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Biomedical subjects

A Klipstein

Publications and source records attributed to A Klipstein.

13 recordsLinked to original sources
PubMed2005

Relationship between perceived exertion and mean power frequency of the EMG signal from the upper trapezius muscle during isometric shoulder elevation.

The aim of the study was to investigate the relationship between a fatigue-induced increase of perceived exertion in the neck with a decrease of mean power frequency (MPF) in the surface electromyography (sEMG) signal during repeated shoulder elevation endurance tasks. About Thirty-two healthy women (age range 20-62) performed two maximum 6-min shoulder elevation endurance tasks at 30% of their maximal voluntary contraction (MVC) level, separated by a rest of 6 min. During these exercises, perceived exertion was estimated using the Borg scale (range 0-10), whereas the MPF of the sEMG signal from the upper trapezius was simultaneously detected. Linear regression analysis was applied over time for each trial and subject for both MPF and Borg scale rating values. The MPF was normalized by the intercept of the linear regression analysis. The resulting slopes of normalized mean power frequency (nMPF) and Borg scale rating were correlated with each other by linear regression for both trials. In order to investigate the individual behavior of fatigue effects between trials, Delta (trial 2-trial 1) slopes of nMPF and Borg scale ratings were calculated for each subject. These slopes of nMPF and Borg scale ratings were correlated with each other as well by linear regression. The increase of Borg scale ratings, as well as the decrease of nMPF, were significantly higher in trial 2 than trial 1 (P<0.01). The results show a linear correlation between slopes of nMPF and Borg scale ratings for both trials 1 and 2 (r=0.76, P<0.01). Trial-to-trial slopes (Delta (trial 2-trial 1)) of nMPF and Borg scale rating, were also significantly correlated (r=0.68, P<0.05). Thus, the individually sensed increase of perceived exertion in the neck during trial 2 was accompanied by a simultaneously higher detected decrease of nMPF. These findings indicate a close relationship between subjective perception of exertion in the neck and objectively assessed muscle fatigue of the upper trapezius.

Adult↗
PubMed2005

Neuromuscular assessment in elderly workers with and without work related shoulder/neck trouble: the NEW-study design and physiological findings.

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.

Adult↗
PubMed2005

Comparative assessment of study groups of elderly female computer users from four European countries: questionnaires used in the NEW study.

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.

Case-Control Studies↗
PubMed2004

Perceived work demands, felt stress, and musculoskeletal neck/shoulder symptoms among elderly female computer users. The NEW study.

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.

Case-Control Studies↗
PubMed2003

Continuous, intermitted and sporadic motor unit activity in the trapezius muscle during prolonged computer work.

The Cinderella hypothesis postulates the continuous activity of specific motor units (MUs) during low-level muscle contraction. The MUs may become metabolically overloaded, with the subject developing muscle pain and strain. The hypothesis requires MUs that are active for a time long enough to actually damage muscle fibers. The aim of this study was to determine if there are continuously active MUs in the right trapezius muscle during normal computer work using a computer mouse. Fourteen healthy subjects executed an interactive computer-learning program (ErgoLight) for 30 min. Six-channel intramuscular EMG and two-channel surface EMG signals were recorded from two positions of the trapezius muscle. Decomposition was achieved with automated, multi-channel, long-term decomposition software (EMG-LODEC). In two out of the 14 subjects, three MUs were continuously active throughout the 30 min. Although the majority of the MUs were active during only part of the experimental session, an ordered on-off behavior (e.g. substitution) pattern was not observed. As long-lasting activity was verified in some subjects, the results support the Cinderella hypothesis. However, it cannot be concluded here how long the MUs could stay active. If continuous activity overloads low threshold MUs, the potential exists for selective fibre injuries in low threshold MUs of the trapezius muscle in subjects exposed to long-term computer work.

Adult↗
PubMed2003

Course of low back pain among nurses: a longitudinal study across eight years.

AIMS: To describe the course of low back pain (LBP) among nurses across eight years. METHODS: A longitudinal study was performed with a follow up at 1 and 8 years among nurses employed by a large university hospital in Switzerland. A modified version of the Nordic Questionnaire was distributed to obtain information about demographic data, occupational activities, and various aspects of LBP. A clinical examination and several functional tests were used to overcome the problems associated with subjective pain reporting. Nurses having answered the questionnaire on all three occasions (n = 269) were classified into subgroups according to their pain intensity. For each subgroup the course of LBP was recorded. RESULTS: LBP was highly prevalent with an annual prevalence varying from 73% to 76%. A large percentage (38%) indicated the same intensity of LBP on all three occasions. The proportion of nurses reporting repeated increase of LBP (19%) was approximately as large as the proportion who complained about repeated decrease of LBP (17%). CONCLUSION: It became evident that LBP poses a persistent problem among nurses. Over an eight year period almost half of the nurses indicated the same intensity of LBP, thus supporting a recurrent rather than a progressive nature of LBP.

Adult↗
PubMed2001

[Management of non-specific musculoskeletal disorders--role of ergonomics].

Non-specific musculoskeletal disorders are a major health problem. Despite good prognosis socio-economic burden is important. Just a few treatment strategies are known to reduce work-disability. An early ergonomic assessment helps to determine the level of disability and further rehabilitation strategies. An assessment consists of a self-rating of the physical capacities and a physical performance test. Work-place demands and psychosocial factors should also be considered by interview. An ergonomic work-place analysis supports this information and facilitates reintegration. Furthermore, work-place adaptations can be performed.

Adult↗
PubMed1999

[Muscle strength and gait patterns of depressed people].

BACKGROUND: Gait characteristic and muscle power are often described in the clinical literature but with little empirical support. We assessed some parameters of gait and muscle power using simple and standardized methods within a framework based principally on classic clinical observations of depression. METHOD: 20 depressed inpatients were examined with standard tests of isometric muscle power and gait parameters, which measure step length, average walking speed, maximal walking speed, and three-minute walk distance. The results were compared with those of 20 matched healthy controls. The examination procedure was repeated after a three week period of inpatient treatment and significant symptomatic improvement. RESULTS: As predicted by our hypothesis depressed patients' muscle power and gait characteristics differed clearly from normal controls. Significant improvements after 3 weeks of inpatient treatment were found above all in extension of the knee and extension of the elbow tests as well as in all measures of our gait analysis. However, all gait parameters still differed significantly from those of healthy controls. CONCLUSIONS: Using simple but reliable tests which were used for the first time in psychiatry we examined certain relationships between depression and motor function in a moderately to severely depressed inpatient sample.

Case-Control Studies↗
PubMed1997

[In the gray area between body, psyche and social difficulties. II: Psychiatric assessment of somatoform disorders (exemplified by chronic pain patients].

Medico-legal assessment for long-term disability benefits in patients with mainly somatoform pain disorders is in increasing demand. Since impairment does not explain the loss of function in somatoform disorders, the expert must determine to what extent the patient is able to cope more actively with pain in order to attain a higher level of functioning. Consistency of behavioral signs, flexibility and initiative in the way of coping are helpful criteria in this respect. Special attention is given to problems in the assessment of migrants with these disorders. We strongly support the concept of an interdisciplinary approach in medico-legal assessment. Postgraduate medical training in this field should receive greater attention accordingly.

Disability Evaluation↗
PubMed1997

[In the grey area body body, psyche and social difficulties. I: New developments in diagnosis and therapy of somatoform disorders (exemplified by chronic pain patients)].

The so-called psychosomatic or functional conditions (notably somatoform pain disorders) often cause difficulties in diagnostic classification, clinical management and assessment of disability. Recent trends in diagnosis are reviewed. We describe our first clinical experience of interdisciplinary evaluation of pain patients by functional capacity evaluation and an ergonomically oriented rehabilitation program. This interdisciplinary approach could constitute a new field of close collaboration between physiatry/physical medicine, physiotherapy and psychiatry.

Adaptation, Psychological↗
PubMed1996

[Femoropatellar pain syndrome--conservative therapeutic possibilities].

Patello-femoral knee pain is a frequent problem the general practitioners, rheumatologists and orthopedists are confronted with. Very often, no exact structural diagnosis can be made. Studies on the natural history of PFPS are lacking. Nevertheless, conservative treatment has been successful in most of the cases. In this respect, management being pertinent to each patient and problem is important. Four categories of frequently affected patients are discussed in this article: young people in their adolescence, well trained athletes, athletes at the end of their career and patients in the 'second half' of their life. The stages of soft-tissue healing in the course of treatment over a long time are of importance. In the sense of a secondary prevention, the intrinsic and extrinsic risk factors have to be considered as well. The taping technique offers an easy and effective treatment method. It usually pulls the patella medially, thereby 'unloading' the joint and the surrounding soft tissues. In an early stage, this results in an analgesic effect and allows an early functional load. In a later stage, the patella tape helps to prevent reinjury.

Adolescent↗
PubMed1995

[Left ventricular function in post-endocarditis aortic insufficiency and aortic-annular ectasia].

BACKGROUND: The duration of valvular regurgitation is an important determinant of left ventricular function in the presence of severe volume overload. PURPOSE: To evaluate the effect of aortic regurgitation (aortoannullar dilatation vs. history of bacterial endocarditis) on left ventricular (LV) function. PATIENTS: Between February 1976 and January 1993 45 patients (mean; age 45 +/- 12 years) underwent diagnostic evaluation for clinical purposes. Patients were divided into three groups: group 1 consisted of 17 patients with normal LV function (controls), group 2 of 11 patients with severe aortic regurgitation due to aortoannullar dilatation (AAD) and group 3 of patients with severe aortic regurgitation and a history of bacterial endocarditis (BE). METHODS: LV function was assessed by biplane LV-angiography and simultaneous pressure recordings. The ejection fraction and peak systolic wall stress were calculated in all patients. Systolic and diastolic LV function was determined and compared within the three groups. RESULTS: Heart rate, mean aortic pressure and cardiac index were similar in the three groups. The mean aortic diameter was significantly increased in group 2 when compared to the other two groups (p < 0,001). Systolic function was significantly reduced in both groups with aortic regurgitation when compared to the control patients. The end diastolic pressure-volume relationship was shifted to the right in patients with aortic regurgitation, but only 3 patients with a history of bacterial endocarditis showed severe diastolic dysfunction. CONCLUSIONS: No hemodynamic differences were observed in patients with severe aortic regurgitation with regard to the etiology or time course of LV volume overload. However, 17% of the patients with a history of bacterial endocarditis had severe diastolic dysfunction, which is probably due to the faster development of volume overload after bacterial endocarditis.

Adult↗