinical dental work during a six-year period. Body postures and movements of 12 dentists were assessed by inclinometry synchronised to video recordings of their work. No rationalisation effects could be shown in terms of a reduction in non-value-adding work ('waste'), and at job level, no major differences in mechanical exposure could be shown between baseline and follow-up. The present rationalisation measures in dentistry do not seem to result in rationalisation at job level, but may potentially be more successful at the overall dental system level. In contrast to many previous investigations of the mechanical exposure implications of rationalisation, the present rationalisation measures did not increase the level of risk for dentists. It is highlighted that all occupations involved in the production system should be investigated to assess production system sustainability.

In literature, different methods have been suggested for the computation of muscle relative rest time (RRT) from electromyography (EMG), and it is not clear which method is optimal for the large amount of data collected within the NEW project. In the present pilot study we utilized the Swedish part of the data to compare a commonly used individualised threshold, 0.5%