Validation and Reliability of the Neuropathic Pain Scale (NPS) in Multiple Sclerosis

Case report: The feasibility of rTMS with intrathecal baclofen pump for the treatment of unresolved neuropathic pain following spinal cord injury

The main objective of this study was to assess the efficacy and safety of 10 Hz repetitive transcranial magnetic stimulation (rTMS) for the treatment of unresolved neuropathic pain in an individual with spinal cord injury and an intrathecal baclofen pump. A 62-year-old male presented with drug resistant neuropathic pain as a result of a complete spinal cord lesion at T8 level. Pain was classified into four types: pressure pain in the left foot, burning pain in buttocks, burning pain in sternum, and electrical attacks in the trunk. The treatment period involved 6 weeks of rTMS stimulation performed 5 days per week, a 6-week follow up period with no stimulation, and an 8-week top up session period which began 5-weeks after the end of the follow up period. 2004 pulses were delivered at 10Hz over the right-hand representation of the left primary motor cortex at 80% resting motor threshold during each session. Assessments were based on the numerical rating scale (NRS), neuropathic pain scale (NPS), Hamilton Depression and Anxiety rating scales. Following the treatment period there was a 30, 13, and 29% reduction in sternum, buttocks, and left foot pain respectively, as reported by the NRS. During this time, electrical attacks were abolished following the third week of treatment. These changes corresponded to a 38% decrease in NPS scores and a 65 and 25% reduction in anxiety and depressions scores respectively. The changes in sternum, buttocks, and left foot pain reported on the NRS persisted for 1 week following treatment. Top up sessions delivered 11 weeks after the end of the treatment period were unsuccessful in reducing pain to the level achieved during the treatment period. A 13% reduction in NPS was seen during these 8-weeks. Anxiety and depression scores decreased 78 and 67% respectively. The frequency of electrical attacks was zero during this time. rTMS stimulation delivered throughout this study did not cause any interference with the functioning of the intrathecal baclofen pump. This case study illustrates that rTMS may be effective at reducing drug resistant neuropathic pain with certain pain types exhibiting greater propensity for change.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Clinical perspective on pain in multiple sclerosis

Pain is an important and frequent symptom in multiple sclerosis (MS), which leads to a low quality of life, increased disability level, and lack of employment and mental health. Recently, studies have shown increased interest in pain in MS and there is a growing evidence of its prevalence. However, the literature suffers from lack of experimental studies focusing on pain reduction. This topical review summarizes the current knowledge about pain in MS with its definitions, assessments, treatments and rehabilitation within a holistic perspective.

Can self-reported pain characteristics and bedside test be used for the assessment of pain mechanisms? An analysis of results of neuropathic pain questionnaires and quantitative sensory testing

Hyperalgesia and allodynia are frequent in neuropathic pain. Some pain questionnaires such as the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and the Neuropathic Pain Scale (NPS) include self-assessment or bedside testing of hyperalgesia/allodynia. The aim of this study was to determine to what extent LANSS and NPS data are congruent with findings on quantitative sensory testing (QST). Self-reported presence of dynamic mechanical allodynia (DMA) and descriptors of hot, cold, or deep ongoing pain (the NPS and LANSS) as well as bedside findings of mechanical allodynia (LANSS) were compared with signs of DMA and thermal hyperalgesia on QST in 617 patients with neuropathic pain. Self-reported abnormal skin sensitivity (LANSS) showed a moderate concordance with DMA during bedside test (67.9%, κ = 0.391) or QST (52.8%, κ = 0.165). Receiver operating curve analysis for self-reported DMA yielded similar area-under-the-curve values for the LANSS (0.65, confidence interval: 0.59%-0.97%) and NPS (0.71, confidence interval: 0.66%-0.75%) with high sensitivity but low specificity. Self-reported deep pain intensity was higher in patients with blunt pressure hyperalgesia, but not in patients with DMA or thermal hyperalgesia. No correlations were observed between self-reported hot or cold pain quality and thermal hyperalgesia on QST. Self-reported abnormal skin sensitivity has a high sensitivity to identify patients with DMA, but its low specificity indicates that many patients mean something other than DMA when reporting this symptom. Self-reported deep pain is related to deep-tissue hypersensitivity, but thermal qualities of ongoing pain are not related to thermal hyperalgesia. Questionnaires mostly evaluate the ongoing pain experience, whereas QST mirrors sensory functions. Therefore, both methods are complementary for pain assessment.

The Effectiveness of Topical Cannabidiol Oil in Symptomatic Relief of Peripheral Neuropathy of the Lower Extremities

Background:

Peripheral neuropathy can significantly impact the quality of life for those who are affected, as therapies from the current treatment algorithm often fail to deliver adequate symptom relief. There has, however, been an increasing body of evidence for the use of cannabinoids in the treatment of chronic, noncancer pain. The efficacy of a topically delivered cannabidiol (CBD) oil in the management of neuropathic pain was examined in this four-week, randomized and placebocontrolled trial.

Methods:

In total, 29 patients with symptomatic peripheral neuropathy were recruited and enrolled. 15 patients were randomized to the CBD group with the treatment product containing 250 mg CBD/3 fl. oz, and 14 patients were randomized to the placebo group. After four weeks, the placebo group was allowed to crossover into the treatment group. The Neuropathic Pain Scale (NPS) was administered biweekly to assess the mean change from baseline to the end of the treatment period.

Results:

The study population included 62.1% males and 37.9% females with a mean age of 68 years. There was a statistically significant reduction in intense pain, sharp pain, cold and itchy sensations in the CBD group when compared to the placebo group. No adverse events were reported in this study.

Conclusions:

Our findings demonstrate that the transdermal application of CBD oil can achieve significant improvement in pain and other disturbing sensations in patients with peripheral neuropathy. The treatment product was well tolerated and may provide a more effective alternative compared to other current therapies in the treatment of peripheral neuropathy.

Low back pain: critical assessment of various scales

PURPOSE

To study the various pain assessment tools based on their psychometric properties and ease of use.

METHODS

Published articles on psychometric properties of pain tools were accessed and data collected for low back pain (LBP)-specific tools, generic tools, neuropathic LBP tools, tools for cognitively impaired patients, and tools for acute LBP.

RESULTS

Among the LBP-specific tools, Roland Morris Disability Questionnaire (RMDQ) and Oswestry Disability Index (ODI) have good construct validity and reliability, and responsiveness over short intervals. Quebec Back Pain Disability Scale (QBPDS) gauges only disability and sleep. Among the generic tools, McGill Pain Questionnaire (MPQ), West Haven-Yale Multidimensional Pain Inventory (MPI), and Brief Pain Inventory (BPI) show good responsiveness, but BPI is the only tool validated for LBP. Neuropathic Pain Scale (NPS) and Short Form-MPQ-2 (SF-MPQ-2) are both reliable tools for neuropathic LBP. For cognitively impaired patients, Pain Assessment in Advanced Dementia (PAINAD), Abbey Pain Scale (APS), and Doloplus-2 are all reliable tools, but PAINAD has good construct validity. For acute pain, Clinically Aligned Pain Assessment (CAPA) is reliable and responsive, but presently, unidimensional tools and SF-MPQ-2 are the tools most preferred.

CONCLUSION

Based on psychometric properties and ease of use, the best tools for LBP seem to be RMDQ/ODI (among LBP-specific tools), BPI (among generic tools), SF-MPQ-2/NPS (for neuropathic LBP), PAINAD (for cognitively impaired patients), and unidimensional tools and SF-MPQ-2 (for acute pain). Overall, BPI seems to be a tool that can be relied upon the most. These slides can be retrieved under Electronic Supplementary Material.

Neuropathic cancer pain: prevalence, pathophysiology, and management

Neuropathic cancer pain (NCP) is caused by nerve damage attributable to the cancer per se, and/or treatments including chemotherapy, radiotherapy, and surgery; the prevalence is reported to be as high as 40%. The etiologies of NCP include direct nerve invasion or nerve compression by the cancer, neural toxicity, chemotherapy, and radiotherapy. NCP is subdivided into plexopathy, radiculopathy, and peripheral neuropathies, among several other categories. The clinical characteristics of NCP differ from those of nociceptive pain in terms of both the hypersensitivity symptoms (burning, tingling, and an electrical sensation) and the hyposensitivity symptoms (numbness and muscle weakness). Recovery requires several months to years, even after recovery from injury. Management is complex; NCP does not usually respond to opioids, although treatments may feature both opioids and adjuvant drugs including antidepressants, anticonvulsants, and anti-arrhythmic agents, all of which improve the quality-of-life. This review addresses the pathophysiology, clinical characteristics and management of NCP, and factors rendering pain control difficult.

Efficacy and Safety of Transdermal Buprenorphine versus Oral Tramadol/Acetaminophen in Patients with Persistent Postoperative Pain after Spinal Surgery

PURPOSE

Control of persistent pain following spinal surgery is an unmet clinical need. This study compared the efficacy and safety of buprenorphine transdermal system (BTDS) to oral tramadol/acetaminophen (TA) in Korean patients with persistent, moderate pain following spinal surgery.

METHODS

Open-label, interventional, randomized multicenter study. Adults with persistent postoperative pain (Numeric Rating Scale [NRS] ≥ 4 at 14-90 days postsurgery) were enrolled. Patients received once-weekly BTDS (n = 47; 5 μg/h titrated to 20 μg/h) or twice-daily TA (n = 40; tramadol 37.5 mg/acetaminophen 325 mg, one tablet titrated to 4 tablets) for 6 weeks. The study compared pain reduction with BTDS versus TA at week 6. Quality of life (QoL), treatment satisfaction, medication compliance, and adverse events (AEs) were assessed.

FINDINGS

At week 6, both groups reported significant pain reduction (mean NRS change: BTDS -2.02; TA -2.76, both P < 0.0001) and improved QoL (mean EQ-5D index change: BTDS 0.10; TA 0.19, both P < 0.05). The BTDS group achieved better medication compliance (97.8% versus 91.0%). Incidence of AEs (26.1% versus 20.0%) and adverse drug reactions (20.3% versus 16.9%) were comparable between groups.

IMPLICATIONS

For patients with persistent pain following spinal surgery, BTDS is an alternative to TA for reducing pain and supports medication compliance. This trial is registered with Clinicaltrials.gov: NCT01983111.

Using mixed methods case-series evaluation in the development of a guided self-management hybrid CBT and ACT intervention for multiple sclerosis pain

PURPOSE

Two-thirds of the people with multiple sclerosis (pwMS) experience pain. Medications provide minimal relief, and current non-pharmacological interventions lack a clear conceptualization of MS pain. This study explored the potential efficacy of a telephone-supported hybrid cognitive behavior therapy and acceptance and commitment therapy self-management intervention for pwMS based on an empirically supported model of MS pain using a replicated single-case series design.

METHODS

Seven pwMS with varied demographic and disease characteristics completed the 8-week home-based program alongside 3 hours of telephone support. Online questionnaires were completed every four days for 16 weeks (4-weeks baseline, 8-weeks treatment, 4-weeks follow-up). The primary outcomes were pain severity and pain interference. Psychological process variables drawn from the MS pain model were also completed, and post-treatment qualitative interviews conducted.

RESULTS

Simulation modeling analysis (SMA) showed three patients had large improvements in pain outcomes, two showed no change and two worsened. Five participants showed significant change on various psychological process variables. Change in pain catastrophizing was the most consistent finding.

CONCLUSIONS

The findings suggest a self-management program for MS pain with minimal therapy support may be effective for some pwMS, but not those with more complex comorbidities. The participants suggested web-based delivery may simplify the approach, and therapist telephone contact was highly valued. Implications for Rehabilitation This case series suggests a hybrid CBT/ACT self-management workbook program for MS pain improves severity and impact of pain in some pwMS. Pain-related catastrophizing reduced in most pwMS, whilst change in other ACT and CBT process variables varied across the individuals. PwMS feedback suggests a tailored web-based delivery of the program with therapist telephone support may be optimal. PwMS with serious co-morbid depression and very advanced disease may not respond well to this self-management approach.

Prevalence of neuropathic pain in early multiple sclerosis

Background:

Pain is considered a frequent symptom in multiple sclerosis. Neuropathic pain is the type of pain most closely related to the pathology of multiple sclerosis and its prevalence estimates vary largely.

Objective:

We prospectively assessed the prevalence of neuropathic pain in patients with early multiple sclerosis and investigated the association of neuropathic pain with other clinical parameters.

Methods:

A total of 377 outpatients with multiple sclerosis at an early disease stage were included in this prospective study. Mean disease duration was 4.2 years, mean Expanded Disability Status Scale (EDSS) score was 1.6, 96.8% of patients were classified as having relapsing–remitting multiple sclerosis. Neuropathic pain was assessed using the PainDETECT questionnaire (PDQ). Depression, fatigue and cognition were assessed using the Beck Depression Inventory (BDI), the Fatigue Scale for Motor and Cognitive Functions (FSMC) and the Paced Auditory Serial Addition Test.

Results:

PDQ scores indicative of neuropathic pain were found in 4.2% of patients. Regression analysis revealed EDSS, BDI and FMSC scores as strongest predictors of PDQ scores.

Conclusions:

Neuropathic pain appears to be less frequent in early multiple sclerosis than expected and is significantly associated with disability, depression and fatigue. The assessment and therapy of pain in multiple sclerosis should thus take into account neuropsychiatric symptoms already at early disease stages.

Sensitization of the Nociceptive System in Complex Regional Pain Syndrome

BACKGROUND

Complex regional pain syndrome type I (CRPS-I) is characterized by sensory, motor and autonomic abnormalities without electrophysiological evidence of a nerve lesion.

OBJECTIVE

Aims were to investigate how sensory, autonomic and motor function change in the course of the disease.

METHODS

19 CRPS-I patients (17 with acute, 2 with chronic CRPS, mean duration of disease 5.7±8.3, range 1-33 months) were examined with questionnaires (LANSS, NPS, MPI, Quick DASH, multiple choice list of descriptors for sensory, motor, autonomic symptoms), motor and autonomic tests as well as quantitative sensory testing according to the German Research Network on Neuropathic Pain at two visits (baseline and 36±10.6, range 16-53 months later).

RESULTS

CRPS-I patients had an improvement of sudomotor and vasomotor function, but still a great impairment of sensory and motor function upon follow-up. Although pain and mechanical detection improved upon follow-up, thermal and mechanical pain sensitivity increased, including the contralateral side. Increase in mechanical pain sensitivity and loss of mechanical detection were associated with presence of ongoing pain.

CONCLUSIONS

The results demonstrate that patients with CRPS-I show a sensitization of the nociceptive system in the course of the disease, for which ongoing pain seems to be the most important trigger. They further suggest that measured loss of function in CRPS-I is due to pain-induced hypoesthesia rather than a minimal nerve lesion. In conclusion, this article gives evidence for a pronociceptive pain modulation profile developing in the course of CRPS and thus helps to assess underlying mechanisms of CRPS that contribute to the maintenance of patients' pain and disability.

Beyond a physical symptom: the importance of psychosocial factors in multiple sclerosis pain

BACKGROUND AND PURPOSE

Pain affects around two-thirds of people with Multiple Sclerosis (pwMS). Biomedical treatments show limited efficacy. A recently developed cognitive-behavioural model of Multiple Sclerosis (MS) pain suggests several psychosocial factors may worsen pain and related disability. The current study investigated whether psychosocial factors drawn from this model explain significant amounts of the variance in pain severity and interference over and above measures of disease severity and pain subtype.

METHODS

Six hundred and twelve pwMS experiencing pain completed a U.K. wide cross-sectional survey including valid and reliable psychometric questionnaires. Hierarchical regressions determined the relative contribution of disease severity and psychosocial factors to predicting pain severity and interference.

RESULTS

All psychosocial factors including distress, negative beliefs about pain and its consequences, and avoidance of activity, were related to pain outcomes, explaining a further 24% and 30% of the variance in pain severity and interference after controlling for demographic and disease variables. Findings were similar for neuropathic and non-neuropathic pain subgroups.

CONCLUSIONS

All pwMS reported significant pain and associated disability even though over 90% were taking pain medication. Psychosocial factors identified as important in predicting pain severity and, to a greater extent, pain interference are potentially modifiable and may be important treatment targets for both pain subtypes.

Acute Pain Medicine in the United States: A Status Report

BACKGROUND

Consensus indicates that a comprehensive,multimodal, holistic approach is foundational to the practice of acute pain medicine (APM),but lack of uniform, evidence-based clinical pathways leads to undesirable variability throughout U. S. healthcare systems. Acute pain studies are inconsistently synthesized to guide educational programs. Advanced practice techniques involving regional anesthesia assume the presence of a physician-led, multidisciplinary acute pain service,which is often unavailable or inconsistently applied.This heterogeneity of educational and organizational standards may result in unnecessary patient pain and escalation of healthcare costs.

METHODS

A multidisciplinary panel was nominated through the APM Shared Interest Group of the American Academy of Pain Medicine. The panel met in Chicago, IL, in July 2014, to identify gaps and set priorities in APM research and education.

RESULTS

The panel identified three areas of critical need: 1) an open-source acute pain data registry and clinical support tool to inform clinical decision making and resource allocation and to enhance research efforts; 2) a strong professional APM identity as an accredited subspecialty; and 3) educational goals targeted toward third-party payers,hospital administrators, and other key stake holders to convey the importance of APM.

CONCLUSION

This report is the first step in a 3-year initiative aimed at creating conditions and incentives for the optimal provision of APM services to facilitate and enhance the quality of patient recovery after surgery, illness, or trauma. The ultimate goal is to reduce the conversion of acute pain to the debilitating disease of chronic pain.

Towards a better understanding of MS pain: a systematic review of potentially modifiable psychosocial factors

OBJECTIVE

Pain is a common symptom of Multiple Sclerosis (MS). Biomedical treatments achieve only modest reductions in pain severity suggesting that this approach may be too narrow. The aim of this systematic review was to assess evidence for associations between modifiable psychosocial factors and MS pain severity and pain interference and use this evidence to develop a preliminary biopsychosocial model of MS pain.

METHODS

Empirical studies of pain in MS utilising standardised pain severity and pain interference measures were included. Online databases (Cochrane, PsychInfo, EMBASE, CINAHL, Medline, Web of Science and World Cat) and reference sections of included articles were searched, and corresponding authors contacted to identify unpublished studies. Information about design, sample size, MS type, time since diagnosis, psychosocial and pain measures and key findings were extracted. Thirty-one studies were assessed for quality and a narrative synthesis was conducted.

RESULTS

Similar to primary chronic pain, most studies reported small to medium associations between several psychosocial factors and pain severity and interference. Pain catastrophizing showed consistently strong associations with pain interference. Preliminary findings revealed a strong correlation between pain acceptance and pain interference. However, fear-avoidance appeared less important in MS, and other forms of behavioural avoidance were not explored.

CONCLUSIONS

A preliminary model of MS pain outlining specific psychosocial factors is presented with a conceptual formulation from both traditional, and contextual, cognitive-behavioural perspectives. Pain catastrophizing, acceptance, and endurance, as opposed to fear avoidance, responses are highlighted as potentially important treatment targets in MS, and directions for future research are outlined.

How to measure pain in neurological conditions? A systematic review of psychometric properties and clinical utility of measurement tools

OBJECTIVE

To systematically review the psychometric properties and clinical utility of measures of pain in neurological conditions.

DATA SOURCES

Electronic databases (AMED, CINAHL, MEDLINE, PEDro and Web of Knowledge) were searched from their inception to February 2013.

REVIEW METHODS

Studies investigating any measurement tool to assess pain in central nervous system conditions were systematically identified. Data about their psychometric properties and clinical utility were extracted and analysed independently. The strength of the psychometric properties and clinical utility were assessed.

RESULTS

A total of 13 articles met the selection criteria, which assessed 11 measurement tools; eight pain rating scales; one Neuropathic Pain Scale; and two measures of pain interference with every-day life. Most of the pain rating scales were specifically for hemiplegic shoulder pain. None had been sufficiently developed to recommend for use in clinical practice or research. Evaluation of reliability and the ability to detect change were particularly sparse. Reliability depended on the type of tools used. Patients with right hemisphere damage favoured verbal/written responses, while people with left hemisphere damage preferred and reported more effectively using visual/numeric responses. Validity between measures of pain intensity was moderate, while validity with mood or quality of life was weak to moderate.

CONCLUSION

None of the selected measures of pain have been fully developed or evaluated to demonstrate that they provide accurate, relevant reproducible information.

Phenotyping and genotyping neuropathic pain

Despite ongoing efforts, neither effective treatments nor mechanistic understanding of the pathogenesis of human neuropathic pain exists. Genetic association studies may point to the novel molecules that mediate neuropathic pain, facilitating its understanding and management. Several studies used a candidate gene approach to elucidate genetic contribution to neuropathic pain phenotypes; however, the data is limited and inconsistent. Possible reasons include: sample heterogeneity, underpowered study design, population admixture, poor phenotyping, genotyping errors, and statistical analytical mistakes. This article summarizes and discusses current strategies to optimize population-based association studies of human neuropathic pain focusing on principles of measuring neuropathic pain phenotypes and genotyping techniques. We also consider advantages and challenges of study designs and statistical analyses.

NeuPSIG guidelines on neuropathic pain assessment

This is a revision of guidelines, originally published in 2004, for the assessment of patients with neuropathic pain. Neuropathic pain is defined as pain arising as a direct consequence of a lesion or disease affecting the somatosensory system either at peripheral or central level. Screening questionnaires are suitable for identifying potential patients with neuropathic pain, but further validation of them is needed for epidemiological purposes. Clinical examination, including accurate sensory examination, is the basis of neuropathic pain diagnosis. For more accurate sensory profiling, quantitative sensory testing is recommended for selected cases in clinic, including the diagnosis of small fiber neuropathies and for research purposes. Measurement of trigeminal reflexes mediated by A-beta fibers can be used to differentiate symptomatic trigeminal neuralgia from classical trigeminal neuralgia. Measurement of laser-evoked potentials is useful for assessing function of the A-delta fiber pathways in patients with neuropathic pain. Functional brain imaging is not currently useful for individual patients in clinical practice, but is an interesting research tool. Skin biopsy to measure the intraepidermal nerve fiber density should be performed in patients with clinical signs of small fiber dysfunction. The intensity of pain and treatment effect (both in clinic and trials) should be assessed with numerical rating scale or visual analog scale. For future neuropathic pain trials, pain relief scales, patient and clinician global impression of change, the proportion of responders (50% and 30% pain relief), validated neuropathic pain quality measures and assessment of sleep, mood, functional capacity and quality of life are recommended.

Diagnosis and assessment of neuropathic pain

Neuropathic pain and pain that has a predominant neuropathic component can be difficult to diagnose in primary care. Several screening questionnaires that incorporate patient symptoms and signs have been developed, and some are supplemented with simple bedside clinical tests for nerve dysfunction. These tools should enable a more rapid and confident diagnosis by the nonspecialist and the earlier start of appropriate treatment.

A review of central neuropathic pain states

PURPOSE OF REVIEW

Central neuropathic pain is an important and disabling but often neglected problem following central nervous system lesions. The present review highlights recent advances in the understanding of the underlying mechanisms and in the diagnosis and treatment of central pain.

RECENT FINDINGS

Within the past year, the field of central pain has moved toward a more integrative understanding of central pain. The involvement of nonneuronal cells and interaction between multiple areas of the central nervous system has been recognized as important in the underlying mechanisms. The interest for conditions other than spinal cord injury, multiple sclerosis, and stroke has increased, and continued discussions on clear clinical diagnostic criteria are needed. The treatment of central pain is still a great challenge, but recent evidence points to tricyclic antidepressants, gabapentin and pregabalin, and selective serotonin-noradrenaline reuptake inhibitors as first-line drugs in central pain. An increased understanding of the psychosocial aspects of central pain also has implications for the treatment.

SUMMARY

Increased insight into the mechanisms of central pain will hopefully lead to increased efforts to study mechanism-based treatment of central pain.

Pregabalin in the management of central neuropathic pain

Central neuropathic pain is a painful condition, often severe, that occurs in a person who is already affected by an injury or disease of the brain or spinal cord. This dual insult is especially threatening to the quality of life of a person and their ability to perform even the most basic of tasks. Despite this high level of suffering there are relatively few trials investigating the management of central neuropathic pain. However, two randomised placebo-controlled studies have recently emerged demonstrating efficacy of pregabalin in reducing central neuropathic pain due to spinal cord injury and central poststroke pain. Pregabalin, an anticonvulsant, has been shown to be efficacious in the management of peripheral neuropathic pain of various causes and now may have a role to play in central neuropathic pain.

Pain associated with multiple sclerosis: systematic review and proposed classification

Pain is common in patients with multiple sclerosis (MS), but estimates of its prevalence have varied widely. The literature describing pain in MS patients spans four decades and has employed a range of different methodologies. We undertook a systematic review in order to summarize current understanding of the association between MS and pain and provide a basis for the design and interpretation of future studies. The point prevalence of pain in patients with MS is nearly 50%, and approximately 75% of patients report having had pain within one month of assessment. Pain adversely affects most aspects of health-related quality of life, including functional domains such as the ability to work. The presence of pain in patients with MS is associated with increased age, duration of illness, depression, degree of functional impairment, and fatigue. Several different types of pain are found in patients with MS, including extremity pain, trigeminal neuralgia, Lhermitte's sign, painful tonic spasms, back pain, and headache. Putative mechanisms of pain in patients with MS are discussed, and a classification of pain in MS is proposed. Few randomized clinical trials of treatments for MS pain have been conducted, and the limitations of current knowledge regarding approaches for treating MS pain are discussed. Suggestions for future studies that would increase understanding of the natural history, mechanisms, and treatment of pain in patients with MS are presented.