Nonlinear analysis of human physical activity patterns in health and disease.

The reliable and objective assessment of chronic disease state has been and still is a very significant challenge in clinical medicine. An essential feature of human behavior related to the health status, the functional capacity, and the quality of life is the physical activity during daily life. A common way to assess physical activity is to measure the quantity of body movement. Since human activity is controlled by various factors both extrinsic and intrinsic to the body, quantitative parameters only provide a partial assessment and do not allow for a clear distinction between normal and abnormal activity. In this paper, we propose a methodology for the analysis of human activity pattern based on the definition of different physical activity time series with the appropriate analysis methods. The temporal pattern of postures, movements, and transitions between postures was quantified using fractal analysis and symbolic dynamics statistics. The derived nonlinear metrics were able to discriminate patterns of daily activity generated from healthy and chronic pain states.

Guidelines for anaesthesiologist specialist training in pain medicine.

The Section and Board of Anaesthesiology of the European Union of Medical Specialists aims (EUMS/UEMS) at harmonization of training of anaesthesiologists and at improvement of patient care throughout Europe. Pain medicine is considered to be an area of expertise in anaesthesiology although exclusivity is not claimed. The Section and Board has approved both a core syllabus for pain medicine to be part of the specialist training in anaesthesiology and an additional qualification in pain medicine following the completion of a 5 yr basic specialty training in anaesthesiology. These proposals were prepared by the Working Party on Pain Medicine of the Section and Board. It considers a multidisciplinary approach to pain to contribute to quality in care and has taken the initiative to set up a Multidisciplinary Joint Committee on Pain Medicine within the EUMS/UEMS, for which these guidelines define the area of expertise of anaesthesiology.

[Spinal opioids: mechanisms of action and chronic pain management]. / Opioïdes intrathécaux dans le traitement des douleurs chroniques: mécanismes d'action et aspects cliniques.

The efficacy of spinal opioids is well known, the analgesia is potent and long lasting, due to the central localization of the opioid receptors. The analgesia is intimately related to the inhibition of the nociceptive signal in the spinal cord but side effects are mainly mediated by the activation of the mu opioid receptor in the brain and the brain stem. Only a limited number of controlled clinical studies compared systemic versus spinal administration of morphine in chronic pain patients, and the real benefit for the intrathecal route remains controversial. Implanted devices for a continuous intrathecal delivery of opioids should be prescribed only to patients with intractable chronic pain for which conventional methods were previously ineffective.

An implantable drug delivery system (IDDS) for refractory cancer pain provides sustained pain control, less drug-related toxicity, and possibly better survival compared with comprehensive medical management (CMM).

BACKGROUND: The randomized clinical trial of implantable drug delivery systems (IDDS) plus comprehensive medical management (CMM) versus CMM alone showed better clinical success at 4 weeks for IDDS patients. This 'as treated' analysis assessed if improvements in pain control, drug toxicity and survival were maintained over time. PATIENTS AND METHODS: We compared those who received IDDS with those who did not receive IDDS (non-IDDS). All patients had Visual Analogue Scores (VAS) for pain > or =5/10 on at least 200 mg morphine or equivalent daily. RESULTS: At 4 weeks, 46 of 52 (88.5%) IDDS patients achieved clinical success compared with 65 of 91 (71.4%; P=0.02) non-IDDS patients, and more often achieved > or =20% reduction in both pain VAS and toxicity [35 of 52 (67.3%) versus 33 of 91 patients (36.3%); P=0.0003]. By 12 weeks, 47 of 57 (82.5%) IDDS patients had clinical success compared with 35 of 45 (77.8%; P=0.55) non-IDDS patients, and more often had a > or =20% reduction in both pain VAS and toxicity [33 of 57 (57.9%) versus 15 of 45 patients (33.3%); P=0.01]. At 12 weeks the IDDS VAS pain scores decreased from 7.81 to 3.89 (47% reduction) compared with 7.21 to 4.53 for non-IDDS patients (42% reduction; P=0.23). The 12 week drug toxicity scores for IDDS patients decreased from 6.68 to 2.30 (66% reduction), and for non-IDDS patients from 6.73 to 4.13 (37% reduction; P=0.01). All individual drug toxicities improved with IDDS at both 4 and 12 weeks. At 6 months, only 32% of the group randomized to CMM and who did not cross over to IDDS were alive, compared with 52%-59% for patients in those groups who received IDDS. CONCLUSIONS: IDDS improved clinical success, reduced pain scores, relieved most toxicity of pain control drugs, and was associated with increased survival for the duration of this 6 month trial.

Ambulatory system for the quantitative and qualitative analysis of gait and posture in chronic pain patients treated with spinal cord stimulation.

The physical activity in normal daily life is determined to a large extent by the functional ability of a subject. As a result, the measurement of the physical activity that a subject performs spontaneously could be a useful and objective measurement of disability, particularly in patients with disease-related functional impairment. The aim of this study is to provide an accurate method for the measurement and analysis of the physical activity under normal life conditions. Using three kinematical sensors strapped to the body, both the posture and the gait parameters can be assessed qualitatively and quantitatively. A detailed description of the algorithms used to analyse both the posture and the gait are presented in this paper. Two methods, based on different sensor configurations and signal processing, are proposed for the detection of sitting and standing postures (Methods P1 and P2). Two other methods are used for the quantitative assessment of walking (Methods W1 and W2). The performance of the algorithms (expressed in terms of sensitivity, specificity and error) is based on the comparison of data recorded simultaneously by a non-interfering observer (reference data) with the data provided by the recording system (21 patients, 61 h). Sensitivity and specificity are respectively 98.2% and 98.8% (P1), 97.8% and 98.1% (P2) for sitting; 98.0% and 98.5% (P1), 97.4% and 97.8% (P2) for standing; 97.1% and 97.9% (W1), 92.4% and 94.9% (W2) for walking; and finally, 99.2% and 98.6% for lying. Overall detection errors (as a percent of range) are as follows: 1.15% (P1) and 1.20% (P2) for sitting, 1.36% (P1) and 1.40% (P2) for standing, 1.20% (W1) and 1.60% (W2) for walking and 0.40% for lying. The error for the estimated walking distance and the speed is 6.8% and 9.6%, respectively. We conclude that both methods can be used for the accurate measurement of the basic physical activity in normal daily life. Measurements performed before and after the delivery of a treatment can therefore provide information of unprecedented accuracy and objectivity on the ability of a procedure, in this case spinal cord stimulation, to restore functional capabilities.

Effects of epidural analgesia on pelvic floor function after spontaneous delivery: a longitudinal retrospective study.

The aim of the study was to assess the effects of epidural analgesia on pelvic floor function. Eighty-two primiparous women (group 1, consisting of 41 given an epidural, and group 2 of 41 not given an epidural) were investigated during pregnancy and at 2 and 10 months after delivery by a questionnaire, clinical examination, and assessment of bladder neck behavior, urethral sphincter function and intravaginal/intra-anal pressures. The prevalence of stress urinary incontinence was similar in both groups at 2 months (24% vs. 17%, P = 0.6) and 10 months (22% vs. 7%, P = 0.1), as was the prevalence of decreased sexual vaginal response at 10 months (27% vs. 10%, P = 0.08). Bladder neck behavior, urethral sphincter function and intravaginal and intra-anal pressures showed no significant differences between the two groups. Ten months after spontaneous delivery, there were no significant differences in the prevalence of stress urinary incontinence and decreased sexual vaginal response, or in bladder neck behavior, urethral sphincter function and pelvic floor muscle strength between women who had or had not had epidural analgesia.

Making a case for programmable pumps over fixed rate pumps for the management of fluctuations in chronic pain and spasticity: a literature review.

This paper reviews data supporting the existence of individual, predictable, and unpredictable fluctuations in the severity of chronic pain and spasticity. It also evaluates what is known on the use of implantable programmable drug delivery systems for the management of predictable fluctuations in pain and spasticity. In addition to fixed rate infusion pumps, programmable drug delivery systems have been developed over the past 20 years for the management of predictable pain or spasticity fluctuations. The published literature on experimental and clinical studies of those topics is reviewed and evaluated. Programmable drug delivery systems can tailor dosing to a patient's individual pattern of symptoms, providing more medication during peak intensity of symptoms and less medication when symptoms are reduced. Fluctuations in either pain or spasticity are difficult to predict precisely, and therefore even programmable pumps cannot administer the appropriate amount of medication at any particular time. Ideally, the patient should be able to treat unpredictable fluctuations in symptoms, and a combination of patient controlled analgesia (PCA) with programmable drug delivery systems is currently in development. The future management of unpredictable fluctuations in the intensity of chronic pain and spasticity was subjected to critical evaluation. There seems to be a general agreement on the clinical importance of these phenomena, but stronger evidence is needed for a widespread change in the current management of most chronic pain patients.

Evidence-based review of the literature on intrathecal delivery of pain medication.

Evidence-based medicine depends on the existence of controlled clinical trials that establish the safety and efficacy of specific therapeutic techniques. Many interventions in clinical practice have achieved widespread acceptance despite little evidence to support them in the scientific literature; the critical appraisal of these interventions based on accumulating experience is a goal of medicine. To clarify the current state of knowledge concerning the use of various drugs for intraspinal infusion in pain management, an expert panel conducted a thorough review of the published literature. The exhaustive review included 5 different groups of compounds, with morphine and bupivacaine yielding the most citations in the literature. The need for additional large published controlled studies was highlighted by this review, especially for promising agents that have been shown to be safe and efficacious in recent clinical studies.

Clinical guidelines for intraspinal infusion: report of an expert panel. PolyAnalgesic Consensus Conference 2000.

Consensus guidelines developed by an expert panel are helpful to clinicians when there is variation in practice and lack of a firm evidence base for an intervention, such as intraspinal therapy for pain. An internet-based survey of practitioners revealed remarkable variation in practice patterns surrounding intraspinal therapy. This prompted an interdisciplinary panel with extensive clinical experience in intraspinal infusion therapy to evaluate the results of the survey, the systematic reviews of the literature pertaining to this approach, and their own clinical experience with long-term spinal infusions. The panel proposed a scheme for the selection of drugs and doses for intraspinal therapy, and suggested guidelines for administration that would increase the likelihood of a successful outcome. These expert panel guidelines were designed to provide an initial structure for clinical decision making that is based on the best available evidence and the perspectives of experienced clinicians.

Physical activity monitoring based on accelerometry: validation and comparison with video observation.

The objective of this feasibility study is to evaluate the use of the 'Physilog' device, an ambulatory physical-activity recorder based on acceleration measurement, for the monitoring of daily physical activities. Accelerations measured at the level of the chest and the thigh are recorded by Physilog over a period of 1 h in five normal subjects. A specially designed studio-like room allowing the performance of most usual activities of everyday life is used. A video film synchronised with the Physilog is obtained for each subject to check the accuracy of the data derived from Physilog. Based on the analysis on the average and the deviation of the acceleration signal, an algorithm is developed to classify the activities in four categories, i.e. lying, sitting, standing and locomotion. Compared with the video observations, the results from the algorithm show an overall misclassification of 10.7%, which is mainly due to confusion between dynamic activities and the standing posture. In contrast, the misclassification between postures is negligible. It is concluded that Physilog can be used in the clinical setting for the reliable measurement and long-term recording of most usual physical activities.

Influence of patient's dressing on spontaneous physical activity and length of hospital stay in surgical patients.

Wearing hospital gown (HG) as opposed to plain-clothes (PC) may contribute to the general state of inactivity of hospitalised patients. We designed a randomized study to determine the influence of clothing on the level of spontaneous physical activity (SPA) and to assess the length of hospital stay. Using triaxial accelerometry we measured the SPA in two groups of surgical patients, before and after an elective operation. Twenty eight patients received instructions to wear plain-clothes (group PC) during their stay in the hospital as soon as possible from a surgical point of view. Twenty-nine patients, serving as a control group, did not receive any specific instructions and as a result, were mostly wearing hospital gowns (group HG). Following the admission to the hospital, both groups showed a 50% decrease in SPA when compared to the recordings obtained during the last 24 hours spent at home. During the postoperative period, the SPA increased progressively in both groups. Although patients in group PC tended to be more active than those in the control group, the SPA was not significantly different (P = 0.4). Similarly, patients in group PC left the hospital 10 hours earlier than patients in group HG (P = 0.4). The power of our study was nevertheless low and a sample size of 700 patients might show statistically significant results. We conclude that wearing plain-clothes when hospitalized for elective surgery is not associated with complications and could be included in postoperative rehabilitation program.

[Hypnosis and self-hypnosis administered and taught by nurses for relief of chronic pain: a controlled clinical trial]. / Hypnose und Selbsthypnose von Pflegenden angewandt und instruiert zwecks Linderung chronischer Schmerzen: eine kontrollierte klinische Studie.

In this controlled clinical trial hypnosis and self-hypnosis were evaluated when used as an adjuvant treatment to instrumental and pharmacological management of chronic pain. The study took place in a hospital specialized in the treatment of outpatients suffering from chronic pain. Hypnosis and self-hypnosis were administered and taught by nurses who had been trained just recently for this very purpose. Under the conditions of the study it was not possible to measure an effect of hypnosis on pain despite some subjective feeling of usefulness. However, it should be taken into account that this form of adjuvant therapy was used for the first time in that hospital for the purpose of the study and, therefore, took place in an artificial setting. It could well be that the same therapy administered in the proper therapeutic environment of a specialized institution could show beneficial effects on pain.

Alternative intrathecal agents for the treatment of pain.

There is a need to develop alternative agents for intrathecal pain therapy for patients who either cannot tolerate the side effects of or who no longer obtain sufficient analgesia with opioids. The experimental use of several compounds in intrathecal drug delivery is currently in progress, with the development of clonidine as the single most important advance in the improvement of pain treatment. Clonidine, an α(2) -adrenergic receptor agonist, appears to be safe and effective in the treatment of cancer and nonmalignant pain, with its effects most pronounced in patients whose pain consists of a neuropathic component. Other possible effective agents for intrathecal delivery include bupivacaine, octreotide, and SNX-111. The preclinical and clinical profiles for these promising new intrathecal pain medications are discussed.

Future trends in the development of local drug delivery systems: intraspinal, intracerebral, and intraparenchymal therapies.

Due to successful use of intrathecal drug delivery in the management of refractory pain and spasticity, new agents and indications are now being investigated. Preclinical studies of neurotrophic factors, molecules necessary for neuroneal survival and development, suggest that these agents may be beneficial for patients with neurologic disorders. Because neurotrophic factors do not cross the blood-brain barrier following systemic administration, local delivery routes, including intrathecal, intracerebroventrical, and intraparenchymal routes, are being studied; research is being conducted on intrathecal delivery for amyotrophic lateral sclerosis (ALS), intracerebroventricular delivery for Parkinson's disease and Alzheimer's disease, and intrahippocampal delivery for seizure disorders. Treatment of other neurologic disorders, such as brain tumors and HIV-related viral infections, also may be optimized by methods of local drug delivery, including intratumoral and intraparenchymal administration of potentially effective agents. Intraspinal, intratumoral, and intraparenchymal routes of administration are speculated to become critical components of treatment for a variety of neurological indications.

Intrathecal implants of bovine chromaffin cells alleviate mechanical allodynia in a rat model of neuropathic pain.

Intrathecal implants of adrenal chromaffin cells are known to release analgesic substances such as catecholamines and opioid peptides. In the present study, bovine chromaffin cells were encapsulated in a permselective polymer membrane which protects the cells from the host immune system and allows grafting of xenogeneic cells without immunosuppression. The effects of such implants were evaluated on the pain behavior resulting from a chronic constrictive injury (CCI) of the rat sciatic nerve. Sprague-Dawley rats with a unilateral lesion were implanted in the lumbar subarachnoid space and tested for mechanical/thermal allodynia and hyperalgesia. A significant reduction in pain was observed after mechanical non-nociceptive stimulation in animals implanted with chromaffin cells. Furthermore, these animals showed decreased signs of spontaneous pain. However, response to thermal non-noxious stimuli or to painful mechanical stimuli was not significantly decreased. Abundant clusters of viable chromaffin cells intensely labeled with the anti-tyrosine hydroxylase antibodies were observed in the retrieved implants. These results establish the analgesic efficacy of intrathecal encapsulated chromaffin cells in a chronic pain model of nerve injury. Immunoprotected allo- or xenogeneic chromaffin cells acting as 'mini pumps' continuously delivering neuroactive substances could be a useful therapy for patients suffering from neuropathic pain.

Tropisetron for treating established postoperative nausea and vomiting: a randomized, double-blind, placebo-controlled study.

UNLABELLED: Tropisetron can prevent postoperative nausea and vomiting (PONV) at doses smaller than those used to control chemotherapy-induced nausea and vomiting. In this placebo-controlled study, the efficacy and tolerability of three different doses of tropisetron were compared for the treatment of established PONV after surgical procedures in general anesthesia. Of 1513 patients who satisfied inclusion criteria, 314 experiencing PONV during the first 2 h after recovery from anesthesia were treated with one of three different doses of tropisetron (0.5, 2, or 5 mg) or placebo, administered i.v. as a single dose. Patients were then observed during 24 h for efficacy and tolerability. All three doses of tropisetron were significantly better than placebo in controlling emetic episodes and in reducing the need for rescue treatment. There were no significant differences among the three doses. However, in the subgroup of patients who had previous PONV, and in those randomized for nausea alone, the 2-mg and 5-mg doses controlled emetic episodes better than the 0.5-mg dose. All studied doses of tropisetron were well tolerated and did not affect vital signs. We conclude that a single i.v. administration of tropiestron significantly reduces the recurrence of emetic episodes in patients with established PONV after elective surgery with general anesthesia. Its optimal dose seems to be 2 mg. IMPLICATIONS: Three hundred-fourteen patients suffering from postoperative nausea and vomiting received different i.v. doses of a new antiemetic drug, tropisetron, to determine the lowest effective dose. We found that a single i.v. administration of tropisetron significantly reduced postoperative nausea and vomiting after elective surgery with general anesthesia.

Immunoisolated xenogenic chromaffin cell therapy for chronic pain. Initial clinical experience.

BACKGROUND: Chromaffin cells from the adrenal gland secrete a mixture of compounds that have a strong analgesic effect, especially when administered intrathecally. Many studies in animal models have shown that discordant xenogeneic cell isolates, including chromaffin cells, can survive and have biologic effects when transplanted within a semipermeable membrane capsule. METHODS: To evaluate the clinical potential of encapsulated cell therapy, a human-scale implant containing bovine chromaffin cells was developed, characterized, and implanted in the subarachnoid space of seven patients with severe chronic pain not satisfactorily managed with conventional therapies. Patients received no pharmacologic immunosuppression. Cell devices were implanted during minimally invasive surgery, and device design allowed retrieval. All devices were recovered after implant periods of 41 to 176 days. RESULTS: Postexplant histologic analysis, immunostaining, and secretory function all confirmed survival and biochemical function of the encapsulated cells. Reductions in morphine intake and improvement in pain ratings were observed in several patients. CONCLUSIONS: This study represents the first successful trial of encapsulated xenogeneic cells in humans. The preliminary findings of pain reduction warrant the initiation of a randomized, double-blind phase II study to evaluate the potential efficacy of the procedure.