Neurosensory component of hand-arm vibration syndrome: a 22-year follow-up study.

BACKGROUND: Knowledge about the long-term course of the neurologic component of hand-arm vibration syndrome (HAVS) is scarce. AIMS: To study the course and prognostic factors of the neurosensory component of HAVS over a period of 22 years. METHODS: Forty male sheet metal workers, with a mean age of 60 (range 45-78) years at follow-up, were examined with a test battery in 1994 and 2017. At baseline, the sample comprised 27 workers with HAVS symptoms and 13 workers without HAVS symptoms. Among the 27 workers, 25 workers reported work-related hand-arm vibration during follow-up (mean 3639 h). In 2017, the mean time since vibration stopped was 8.4 years. RESULTS: Among the 27 workers with HAVS in 1994, no overall statistically significant change was observed in hand numbness (Stockholm Workshop Scale), shoulder/arm pain (pain scale) or finger pain from 1994 to 2017. However, vibration exposure during follow-up was associated with increased finger pain. Cotinine, carbohydrate-deficient transferrin, glycosylated haemoglobin and folate were not associated with changes in neurosensory symptoms or manual dexterity (Grooved Pegboard) from 1994 to 2017. A diagnosis of HAVS in 1994 did not predict poor hand strength 22 years later. Isolated hand numbness (without white finger attacks) was more common at baseline than at follow-up. CONCLUSIONS: This 22-year follow-up study indicates a tendency towards irreversibility of hand numbness and finger pain in workers with HAVS. Continued vibration exposure seems to predict increased finger pain. Our findings highlight the importance of HAVS prevention.

A systematic review of working conditions and occupational health among immigrants in Europe and Canada.

BACKGROUND: A systematic attempt to summarize the literature that examines working conditions and occupational health among immigrant in Europe and Canada. METHODS: We established inclusion criteria, searched systematically for articles included in the Medline, Embase and Social Sciences Citation Index databases in the period 2000-2016 and checked the reference lists of all included papers. RESULTS: Eighty-two studies were included in this review; 90% were cross-sectional and 80% were based on self-report. Work injuries were consistently found to be more prevalent among immigrants in studies from different countries and in studies with different designs. The prevalence of perceived discrimination or bullying was found to be consistently higher among immigrant workers than among natives. In general, however, we found that the evidence that immigrant workers are more likely to be exposed to physical or chemical hazards and poor psychosocial working conditions is very limited. A few Scandinavian studies support the idea that occupational factors may partly contribute to the higher risk of sick leave or disability pension observed among immigrants. However, the evidence for working conditions as a potential mediator of the associations between immigrant status and poor general health and mental distress was very limited. CONCLUSION: Some indicators suggest that immigrant workers in Europe and Canada experience poorer working conditions and occupational health than do native workers. However, the ability to draw conclusions is limited by the large gaps in the available data, heterogeneity of immigrant working populations, and the lack of prospectively designed cohort studies.

[Doctor Eyvind Kraft--halfway around the world in the 1880s]. / Lege Eyvind Kraft--jorden halvveis rundt i 1880-årene.

More than every second Norwegian 19th century physician made one or more study trips abroad. Some of them were probably more inspired by love of adventure than by the prospect of gaining new medical insight. This was probably also true of my great-grandfather, Eyvind Kraft. Shortly after completing medical school in 1879, he left Norway on the "Musca", an emigrant vessel, bound for Hawaii. He returned home approximately six years later to establish a sanatorium. In the meantime he worked as a ship's doctor, made a contribution to the understanding of the contagiousness of leprosy, and was among the founding members of the first medical society in the state of Wisconsin. Back in Norway he worked at the sanatorium, but also as a general practitioner and among fishermen during the seasonal fisheries. He had to travel to the Continent in an attempt to cure his "nerve disease". Eyvind Kraft's life tells an exciting story of exotic places and of the view of disease in his time.

[Late effects of low-voltage electricity accidents. Rotator cuff tendinitis, hearing loss and neuropsychological dysfunction]. / Senfølger av lavspent strømgjennomgang. Rotatortendinose, hørselstap og mulig neuropsykologisk funksjonstap.

This article describes the symptomatology of three patients following electrical accidents. The flow of the current was from hand to hand, voltage was 220/380 V, and duration was at least a few seconds for all patients. The development of symptoms was the same, and may be explained as a thermal effect of electricity on the tissue. Initially the patients experienced transient confusion, followed by stiff muscles after 1 to 3 days, and then pain in the muscle attachments and joints close to path of the current. This pain increased slowly during the first two weeks. Recovery was gradual, but often incomplete. The case notes showed that electrical accidents may be followed by chronic rotator cuff tendinitis. The clinical examination also revealed a hearing loss at about 2,000 Hz and above 4,000 Hz. The neuropsychological testing indicated a diffuse impaired function in only one patient.

Reliability of myoelectric trapezius muscle activity in repetitive light work.

The aim of this study was to evaluate the reliability of selected electromyographic (EMG) parameters describing the muscle activity in repetitive light work. EMG from the trapezius muscle of twelve female workers were recorded during a 20-min work session, morning and afternoon; Monday, Wednesday, Friday and the following Monday. The estimated reliability coefficient was 0.59 for static muscle activity and 0.85 for short interruptions in muscle activity (EMG gaps) during work. The reliability coefficient was 0.94 for the EMG signal's average median frequency of test contractions associated with the work session. The median frequency declined significantly during the work session. No time trend was found during the day or the week for these parameters. Consequently, it is possible to get representative measurements of the mentioned EMG parameters during repetitive light work by a recording taken at any time of the day or week.

[Occupational and individual risk factors of muscular pain]. / Arbeidsrelaterte og individuelle risikofaktorer for muskelsmerte.

It is suggested that occupational exposure to muscle load should be described by three factors to indicate health risks: level, repetitiveness and duration. A reduction in level is beneficial if the level is high (> 10-15% MVC). However, even a low level involves risk of musculoskeletal complaints if the exposure is repetitive. A reduction of the occupational exposure from 7-8 hours to 4-5 hours per day delays the development of musculoskeletal complaints, but does not provide long-term reduction of risk with frequent repetitions. When interventions are carried out to reduce the risk of occupational musculoskeletal complaints, it is necessary to consider psychosocial and individual constitutional factors in addition to the three factors constituting the occupational exposure to muscle load.

Development of trapezius myalgia among female workers performing light manual work.

The aim of this prospective study was to detect a possible development of trapezius myalgia likely to be work-related in initially healthy female packers. Symptoms were recorded on a five-step intensity scale in a daily diary and in an interview at ten-week intervals. All of the subjects were interviewed concerning assumed risk factors during work and leisure time, and a clinical examination was performed. Within their first year of employment, 17 of 30 subjects developed work-related trapezius myalgia of sufficient intensity to be classified as patients. The median time before a clinically confirmed patient status was 23 (range 6-51) weeks. The symptoms showed a fluctuating pattern, decreasing on the weekends and during some holidays. In conclusion, likely work-related trapezius myalgia of a nonchronic character showed a high one-year cumulative incidence at a plant with repetitive light work.

Electromyographic evaluation of muscular work pattern as a predictor of trapezius myalgia.

Electromyographic (EMG) measurements and interviews concerning muscular pain and disability were performed prospectively every 10th week on 30 healthy new female employees of a chocolate manufacturing plant. The static muscle activity and rate of short unconscious interruptions in EMG activity (EMG gaps) of the trapezius muscle during repetitive work tasks were evaluated as possible risk factors for patient status with trapezius myalgia. At the start of employment, the static and median contraction levels were significantly higher in future patients than in the rest of the subjects (nonpatients). In subsequent recordings these values were reduced to the level of the nonpatients. Throughout the study, the future patients had a lower frequency of EMG gaps than the nonpatients. A regression analysis showed a significant value for a low rate of EMG gaps to predict future patient status.

The reproducibility of test contractions for calibration of electromyographic measurements.

The main purpose of this study was to evaluate the reproducibility of electromyographic (EMG) measurements and specifically to test a calibration procedure with submaximal test contractions. Bipolar surface electrodes (20 mm fixed distance) were repositioned by a tracing sheet on both trapezius muscles, halfway between acromion and processus prominens. Submaximal test contractions were performed by keeping both arms straight abducted 90 degrees and forward flexed 10 degrees for 15-s periods. The arm position could be precisely reproduced in the frontal plane, but deviated forwards by 4 degrees in the horizontal plane, where the sensitivity of the EMG response to arm position was lowest. The electrodes were repositioned within a radius of 3 mm with a probability of 90%. Large deviations in the EMG response were found within this radius and a significant depression of the EMG response was recorded over the middle part of the muscle (the innervation zone?). This change in sensitivity of the EMG response with electrode position occurred in parallel for the test and maximal contractions. The total coefficient of variation was estimated to be 23% for recurrent EMG measurements using the calibration procedure described.

Pattern of muscle activity during stereotyped work and its relation to muscle pain.

Standardized and machine-paced work tasks at a packing machine were examined to evaluate interindividual variability of muscle activity patterns. Ten trained female workers, without musculo-skeletal complaints at the time of the recording, performed the work tasks while electromyographic (EMG) recordings were obtained from both upper trapezius muscles. Static muscle activity and periods of between 0.2 and 2 s duration with low muscle activity, EMG gaps, were analysed. Complaints of muscular fatigue, soreness or pain in the neck and shoulders during the last 12 months were recorded. The level of static muscle activity was 1.6 (range 0.4 to 2.5) per cent of maximal voluntary contraction and median number of EMG gaps was 4.8 (range 0.8 to 20) per minute. Workers with previous episodes of complaints (five subjects) had higher levels of static muscle activity and fewer EMG gaps than workers without such episodes (p less than 0.05, Wilcoxon 2-sample test, one-tailed). Considerable interindividual variability of muscle activity patterns was found in spite of stereotyped work. No causal relations may be inferred from the correlation between the level of trapezius activity and complaints, though it indicates that individual, inexpedient muscle activity patterns may constitute an important risk factor for development of musculo-skeletal complaints.