Effects of functional electric stimulation on the neuromuscular system

Four groups of patients with low back pain and a group of healthy subjects participated in a study to investigate the effects of administering three different muscle conditioning protocols on the functional output of the neuromuscular system. Quadriceps muscle weakness was identified in patients suffering from low back pain. The weakness was attributed to pain and its associated effect on reduced activity and disuse. The muscle conditioning methods used were: functional electric stimulation at low frequency of 20 Hz (group S20), functional electric stimulation at 50 Hz (group S50), and isometric training (group ISOM). Two groups served as controls. The first group (CONT1) consisted of low back pain patients that did not go through any of the previously mentioned special muscle conditioning programs. The second control group (CONT2) consisted of healthy subjects. Changes in the output of the neuromuscular system were quantified through measures of maximum voluntary contraction force, limb girth, and several measures of electromyographic activity. Results suggested that both functional electric stimulation and isometric exercises were significantly effective in increasing muscle strength over the experimental period of two weeks. Moreover, for the sample and conditions used in this study, functional electric stimulation at 20 Hz was more effective in increasing muscle strength than that at 50 Hz or isometric exercise. Isometric exercise was effective in increasing motor unit recruitment of both the exercised and the contralateral muscles. The results suggest that the underlying mechanism of effectiveness of functional electrical stimulation, in this case, is related to peripheral factors with no significant involvement of higher levels of the central nervous system or the brain. A conceptual model for the underlying mechanism of functional electric stimulation action is proposed based on the findings of this study. It was concluded that electric stimulation, when used according to the protocol described in this study, is a very effective and a viable muscle strengthening technique

Validity of the Dictionary of Occupational Titles Residual Functional Capacity Battery

BACKGROUND DATA:The Dictionary of Occupational Titles (DOT) is a U.S. government publication that defines each job in the United States according to 20 job factors. Fishbain et al. (Spine 1994;19:872-80) developed a DOT residual functional capacity (RFC) battery whose predictive validity for employment/unemployment had not been tested previously. OBJECTIVES:The purposes of this study were as follows(a) to determine whether results of a DOT-RFC battery performed at completion of pain facility treatment predicted employment status at 30 months' follow-up and (b) to determine whether the DOT-RFC battery predicted employment capacity as determined by the DOT employment levels of the chronic pain patients' (CPPs) jobs. STUDY DESIGN:This is a prospective low back pain CPP pain facility treatment study using employment status and the DOT occupational levels as outcome measures. METHODS:One hundred eighty-five consecutive CPPs who fitted the selection criteria completed a DOT-RFC battery at the completion of pain facility treatment and were contacted at 1, 3, 6, 12, 18, 24, and 30 months for determination of their employment status and DOT employment level. Eight DOT job factors plus pain and worker compensation status were found to be significantly different between employed and unemployed CPPs and between those employed in different DOT employment levels. For the 10 variables, stepwise discriminant analysis was used to select final predictor variables. Sensitivity and specificity were calculated along with pain level cutpoints that separated the groups. RESULTS:The eight DOT job factors found to be statistically significant between groups were the followingstooping, climbing, balancing, crouching, feeling shapes, handling left and right, lifting, carrying, and pain and worker compensation status. In the discriminant analysis, these variables could discriminate between the employed and unemployed categories, with a sensitivity and specificity of approximately 75%. The pain level cutpoint between employed and unemployed was 5.4 on a 10-point scale. CONCLUSIONS:We cannot as yet predict DOT-RFC employment levels. However, if a CPP can pass the above eight DOT job factors and has a pain level less than the 5.4 cut-point, that CPP will have a 75% chance of being employed at 30 months after treatment at the pain facility. Therefore, some DOT-RFC battery job factors demonstrate a predictive validity in the "real work world.

Functional Capacity and Residual Functional Capacity and Their Utility in Measuring Work Capacity

ObjectiveThe pain physician is often asked to establish the medical impairment of the chronic pain patient (CPP) and from that determination ascertain the work capacity of the CPP. Functional capacity (FC) testing has recently been introduced as a more objective and accurate way of facilitating the determination of work capacity. However, there are conceptual problems with the measurement of FC. These will be reviewed and the relationship of FC to residual functional capacity (RFC) will be determined. Finally, a method for measuring RFC in a job-specific manner will be suggested.Data SourcesThe literature in reference to the measurement of medical impairment, FC, and RFC was reviewed.Study SelectionStudies appropriate to the objective of this review were selected for inclusion.ConclusionsThe FC and RFC are poorly defined. Lack of definition has interfered with design of appropriate test batteries specific to work capacity. To circumvent this problem a job-specific RFC measurement method is suggested. This method is based on the Dictionary of Occupational Titles

The Prediction of Return to the Workplace After Multidisciplinary Pain Center Treatment

The prediction of return to the workplace after Multidisciplinary Pain Center (MPC) treatment has become a major research area. To delineate the variables that predict this outcome, the authors reviewed 164 multidisciplinary outcome studies. Of these, 79 addressed work as an outcome variable. Twenty-six studies attempted to identify patient variables predicting return to the workplace. These latter studies were critically inspected for eight methodological criteriapain location, follow-up time interval, response percentage and follow-up method, return to work subcategorization, vocational movement, univariate vs. multivariate statistics, multicolinearity and variance, and statistical treatment of dropouts. In addition, other disability studies besides those in the chronic pain area were reviewed for return to the workplace predictor variables. Of these 26 studies, only a few appeared to satisfy the criteria examined. In addition, many studies were in conflict with one another on whether a variable was predictive. The review of the nonchronic pain/disability prediction literature yielded a large number of potential predictors that related to the work area. It is unclear which variables or set of variables predict return to the workplace after MPC treatment. Chronic pain studies may be neglecting the work area as an important source of return to the workplace predictor variables