Biomedical subjects

H J Sallé

Publications and source records attributed to H J Sallé.

At least 19 recordsLinked to original sources

PubMed1999

Prognostic factors for chronic disability from acute low-back pain in occupational health care.

OBJECTIVES: This study attempted to determine the prognostic indicators of low-back pain in an occupational health setting. METHODS: The identification of prognostic factors of (i) functional disability after 3 months' follow-up, (ii) functional disability after 12 months' follow-up, and (iii) time to return to work among 120 workers who reported to an occupational health unit and were off work with low-back pain for at least 10 days. Crude and adjusted odds ratios and hazard ratios with 95% confidence intervals were estimated for the 3 outcome measures. RESULTS: Factors related to a longer time to return to work were radiating pain, high functional disability at the beginning of the study, problems in relations with colleagues, and high work tempo and work quantity. High functional disability at the beginning of the study and a high avoidance coping style predicted functional disability at 3 months. Functional disability at 12 months was more accurately predicted by work-related and psychosocial factors. CONCLUSIONS: Especially radiating pain and functional disability predict a long duration of low-back pain in occupational health practice. Occupational physicians should also note work-related and psychosocial characteristics.

Acute Disease↗

PubMed1995

Pregnant women and working surface height and working surface areas for standing manual work.

Physically loading aspects of work may have adverse effects on the health of both the pregnant woman and the unborn child. Improving the fit between the pregnant woman and the workplace layout contributes to minimizing the load associated with given tasks. The aim of this paper is to evaluate two layout aspects for standing manual work, namely working surface height and working surface areas, for the condition of pregnancy. Two approaches were used. (1) The effects of changed body dimensions were evaluated with regard to (a) fit problems while working at a workplace in accordance with common guidelines and (b) the validity of assumptions of these guidelines. (2) The appreciation of relevant aspects of workplace layout at a specific manual task was assessed. Twenty-seven women were examined in pregnant and non-pregnant conditions. The first approach showed that fit problems are likely: guideline working surface height is just (2-7 cm) under the most protruding abdominal point, and areas based on non-pregnant abdominal depth are relatively large in pregnant condition. Further, existing methods to assess working surface areas have various assumptions that are not valid in pregnant condition. The second approach showed that at a specific manual task, women in late pregnancy preferred a considerably lower table height than the common guideline heights. Possibly, abdominal height becomes a relevant design factor with regard to working surface height during pregnancy. The task position on the working surface at which effort started became closer to the table edge due to pregnancy. Both approaches show that common guideline working surface heights for manual work, and working surface areas assessed in non-pregnant condition seem not suitable in pregnant condition.

Journal Article↗

PubMed1994

Comparison of two techniques to measure the motor nerve refractory period distribution.

The techniques introduced by Ingram et al. and by Kimura to assess the motor nerve refractory period distribution were compared in the peroneal nerve of 28 healthy subjects. Twenty of these subjects were examined twice with an interval of 6-20 days. Results obtained with Ingram's technique yielded a narrower refractory period distribution, displayed less inter-individual variability, and were more reproducible than those obtained with Kimura's technique. The mean refractory period for the 5% slowest recovering fibres (MRP95) was 1.51 msec (S.D. 0.14) for Ingram's technique and 2.15 msec (S.D. 0.72) for Kimura's technique. The coefficient of variation of the MRP95 was 8% for Ingram's technique, and 22% for Kimura's technique. The present data do not allow a definite conclusion concerning the association of refractory period with age, gender and height. Ingram's technique would be favoured for practical application over Kimura's technique on the basis of this study.

Action Potentials↗

PubMed1993

Comparison of two techniques to measure the motor nerve conduction velocity distribution.

Hopf's technique to measure the distribution of motor nerve conduction velocities (DMCV) has been compared with the technique introduced by Ingram et al. in the peroneal nerve of 28 healthy subjects 41.2 (S.D. 8.4) years. Twenty subjects were examined twice. Both techniques yielded an equal DMCV and equally reproducible results. Group mean velocities for the slowest examined (MNCV95) motor nerve fibres were 39.0 m/sec (S.D. 3.3) for Ingram's technique and 38.6 (S.D. 3.6) for Hopf's technique. The conventional MNCV was always slower than the velocity of the 5% fastest fibres estimated from the DMCV. Ingram's technique may have a number of merits which may have been obscured by measurement in the peroneal nerve, which may be of advantage in shorter nerve segments or faster nerve fibres. On the basis of our data in the peroneal nerve of healthy subjects no preference can be given for either of the techniques.

Action Potentials↗

PubMed1993

Verification of effects on the nervous system of low level occupational exposure to CS2.

Neurotoxic effects associated with long term low level occupational exposure to CS2 were reinvestigated four years after the initial study in the same group of workers. The second study concerned 44 exposed and 31 matched control workers. For both studies a personal cumulative exposure Ec was calculated based on function specific exposure levels and the occupational histories, which were carefully re-established. The exposed workers' average Ec was 192 and 213 ppm-years (first and second study respectively). Where possible the values of both data sets were used in a final combined analysis. Effects were found on the motor nerve conduction velocity of the fast (-0.9 m/s) and slow (-1.0 m/s) fibres of the peroneal nerve, the sensory nerve conduction velocity in the hand and arm segment of the median (-2.1 m/s) and ulnar (-1.3 m/s) nerves, and in the sural nerve (-1.3 m/s). An increased refractory period was found in the sural nerve (+ 0.2 ms, + 11%), but not in the peroneal nerve. For the autonomic nervous system an effect was found on the heart frequency response to isometric muscle contraction (-4.7 beats/min, -26%) and maximal forced respiration (-3.2 beats/min, -16%). This study shows the importance of a detailed evaluation of past exposure data. The reinvestigation enabled a more precise estimation of the effects of CS2, which is particularly desirable at around threshold exposure.

Autonomic Nervous System Diseases↗

PubMed1991

Nerve function in workers with long term exposure to trichloroethene.

Certain functions of the nervous system were examined in 31 printing workers (mean age 44) exposed to trichloroethene (mean duration 16 years) and 28 controls (mean age 45). In the sural nerve the conduction velocity (SNCV), response amplitude, and refractory period (SRP) were measured. The latencies of the masseter and the blink reflex were determined to test the trigeminal nerve. In the peroneal nerve the conduction velocity of fast and slow nerve fibres, the response amplitude, and the refractory period were determined. As a measure of autonomic nerve function the response of the heart rate was determined to isometric muscle contraction and deep breathing. Individual cumulative exposure was calculated on the basis of exposure levels in the past. The mean cumulative exposure of the exposed workers was 704 ppm x years. For the assessment of the exposure effect relation a multiple linear regression model was used. A slight reduction (-1.1 m/s) in the SNCV was found and a prolongation (0.4 ms) of the SRP (mean of the controls 1.95 ms). The latency of the masseter reflex (mean 10.4 ms) had increased (0.4 ms). With respect to the blink reflex no prolongation was found. No impairment was found in the functions of motor and autonomic nerves. This study shows that the refractory period may be a sensitive indicator of preclinical toxic neuropathies. Long term exposure to trichloroethene at threshold limit values (about 35 ppm) may slightly affect the trigeminal and sural nerves.

Adult↗

PubMed1990

Special nerve functions and colour discrimination in workers with long term low level exposure to carbon disulphide.

Certain functions of the peripheral and autonomic nervous systems, and colour discrimination were examined in 45 workers (mean age 49; mean exposure to carbon disulphide (CS2) 20 years) and 37 controls (mean age 48). Conduction velocity and refractory period of the peroneal and sural nerves were determined. The conduction velocity of the slower fibres of the peroneal nerve was measured by means of an improved method that makes use of the refractory period. Function of autonomic nerves was assessed by measuring the variation in heart rate during rest, during deep breathing, and during isometric muscle contraction. Colour discrimination was evaluated by the Lanthony desaturated test. Individual cumulative exposure to CS2 was calculated on the basis of exposure in the past and individual job history. Mean cumulative exposure was 165 ppm-years. The peroneal nerves of exposed workers showed a decrease (-1.0 m/s) in conduction velocity of the slow fibres and a prolongation (0.1 ms) of the refractory period (mean 1.6 ms) compared with controls. These effects were related to cumulative exposure. No impairment of function of the sural nerve or of colour discrimination was found. The muscle heart reflex was decreased in the exposed group, but this was not related to cumulative exposure. This study has established more firmly that a decrease in conduction velocity of slow motor fibres occurs at low levels of exposure to CS2. Extrapolation of the results suggests that small effects may occur after 40 years of exposure to concentrations below the present threshold limit value (10 ppm).

Autonomic Nervous System↗

PubMed1986

Tremor in workers with low exposure to metallic mercury.

In a fluorescent lamp production factory, a newly developed lightweight balance-tremormeter was used to measure postural tremor of the finger in 21 workers (ages 28 to 61) exposed for 0.5-19 yr to metallic mercury. In addition, tremor was measured in an indirect way by means of a "hole-tremormeter." The excretion of mercury in urine was 9-53 (average 20) mumol/mol creatinine. With increasing mercury excretion, the following parameters increased: the acceleration of the tremor, the contribution of the neuromuscular component (8-12 Hz) to the power spectrum of the acceleration, the width of the power-spectrum and the score on the hole-tremormeter. The study indicates that exposure to metallic mercury below the current TLV (50 micrograms/m3) may increase the tremor of the finger.

Dose-Response Relationship, Drug↗

PubMed1986

Tremor, effect of physical load and reproducibility.

The effect of three kinds of moderate physical loads on the tremor of the middle finger was studied in eight males: cycling 15 min on an ergometer at a heart rate of 140 beats/min (general dynamic load); lifting a mass of 1 kg by the middle finger at a rate of 30 times/min for 5 min (local dynamic load); and carrying in each hand a 15 kg mass for 5 min. Few effects were observed: 10% decrease of RMS acceleration after local dynamic load and some changes in the power spectrum after general dynamic load. It is concluded that the effect of recent, short time physical load of moderate extent can be neglected as a disturbing factor in the study of the effects of toxic exposure on postural tremor. The inter- and intra-individual variation (over 4 weeks) in nine males and nine females also was studied. The intra-individual variation ranged from 4% for the mean frequency to 35% for the 0-4 Hz band of the power spectrum. The inter-individual variation ranged from 8% for the mean frequency to more than 60% for some frequency bands of the power spectrum. It is concluded that the mean frequency possibly is a sensitive parameter in epidemiologic studies on effects of external toxic exposure on tremor.

Biomechanical Phenomena↗

PubMed1985

Vibratory and tactile sense of the fingers after working with sanders.

Twenty-four volunteers worked four times in a laboratory under realistic conditions for 80 min with a relatively intensely vibrating plane-sander and a less intensely vibrating band-sander (each sander twice). Immediately before and after exposure, the left and right third finger was measured for vibratory sense with a 100 Hz rod-vibrameter and for width- and depth-sense by means of an apparatus modified after Carlson. The reproducibility of the parameters was poor: coefficients of intra-individual variation were 20 to 60%. After using the plane-sander the threshold of the width-sense in the right hand increased relative to the effect of the band-sander by 17% of the pre-exposure value; in the left hand no increase was found. The thresholds of the depth-sense and vibratory sense showed no change. The study suggests that brief vibration exposure below the ISO-guideline may cause some reduction of sensibility. One should be cautious in applying these tests. An exposure-free interval of at least several hours is recommended when studying chronic effects of vibration exposure.

Adult↗

PubMed1984

Comparison of five methods for measurement of vibratory perception.

Five methods for the measurement of vibratory perception (using three different vibrameters ) have been compared by determining the vibratory perception threshold in 12 subjects on two days (with a 3-d interval). One device with a vibrating rod (manufactured by MUAB ) was used, the rod being applied either to the finger-tip (rod-tip) and on the proximal phalanx (rod-phalanx). The other devices were fitted with vibrating pins. In one apparatus all pins vibrated in phase (pin-phase), in the other ( Optacon ) the pins in adjacent rows vibrated in opposite phase. The latter one was used with a continuous (pin-cont) and with a "yes-no" procedure (pin-y/n). Mean vibratory perception threshold differed considerably: from 0.09 micron (pin-y/n) to 0.61 micron (pin-phase). No learning effect was found between the two days of measurement. The correlation between the measurements on both days (a measure for the reproducibility) was about the same for all methods (from 0.71 to 0.86). Intra-individual variation amounted to 30 to 50%. The low correlation of pin-cont and pin-y/n with the other methods (0.06 to 0.44), if compared with the correlations among the remaining methods (0.53 up to 0.83), suggests that with the Optacon different sensory properties are measured. Apart from the unclear relevance of the measurement of vibratory perception for early diagnosis of neurologic diseases, these results indicate that further investigation and standardization of methods is necessary before they can be used in practice as a screening-method.

Adult↗

PubMed1979