Search PubMed⌕ Search

Biomedical subjects

M Nordin

Publications and source records attributed to M Nordin.

At least 19 recordsLinked to original sources
PubMed2004

Low back pain in Mozambican adolescents.

Recent literature shows that the prevalence of low back pain (LBP) in adolescents living in Western countries approaches that of adults 18-55 years of age. Moreover, epidemiological studies have also shown that the frequency of different rheumatic disorders in developing countries is similar to that found in Western industrialized regions. The purpose of this study was to ascertain the prevalence of LBP and to explore some risk factors among adolescents living in different zones of Mozambique. A previously validated questionnaire was distributed to schoolchildren of grades 6 and 7 living in three different residential/social regions of the country. Two hundred four (204) children participated in the survey. Median age was 13 years (age range 11-16 years) and 46% were boys. Several episodes of LBP interfering with usual activities during the previous year were reported by 13.5% of the sample. Living in the wealthier urban center (as compared with the peripheral regions) and walking >30 min per day to and from school were associated with an increased risk of LBP (OR 3.1, 95% CI 0.99-9.48, and OR 4.8, 95% CI 1.61-14.28, respectively).

Adolescent↗
PubMed2003

Arousal increases baroreflex inhibition of muscle sympathetic activity.

AIM: Surprising sensory stimuli causing arousal are known to evoke short-lasting activation of human sympathetic activity in skin but not in muscle nerves. In fact, anecdotal observations suggest that muscle sympathetic activity may be inhibited. To test this hypothesis, the effects of surprising somatosensory (electrical skin pulses) or visual (flash) stimuli on multiunit muscle sympathetic activity were studied in 36 healthy subjects, aged 19-71 years. METHODS: The stimuli were given either 200 or 400 ms after the R-wave of the electrocardiogram. Dummy stimuli, consisting of trigger pulses without sensory stimuli, served as controls. RESULTS: On a group basis, a single sensory stimulus of either type attenuated the amplitude of one or two sympathetic bursts, while no such effects occurred after dummy stimuli. Individually, the inhibition was evoked by at least one stimulus modality or delay in 16 subjects, whereas in three subjects no significant inhibition occurred. Electrodermal signs of skin sympathetic activation were present in all subjects. Compared with one, five repeated electrical skin pulses induced only minor additional inhibition of muscle sympathetic activity, indicating marked habituation of the neural response. In nine subjects, the experiments were repeated once and in three subjects twice (with intervals of 2-3 months); in 11 of the 12 subjects, the sympathetic effects were reproducible. In the group of subjects without significant sympathetic inhibition the stimuli induced a small, transient increase of mean blood pressure, which was not present in the group with sympathetic inhibition. CONCLUSION: The finding that different sensory stimuli induce similar effects that habituate markedly on repetition suggests that the inhibition of muscle sympathetic activity is because of arousal. The interindividual differences in sympathetic and blood pressure effects may be part of interindividual differences in behavioural responses to stress.

Adult↗
PubMed2002

A 2-year prospective longitudinal study on low back pain in primary school children.

There is increasing evidence that non-specific low back pain (LBP) is common among children and adolescents, but there are few longitudinal studies on this subject. This is a longitudinal prospective study aimed at finding factors associated with the prediction of low back pain in schoolchildren aged 9-12 years, which is a younger age group than has previously been studied. This study was performed on school children in the city of Antwerp, Belgium. A total of 287 children filled out a questionnaire and were examined at the beginning of the study (T1) and 2 years later (T2). The questionnaire asked about back pain, general health, health perceptions, quality of life perceptions, sports, leisure, daily life, school life (weight of satchel.) and some issues related to parents (smoking, LBP). The questionnaire reliability was tested. Logistic regression was used to analyse the data. No predictors for LBP in children could be identified. Using logistic regression techniques, we analysed the children who reported no lifetime episode of LBP at both T1 and T2, the children who did report a lifetime episode at both T1 and T2 and also those who reported a history of LBP at T2 only (New LBP). At T2 there were 51 children (17.8%) reporting suffering at least one lifetime episode of LBP who had not reported such an episode at T1. Only one parameter showed a statistical difference: New LBP was observed significantly more frequently in children who do not walk to school ( P<0.0001). An interesting point of this study is that a number of children who had reported a history of LBP at T1 did not do so at T2. It may be that LBP in children is so benign and its natural history so favourable that the memory of the episode fades away. It is extremely interesting to note that among the few significant variables, those related to general well-being and self-perception of health, are prominent. It appears, therefore, that psychological factors play a role in the experience of LBP in a similar way to what has been reported in adults. Poor self-perception of health (health belief) could be a factor behind the reporting of LBP. Some variables linked to consequences of LBP (absence from school or from gym and visit to a doctor) play a significant role in reporting LBP, which suggests that those "health care" factors may reinforce a feeling of disease severity.

Causality↗
PubMed2001

Recovery of impaired muscle function in severe sciatica.

This is a prospective cohort study of patients with acute treated severe sciatica. The objectives of the study are, firstly, to describe the recovery of muscle performance by manual and isokinetic muscle testing in patients with acute severe sciatica over 1 year, and secondly, to discuss the potential clinical relevance of the isokinetic testing of the ankle for patients with acute sciatica. In clinical daily practice, muscle performance is evaluated by means of isometric manual tests. Different authors using manual muscle tests have reported the long-term outcome of the muscle function in patients with sciatica. Overall, the results are good in terms of the recovery of muscle strength. However, it is not clear whether the isometric strength is sufficiently relevant to evaluate the more complete muscle performance of the affected muscles in patients with sciatica. This study presents data on the muscle recovery measured with manual testing and isokinetic testing of patients with severe sciatica. Consecutive patients admitted to the Cantonal Hospital for conservative management of severe acute sciatica were eligible for inclusion in the study. Patients were evaluated at admission, discharge, and follow-up at 3, 6, and 12 months. All the visits included a standardized clinical examination and the completion of questionnaires. Imaging and electromyography were conducted at the first visit. Isokinetic muscle tests at 30 degrees/s and 120 degrees/s were performed at discharge and follow-up visits. Manual and isokinetic tests were performed on foot and ankle flexor and extensor muscles. Eighty-two consecutive patients (66% men), with a mean age of 43 (+/-10.3) years, entered the study. The prevalence of major muscle weakness was low, with 7% of patients unable to perform toe walking and 11% unable to walk on the heel at visit one. Moreover, motor deficit defined as a score of 4 or less (out of 5) was found in 15% of subjects at the first evaluation. Such severe deficits were not found during the last three visits. The isokinetic tests showed a higher prevalence of muscle function impairment. At visit 5, the isokinetic test showed impaired muscle function recovery from 23% to 32%, while the manual test showed almost full recovery. The issues of agreement between manual and isokinetic muscle testing are discussed. In this selected and homogeneous cohort of patients, the prevalence of motor deficit was rather low and the outcome excellent according to the results of the manual testing. Isokinetic muscle tests showed a higher prevalence of deficit and a much slower recovery. The manual muscle test is a crude clinical test. For more indepth muscle performance evaluation, additional testing may be necessary, especially for those patients with physically demanding jobs or activities.

Adult↗
PubMed2001

The test-retest reliability of a new occupational risk factor questionnaire for outcome studies of low back pain.

This study reports the test-retest reliability of a 25-item occupational risk factor questionnaire that can be self-administered in clinical settings and used in outcome studies of low back pain or return to work programs. Subjects were 24 patients (workers on sick leave due to acute low back pain), 29 co-workers on active duty in the same jobs in a utility company, and 53 supervisors. Eighty-six subjects were re-tested within a mean interval of 7-10 days; one group of 20 supervisors was re-tested within 81 days. The questionnaire was self-administered during individual interviews. Reliability was estimated by the kappa statistic as the agreement on the scores within the raters in each group. The agreement ranged from 'slight' (0.15) to 'almost perfect' (0.93) when the re-test interval was less than 43 days. Patients and non-patients were consistent in their assessment of the job demands. rights reserved.

Disability Evaluation↗
PubMed2001

Testing apparatus and experimental procedure for position specific normalization of electromyographic measurements of distal upper extremity musculature.

OBJECTIVE: An apparatus and procedure are described to determine position specific normalization coefficients for surface EMG of upper extremity musculature. STUDY DESIGN: Thirty-nine subjects were tested three times. Repeatability of EMG measurements across test sessions was determined by computing intraclass correlation coefficients. Two-way analysis of variance was used to test upper extremity position dependent differences in EMG measurements. BACKGROUND: EMG measurements are susceptible to error from skin movement and muscle length changes, both of which may occur when upper extremity positions vary. Normalization of the EMG signal without consideration for such positional influences may lead to erroneous conclusions regarding muscle activation during functional tasks. METHOD: An apparatus was designed that allowed subjects to perform three repetitions of maximum elbow flexion, forearm pronation, wrist extension, and wrist flexion with the forearm in neutral and pronated positions. Surface EMG was sampled from eight muscles. Mean EMG on maximum voluntary contraction was computed, and resting EMG was subtracted to obtain EMG normalization coefficients. RESULTS: Upper extremity position affected the EMG normalization coefficient for biceps brachii, which was lower in the pronated position, and extensor carpi radialis, which was higher in the pronated position (P<0.00625). CONCLUSIONS: The apparatus accommodates various combined positions of the elbow, forearm and wrist. The normalization procedure is efficient for testing subjects who are being observed during functional tasks. Only two muscles were affected by upper extremity position, but group trends were not always consistent with individual behavior. This method would ensure the use of appropriate EMG normalization coefficients regardless of individual variation. RELEVANCE: This method is effective for normalizing EMG signals using task specific upper extremity positions. It may be used to test isometric exertions of distal upper extremity musculature for clinical and research purposes.

Adult↗
PubMed2001

Evaluation of the Abbott AxSYM cytomegalovirus (CMV) immunoglobulin M (IgM) assay in conjunction with other CMV IgM tests and a CMV IgG avidity assay.

The measurement of the avidity of cytomegalovirus (CMV) immunoglobulin G (IgG) antibodies has been shown by several investigators to be useful in identifying and excluding primary CMV infections in pregnant women. In this work, we examined the diagnostic utility of reflex testing of CMV IgM-positive specimens from pregnant women by using a CMV IgG avidity assay. The utility of this approach was directly dependent on the sensitivity of the CMV IgM assay employed during the initial screen. The higher initial reactivity rate of the AxSYM CMV IgM assay was necessary in order to detect CMV IgM in specimens containing low-avidity CMV IgG antibodies, indicative of a primary CMV infection, which other CMV IgM assays (Behring, Vidas, Captia, and Eurogenetics) fail to detect in some cases. The use of the AxSYM CMV IgM assay, followed by an avidity test, should result in more accurate diagnosis of CMV infection in pregnant women.

Antibodies, Viral↗
PubMed2001

Sleepiness and recovery in schedule change and the eighty-four hour workweek.

The aims were to evaluate sleepiness and recovery during a schedule change, and during an 84-hours workweek. The control group (16 men) stayed on a six-week schedule, whereas the intervention group (12 men) transferred to a seven-week schedule. Sleepiness was estimated, using the KSS-scale, four times during the first and the third night in the fifth or sixth shift week. Recovery was assessed through four estimations on days one, three and five during the week off. Statistical testing was carried out using repeated measurement ANOVA. Sleepiness at night was affected by night (F = 4.90, p < 0.05) and hour (F = 33.64, p < 0.001) in both groups. The intervention group was sleepier during the first recovery day compared to the control group (F = 4.02, p < 0.05). Analysis of the 84-hour-week showed an effect of night (F = 8.98, p < 0.05) and hour (F = 71.60, p < 0.001) on night work, and day (F = 22.49, p < 0.01) and hour (F = 6.66, p < 0.05) on recovery. Sleepiness was more pronounced on the first recovery day (F = 23.08, p < 0.01). The seven-week schedule showed no effect that differed from that of the control group on sleepiness during the night shift. After the 84-hour workweek the workers recovered in about three days. The new schedules may affect the first recovery day negatively.

Adaptation, Psychological↗
PubMed2000

[Cytostatic therapy reduces the immune defense. Children treated for leukemia have impaired immunity against measles and rubella].

A study is summarized analyzing the levels of serum antibodies against vaccination antigens in 43 children treated for acute lymphoblastic leukemia. Two different therapeutical regimens were used. All children had been immunized against measles and rubella before being diagnosed with leukemia. Eight of the 24 children treated 1986-1991 lacked protective levels of antibodies against measles; four of the 24 children lacked antibodies against rubella. In the second cohort of children (n = 16) treated from 1992 and onwards, nine lacked protective levels of antibodies against measles, eight lacked antibodies against rubella.

Antibodies, Viral↗
PubMed1999

Recovery of severe sciatica.

STUDY DESIGN: A prospective study of patients with acute severe sciatica. OBJECTIVES: To 1) describe the characteristics of patients with acute severe sciatica and the agreement among different diagnostic tests, 2) describe overall recovery during 1 year in terms of perceived disability, and pain, and 3) explore acute-phase predictors of failure to recover at 1 year. SUMMARY OF BACKGROUND DATA: The development of imaging techniques has been very impressive during recent decades. However, different authors have highlighted the prevalence of abnormal images among asymptomatic subjects. These findings increase the difficulty of interpreting the results from the diagnostic techniques used with each individual patient. Furthermore, other clinical and biopsychosocial variables need to be explored for their associations with recovery or failure to recover. This study aimed to explore those associations. METHODS: Consecutive patients admitted to the hospital for conservative management of severe acute sciatica were eligible for inclusion in the study. Patients were evaluated at admission, discharge, and 3, 6, and 12 months. All the visits included a standardized clinical examination and the completion of questionnaires that included items on demographics, pain, perceived disability, and quality of life. Imaging and blood samples were collected at the first visit, and an electromyogram was taken for sciatica lasting at least 3 weeks. RESULTS: The study included 82 consecutive patients (66% men) with a mean age of 43 +/- 10.3 years. The mean intensity of pain, on a visual analog scale of 0 to 100 (VAS) at Visit 1, was 73. The straight leg raising test was positive in 78% of the patients, with a mean value of 59 degrees +/- 18 degrees. The contralateral straight leg raising test was positive in 20% of the patients. Imaging was positive for disc herniation in 74% and electromyogram was positive in 62% of cases. These two diagnostic tests showed a good to excellent total agreement (58-87%) with the straight leg raising tests and the presence of radiating pain below the knee. The recovery of clinical symptoms and signs was observed mainly within the first 3 months. However, clinical recovery and perceived recovery was not complete in most cases. CONCLUSIONS: In most cases, there was good to excellent agreement among the different diagnostic tests. None of the tests was predictive of recovery. The presence of blood antibodies against 3'LM1 (IgM + IgG) and GD1a (IgM) was significantly associated (P < 0.023) with neurologic symptoms and signs. However, the meaning of these antibodies remains unclear. Only a minority of the patients (29%) had fully recovered after 12 months. Within the 1-year follow-up, one third of the patients had surgery.

Adult↗
PubMed1999

Low back pain in a population of school children.

A study was undertaken to analyse the prevalence of low back pain (LBP) and confounding factors in primary school children in the city of Antwerp. A total of 392 children aged 9 were included in the study. All children completed a validated three-page questionnaire and they all underwent a specific lumbar spine oriented medical examination during their annual routine medical school control. This examination was performed by the city school doctors. The questionnaire was composed of easy "yes/no" questions and visual analogue scales. Statistical analysis was performed using Student's t-test and chi-squared test at the significance level P < 0.05. The prevalence of LBP was high. No gender difference was found. A total of 142 children (36%) reported having suffered at least one episode of LBP in their lives. Of these, 33 (23%) had sought medical help for LBP from a doctor or physiotherapist. Sixty-four percent of children reporting LBP said that at least one of their parents suffered from or complained of LBP. This was significantly higher than for the children who did not report having suffered LBP. The way in which the school satchel was carried (in the hand, on the back) had no bearing on the incidence of LBP. There was significantly more LBP in children who reported playing video games for more than 2 h per day, but this was not so for television watchers. The visual analogue scales concerning general well-being were all very significantly correlated with self-reported LBP, with children who reported LBP being more tired, less happy, and worse sleepers. Of the 19 clinical parameters taken down during the medical examination, only one was significantly more prevalent in the group of children reporting LBP: pain on palpation at the insertion site on the iliac crest of the ilio-lumbar ligament. From this study we can establish that there are few clinical signs that can help to single out school children with LBP.

Child↗
PubMed1999

Physical therapy: exercises and the modalities: when, what, and Why?

This article reviews the evidence for using modalities and/or exercise treatment in patients with nonspecific low back pain. Poor evidence of efficacy exists for the use of modalities in this patient group. Exercises are beneficial for patients with subacute and chronic nonspecific low back pain. Further studies are needed for type, frequency, duration, and intensity of exercises.

Exercise Therapy↗
PubMed1998

Postural after-contractions in man attributed to muscle spindle thixotropy.

1. It is an old observation that non-volitional arm abduction movements accompanied by a sensation of arm lightness often occur as an after-effect following forceful voluntary arm abductor contractions against a restraint. In the present study we have tested the hypothesis that such non-volitional, so-called 'postural after-contractions' are tonic reflex responses to an enhanced resting discharge in primary muscle spindle afferents which in turn is a consequence of thixotropy-dependent enhanced stiffness of intrafusal muscle fibres. 2. Results obtained in ten volunteers show that the arm abductor after-contraction phenomenon in man is most readily evoked by a type of conditioning procedure which in various respects mimics the procedure proven in animal experiments to be particularly effective in producing thixotropy-dependent excitation of primary spindle endings. 3. It is also shown that changes in arm abductor intramuscular temperature affect the strength of the after-contractions in a direction predicted by the thixotropy hypothesis. 4. Attention is drawn to several similarities between the after-contraction phenomenon with accompanying sensory illusions and the tonic reflex responses and illusions that can be induced when primary spindle endings are excited by muscle vibration. 5. The results support our hypothesis that postural after-contractions are induced by activity in primary muscle spindle afferents as a consequence of thixotropic properties of intrafusal muscle fibres. Central excitability changes following the conditioning voluntary effort may contribute to the phenomenon.

Adult↗
PubMed1998

Health care providers should use a common language in relation to low back pain patients.

Uncertainty is the rule rather than the exception when it comes to the underlying causes of 'common' or 'non-specific' low back pain. It may be called many names, depending on whether the diagnostic term is descriptive, anatomopathological or physiopathological. Classifications have been devised, including various criteria: symptoms and signs, duration, treatment, consequences of low back pain on the patients' daily life, etc. Because back pain frequently runs a recurrent course, functional and pain outcomes need to be considered separately: chronic disability and chronic pain may not be parallel. Thus, pain duration (e.g. acute, transient, recurrent, chronic) is only one element in the definition of chronicity. These difficulties in defining and classifying non-specific low back pain may lead to communication problems among health professionals as well as between patients and health professionals. These difficulties raise questions such as: what kind of diagnostic term should we use to avoid dramatization of non-specific low back pain? how can we improve the definition of long-term low back pain? and how can we assure and reassure the patient that this condition is benign in the majority of the population?

Chronic Disease↗