Non-invasive brain and spinal stimulation for pain and related symptoms in multiple sclerosis: a systematic review

Background: Neuropathic and nociceptive pain frequently affect patients with multiple sclerosis (MS), with a prevalence close to 90% and significant impact on general health and quality of life. Pharmacological strategies are widely used to treat pain in MS, but their effectiveness and side-effects are controversial. Among non-pharmacological treatments for pain, non-invasive brain and spinal stimulation (NIBSS) has shown promising preliminary results in MS.Objective: Systematic review to investigate the effect of NIBSS for the management of pain in MS.Methods: A literature search using Pubmed, Science Direct and Web of Science was conducted from databases inception to February 21, 2020 for studies assessing the analgesic effect of NIBSS on pain in MS.Results: A total of 279 records were title- and abstract-screened, nine were assessed for full text and included. The NIBSS techniques explored were transcranial direct current stimulation (N = 5), transcranial magnetic stimulation (N = 2), transcranial random noise stimulation (N =1), transcutaneous spinal direct current stimulation (N = 1). The targets were the primary motor cortex (M1; N = 4), the left dorsolateral pre-frontal cortex (DLPFC; N = 3), the spinal cord (N = 1), unspecified brain target (N = 1). The study designs were randomized (N = 7), open label (N = 1), single case report (N = 1). Despite the differences in study design, target and NIBSS technique that impeded a meta-analysis, all the studies converge in showing a significant improvement of pain after active NIBSS with less consistent effects on other symptoms of the pain-related cluster (depression, fatigue, cognition) and quality of life.Conclusions: Excitatory NIBSS over M1, left DLPFC and spinal cord appear to be the most effective protocols for pain in MS. Open questions include the use of neurophysiological or neuroimaging surrogate outcome measures, the stratification of patients according to the clinical profiles and underlying pathogenetic mechanisms and the combination of NIBSS to pharmacological treatment, neurorehabilitation, or psychotherapy to improve the clinical effect. The duration of the effect to NIBSS and the feasibility and efficacy of telemedicine NIBSS protocols are other open key questions

Electrical stimulation of injected muscles to boost botulinum toxin effect on spasticity: rationale, systematic review and state of the art

Botulinum toxin type A (BoNT-A) represents a first-line treatment for spasticity, a common disabling consequence of many neurological diseases. Electrical stimulation of motor nerve endings has been reported to boost the effect of BoNT-A. To date, a wide range of stimulation protocols has been proposed in the literature. We conducted a systematic review of current literature on the protocols of electrical stimulation to boost the effect of BoNT-A injection in patients with spasticity. A systematic search using the MeSH terms "electric stimulation", "muscle spasticity" and "botulinum toxins" and strings "electric stimulation [mh] OR electrical stimulation AND muscle spasticity [mh] OR spasticity AND botulinum toxins [mh] OR botulinum toxin type A" was conducted on PubMed, Scopus, PEDro and Cochrane library electronic databases. Full-text articles written in English and published from database inception to March 2021 were included. Data on patient characteristics, electrical stimulation protocols and outcome measures were collected. This systematic review provides a complete overview of current literature on the role of electrical stimulation to boost the effect of BoNT-A injection for spasticity, together with a critical discussion on its rationale based on the neurobiology of BoNT-A uptake

Botulinum neurotoxin type A for the treatment of pain: not just in migraine and trigeminal neuralgia

BACKGROUND: Despite their huge epidemiological impact, primary headaches, trigeminal neuralgia and other chronic pain conditions still receive suboptimal medical approach, even in developed countries. The limited efficacy of current pain-killers and prophylactic treatments stands among the main reasons for this phenomenon. Botulinum neurotoxin (BoNT) represents a well-established and licensed treatment for chronic migraine, but also an emerging treatment for other types of primary headache, trigeminal neuralgia, neuropathic pain, and an increasing number of pain conditions. METHODS: We searched and critically reviewed evidence for the efficacy of BoNT for the treatment of chronic pain. RESULTS: Meta-analyses and randomized controlled trials (RCTs) suggest that BoNT potentially represents a multi-purpose drug for the treatment of pain in several disorders due to a favorable safety profile and a long-lasting relief after a single injection. CONCLUSIONS: BoNT is an emerging treatment in different pain conditions. Future RCTs should explore the use of BoNT injection therapy combined with systemic drugs and/or physical therapies as new pain treatment strategies

Noninvasive peripheral vagal nerve stimulation prevents migraine aura: A case report

We describe a patient affected by migraine with visual and somatosensory aura, whose symptoms were consistently attenuated by noninvasive peripheral vagal nerve stimulation (nVNS) in multiple prospectively recorded attacks. When compared with the current standard of care, nVNS significantly reduced the duration of visual aura in all the attacks ( n = 5) and prevented the somatosensory aura in three of the five attacks. The overall duration of nVNS-treated auras was 19.0 ± 4.2 min, significantly shorter than the duration of aura in attacks treated with standard of care (103.8 ± 10.3 min). This single-case study requires confirmation in a larger sample size, but we believe that this first report is suggestive of likely efficacy given the relatively high number of treated attacks and the consistent effect of nVNS

Characterization of the peripheral FAAH inhibitor, URB937, in animal models of acute and chronic migraine.

Inhibiting the activity of fatty-acid amide hydrolase (FAAH), the enzyme that deactivates the endocannabinoid anandamide, enhances anandamide-mediated signaling and holds promise as a molecular target for the treatment of human pathologies such as anxiety and pain. We have previously shown that the peripherally restricted FAAH inhibitor, URB937, prevents nitroglycerin-induced hyperalgesia - an animal model of migraine - and attenuates the activation of brain areas that are relevant for migraine pain, e.g. trigeminal nucleus caudalis and locus coeruleus. The current study is aimed at profiling the behavioral and biochemical effects of URB937 in animal models of acute and chronic migraine. We evaluated the effects of URB937 in two rat models that capture aspects of acute and chronic migraine, and are based on single or repeated administration of the vasodilating drug, nitroglycerin (NTG). In addition to nocifensive behavior, in trigeminal ganglia and medulla, we measured mRNA levels of neuropeptides and pro-inflammatory cytokines along with tissue levels of anandamide and palmitoylethanolamide (PEA), an endogenous agonist of peroxisome proliferator-activated receptor type-a (PPAR-a), which is also a FAAH substrate. In the acute migraine model, we also investigated the effect of subtype-selective antagonist for cannabinoid receptors 1 and 2 (AM251 and AM630, respectively) on nocifensive behavior and on levels of neuropeptides and pro-inflammatory cytokines. In the acute migraine paradigm, URB937 significantly reduced hyperalgesia in the orofacial formalin test when administered either before or after NTG. This effect was accompanied by an increase in anandamide and PEA levels in target neural tissue, depended upon CB1 receptor activation, and was associated with a decrease in calcitonin gene-related peptide (CGRP), substance P and cytokines TNF-alpha and IL-6 mRNA. Similar effects were observed in the chronic migraine paradigm, where URB937 counteracted NTG-induced trigeminal hyperalgesia and prevented the increase in neuropeptide and cytokine transcription. The results show that peripheral FAAH inhibition by URB937 effectively reduces both acute and chronic NTG-induced trigeminal hyperalgesia, likely via augmented anandamide-mediated CB1 receptor activation. These effects are associated with inhibition of neuropeptidergic and inflammatory pathways

Body Weight Support Combined With Treadmill in the Rehabilitation of Parkinsonian Gait: A Review of Literature and New Data From a Controlled Study

Background: Gait disorders represent disabling symptoms in Parkinson's Disease (PD). The effectiveness of rehabilitation treatment with Body Weight Support Treadmill Training (BWSTT) has been demonstrated in patients with stroke and spinal cord injuries, but limited data is available in PD.Aims: The aim of the study is to investigate the efficacy of BWSTT in the rehabilitation of gait in PD patients.Methods: Thirty-six PD inpatients were enrolled and performed rehabilitation treatment for 4-weeks, with daily sessions. Subjects were randomly divided into two groups: both groups underwent daily 40-min sessions of traditional physiokinesitherapy followed by 20-min sessions of overground gait training (Control group) or BWSTT (BWSTT group). The efficacy of BWSTT was evaluated with clinical scales and Computerized Gait Analysis (CGA). Patients were tested at baseline (T0) and at the end of the 4-weeks rehabilitation period (T1).Results: Both BWSTT and Control groups experienced a significant improvement in clinical scales as FIM and UPDRS and in gait parameters for both interventions. Even if we failed to detect any statistically significant differences between groups in the different clinical and gait parameters, the intragroup analysis captured a specific pattern of qualitative improvement associated to cadence and stride duration for the BWSTT group and to the swing/stance ratio for the Control group. Four patients with chronic pain or anxious symptoms did not tolerate BWSTT.Conclusions: BWSTT and traditional rehabilitation treatment are both effective in improving clinical motor functions and kinematic gait parameters. BWSTT may represent an option in PD patients with specific symptoms that limit traditional overground gait training, e.g., severe postural instability, balance disorder, orthostatic hypotension. BWSTT is generally well-tolerated, though caution is needed in subjects with chronic pain or with anxious symptoms.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT0381540

The Effects of Transcutaneous Spinal Direct Current Stimulation on Neuropathic Pain in Multiple Sclerosis: Clinical and Neurophysiological Assessment

Background: Central neuropathic pain represents one of the most common symptoms in multiple sclerosis (MS) and it seriously affects quality of life. Spinal mechanisms may contribute to the pathogenesis of neuropathic pain in MS. Converging evidence from animal models and neurophysiological and clinical studies in humans suggests a potential effect of transcranial direct current stimulation (tc-DCS) on neuropathic pain. Spinal application of DCS, i.e., transcutaneous spinal DCS (ts-DCS), may modulate nociception through inhibition of spinal reflexes. Therefore, ts-DCS could represents an effective, safe and well-tolerated treatment for neuropathic pain in MS, a largely unexplored topic. This study is a pilot randomized double-blind sham-controlled trial to evaluate the efficacy of ts-DCS on central neuropathic pain in MS patients.Methods: Thirty-three MS patients with central neuropathic pain were enrolled and randomly assigned to two groups in a double-blind sham-controlled design: anodal ts-DCS group (n = 19, 10 daily 20-min sessions, 2 mA) or sham ts-DCS group (n = 14, 10 daily 20-min sessions, 0 mA). The following clinical outcomes were evaluated before ts-DCS treatment (T0), after 10 days of treatment (T1) and 1 month after the end of treatment (T2): neuropathic pain symptoms inventory (NPSI), Ashworth Scale (AS) for spasticity and Fatigue Severity Scale (FSS). A subgroup of patients treated with anodal ts-DCS (n = 12) and sham ts-DCS (n = 11) also underwent a parallel neurophysiological study of the nociceptive withdrawal reflex (NWR) and the NWR temporal summation threshold (TST), two objective markers of pain processing at spinal level.Results: Anodal ts-DCS group showed a significant improvement in NPSI at T1, which persisted at T2, while we did not detect any significant change in AS and FSS. Sham ts-DCS group did not show any significant change in clinical scales. We observed a non-significant trend towards an inhibition of NWR responses in the anodal ts-DCS group at T1 and T2 when compared to baseline.Conclusions: Anodal ts-DCS seems to have an early and persisting (i.e., 1 month after treatment) clinical efficacy on central neuropathic pain in MS patients, probably through modulation of spinal nociception.Clinical Trial Registration:www.ClinicalTrials.gov, identifier #NCT02331654

Negative Short-Term Outcome of Detoxification Therapy in Chronic Migraine With Medication Overuse Headache: Role for Early Life Traumatic Experiences and Recent Stressful Events

Background: Early traumatic experiences and Stressful episodes appear to be associated to the development and perpetuation of chronic pain disorders and to dependence-related behaviors.Objective: The present study evaluated whether these factors can be predictors, together with psychiatric conditions, of the outcome of a detoxification treatment in patients suffering from chronic migraine and medication-overuse headache in a 2-month follow-up.Methods: Consecutive patients undergoing a detoxification program as therapy for treating chronic migraine and medication overuse headache at the Pavia Headache Center were analyzed. During this program, lasting about 1 week, all patients received the standard CARE in-patient withdrawal protocol, which consisted in discontinuing abruptly the overused drug(s) and receiving daily detoxification therapy. Data on childhood traumatic events and recent stressful ones were analyzed by means of the Childhood Trauma Questionnaire and Stressful life-events Questionnaire. Psychiatric conditions were evaluated using the Structured Clinical Interview for Diagnostic and Statistical Manual of mental disorders.Results: A total of 166 (80% females; mean age 44.7) patients completed the follow-up at 2 months after the detoxification program: of these 118 (71%) (78% females; mean age 44.7) stopped overuse and reverted to an episodic pattern of headache (Group A); 19 (11%) (89% females; mean age 41.3) kept overusing and maintained a chronic pattern of headache (Group B); and 29 (18%) (79% females; mean age 46.9) stopped overuse without any benefit on headache frequency (Group C). At the multivariate analyses, a higher number of early life emotional distress (Odds Ratio 11.096; p = 0.037) arose as a prognostic factor for the outcome in Group B, while major depression during life-time (Odds Ratio 3.703; p = 0.006) and higher number of severe stressful episodes in the past 10 years (Odds Ratio 1.679; p = 0.045) were prognostic factors for the outcome of Group C.Conclusions: Data suggest that early life traumas and stressful events have a negative impact on the outcome of the detoxification program in subjects overusing acute medication for headache. The history of emotional childhood traumas is associated to the failure to cease overuse, whereas recent very serious life events are associated to the persistence of headache chronicity

Multiscale Entropy Algorithms to Analyze Complexity and Variability of Trunk Accelerations Time Series in Subjects with Parkinson’s Disease

The aim of this study was to assess the ability of multiscale sample entropy (MSE), refined composite multiscale entropy (RCMSE), and complexity index (CI) to characterize gait complexity through trunk acceleration patterns in subjects with Parkinson's disease (swPD) and healthy subjects, regardless of age or gait speed. The trunk acceleration patterns of 51 swPD and 50 healthy subjects (HS) were acquired using a lumbar-mounted magneto-inertial measurement unit during their walking. MSE, RCMSE, and CI were calculated on 2000 data points, using scale factors (t) 1-6. Differences between swPD and HS were calculated at each t, and the area under the receiver operating characteristics, optimal cutoff points, post-test probabilities, and diagnostic odds ratios were calculated. MSE, RCMSE, and CIs showed to differentiate swPD from HS. MSE in the anteroposterior direction at t4 and t5, and MSE in the ML direction at t4 showed to characterize the gait disorders of swPD with the best trade-off between positive and negative posttest probabilities and correlated with the motor disability, pelvic kinematics, and stance phase. Using a time series of 2000 data points, a scale factor of 4 or 5 in the MSE procedure can yield the best trade-off in terms of post-test probabilities when compared to other scale factors for detecting gait variability and complexity in swPD

Development and validation of the ID-EC - The ITALIAN version of the identify chronic migraine

Background: Case-finding tools, such as the Identify Chronic Migraine (ID-CM) questionnaire, can improve detection of CM and alleviate its significant societal burden. We aimed to develop and validate the Italian version of the ID-CM (ID-EC) in paper and as a smart app version in a headache clinic-based setting. Methods: The study investigators translated and adapted to the Italian language the original ID-CM questionnaire (ID-EC) and further implemented it as a smart app. The ID-EC was tested in its paper and electronic version in consecutive patients referring to 9 Italian tertiary headache centers for their first in-person visit. The scoring algorithm of the ID-EC paper version was applied by the study investigators (case-finding) and by patients (self-diagnosis), while the smart app provided to patients automatically the diagnosis. Diagnostic accuracy of the ID-EC was assessed by matching the questionnaire results with the interview-based diagnoses performed by the headache specialists during the visit according to the criteria of International Classification of Headache Disorders, III edition, beta version. Results: We enrolled 531 patients in the test of the paper version of ID-EC and 427 in the validation study of the smart app. According to the clinical diagnosis 209 patients had CM in the paper version study and 202 had CM in the smart app study. 79.5% of patients returned valid paper questionnaires, while 100% of patients returned valid and complete smart app questionnaires. The paper questionnaire had a 81.5% sensitivity and a 81.1% specificity for case-finding and a 30.7% sensitivity and 90.7% specificity for self-diagnosis, while the smart app had a 64.9% sensitivity and 90.2% specificity. Conclusions: Our data suggest that the ID-EC, developed and validated in tertiary headache centers, is a valid case-finding tool for CM, with sensitivity and specificity values above 80% in paper form, while the ID-EC smart app is more useful to exclude CM diagnosis in case of a negative result. Further studies are warranted to assess the diagnostic accuracy of the ID-EC in general practice and population-based settings