| 1. |
- Dahlin, Lars, et al.
(författare)
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Low myelinated nerve-fibre density may lead to symptoms associated with nerve entrapment in vibration-induced neuropathy.
- 2014
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Ingår i: Journal of Occupational Medicine and Toxicology. - : Springer Science and Business Media LLC. - 1745-6673. ; 9:1
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Forskningsöversikt (refereegranskat)abstract
- Prolonged exposure to hand-held vibrating tools may cause a hand-arm vibration syndrome (HAVS), sometimes with individual susceptibility. The neurological symptoms seen in HAVS are similar to symptoms seen in patients with carpal tunnel syndrome (CTS) and there is a strong relationship between CTS and the use of vibrating tools. Vibration exposure to the hand is known to induce demyelination of nerve fibres and to reduce the density of myelinated nerve fibres in the nerve trunks. In view of current knowledge regarding the clinical effects of low nerve-fibre density in patients with neuropathies of varying aetiologies, such as diabetes, and that such a low density may lead to nerve entrapment symptoms, a reduction in myelinated nerve fibres may be a key factor behind the symptoms also seen in patients with HAVS and CTS. Furthermore, a reduced nerve-fibre density may result in a changed afferent signal pattern, resulting in turn in alterations in the brain, further prompting the symptoms seen in patients with HAVS and CTS. We conclude that a low nerve-fibre density lead to symptoms associated with nerve entrapment, such as CTS, in some patients with HAVS.
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| 2. |
- Persson, Bodil, et al.
(författare)
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Urinary 2,5-hexanedione excretion in cryptogenic polyneuropathy compared to the general Swedish population
- 2013
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Ingår i: Journal of Occupational Medicine and Toxicology. - : BioMed Central. - 1745-6673. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background2,5-hexanedione (2,5-HD) is the main neurotoxic metabolite of methyl-n-butyl ketone (MBK) and n-hexane, and known to cause polyneuropathy. The aim of our study was to compare the urinary levels of 2,5-HD between cases with cryptogenic polyneuropathy and the general Swedish population, and to elucidate the role of certain external factors.MethodsMorning urine samples were collected from 114 cases with cryptogenic polyneuropathy (77 men and 37 women) and 227 referents (110 men and 117 women) randomly selected from the population registry. None had any current occupational exposure to n-hexane or MBK. The urine samples were analysed by a gas chromatographic method based on acidic hydrolysis.ResultsCases had statistically higher urinary levels of 2,5-HD (0.48 mg/L) than the general population (0.41 mg/L) and men higher excretion than women (0.48 mg/L and 0.38 mg/L, respectively). There was no difference in 2,5-HD levels between current smokers and non-smokers. Occupational exposure to xylene, alcohol consumption and ever exposed to general anaesthesia were associated with lower excretion in men while for occupational exposure to nitrous oxide in women higher excretion was seen. Higher excretion of 2,5 HD was inversely related to increasing age.ConclusionsSignificantly higher levels of urinary 2,5-HD were seen in men and cryptogenic polyneuropathy cases seemingly unexposed to n-hexane. Hypothetically, this might be due to either differences in metabolic patterns or some concealed exposure. The difference in means between cases and the general population is small and can therefore not allow any firm conclusions of the causality, however.
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| 3. |
- Edlund, Maria, 1972, et al.
(författare)
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Physical capacity and psychological mood in association with self-reported work ability in vibration-exposed patients with hand symptoms.
- 2012
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Ingår i: Journal of occupational medicine and toxicology (London, England). - : Springer Science and Business Media LLC. - 1745-6673. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: The aim of this study was to investigate whether self-reports of work ability correlated to the results of quantitative tests measuring physical capacity and a questionnaire assessing psychological mood in vibration-exposed patients with hand symptoms. METHODS: The participants comprised 47 patients (36 men and eleven women) with exposure to hand vibration and vascular and/or neurological symptoms in the hands. They performed several quantitative tests (manual dexterity, hand grip strength, finger strength) and completed the Work Ability Index (WAI) and Hospital Anxiety and Depression Scale (HADS) questionnaires. RESULTS: Correlation analysis revealed statistically significant associations between the WAI results, the HADS indices, hand grip and finger strength, and manual dexterity measured using the Purdue Pegboard(R). Multiple regression analysis revealed age and HADS indices as the strongest predictors of work ability. CONCLUSIONS: The patient's age and psychological mood may be stronger predictors of work ability compared with results from tests measuring physical capacity of the hands in vibration-exposed patients with hand symptoms. When using the WAI as an instrument for assessing work ability in these patients, health care providers need to be more aware of the impact of the psychological mood.
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| 4. |
- Gerhardsson, Lars, 1952, et al.
(författare)
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Quantitative neurosensory findings, symptoms and signs in young vibration exposed workers.
- 2013
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Ingår i: Journal of occupational medicine and toxicology (London, England). - : Springer Science and Business Media LLC. - 1745-6673. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background: Long-term exposure to hand-held vibrating tools may cause the hand arm vibration syndrome (HAVS) including vibration induced white fingers and sensorineural symptoms. The aim was to study early neurosensory effects by quantitative vibrotactile and monofilament tests in young workers with hand-held vibration exposure. Methods: This cross-sectional study consisted of 142 young, male machine shop and construction workers with hand-held exposure to vibrating tools. They were compared with 41 non-vibration exposed subjects of the same age-group. All participants passed a structured interview, answered several questionnaires and had a physical examination including the determination of vibrotactile perception thresholds (VPTs) at two frequencies (31.5 and 125 Hz) and Semmes Weinstein ’ s Monofilament test. Results: In the vibration exposed group 8% of the workers reported episodes of tingling sensations and 10% numbness in their fingers. Approximately 5 – 10% of the exposed population displayed abnormal results on monofilament tests. The vibrotactile testing showed significantly increased VPTs for 125 Hz in dig II bilaterally (right hand, p = 0.01; left hand, p = 0.024) in the vibration exposed group. A multiple regression analysis (VPT - dependent variable; age, height, examiner and five different vibration dose calculations – predictor variables) in dig II bilaterally showed rather low R 2 -values. None of the explanatory variables including five separately calculated vibration doses were included in the models, neither for the total vibration exposed group, nor for the highest exposed quartile. A logistic multiple regression analysis (result of monofilament testing - dependent variable; age, height, examiner and five vibration dose calculations – predictor variables) of the results of monofilament testing in dig II bilaterally gave a similar outcome. None of the independent variables including five calculated vibration doses were included in the models neither for the total exposed group nor for the highest exposed quartile. Conclusion: In spite of the fairly short vibration exposure, a tendency to raised VPTs as well as pathologic monofilament test results was observed. Thus, early neurophysiologic symptoms and signs of vibration exposure may appear after short-term exposure also in young workers.
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| 5. |
- Lunner Kolstrup, Christina
(författare)
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Work-related musculoskeletal discomfort of dairy farmers and employed workers
- 2012
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Ingår i: Journal of Occupational Medicine and Toxicology. - : Springer Science and Business Media LLC. - 1745-6673. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dairy farming is physically demanding and associated with a high frequency of musculoskeletal disorders (MSD). This study investigated and compared work-related MSD, ergonomic work factors and physical exertion in farmers and employed farm workers on dairy farms in Sweden. Methods: The study comprised 66 dairy farmers, and 37 employed dairy farm workers. A modified version of the general Standardised Nordic Questionnaire was used for analyses of perceived MSD in nine different parts of the body. Perceived physical discomfort was assessed using questions concerning ergonomic work factors. A rating scale was used for analyses of perceived physical exertion. Information about participant demographics was also collected. The response rate amounted to 70%. Results: The most frequently reported MSD in farmers and farm workers were located in the lower back (50% and 43%, respectively) and the shoulders (47% and 43%, respectively). MSD were also frequently reported in the neck (33%) among farmers, and in the hands/wrist (41%) among farm workers. MSD in the elbows (23%) and feet (21%) were significantly more frequently reported by farmers than farm workers (5%). Female farmers and farm workers both reported significantly higher frequencies of MSD in the neck (48% and 56%, respectively) and hands/wrists (44% and 61%, respectively) than their male colleagues (24% and 5%; 10% and 21%, respectively). In addition, female farm workers had significantly higher reported frequencies of MSD in the upper and lower back (39% and 61%, respectively) than their male counterparts (5% and 26%, respectively). Milking was perceived as a weakly to moderately physically demanding work task. Repetitive and monotonous work in dairy houses was the ergonomic work factor most frequently reported as causing physically discomfort among farmers (36%) and farm workers (32%), followed by lifting heavy objects (17% and 27%, respectively). Female workers had significantly more reported discomfort from repetitive and monotonous work than their male counterparts (50% and 16%, respectively). Conclusion: Despite the technical developments on modern dairy farms, there is still a high prevalence of MSD and discomfort from ergonomic work factors, particularly among female workers.
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| 6. |
- Sandén, Helena, et al.
(författare)
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Nerve conduction in relation to vibration exposure - a non-positive cohort study.
- 2010
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Ingår i: Journal of occupational medicine and toxicology. - : Springer Science and Business Media LLC. - 1745-6673. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT:Background Peripheral neuropathy is one of the principal clinical disorders in workers with hand-arm vibration syndrome. Electrophysiological studies aimed at defining the nature of the injury have provided conflicting results. One reason for this lack of consistency might be the sparsity of published longitudinal etiological studies with both good assessment of exposure and a well-defined measure of disease. Against this background we measured conduction velocities in the hand after having assessed vibration exposure over 21 years in a cohort of manual workers. Methods The study group consisted of 155 male office and manual workers at an engineering plant that manufactured pulp and paper machinery. The study has a longitudinal design regarding exposure assessment and a cross-sectional design regarding the outcome of nerve conduction. Hand-arm vibration dose was calculated as the product of self-reported occupational exposure, collected by questionnaire and interviews, and the measured or estimated hand-arm vibration exposure in 1987, 1992, 1997, 2002, and 2008. Distal motor latencies in median and ulnar nerves and sensory nerve conduction over the carpal tunnel and the finger-palm segments in the median nerve were measured in 2008. Before the nerve conduction measurement, the subjects were systemically warmed by a bicycle ergometer test. Results There were no differences in distal latencies between subjects exposed to hand-arm vibration and unexposed subjects, neither in the sensory conduction latencies of the median nerve, nor in the motor conduction latencies of the median and ulnar nerves. Seven subjects (9%) in the exposed group and three subjects (12%) in the unexposed group had both pathological sensory nerve conduction at the wrist and symptoms suggestive of carpal tunnel syndrome. Conclusion Nerve conduction measurements of peripheral hand nerves revealed no exposure-response association between hand-arm vibration exposure and distal neuropathy of the large myelinated fibers in a cohort of male office and manual workers.
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| 7. |
- Gerhardsson, Lars, 1952, et al.
(författare)
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Test-retest reliability of neurophysiological tests of hand-arm vibration syndrome in vibration exposed workers and unexposed referents
- 2014
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Ingår i: Journal of Occupational Medicine and Toxicology. - : Springer Science and Business Media LLC. - 1745-6673. ; 9:38
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exposure to hand-held vibrating tools may cause the hand-arm vibration syndrome (HAVS). The aim was to study the test-retest reliability of hand and muscle strength tests, and tests for the determination of thermal and vibration perception thresholds, which are used when investigating signs of neuropathy in vibration exposed workers. Methods: In this study, 47 vibration exposed workers who had been investigated at the department of Occupational and Environmental Medicine in Gothenburg were compared with a randomized sample of 18 unexposed subjects from the general population of the city of Gothenburg. All participants passed a structured interview, answered several questionnaires and had a physical examination including hand and finger muscle strength tests, determination of vibrotactile (VPT) and thermal perception thresholds (TPT). Two weeks later, 23 workers and referents, selected in a randomized manner, were called back for the same test-procedures for the evaluation of test-retest reliability. Results: The test-retest reliability after a two week interval expressed as limits of agreement (LOA; Bland-Altman), intra-class correlation coefficients (ICC) and Pearson correlation coefficients was excellent for tests with the Baseline hand grip, Pinch-grip and 3-Chuck grip among the exposed workers and referents (N = 23: percentage of differences within LOA 91 - 100%; ICC-values >= 0.93; Pearson r >= 0.93). The test-retest reliability was also excellent (percentage of differences within LOA 96-100 %) for the determination of vibration perception thresholds in digits 2 and 5 bilaterally as well as for temperature perception thresholds in digits 2 and 5, bilaterally (percentage of differences within LOA 91 - 96%). For ICC and Pearson r the results for vibration perception thresholds were good for digit 2, left hand and for digit 5, bilaterally (ICC >= 0.84; r >= 0.85), and lower (ICC = 0.59; r = 0.59) for digit 2, right hand. For the latter two indices the test-retest reliability for the determination of temperature thresholds was lower and showed more varying results. Conclusion: The strong test-retest reliability for hand and muscle strength tests as well as for the determination of VPTs makes these procedures useful for diagnostic purposes and follow-up studies in vibration exposed workers.
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