Psychosomatic pain in children: A psychomuscular tension reaction?

Although recurrent psychosomatic pain is a common paediatric condition, our understanding of it is still limited. In this article, the clinical picture is presented and the concept of psychosomatic pain is discussed. Some recent scientific data are presented including a controlled blind study of pain pressure thresholds showing significantly reduced mean values over common pain areas in a group of children with psychosomatic pain. According to another study, these children also have significantly reduced concentrations of the hypothalamic hormone oxytocin and cortisol. With these data as a point of departure, a model for psychosomatic pain reaction is outlined in which stress is assumed to induce muscular tension, in turn triggering the nociceptive process. In this psychosomatic reaction, the hypothalamus is believed to have a central regulatory function.

Agency orientation and chronic musculoskeletal pain: effects of a group learning program based on the personal construct theory

OBJECTIVE

This study evaluated the effects of a group learning program on patients with chronic musculoskeletal pain and high absenteeism and investigates what characterizes those patients who may benefit from such a program. The learning program was based on personal construct theory. The theory included the following: (1) participation in an educational program is related to a favorable outcome across the outcome measures (pain, pain coping, management of daily life, absenteeism, and use of health care), (2) patients with high agency orientation (i.e., inner-directed) cope with their pain and manage daily life in a better manner than do patients with low agency orientation (i.e., outer-directed), and (3) patients with high personal control, measured in terms of agency orientation, in terms of health locus of control, or in both terms, will benefit more from the educational program than will patients with low personal control.

DESIGN

The study was a randomized controlled study.

PATIENTS

One hundred and sixteen patients with chronic musculoskeletal pain and high absenteeism answered a questionnaire before and after the intervention program. The intervention group (n = 61) consisted of nine subgroups geographically spread through the eastern part of Norway and met for four hours every 2 weeks from February 1997 to October 1997. A total of 12 meetings were held.

RESULTS

The intervention group reported a significantly higher score for the variable "management of everyday life" (p <0.005) and for the variable "health care consumption" (p <0.001) than did the control group. Patients with high agency orientation benefited more from the program with regard to pain reduction and improved pain coping than did those patients with low agency orientation (p <0.05). Patients with high agency orientation also reported less absenteeism than did those patients with low agency orientation (p <0.05).

Shoulder-arm muscle load and performance during control operation in forestry machines. Effects of changing to a new arm rest, lever and boom control system

Three work station design studies in forestry machines were carried out with regard to shoulder/arm muscle load. (1) In an arm rest study, a movable (in the sagittal plane) arm rest was compared with a fixed one; (2) in a lever study, a mini lever with a small deflection was compared with an ordinary hand lever; (3) in a boom control study, a computer controlled boom system was compared with an ordinary boom system. In the arm rest study eight male subjects carried out lever operations in the laboratory. In the lever and boom studies, 15 male forestry students operated forwarders. Muscle load, cycle time, skill, perceived exertion, heart rate and preferred set up were recorded. The muscle loads on the upper trapezius, infraspinatus, extensor carpi ulnaris and flexor carpi radialis were recorded by electromyography. With mini lever and movable arm rest the upper trapezius load was reduced with preserved or decreased cycle time, although the grand mean of the 'static' load level was only about 2% of maximal voluntary contraction (MVC) and the effects of the new designs were small (about 0.7% MVC). The subjects preferred the lever/arm rest also giving the lowest muscle load. No differences between levers or arm rests were found in skill, perceived exertion or heart rate. It was not possible to draw any definitive conclusions regarding effects of the boom control system, due to technical problems. According to the literature, the duration of lever operation has increased considerably in forestry during recent years as part of a rationalization process. Partly due to this, it is suggested that the investigated work station improvements may not be sufficient to eliminate the risk for shoulder-neck disorders.

A model for solving work related musculoskeletal problems in a profitable way

Interventions against occupational musculoskeletal disorders are usually performed by ergonomists. An overview of the literature shows that ergonomists often are unsuccessful; musculoskeletal disorders may be prevalent at workplaces where large ergonomic resources have been put in, thus illustrating the significance of other factors in addition to those against which the intervention is applied. It is claimed that some modern rationalization strategies may offer a potential for 'good' ergonomics. Thus, prevailing management approaches often now focus on team building, flat organizations, training of multiple skills and so on. The main scope of the present issue of Applied Ergonomics is to throw light on this possibility of 'achieving ergonomics impact through management intervention'. This present paper presents a historical overview of occupational physical work load as a function of ergonomics, as well as rationalizations and concludes with a more elaborate discussion of the present intervention concept for solving work related musculoskeletal problems in a profitable way. Rationalization and guidelines for physical work load are the basic parameters in the present intervention concept. Due to this the present special issue also presents historical overviews of the development of these parameters (Westgaard and Winkel; Bjorkman). 'Achieving ergonomics impact through management intervention' is illustrated through two case studies (Kadefors et al and Bao et al). They demonstrate an obvious ergonomic potential offered by the presented intervention concept. However, the two case studies also describe several practical obstacles which need to be further investigated in future intervention research.

Muscle coordination and choice-reaction time tests as indicators of occupational muscle load and shoulder-neck complaints

The use was explored of psychomotor tests as indicators of the risk of shoulder-neck disorders in workers with low-level static loads on the shoulder muscles. Two groups of workers performing office work and light production work were studied. A muscle coordination test with continuous movement of the arm and hand between three target areas and a psychogenic tension test, posing mental demands and with minimal requirement for body movements, aimed to quantify muscle activity in excess of that needed for biomechanical purposes. The electromyogram (EMG) recording of the active trapezius muscle in the muscle coordination test correlated with the median and static EMG values of the vocational (i.e. during the normal work task) trapezius recording both for the office and production workers, but showed no correlation with shoulder-neck complaints. The EMG responses in the psychogenic tension test and of the passive (contralateral) trapezius in the muscle coordination test correlated best with the parameters showing short, spontaneous pauses in the EMG recording of occupational load. For the office workers, but not for the production workers these parameters also correlated with shoulder-neck complaints and the presence of psychosocial problems. Psychomotor tests may thus be useful as indicators of the risk of shoulder-neck complaints in certain occupations, but further experimentation is needed to validate this conclusion.