Transcutaneous electrical nerve stimulation (TENS) treatment outcome in long-term users

OBJECTIVE

Previous reviewers of the literature on transcutaneous electrical nerve stimulation (TENS) outcome have concluded the following: (a) there are few long-term TENS follow-up studies, and (b) fewer studies have addressed the effect of long-term TENS use on outcome variables other than pain (e.g., function). DESIGN/SETTING/PARTICIPANTS/OUTCOME MEASURES: From a population of 2,003 chronic pain patients (CPPs) who bought a TENS device for pain management, 506 patients were randomly selected and interviewed by telephone long enough after purchase to allow at least 6 months of TENS use. The interview process used a structured "skip" questionnaire designed to assess the CPPs' perceptions regarding the effectiveness of TENS for a variety of outcome variables. Of the 506 CPPs interviewed, 376 (74.3%) had used their TENS device for 6 months or longer and were defined as long-term users. The responses of this group of CPPs to the telephone questionnaire were then subjected to statistical analysis.

RESULTS

Paired t-tests, correlated z-tests, SS Wilks, and chi-square tests demonstrated statistically significant change or improvement (p < 0.05) that paralleled the introduction of TENS use in the following outcome variables: less pain interference with work, home, and social activities; increased activity level and pain management; decreased use of other therapies (e.g., physical therapy, occupational therapy, chiropractic); decreased use of narcotics, tranquilizers, muscle relaxants, nonsteroidal anti-inflammatory drugs and steroids.

CONCLUSIONS

The results suggest that TENS is associated with improvement on multiple outcome variables in addition to pain relief for CPPs who are long-term users. Also, for some CPPs, long-term TENS use continues to be effective.

Age differences in sensitivity to H2O2- or NO-induced reductions in K(+)-evoked dopamine release from superfused striatal slices: reversals by PBN or Trolox

Previous research has indicated that many age-related functional alterations may be the result of a decreased ability of the organism to respond to oxidative stress (OS). However, this hypothesis is based on indirect indices of function (e.g., increased vulnerability of hepatocytes from senescent animals to H2O2-induced DNA damage, increases in lipofuscin accumulation). More direct tests of this hypothesis, especially as it relates to brain aging, have not been extensively undertaken. Present experiments were carried out to make such tests by examining age differences in the sensitivity to OS on reductions in striatal dopamine (DA) release. Thus, K(+)-evoked DA (K(+)-ERDA) release from superfused striatal slices from young (6-8 month) and old (24-25 month) animals was examined following either: (a) application of the NO-generator sodium nitroprusside or (b) preincubation with H2O2. In order to assess the specific effects of OS on muscarinic (mAChR) sensitivity, oxotremorine-enhancement of K(+) -ERDA was examined following incubation with H2O2. Results showed that the striatal tissue from the old animals showed greater sensitivity to both H2O2 and NO than young animals, and stimulated DA decreased at lower concentrations of these agents (e.g., NO--100 microM young, 30 microM old). In addition, H2O2 was also effective in reducing oxo-enhanced K(+)-ERDA and was more effective as a function of age. If the striatal tissue was incubated in either Trolox (alpha-tocopherol) or alpha-phenyl-n-tert-butyl nitrone (PBN) prior to OS, the negative effects of NO. and H2O2 were reversed in both age groups. Results are discussed in terms of age-related membrane and endogenous antioxidant alterations that could induce increases in sensitivity to OS and the specificity of antioxidants in reducing this sensitivity in key functional systems.

Physician limitations when assessing work capacity: a review

Literature evidence indicates that physicians have great difficulty in translating medical impairment into functional limitation and thereby establishing the work capacity or the residual functional capacity (RFC) of the injured worker. This is especially true for the chronic pain patient (CPP). Development of quantitative methods for the measurement of functional capacity (FC), have not improved the problems involved in the measurement of RFC and the translation of RFC into the demand minimum functional capacity (DMFC) of some job or jobs. The relationship between FC, RFC, work capacity and DMFC is reviewed. We have developed a method/battery for measuring RFC in CPPs utilizing the Dictionary of Occupational Titles (DOT) which is readily translatable into DMFC of some job or jobs. Suggestions are made for future directions in the measurement of work capacity.

Area specific alterations in muscarinic stimulated low Km GTPase activity in aging and Alzheimer's disease: implications for altered signal transduction

Carbachol-stimulated low Km GTPase activity (an index of muscarinic receptor-G protein coupling) was examined in hippocampus, basal ganglia, orbital frontal gyrus and superior frontal gyrus obtained from mature, aged and Alzheimer's Disease (AD) groups. Results indicated that carbachol-stimulated low Km GTPase activities in basal ganglia were as follows: mature controls > aged > AD, and there was a trend toward a similar pattern of decline in the hippocampus. No differences were seen in the two cortical areas examined; however, carbachol-stimulated low Km GTPase activity was small in the mature controls. Importantly, there were significant negative correlations between disease duration and carbachol-stimulated low Km GTPase activity in all areas examined except the orbital frontal gyrus. The longer the duration of the disease the lower the carbachol-stimulated low Km GTPase activity. Results suggest that age and disease-related changes in mAChR-G protein interactions in the basal ganglia may contribute to reduced signal transduction (ST). In addition, since decreased carbachol-stimulated low Km GTPase activity has also been observed in the aged rat; thus, investigations of the factors involved in decrements in signal transduction in the aged rat may be useful for understanding these alterations in aged humans or victims of AD.

Functional electrical stimulation treatment of postradiculopathy associated muscle weakness

Eighteen chronic pain patients (CPPs) with postradiculopathy-associated muscle weakness were entered into a nonrandomized functional electrical stimulation (FES) clinical treatment study to determine if FES can improve postradiculopathy associated muscle weakness. Because of the clinical nature of the unit, the CPPs could not be denied treatments other than FES. To control for these other treatments, the CPPs were used as their own controls with two control conditions, ie, where possible, the contralateral probable normal muscle was used as a control (control 1) and; in a subgroup of CPPs (n = 6), FES treatment was initially withheld to the probable weak muscle (control 2). Strength was measured as isometric maximum voluntary contraction (IMVC) and was used as the outcome treatment variable. IMVC was measured in both the probable weak and contralateral probable normal muscles at entrance into the Pain Center, at beginning of FES treatment, at completion of FES treatment, and for the control 2 condition at the end of the non-FES treatment period. Statistical analyses of the IMVC strength results using the two control conditions indicated (1) both the FES-treated and untreated muscles increased significantly in IMVC strength, (2) improvement in IMVC strength for FES-treated muscles was significantly greater than for probable normal FES-untreated muscles and, (3) improvement in IMVC strength in FES-treated muscles was significantly greater during the FES-treatment period than during the non-FES treatment period. FES treatment of postradiculopathy-associated muscle weakness in CPPs seems to increase the strength of the probable weak muscle above the increase in strength provided by other concurrent treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring residual functional capacity in chronic low back pain patients based on the Dictionary of Occupational Titles

STUDY DESIGN

This study designed and tested a functional battery based on the Dictionary of Occupational Titles (DOT).

OBJECTIVES

Such a battery can be used to measure residual functional capacity (RFC) in chronic pain patients (CPP) and results can be matched against the demand minimum functional capacities (DMFC) of DOT jobs.

SUMMARY OF BACKGROUND DATA

Physicians have difficulty translating medical impairment into functional limitation and thereby establishing the RFC of CPPs.

METHODS

The DOT, a USA government publication, provides information about physical demands of every USA job according to 36 factors and subfactors. The authors defined and developed a functional battery based on these factors/subfactors. This battery was tested on 67 consecutive CPPs to determine the percentage of CPPs able to pass specific job factors and the full battery and return to some DOT job, and evaluated the effects of pain on battery performance. The data were factor analyzed.

RESULTS

The battery determined if CPPs could perform DOT job factors and had the necessary RFC to be placed in a DOT job. The vast majority of CPPs could not pass the full battery and the presence of pain and original job classification predicted whether a CPP could perform a job factor. Factor analyses grouped the factors into four independent categories supporting the design of the battery.

CONCLUSION

The battery can assess whether CPPs are able to return to work.

Changes in G protein-mediated signal transduction in aging and Alzheimer's disease

Previous reports have shown that there are age-related reductions in muscarinic receptor (mAChR) sensitivity to agonist stimulation. Our research has elucidated the mechanisms involved in this loss. These studies have shown that this decline is the result of decreases in mAChR concentration, reductions in the number of neuronal cells, and altered phosphoinositide (PI)-mediated signal transduction (ST). The decrements in PI-mediated ST are observed as a reduced ability of muscarinic (m) agonists to enhance K(+)-evoked release of DA (K+ ERDA) from striatal slices from old rats. Additional experiments indicated that the locus of the ST deficits appears to be at the mAChR-G protein interface, since attempts to bypass this interface reduced m-enhanced K+ ERDA deficits in the striata from old rats. Moreover, it appears that the ability of mAChR to decouple from their respective G proteins is reduced as a function of age, since carbachol-stimulated low KM GTPase activity was found to be reduced in hippocampal and striatal tissue obtained from old rats. Similar findings were observed in this parameter in AD hippocampus and basal ganglia. Further reductions were seen in carbachol-stimulated low KM GTPase as a function of the duration of the disease. Results are discussed in terms of structural membrane alterations in aging and disease that may lead to reductions in the efficacy of receptor-G protein coupling/uncoupling.

Functional capacity and residual functional capacity and their utility in measuring work capacity

OBJECTIVE

The 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 SOURCES

The literature in reference to the measurement of medical impairment, FC, and RFC was reviewed.

STUDY SELECTION

Studies appropriate to the objective of this review were selected for inclusion.

CONCLUSIONS

The 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.

Periodontal screening and recording: perceptions and effects on practice

Despite recent clinical innovations, there are considerable periodontal treatment needs for the general population. This study shows that dentists believe the new periodontal screening method will be useful in determining and providing treatment needs.

Opiate detoxification protocols. A clinical manual

The purpose of any opiate detoxification protocol is to minimize or eliminate the signs and symptoms associated with opiate withdrawal, thereby decreasing the chances of relapse to opiate dependence. In the last few years, because of the development of new medications such as clonidine, for the treatment of opiate withdrawal, a number of new protocols have been developed. Four different types of protocols are reviewed and outlined: methadone substitution/detoxification, codeine or other opiate substitution/detoxification, opiate of choice detoxification, and buprenorphine substitution/detoxification. In addition, six protocols utilizing clonidine are presented, including a protocol utilizing opiate antagonist precipitated withdrawal. Finally, two protocols that utilize naltrexone are outlined, and adjunct medications potentially useful in opiate detoxification are reviewed. Some suggestions for the treatment of drug-seeking behavior during detoxification and the advantages and disadvantages of the various protocols are summarized.

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 variables 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 criteria: pain location, follow-up time interval, response percentage and follow-up method, return to work subcategorization, vocational movement, univariate vs. multivariate statistics, multi-colinearity 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.

The effects of aging on muscarinic receptor/G-protein coupling in the rat hippocampus and striatum

In the striatum and hippocampus, there is a loss of sensitivity to muscarinic agonists with age which has been traced to events early in the signal transduction pathway. Our laboratory has therefore focussed on investigations at this level. The current experiments investigate the effects of age on G-protein/receptor interactions by using competitive binding assays to measure the ability of GppNHp to decrease the proportion of receptors bound to G-proteins in the absence and the presence of added Mg2+. L-[3H]Quinuclidinyl benzilate was used as a nonselective ligand and [3H]pirenzepine as an M1 selective ligand. We find that: (1) muscarinic receptors and G-proteins in the striatum appear to become loosely coupled with age, with no change in Mg2+ sensitivity. (2) M1-receptor/G-protein complexes in the hippocampus display increased sensitivity to the presence of Mg2+ with age, with those from old but not young tissue requiring added Mg2+ in order to uncouple. This effect, however, may not be M1 specific.

Multicenter comparison of once- and twice-daily isradipine to hydrochlorothiazide for the treatment of hypertension in elderly patients

After 8 weeks of isradipine, a twice-a-day dihydropyridine calcium channel blocker, 49% of elderly patients showed a complete response (sitting diastolic blood pressure less than or equal to 85 mm Hg) and 36% showed a partial response (sitting diastolic blood pressure decrease greater than or equal to 10 mm Hg) for an 85% total response rate. Hydrochlorothiazide gave a complete response in 36% of the patients and a partial response in 33%, for a 69% total response rate (p less than 0.0046). Because elderly subjects have reduced clearance for many drugs, we determined how those who responded to twice-a-day administration would respond to once-a-day administration. After 4 weeks of isradipine administered once a day, 54% of the patients showed a complete or partial response, whereas 38% of the patients who were changed to placebo showed a response. In contrast, 82% of patients receiving hydrochlorothiazide once a day showed a response, whereas 60% of patients who were changed to placebo showed a response. These data indicate that the standard formulation of isradipine was not effective when administered once a day.

One-year follow-up of infants with abstinence-associated seizures

Fourteen infants with neonatal abstinence-associated seizures were assessed neurodevelopmentally during the first year of life. Despite abnormal neurologic examination results in eight of 12 infants at 2 to 4 months of age, nine of 12 infants had normal neurologic examination results at follow-up (two infants were unavailable for follow-up; one infant died of acquired immunodeficiency syndrome). Nine neonatal electroencephalograms were abnormal; seven of eight of these abnormal tracings normalized during the follow-up period. Bayley developmental scores remained normal during the first year of life and did not differ from either passively addicted infants without seizures or from published population norms. This short-term favorable prognosis for abstinence-associated seizures differs from that associated with neonatal seizures due to other causes. This observed improvement in neurologic function may be based on replenishment of neurotransmitters following transient depletion in the neonatal period.