Central post-stroke pain--the effect of high and low frequency TENS

Sensory retraining for Central Post-Stroke Pain: A subgroup analysis within a randomized controlled trial

BACKGROUND

Explicit Sensory Retraining (SR) has been suggested for pain management in several neuropathic pain syndromes.

OBJECTIVES

To study the effectiveness of SR on Central Post Stroke Pain (CPSP) symptoms.

METHODS

A preplanned subgroup of 23 subjects post-stroke reporting central pain were randomized within a larger study, to receive either explicit sensory discrimination retraining (SR) (in subgroup n = 11) or implicit repeated exposure to stimuli (RE) (in subgroup n = 12), applied to the lower limb. Pain intensity measured by VAS, measures of sensory ability; balance and gait activities; and participation were assessed by a blinded assessor at four points in time.

RESULTS

A group*time interaction effect was demonstrated (p = 0.04) for VAS, as for the SR treatment group VAS decreased from 56/100 to 23/100. Nine out of eleven subjects in the SR group demonstrated positive response to treatment. Pain alleviation was maintained at follow-up. A similar interaction effect was found for tactile threshold (p = 0.03). Significant improvement was noted for all other variables with no group differences.

CONCLUSION

This study provides preliminary evidence to the clinically relevant positive effect of explicit sensory retraining for subjects with CPSP. The positive effect on tactile threshold detection could potentially indicate pain alleviation mechanisms.

[Neuropathic pain syndromes in patients with multiple sclerosis]

Among the numerous pain syndromes (PS) of various localizations and types, observed in patients with multiple sclerosis (MS), the greatest attention of researchers is attracted by neuropathic PS. Neuropathic PS are often present already in the early stage of MS, significantly reduce the quality of life, hinder the social adaptation of patients, poorly respond to therapy. Central neuropathic PS, which pathogenesis is closely related with plaques in the central nervous system, are most common in patients with MS. Diagnostics of neuropathic PS in MS is based mainly on typical clinical symptoms; MRI and neurophysiological methods data are of secondary importance. This review focuses on modern concepts of three main neuropathic PS in MS: ongoing extremity pain, trigeminal neuralgia and Lhermitte's sign. Clinical symptoms of neuropathic PS, current ideas about their pathogenetic mechanisms, MRI and neurophysiological techniques data and the existing approaches to conservative therapy and surgical treatment based on randomized trials data are presented.

Effects of Non-Invasive Brain Stimulation on Clinical Pain Intensity and Experimental Pain Sensitivity Among Individuals with Central Post-Stroke Pain: A Systematic Review

Purpose

Central post-stroke pain (CPSP) is a neuropathic disorder resulting in pain and disability. An emerging treatment for CPSP is non-invasive brain stimulation including direct current stimulation [tDCS] and repetitive transcranial magnetic stimulation [rTMS]. This systematic review analyzes the efficacy and quality of non-invasive brain stimulation intervention studies for CPSP.

Methods

Studies were sought from three research databases published between 2007 and 2017. Studies were included if the sole intervention was non-invasive brain stimulation and the primary outcome either clinical or experimental pain intensity. Studies were qualitatively assessed for risk of bias.

Results

Of 1107 articles extracted, six met eligibility criteria. Five studies found a decrease in pain intensity (p<0.05) immediately and 3 weeks after rTMS or tDCS was delivered over the primary motor cortex. For experimental pain, one study found thermal pain thresholds improved for those receiving tDCS compared to sham (p<0.05), while another found normalization of the cold detection threshold only after rTMS (p<0.05). Qualitative assessment revealed only one study rated as "excellent/good" quality, while the other five were rated as "fair" or "poor".

Conclusion

Non-invasive brain stimulation may have a therapeutic effect on pain level for individuals with CPSP, as evidenced by significant decreases in clinical and experimental pain scores. However, despite the impact of CPSP and the promise of non-invasive brain stimulation, few rigorous studies have been performed in this area. Future studies should aim to standardize treatment parameters, measure both clinical and experimental pain, and include long-term follow-up.

Acupuncture in the Treatment of Hypertension and Stroke

This article identifies and comments on published studies of acupuncture treatment for hypertension and stroke. In all, 27 appropriate papers were analysed: 13 were hypertension papers with 3 being of controlled trials, and 14 were stroke papers with 5 controlled trials. The articles consisted of randomised controlled trials (RCTs), controlled trials, and case series studies. The hypertension papers also involved some cohort studies. In general, sample sizes of these studies were small.

Acupuncture in these papers was used as a secondary intervention for treating hypertension and as a tertiary intervention for stroke rehabilitation. The RCTs (the top of the hierarchy of evidence) of hypertension showed that acupuncture was not more effective than sham acupuncture or the anti-hypertensive drug, reserpine; however, all the case series suggested that acupuncture was an effective treatment. The RCT evidence for stroke showed that the effectiveness of acupuncture was similar to that of conventional treatment. The conclusion was that from the papers analysed there is insufficient evidence to show that acupuncture produces better results than other treatments for hypertension or stroke.

Guidelines for Adult Stroke Rehabilitation and Recovery: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this guideline is to provide a synopsis of best clinical practices in the rehabilitative care of adults recovering from stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statement Oversight Committee and the AHA's Manuscript Oversight Committee. The panel reviewed relevant articles on adults using computerized searches of the medical literature through 2014. The evidence is organized within the context of the AHA framework and is classified according to the joint AHA/American College of Cardiology and supplementary AHA methods of classifying the level of certainty and the class and level of evidence. The document underwent extensive AHA internal and external peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Stroke rehabilitation requires a sustained and coordinated effort from a large team, including the patient and his or her goals, family and friends, other caregivers (eg, personal care attendants), physicians, nurses, physical and occupational therapists, speech-language pathologists, recreation therapists, psychologists, nutritionists, social workers, and others. Communication and coordination among these team members are paramount in maximizing the effectiveness and efficiency of rehabilitation and underlie this entire guideline. Without communication and coordination, isolated efforts to rehabilitate the stroke survivor are unlikely to achieve their full potential.

CONCLUSIONS

As systems of care evolve in response to healthcare reform efforts, postacute care and rehabilitation are often considered a costly area of care to be trimmed but without recognition of their clinical impact and ability to reduce the risk of downstream medical morbidity resulting from immobility, depression, loss of autonomy, and reduced functional independence. The provision of comprehensive rehabilitation programs with adequate resources, dose, and duration is an essential aspect of stroke care and should be a priority in these redesign efforts. (Stroke.2016;47:e98-e169. DOI: 10.1161/STR.0000000000000098.).

The antalgic effects of non-invasive physical modalities on central post-stroke pain: a systematic review

[Purpose] This study systematically reviewed the antalgic effects of non-invasive physical modalities (NIPMs) on central post-stroke pain (CPSP). [Subjects and Methods] Clinical studies were sought on September 2015 in 10 electronic databases, including Medline and Scopus. The searching strings were “central pain and stroke” and “treatment, and physical or non-pharmacological”. The inclusion and exclusion criteria were set for screening the clinical articles by two reviewers. Pain scores on visual analog scale in an article were used as the outcome measure for resulting judgment. The NIPMs intervention summarized from the eligible articles was rated from Levels A to C according to Evidence Classification Scheme for Therapeutic Interventions. [Results] Over 1200 articles were identified in the initial searches and 85 studies were retrieved. Sixteen studies were eligible and judged. Caloric vestibular stimulation (n=3), heterotopic noxious conditioning stimulation (n=1), and transcutaneous electrical stimulation (n=1) were rated below Level C. Transcranial direct current stimulation (TDCS; n=2) and transcranial magnetic stimulation (TMS; n=9) were rated as Level B. [Conclusion] The findings suggest that TMS and TDCS were better than other treatments for CPSP relief but the studies were of insufficient quality.

Functional characterization of a mouse model for central post-stroke pain

Background

Stroke patients often suffer from a central neuropathic pain syndrome called central post-stroke pain. This syndrome is characterized by evoked pain hypersensitivity as well as spontaneous, on-going pain in the body area affected by the stroke. Clinical evidence strongly suggests a dysfunction in central pain pathways as an important pathophysiological factor in the development of central post-stroke pain, but the exact underlying mechanisms remain poorly understood. To elucidate the underlying pathophysiology of central post-stroke pain, we generated a mouse model that is based on a unilateral stereotactic lesion of the thalamic ventral posterolateral nucleus, which typically causes central post-stroke pain in humans.

Results

Behavioral analysis showed that the sensory changes in our model are comparable to the sensory abnormalities observed in patients suffering from central post-stroke pain. Surprisingly, pharmacological inhibition of spinal and peripheral key components of the pain system had no effect on the induction or maintenance of the evoked hypersensitivity observed in our model. In contrast, microinjection of lidocaine into the thalamic lesion completely reversed injury-induced hypersensitivity.

Conclusions

These results suggest that the evoked hypersensitivity observed in central post-stroke pain is causally linked to on-going neuronal activity in the lateral thalamus.

A Comprehensive Review of Central Post-Stroke Pain

Although central post-stroke pain is widely recognized as a severe chronic neuropathic pain condition, its consolidated definition, clinical characteristics, and diagnostic criteria have not been defined due to its clinically diverse features. The present study was undertaken to comprehensively review current literature and provide a more complete picture of central post-stroke pain with respect to its definition, prevalence, pathophysiology, clinical characteristics, and diagnostic problems, and to describe the range of therapies currently available. In particular, nursing care perspectives are addressed. It is hoped that this review will help nurses become knowledgeable about central post-stroke pain and provide valuable information for the drafting of effective nursing care plans that improve outcomes and quality of life for patients with central post-stroke pain.

Pharmacological management of central post-stroke pain: a practical guide

Pain is one of the most troublesome sequelae of stroke. Some of this post-stroke pain is caused by the brain lesion itself; this is called central post-stroke pain (CPSP). Although the prevalence of CPSP is low (1-8 %), persistent, often treatment-resistant, painful sensations are a major problem for stroke patients. The pathogenesis of CPSP remains unknown, but suggested underlying causes include hyperexcitation in the damaged sensory pathways, damage to the central inhibitory pathways, or a combination of the two. For pharmacological treatment, amitriptyline, an adrenergic antidepressant, is currently the first-line drug for CPSP. However, its effect is frequently incomplete and a high dose is commonly not tolerated in stroke patients. Lamotrigine, an antiepileptic, was also found to be effective in a controlled trial and can be used as an alternative or additive therapy. GABAergic drugs with potential calcium channel-blocking effects, such as gabapentin or pregabalin, have recently emerged as a potentially useful therapy. These drugs are effective in various neuropathic pain syndromes, but their effect on CPSP remains to be proven. Pregabalin may improve pain-related anxiety and sleep disturbances. Fluvoxamine and mexiletine may be used adjunctively in some patients. Non-pharmacological treatments such as motor cortex stimulation or deep brain stimulation are used in some centers, but are not proven to be effective. Further well designed clinical trials as well as basic research should be performed to improve our understanding of the pathophysiology of CPSP and to develop better treatment strategies.

[Issues involved with supply of medical and hygienic materials to home care patients]

Questionnaires were mailed to doctors and nurses who are involved in home care to survey their observations on medical and hygienic materials and its supply to home care patients. Some of the survey items, such as problems encountered frequently, areas where an improvement was needed most and concerns that are often raised in suppling of medical and hygienic materials for home care patients, were analyzed by the Berelson's content analysis method to observe problems in suppling adequate medical and hygienic materials. As a result, 5 categories and 17 subcategories were formed. The recognized future issues were: policies concerning support extended to medical organizations and disseminate information of the system, which medical and hygienic materials supplied to home care patients.

Practical considerations in the assessment and treatment of pain in adults with physical disabilities

Adults aging with physical disabilities experience a variety of pain disorders that affect their functionality and QOL. It is important that clinicians caring for this population be knowledgeable about this common symptom and be able to perform a thorough history and physical examination. In addition, it is imperative to have a good working knowledge of the strengths and limitations of the treatments available.

Central post-stroke pain syndrome: yet another use for gabapentin?

Although gabapentin was originally developed for treating partial seizures, it has been used mainly to treat various peripheral neuropathic pain conditions; however, there is very limited experience with gabapentin for the treatment of pain conditions of the central nervous system like central post-stroke pain syndrome. We report the case of a 45-yr old man with central post-stroke pain syndrome who failed to respond to a variety of oral analgesics, but within 2 wk of the inception of gabapentin therapy, his average pain was significantly reduced and his level of function improved. We conclude that gabapentin may be an effective medication for the treatment of central post-stroke pain syndrome.

Repetitive epileptic fits--a possible adverse effect after transcutaneous electrical nerve stimulation (TENS) in a post-stroke patient

A case of repetitive epileptic fits in a post stroke patient after transcutaneous electrical nerve stimulation (TENS) is presented. It seems more likely than not that the TENS triggered the repetitive fits in this patient. Although the risk of this adverse effect seems to be small, it should be borne in mind when TENS is used in a post-stroke patient. Since TENS is now used commonly in post-stroke patients, this problem is worthy of further study.

Central pain and dysesthesia syndrome

This article presents recent observations about different recognized central pain syndromes (CPS) and discusses them in light of contemporary microelectrode and imaging findings. Different theories regarding the generation of CPS are reviewed, with an emphasis on difficulties in diagnosis and treatment. The author discourages destructive procedures for treatment of CPS, favoring, instead, reversible procedures such as stimulation techniques and drug delivery systems.

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.

Dysaesthesiae induced by physiological and electrical activation of posterior column afferents after stroke

Six of 48 stroke patients had functionally limiting dysaesthesiae induced by repetitive light touch, joint movement, or neuromuscular electrical stimulation (NMS). Only one of these six patients had a thalamic lesion. Quantitative sensory testing showed substantial impairment of pain and temperature sensation in all six patients, whereas light touch, vibration and position sense, and graphaesthesia were normal (three patients) or relatively spared (three patients). By contrast, none of 15 stroke patients in whom NMS did not evoke dysaesthesiae had clinical evidence of dissociated sensory loss. Conscious perception of joint movement and light touch is mediated mainly by the same population of large myelinated fibres activated preferentially by low intensity electrical stimulation. It is suggested that activation of these non-nociceptive, presumably dorsal column, afferents may contribute to dysaesthesiae in some patients with sensory loss after stroke.