Home-based self-administered transcranial direct current stimulation in older adults with knee osteoarthritis pain: An open-label study

Home-Based, Remotely Supervised Transcranial Direct Current Stimulation Improves the Overall Pain Experience of Older Adults With Knee Osteoarthritis

Objective: Chronic pain in knee osteoarthritis (OA) is a multidimensional phenomenon requiring thorough assessment and appropriate treatment. We assessed the impact of home-based, remotely supervised transcranial direct current stimulation (tDCS) on the overall pain experience of older adults with knee OA by simultaneously examining its effects on multiple pain domains-pain intensity, pain interference, and pain catastrophizing-using multigroup latent transition analysis (LTA). Methods: This secondary analysis of a randomized clinical trial involved 120 participants with knee OA pain, randomly assigned in a 1:1 ratio to receive 15 daily sessions of 2-mA tDCS or sham tDCS (20 min per session) over three weeks, with real-time remote supervision. Pain intensity was measured using the Numeric Rating Scale (NRS) and the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Pain interference was measured using the WOMAC functional scale. Pain catastrophizing was assessed using the Pain Catastrophizing Scale (PCS). All the measures were assessed at baseline and at the end of each week (weeks 1, 2, and 3), after the participants had completed five tDCS sessions per week. Multigroup LTA enabled the simultaneous measurement of multiple pain domains and analysis of their changes as a function of intervention exposure by modeling the transition probabilities of latent classes and comparing these changes between the groups. Results: Based on the NRS, WOMAC, and PCS scores, three latent categories were identified: "high pain (all scores high)," "moderate pain (all scores moderate)," and "low pain (all scores low)." Active group participants with "moderate pain" at baseline had a 24.2% probability of transitioning to "low pain" after Week 1, whereas sham group participants remained stagnant during this interval. Notably, 37.6% of active group participants with "high pain" at Week 1 transitioned to "moderate pain," while 35.8% of those with "moderate pain" at Week 1 transitioned to "low pain" by Week 2 (after an additional five sessions). Nevertheless, no noticeable changes were observed in the sham group during this period. No pronounced intervention effects were noted by Week 3. Conclusions: Simultaneously modeling pain-related measures enriches our understanding of the efficacy of tDCS in improving the overall pain experience among older adults with knee OA. Trial Registration: ClinicalTrials.gov identifier: NCT04016272.

Independent effects of transcranial direct current stimulation and social influence on pain

ABSTRACT

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulatory technique with the potential to provide pain relief. However, tDCS effects on pain are variable across existing studies, possibly related to differences in stimulation protocols and expectancy effects. We investigated the independent and joint effects of contralateral motor cortex tDCS (anodal vs cathodal) and socially induced expectations (analgesia vs hyperalgesia) about tDCS on thermal pain. We employed a double-blind, randomized 2 × 2 factorial cross-over design, with 5 sessions per participant on separate days. After calibration in Session 1, Sessions 2 to 5 crossed anodal or cathodal tDCS (20 minutes 2 mA) with socially induced analgesic or hyperalgesic expectations, with 6 to 7 days between the sessions. The social manipulation involved videos of previous "participants" (confederates) describing tDCS as inducing a low-pain state ("analgesic expectancy") or hypersensitivity to sensation ("hyperalgesic expectancy"). Anodal tDCS reduced pain compared with cathodal stimulation (F(1,19.9) = 19.53, P < 0.001, Cohen d = 0.86) and analgesic expectancy reduced pain compared with hyperalgesic expectancy (F(1,19.8) = 5.62, P = 0.027, Cohen d = 0.56). There was no significant interaction between tDCS and social expectations. Effects of social suggestions were related to expectations, whereas tDCS effects were unrelated to expectancies. The observed additive effects provide novel evidence that tDCS and socially induced expectations operate through independent processes. They extend clinical tDCS studies by showing tDCS effects on controlled nociceptive pain independent of expectancy effects. In addition, they show that social suggestions about neurostimulation effects can elicit potent placebo effects.

Exploring whether home-based neuromodulation can boost the analgesic effects of exercise in people with knee osteoarthritis: protocol for a double-blinded, pilot randomised controlled trial

INTRODUCTION

Knee osteoarthritis (OA) represents a leading cause of disability globally. Exercise has been demonstrated to improve pain and function in people with knee OA. However, when in pain, commencement of exercise is difficult, and clinical effects with such interventions are often modest. Recently, transcranial direct current stimulation (tDCS), a form of non-invasive brain stimulation, has been shown to bolster the pain-relieving effect of exercise in experimental settings. While promising, the utility of employing this approach beyond the research environment is yet to be elucidated. Therefore, this pilot study aims to investigate the feasibility, safety, adherence, tolerability and preliminary efficacy of tDCS and exercise in home-based settings to improve pain and function in people with knee OA.

METHODS AND ANALYSIS

This protocol is for a pilot randomised, double-blinded, sham-controlled trial. 24 individuals with idiopathic knee OA will be randomised to receive either active tDCS+exercise (Intervention) or sham tDCS+exercise (Control) at home. Participants will receive 20 min of tDCS 5 days per week for the first 2 weeks of this 8-week trial. Participants in both groups will complete a lower limb strengthening programme 3 days per week for the entire 8 weeks. Outcome measures of feasibility (acceptability, satisfaction, retention), safety, adherence and tolerability will be assessed throughout the trial period, with clinical outcomes of pain and function assessed before and following the intervention. Feasibility, safety, adherence and tolerability outcomes will be explored descriptively using frequencies and percentages. To examine preliminary efficacy, within-group and between-group changes in pain and functional measures will be analysed.

ETHICS AND DISSEMINATION

This protocol obtained ethical approval from the Queensland University of Technology Human Research Ethics Committee (HREA 2024-8302-20200). All participants will provide written informed consent. The findings of the study will be disseminated via journal publications and international conference proceedings.

TRIAL REGISTRATION NUMBER

ACTRN12624000397516p.

Comparison of responders and nonresponders with knee osteoarthritis after transcranial direct current stimulation

AIM

The study compared responders and nonresponders to transcranial direct current stimulation (tDCS) regarding clinical pain outcomes in knee osteoarthritis (OA) patients.

PATIENTS AND METHODS/MATERIALS

Sixty participants received home-based active tDCS, and clinical pain outcomes were compared between responders and nonresponders.

RESULTS

Latent class growth analyses classified 41 participants as responders and 19 as nonresponders. Responders showed significantly greater decreases in pain intensity from baseline to post intervention than nonresponders (p < .001). Participants with higher BMI (p = .02) and weight (p = .005) were more likely to respond, while no significant sociodemographic differences were found.

CONCLUSIONS

Identifying characteristics of nonresponsive tDCS subgroups can tailor treatments for each group.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT04016272.

Home-based, Remotely Supervised, 6-Week tDCS in Patients With Both MCI and Depression: A Randomized Double-Blind Placebo-Controlled Trial

As depressive symptom is considered a prodrome, a risk factor for progression from mild cognitive impairment (MCI) to dementia, improving depressive symptoms should be considered a clinical priority in patients with MCI undergoing transcranial direct current stimulation (tDCS) intervention. We aimed to comprehensively evaluate the efficacy of the home-based and remotely monitored tDCS in patients with both MCI and depression, by integrating cognitive, psychological, and electrophysiological indicators. In a 6-week, randomized, double blind, and sham-controlled study, 37 community-dwelling patients were randomly assigned to either an active or a sham stimulation group, and received 30 home-based sessions of 2 mA tDCS for 30 min with the anode located over the left and cathode over the right dorsolateral prefrontal cortex. We measured depressive symptoms, neurocognitive function, and resting-state electroencephalography. In terms of effects of both depressive symptoms and cognitive functions, active tDCS was not significantly different from sham tDCS. However, compared to sham stimulation, active tDCS decreased and increased the activation of delta and beta frequencies, respectively. Moreover, the increase in beta activity was correlated with the cognitive enhancement only in the active group. It was not possible to reach a definitive conclusion regarding the efficacy of tDCS on depression and cognition in patients with both MCI and depression. Nevertheless, the relationship between the changes of electrophysiology and cognitive performance suggests potential neuroplasticity enhancement implicated in cognitive processes by tDCS.

An Educational Program for Remote Training and Supervision of Home-Based Transcranial Electrical Stimulation: Feasibility and Preliminary Effectiveness

OBJECTIVES

There has been recent interest in the administration of transcranial electrical stimulation (tES) by a caregiver, family member, or patient themselves while in their own homes (HB-tES). The need to properly train individuals in the administration of HB-tES is essential, and the lack of a uniform training approach across studies has come to light. The primary aim of this paper is to present the HB-tES training and supervision program, a tele-supervised, instructional, and evaluation program to teach laypersons how to administer HB-tES to a participant and to provide a standardized framework for remote monitoring of participants by teaching staff. The secondary aim is to present early pilot data on the feasibility and effectiveness of the training portion of the program based on its implementation in 379 sessions between two pilot clinical trials.

MATERIALS AND METHODS

The program includes instructional materials, standardized tele-supervised hands-on practice sessions, and a system for remote supervision of participants by teaching staff. Nine laypersons completed the training program. Data on the feasibility and effectiveness of the program were collected.

RESULTS

No adverse events were reported during the training or any of the HB-tES sessions after the training. All laypersons successfully completed the training. The nine laypersons reported being satisfied with the training program and confident in their tES administration capabilities. This was consistent with laypersons requiring technical assistance from teaching staff very infrequently during the 379 completed sessions. The average adherence rate between all administrators was >98%, with seven of nine administrators having 100% adherence to the scheduled sessions.

CONCLUSIONS

These findings indicate that the HB-tES program is effective and is associated with participant satisfaction.

SIGNIFICANCE

We hope that the remote nature of this training program will facilitate increased accessibility to HB-tES research for participants of different demographics and locations. This program, designed for easy adaptation to different HB-tES research applications and devices, also is accessible online. The adoption of this program is expected to facilitate uniformity of study methods among future HB-tES studies and thereby accelerate the pace of tES intervention discovery.

The Application of tDCS to Treat Pain and Psychocognitive Symptoms in Cancer Patients: A Scoping Review

Background

The use of transcranial direct current stimulation (tDCS) to modulate pain, psychological aspects, and cognitive functions has increased in recent years. The present scoping review aims to investigate the use of tDCS in cancer patients and its significant impact on psychocognitive and pain related symptoms.

Methods

From the earliest available date to June 2023, a comprehensive search was conducted in three electronic scientific databases-PubMed, Scopus, and Embase-and other supplementary sources. Ten relevant studies were identified and included, comprising single case studies, randomized controlled trials, pilot studies, and one retrospective study. PRISMA guidelines for scoping reviews were followed.

Results

These studies investigated the use of tDCS to improve pain and psychocognitive aspects in patients with various types of cancer, including breast, oral, bladder, lung, pancreatic, head and neck cancer, hepatocellular carcinoma, and meningioma. Overall, the results suggest that tDCS has shown efficacy in relieving pain, reducing anxiety and depression, and improving cognitive function in cancer patients.

Conclusion

Due to the limited number and high heterogeneity of the existing literature in this field, more investigation and the establishment of standardized protocols would be required to obtain more conclusive evidence.

Comorbid treatment of traumatic brain injury and mental health disorders

BACKGROUND

The Emory Healthcare Veterans Program (EHVP) is a multidisciplinary intensive outpatient treatment program for post-9/11 veterans and service members with invisible wounds, including posttraumatic stress disorder (PTSD), traumatic brain injury (TBI), substance use disorders (SUD), and other anxiety- and depression-related disorders.

OBJECTIVE

This article reviews the EHVP.

METHODS

The different treatment tracks that provide integrated and comprehensive treatment are highlighted along with a review of the standard, adjunctive, and auxiliary services that complement individualized treatment plans.

RESULTS

This review particularly emphasizes the adjunctive neurorehabilitation service offered to veterans and service members with a TBI history and the EVHP data that indicate large reductions in PTSD and depression symptoms across treatment tracks that are maintained across 12 months follow up. Finally, there is a discussion of possible suboptimal treatment response and the pilot programs related to different treatment augmentation strategies being deploying to ensure optimal treatment response for all.

CONCLUSION

Published data indicate that the two-week intensive outpatient program is an effective treatment program for a variety of complex presentations of PTSD, TBI, SUD, and other anxiety- and depression-related disorders in veterans and active duty service members.

Effectiveness of Transcranial Direct Current Stimulation in Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Sham-Controlled Trials

OBJECTIVE

The aim of the study is to assess the effectiveness of transcranial direct current stimulation in knee osteoarthritis.

METHODS

The study searched PubMed, Cochrane Library, Embase, and Scopus databases until August 3, 2023, and identified randomized controlled trials evaluating the effects of transcranial direct current stimulation in knee osteoarthritis whose outcomes using pain scores or functional scales. The selected randomized controlled trials were subjected to meta-analysis and risk of bias assessment.

RESULTS

Seven randomized controlled trials involving 488 patients were included in this meta-analysis. Compared with the control group, the transcranial direct current stimulation group exhibited significant improvement in pain scores after treatment (standardized mean difference = 1.03; 95% confidence interval: 0.70 to 1.35; n = 359; I2 = 46%), pain scores during follow-up (standardized mean difference = 0.83; 95% confidence interval: 0.21 to 1.45; n = 358; I2 = 86%), and Western Ontario and McMaster Universities Osteoarthritis scores after treatment (standardized mean difference = 4.76; 95% confidence interval: 0.16 to 9.53; n = 319; I2 = 74 % ), but Western Ontario and McMaster Universities Osteoarthritis scores during follow-up did not differ significantly between the groups (standardized mean difference = 0.06; 95% confidence interval: -0.2 to 0.32; n = 225; I2 = 0%).

CONCLUSIONS

Transcranial direct current stimulation is a promising therapy for knee osteoarthritis. Further investigation using large-scale, high-quality randomized controlled trials is necessary for optimal transcranial direct current stimulation approach in knee osteoarthritis.

Efficacy of transcranial direct current stimulation in patients with knee osteoarthritis: A systematic review

OBJECTIVE

Transcranial direct current stimulation (tDCS) has demonstrated its efficacy in alleviating pain among individuals with musculoskeletal disorders. This review focuses on the application of tDCS as a therapeutic intervention for managing knee osteoarthritis (OA), a prevalent musculoskeletal condition. The primary objective is to assess the effectiveness of tDCS(add-on tDCS and /or stand-alone tDCS), whether as an add-on to existing treatments or as a standalone therapy, in reducing pain and enhancing functional capacity in patients with knee OA.

METHODS

A comprehensive search was conducted across multiple databases, including PubMed, Science Direct, OVID, MEDLINE, CINAHL, EMBASE, ProQuest, and Google Scholar, and Web of Science. The search terms employed were "Transcranial direct current stimulation" or "tDCS" in combination with "Osteoarthritis" or "OA" and "knee." After eliminating duplicates and studies that did not meet the inclusion criteria, a total of 14 relevant articles were identified for review.

RESULTS

Among the included studies, twelve reported statistically significant improvements in pain levels when comparing the active tDCS group to the sham tDCS group. Only two studies reported no significant difference in pain intensity between the active tDCS and sham tDCS groups. Findings regarding functional abilities were diverse, with some studies demonstrating a significant enhancement in functional outcomes in the active tDCS group, while others observed no statistically significant differences.

CONCLUSION

The results of this review suggest that tDCS holds promise as a pain management intervention for individuals with knee OA. Notably, anodal tDCS applied over the primary motor cortex (M1) appears to be particularly effective in alleviating pain in patients with knee OA. However, the impact of tDCS on functional performance appears to be limited.

The effects of anodal tDCS on pain reduction in people with knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVES

To synthesise the literature on the efficacy of primary motor cortex anodal transcranial direct current stimulation (M1-a-tDCS), as a standalone or priming technique, for pain reduction in people with knee osteoarthritis (KOA).

METHODS

The systematic literature search was conducted in MEDLINE, CINAHL, Embase and CENTRAL according to PRISMA statement.

RESULTS

Fourteen studies involving 740 people with KOA were included. In the meta-analysis, six studies compared a-tDCS alone with sham stimulation, and five studies compared a-tDCS combined with other methods with sham stimulation. We found positive effect of a-tDCS alone on pain in KOA (standard mean difference (SMD) -0.52; 95% CI, -0.78 to -0.25; P=0.001; I2 = 69%). Further, a-tDCS with other treatments showed positive effect (SMD -1.23; 95% CI, -1.59 to -0.88; P<0.001; I2 = 48%) on pain in people with KOA. This evidence showed low certainty due to a high risk of bias and imprecision.

DISCUSSION AND CONCLUSION

A-tDCS could be considered as standalone and an adjunct treatment for pain reduction in people with KOA. Future randomised studies should address quality issues, including small sample size, to enhance the overall certainty of the findings.

SIGNIFICANCE

A-tDCS can be used as a standalone and adjunct treatment for KOA.

STUDY REGISTRATION

PROSPERO number CRD42021255114.

Management of Chronic Pain and PTSD in Veterans With tDCS+Prolonged Exposure: A Pilot Study

INTRODUCTION

Chronic pain and posttraumatic stress disorder (PTSD) are prevalent comorbid conditions, particularly in Veterans; however, there are few integrated treatments for chronic pain and PTSD. Instead, interventions are typically implemented separately and may involve addictive opioids. Although there are highly effective, non-pharmacological treatments for PTSD, they are plagued by high dropout, which may be exacerbated by comorbid pain, as these PTSD treatments typically require increased activity. Importantly, a noninvasive pain treatment, tDCS (transcranial direct current stimulation) shows indications of effectiveness and may be integrated with psychological treatments, even when delivered via telehealth. This study examines the feasibility and initial efficacy of integrating home telehealth tDCS with prolonged exposure (PE), an evidence-based PTSD treatment.

MATERIALS AND METHODS

Thirty-nine Veterans were contacted, 31 consented to evaluation, 21 were enrolled, and 16 completed treatment and provided pre- and post-treatment data at one of two Veterans Affairs Medical Centers. Transcranial direct current stimulation sessions corresponded with PE exposure assignments, as there is theoretical reason to believe that tDCS may potentiate extinction learning featured in PE.

RESULTS

Patients evinced significant improvement in both pain interference and PTSD symptoms and a trend toward improvement in depression symptoms. However, a significant change in pain intensity was not observed, likely because of the small sample size.

DISCUSSION

The findings provide initial support for the feasibility of an entirely home-based, integrated treatment for comorbid PTSD and pain.

TDCS at home for depressive disorders: an updated systematic review and lessons learned from a prematurely terminated randomized controlled pilot study

The application of transcranial direct current stimulation (tDCS) at home for the treatment of major depressive disorder (MDD) is the subject of current clinical trials. This is due to its positive safety profile, cost-effectiveness, and potential scalability for a wide outreach in clinical practice. Here, we provide a systematic review of the available studies and also a report on the results of a randomized controlled trial (RCT) on tDCS at home for the treatment of MDD. This trial had to be prematurely terminated due to safety concerns. The HomeDC trial is a double-blinded, placebo-controlled, parallel-group study. Patients with MDD (DSM-5) were randomized to active or sham tDCS. Patients conducted tDCS at home for 6 weeks with 5 sessions/week (30 min at 2 mA) anode over F3, cathode over F4. Sham tDCS resembled active tDCS, with ramp-in and ramp-out periods, but without intermittent stimulation. The study was prematurely terminated due to an accumulation of adverse events (AEs, skin lesions), so that only 11 patients were included. Feasibility was good. Safety monitoring was not sufficient enough to detect or prevent AEs within an appropriate timeframe. Regarding antidepressant effects, the reduction in depression scales over time was significant. However, active tDCS was not superior to sham tDCS in this regard. Both the conclusions from this review and the HomeDC trial show that there are several critical issues with the use of tDCS at home that need to be addressed. Nevertheless the array of transcranial electric simulation (TES) methods that this mode of application offers, including tDCS, is highly interesting and warrants further investigation in high quality RCTs.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov .

TRIAL REGISTRATION NUMBER

NCT05172505. Registration date: 12/13/2021, https://clinicaltrials.gov/ct2/show/NCT05172505 . *Consider, if feasible to do so, reporting the number of records identified from each database or register searched (rather than the total number across all databases/registers) **If automation tools were used, indicate how many records were excluded by a human and how many were excluded by automation tools From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. https://doi.org/10.1136/bmj.n71 . For more information, visit: http://www.prisma-statement.org/.

Computer vision-based algorithm to sUppoRt coRrect electrode placemeNT (CURRENT) for home-based electric non-invasive brain stimulation

OBJECTIVE

Home-based non-invasive brain stimulation (NIBS) has been suggested as an adjunct treatment strategy for neuro-psychiatric disorders. There are currently no available solutions to direct and monitor correct placement of the stimulation electrodes. To address this issue, we propose an easy-to-use digital tool to support patients for self-application.

METHODS

We recruited 36 healthy participants and compared their cap placement performance with the one of a NIBS-expert investigator. We tested participants' placement accuracy with instructions before (Pre) and after the investigator's placement (Post), as well as participants using the support tool (CURRENT). User experience (UX) and confidence were further evaluated.

RESULTS

Permutation tests demonstrated a smaller deviation within the CURRENT compared with Pre cap placement (p = 0.02). Subjective evaluation of ease of use and usefulness of the tool were vastly positive (8.04 out of 10). CURRENT decreased the variability of performance, ensured placement within the suggested maximum of deviation (10 mm) and supported confidence of correct placement.

CONCLUSIONS

This study supports the usability of this novel technology for correct electrode placement during self-application in home-based settings.

SIGNIFICANCE

CURRENT provides an exciting opportunity to promote home-based, self-applied NIBS as a safe, high-frequency treatment strategy that can be well integrated in patients' daily lives.

Transcranial Direct Current Stimulation in Nicotine Use: Nursing Implications for Patient Outcomes

ABSTRACT

Tobacco use is a leading cause of cancer, cardiovascular and respiratory disease, and preventable death in the United States. The brains of individuals with nicotine dependence are characterized by damaged mesolimbic pathways in the medial portion of the limbic and frontal lobes, creating positive reinforcing mechanisms. Transcranial direct current stimulation (tDCS) targets this neuroadaptation to improve smokers' nicotine-related outcomes, such as craving and smoking behavior, by depolarizing or hyperpolarizing the neurons of the brain. Recent literature reported promising outcomes in smokers after tDCS treatment interventions. tDCS has great potential for clinical nursing research for tobacco control given its multiple methodological advantages and few disadvantages. Nurse researchers can consider individualized and home-based tDCS interventions for community-based tobacco control research and may need to consider objective outcome measures (e.g., cotinine in urine) and addiction-related cognitive variables (e.g., self-regulation). Users of electronic nicotine delivery systems also need to be considered as participants in tDCS interventions. Additional considerations for nursing research are discussed.

Home-based tDCS for apathy in Alzheimer's disease: a protocol for a randomized double-blinded controlled pilot study

BACKGROUND

Apathy is among the most common behavioral symptoms in dementia and is consistently associated with negative outcomes in Alzheimer's disease (AD). Despite its prevalence and clinical relevance, available pharmacological and non-pharmacological strategies to treat apathy in AD have been marked, respectively, by potentially severe side effects and/or limited efficacy. Transcranial direct current stimulation (tDCS) is a relatively novel non-pharmacological method of neuromodulation with promising results. Compared to previous tDCS formats, recent technological advances have increased the portability of tDCS, which creates the potential for caregiver-administered, home use. Our study aims to evaluate the feasibility, safety, and efficacy of home-based tDCS for the treatment of apathy in AD.

METHODS/DESIGN

This is an experimenter- and participant-blinded, randomized, sham-controlled, parallel-group (1:1 for two groups) pilot clinical trial, involving 40 subjects with AD. After a brief training, caregivers will administer tDCS for participants at home under remote televideo supervision by research staff to ensure the use of proper technique. Participants will be assessed at baseline, during treatment (week 2, week 4, and week 6), and 6 weeks post-treatment. Dependent measures will cover cognitive performance, apathy, and other behavioral symptoms. Data about side effects and acceptability will also be collected.

DISCUSSION

Our study will address apathy, an overlooked clinical problem in AD. Our findings will advance the field of non-pharmacological strategies for neuropsychiatric symptoms, presenting a great potential for clinical translation.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04855643.

Feasibility, Acceptability, and Efficacy of Home-Based Transcranial Direct Current Stimulation on Pain in Older Adults with Alzheimer's Disease and Related Dementias: A Randomized Sham-Controlled Pilot Clinical Trial

Although transcranial direct current stimulation (tDCS) is emerging as a convenient pain relief modality for several chronic pain conditions, its feasibility, acceptability, and preliminary efficacy on pain in patients with Alzheimer's disease and related dementias (ADRD) have not been investigated. The purpose of this pilot study was to assess the feasibility, acceptability, and preliminary efficacy of 5, 20-min home-based tDCS sessions on chronic pain in older adults with ADRD. We randomly assigned 40 participants to active (n = 20) or sham (n = 20) tDCS. Clinical pain intensity was assessed using a numeric rating scale (NRS) with patients and a proxy measure (MOBID-2) with caregivers. We observed significant reductions of pain intensity for patients in the active tDCS group as reflected by both pain measures (NRS: Cohen's d = 0.69, p-value = 0.02); MOBID-2: Cohen's d = 1.12, p-value = 0.001). Moreover, we found home-based tDCS was feasible and acceptable intervention approach for pain in ADRD. These findings suggest the need for large-scale randomized controlled studies with larger samples and extended versions of tDCS to relieve chronic pain on the long-term for individuals with ADRD.

Self-administered transcranial direct current stimulation treatment of knee osteoarthritis alters pain-related fNIRS connectivity networks

Significance

Knee osteoarthritis (OA) is a disease that causes chronic pain in the elderly population. Currently, OA is mainly treated pharmacologically with analgesics, although research has shown that neuromodulation via transcranial direct current stimulation (tDCS) may be beneficial in reducing pain in clinical settings. However, no studies have reported the effects of home-based self-administered tDCS on functional brain networks in older adults with knee OA.

Aim

We used functional near-infrared spectroscopy (fNIRS) to investigate the functional connectivity effects of tDCS on underlying pain processing mechanisms at the central nervous level in older adults with knee OA.

Approach

Pain-related brain connectivity networks were extracted using fNIRS at baseline and for three consecutive weeks of treatment from 120 subjects randomly assigned to two groups undergoing active tDCS and sham tDCS.

Results

Our results showed that the tDCS intervention significantly modulated pain-related connectivity correlation only in the group receiving active treatment. We also found that only the active treatment group showed a significantly reduced number and strength of functional connections evoked during nociception in the prefrontal cortex, primary motor (M1), and primary somatosensory (S1) cortices. To our knowledge, this is the first study in which the effect of tDCS on pain-related connectivity networks is investigated using fNIRS.

Conclusions

fNIRS-based functional connectivity can be effectively used to investigate neural circuits of pain at the cortical level in association with nonpharmacological, self-administered tDCS treatment.

Application of Transcranial Direct Current Stimulation in Sleep Disturbances

Sleep disturbances are common across all age groups, and they encompass a broad range of impairments of daytime functioning and comorbid various clinical conditions. However, current treatment methods for sleep disturbances have several limitations. As the ‘top-down’ pathway is known to play an important role in sleep-wake regulation, and as neuronal activity abnormalities have been reported as a potential pathological mechanism of sleep disturbances, the use of non-invasive brain stimulation—such as transcranial direct current stimulation (tDCS) in treating sleep disturbances—has emerged. In the present review, we first explain the mechanism of tDCS, and we also introduce recent studies that have applied tDCS to sleep disorders, along with other sleep-related tDCS studies. In conclusion, many studies have achieved improvements in sleep state, although some of these studies have reported inconsistent effects of tDCS according to the protocol and the conditions used. Further studies are needed to explore the optimal protocols to use when applying tDCS in each sleep disturbance and to enhance the evidence on the clinical efficacy of tDCS.

Non-invasive brain stimulation for osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease, the prevalence of OA is increasing, and the elderly are the most common in patients with OA. OA has a severe impact on the daily life of patients, this increases the demand for treatment of OA. In recent years, the application of non-invasive brain stimulation (NIBS) has attracted extensive attention. It has been confirmed that NIBS plays an important role in regulating cortical excitability and oscillatory rhythm in specific brain regions. In this review, we summarized the therapeutic effects and mechanisms of different NIBS techniques in OA, clarified the potential of NIBS as a treatment choice for OA, and provided prospects for further research in the future.

Self-administered transcranial direct current stimulation for pain in older adults with knee osteoarthritis: A randomized controlled study

BACKGROUND

Knee osteoarthritis (OA) is a leading cause of pain in older adults. Previous studies indicated clinic-based transcranial direct current stimulation (tDCS) was effective to reduce pain in various populations, but no published studies have reported the efficacy of home-based self-administered tDCS in older adults with knee OA using a randomized clinical study.

OBJECTIVE

The purpose of this study was to evaluate the efficacy and feasibility of tDCS on clinical pain intensity in adults with knee OA pain.

METHODS

One hundred twenty participants aged 50-85 years with knee OA pain were randomly assigned to receive fifteen daily sessions of 2 mA tDCS for 20 min (n = 60) or sham tDCS (n = 60) over 3 weeks with remote supervision via telehealth. Clinical pain intensity was measured by the Numeric Rating Scale and Western Ontario and McMaster Universities Osteoarthritis Index. Also, we collected data on the tDCS experience via a questionnaire.

RESULTS

Participants (68% female) had a mean age of 66 years. Active tDCS significantly reduced pain intensity compared to sham tDCS after completion of the fifteen daily sessions (Cohen's d = 1.20; p-value < 0.0001). Participants showed high levels of satisfaction with their tDCS experience, and there have been no adverse events.

CONCLUSION

We demonstrated that home-based self-administered tDCS was feasible and reduced clinical pain intensity in older adults with knee OA, which can increase its accessibility. Future studies with multi-site randomized controlled trials are needed to validate our findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04016272.

Relieving Chronic Musculoskeletal Pain in Older Adults Using Transcranial Direct Current Stimulation: Effects on Pain Intensity, Quality, and Pain-Related Outcomes

Introduction

Chronic pain is a significant health problem and is particularly prevalent amongst the elderly. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has been proposed to reduce chronic pain. The aim of this study was to evaluate and compare the efficacy of active and sham tDCS in reducing pain in older individuals living with chronic musculoskeletal pain.

Materials and Methods

Twenty-four older individuals (mean age: 68 ± 7 years) suffering from chronic musculoskeletal pain were randomized to receive either anodal tDCS over the contralateral motor cortex (2 mA, 20 min; n = 12) or sham tDCS (20 min; n = 12) for five consecutive days. Pain logbooks were used to measure pain intensity. Questionnaires (McGill Pain Questionnaire, Brief Pain Inventory, Beck Depression Inventory [BDI], Beck Anxiety Inventory, Pain Catastrophizing Scale [PCS], and Margolis Pain Drawing and Scoring System [MPDSS]) were also used to assess pain in its globality.

Results

Analysis of pain logbooks revealed that active tDCS led to a reduction in daily average pain intensity (all p ≤ 0.04), while sham tDCS did not produce any change (p = 0.15). Between-group comparisons for change in pain intensity reduction between active and sham tDCS showed a trend during treatment (p = 0.08) which was significant at the follow-up period (p = 0.02). Active tDCS also improved scores of all questionnaires (all p ≤ 0.02), while sham tDCS only reduced MPDSS scores (p = 0.04). Between-group comparisons for the pain-related outcomes showed significant differences for BDI et PCS after the last tDCS session.

Conclusions

These results suggest that anodal tDCS applied over the primary motor cortex is an effective modality to decrease pain in older individuals. tDCS can also improve other key outcomes, such as physical and emotional functioning, and catastrophic thinking.

The Concept, Development, and Application of a Home-Based High-Definition tDCS for Bilateral Motor Cortex Modulation in Migraine and Pain

Whereas, many debilitating chronic pain disorders are dominantly bilateral (e.g., fibromyalgia, chronic migraine), non-invasive and invasive cortical neuromodulation therapies predominantly apply unilateral stimulation. The development of excitatory stimulation targeting bilateral primary motor (M1) cortices could potentially expand its therapeutic effect to more global pain relief. However, this is hampered by increased procedural and technical complexity. For example, repetitive transcranial magnetic stimulation (rTMS) and 4 × 1/2 × 2 high-definition transcranial direct current stimulation (4 × 1/2 × 2 HD-tDCS) are largely center-based, with unilateral-target focus-bilateral excitation would require two rTMS/4 × 1 HD-tDCS systems. We developed a system that allows for focal, non-invasive, self-applied, and simultaneous bilateral excitatory M1 stimulation, supporting long-term home-based treatment with a well-tolerated wearable battery-powered device. Here, we overviewed the most employed M1 neuromodulation methods, from invasive techniques to non-invasive TMS and tDCS. The evaluation extended from non-invasive diffuse asymmetric bilateral (M1-supraorbital [SO] tDCS), non-invasive and invasive unilateral focal (4 × 1/2 × 2 HD-tDCS, rTMS, MCS), to non-invasive and invasive bilateral bipolar (M1-M1 tDCS, MCS), before outlining our proposal for a neuromodulatory system with unique features. Computational models were applied to compare brain current flow for current laboratory-based unilateral M11 and bilateral M12 HD-tDCS models with a functional home-based M11-2 HD-tDCS prototype. We concluded the study by discussing the promising concept of bilateral excitatory M1 stimulation for more global pain relief, which is also non-invasive, focal, and home-based.

Transcranial direct current and transcranial magnetic stimulations for chronic pain

PURPOSE OF REVIEW

Chronic pain is debilitating and difficult to treat with pharmacotherapeutics alone. Consequently, exploring alternative treatment methods for chronic pain is essential. Noninvasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are increasingly being investigated for their neuropharmacological effects in the treatment of chronic pain. This review aims to examine and evaluate the present state of evidence regarding the use of tDCS and TMS in the treatment of chronic pain.

RECENT FINDINGS

Despite conflicting evidence in the early literature, evidence from recent rigorous research supports the use of tDCS and TMS in treating chronic pain conditions. For both tDCS and TMS, standardized stimulation parameters have been identified with the recommendation for repeated maintenance stimulation to ensure that the analgesic effect is sustained beyond discontinuation of therapy.

SUMMARY

Due to a lack of defined stimulation protocols, early findings on the efficacy of tDCS and TMS are mixed. Although the application of tDCS and TMS as pain relief approaches is still in its early stages, the introduction of standardized stimulation protocols is paving the way for more robust and informed research.

The effect of transcranial direct stimulation as an add-on treatment to conventional physical therapy on pain intensity and functional ability in individuals with knee osteoarthritis: A randomized controlled trial

OBJECTIVE

To investigate the effect of adding transcranial direct current stimulation (tDCS) to conventional physiotherapy treatment (PT) on pain and performance of individuals with knee osteoarthritis (KOA).

METHODS

Eighty people suffering from chronic KOA participated in this study. They were randomly divided into four treatment groups, including PT combined with tDCS over the primary motor cortex (M1), PT combined with tDCS over the primary sensory cortex (S1), PT combined with tDCS over the dorsolateral prefrontal cortex (DLPFC), and PT combined with sham tDCS. A visual analog scale (VAS) for pain intensity, the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire for knee-related disability, and several performance tests (stepping 15 s, chair stand test in 30 s, and walking 4 × 10 m) were used for assessment following 10 sessions of tDCS (T1), and one month after the last session of tDCS (T2).

RESULTS

Differential effects on pain intensity, knee-related disability, and performance were found between groups. Compared to sham tDCS: (i) tDCS over M1 improved VAS pain score, KOOS disability score, and performance tests at T1 and T2; (ii) tDCS over S1 improved VAS pain score at T1 and T2 and KOOS disability score and performance tests at T2; (iii) tDCS over the DLPFC improved VAS pain score at T1 and performance tests at T1 and T2.

CONCLUSION

tDCS could be a beneficial add-on treatment to conventional PT for pain relief, disability reduction and functional improvement in patients with KOA.

Correlation between pain severity and levels of anxiety and depression in osteoarthritis patients: a systematic review and meta-analysis

OBJECTIVES

Osteoarthritis (OA) is a chronic degenerative musculoskeletal disease that causes articular damage and chronic pain, with a prevalence of up to 50% in individuals >60 years of age. Patients suffering from chronic painful conditions, including OA, also frequently report anxiety or depression. A systematic review and meta-analysis were performed to assess the correlation between pain severity and depressive and anxious symptomatology in OA patients.

METHODS

A systematic search was conducted using four databases (PubMed, Medline, Scopus, and Web of Science) from inception up to 14th January of 2020. We included original articles evaluating pain severity and anxiety and/or depression severity in OA-diagnosed patients. Detailed data were extracted from each study, including patients' characteristics and pain, anxiety, and depression severity. When available, the Pearson correlation coefficient between pain and depression severity and pain and anxiety severity was collected and a meta-analysis of random effects was applied.

RESULTS

This systematic review included 121 studies, with a total of 38085 participants. The mean age was 64.3 years old and subjects were predominantly female (63%). The most used scale to evaluate pain severity was the Western Ontario and the McMaster Universities Osteoarthritis Index, while for anxiety and depression, the Hospital Anxiety and Depression Scale was the most used. The meta-analysis showed a moderate positive correlation between pain severity and both anxious (r = 0.31, p < 0.001) and depressive symptomatology (r = 0.36, p < 0.001).

CONCLUSIONS

Our results demonstrate a significant correlation between pain and depression/anxiety severity in OA patients, highlighting the need for its routine evaluation by clinicians.

Transcranial direct current stimulation for knee osteoarthritis: a single-blind randomized sham-controlled trial

OBJECTIVE

To evaluate the effects of transcranial direct current stimulation on pain and other symptoms of knee osteoarthritis.

METHODS

We performed a single-blind randomized sham-controlled trial with two parallel arms in an outpatient clinic of physical medicine and rehabilitation at a teaching hospital. We randomized 54 patients, 30-70 years of age, with knee osteoarthritis into two groups. They had morning stiffness ≤ 30 min, knee pain ≥ 3 months, joint crepitus, and Kellgren-Lawrence grade 1 or 2 on radiographs. For the active stimulation we administered 2 mA current, 20 min for each session and for the sham group 30 s stimulation and 20 min no current. Using the 10/20 International EEG system, the anode was fixed over the contralateral primary motor cortex (C3 or C4), and the cathode was placed on the ipsilateral supraorbital region (Fp1 or Fp2), with respect to the included knee. The program was repeated once daily over 5 consecutive days. Both groups received acetaminophen. We assessed the patients before and after the interventions, and three months post-intervention. The primary outcome was knee pain on the visual analog scale, and the secondary outcome was the Knee injury and Osteoarthritis Outcome Score.

RESULTS

There was a statistically significant reduction in the intensity of pain within sham and active groups (both p < 0.001), but no significant difference between the groups (p = 0.226). Analyses of the Knee injury and Osteoarthritis Outcome Scores showed no clinically important changes.

CONCLUSIONS

Transcranial direct current stimulation does not reduce knee pain, does not abate other symptoms, and does not restore knee function in patients with knee osteoarthritis. The pain reduction in our study could be attributed to either placebo or the acetaminophen effect.

Changes in Experimental Pain Sensitivity from Using Home-Based Remotely Supervised Transcranial Direct Current Stimulation in Older Adults with Knee Osteoarthritis

OBJECTIVE

The present study examined the effects of home-based remotely supervised transcranial direct current stimulation on quantitative sensory testing measurements in older adults with knee osteoarthritis. Participants were hypothesized to experience improved pain measurements over time.

DESIGN

Open-label, single-arm trial.

SETTING

Southeast Texas between March and November 2018 at a nursing school and participant homes.

SUBJECTS

Older adults (aged 50-85 years) with self-reported unilateral or bilateral knee osteoarthritis pain who met eligibility criteria set by the American College of Rheumatology.

METHODS

The intervention was applied with a constant current intensity for 20 minutes every weekday for two weeks (10 total sessions). Quantitative measures of pain were collected three times over 10 days (days 1, 5, and 10) and included heat threshold and tolerance, pressure pain threshold, punctate mechanical pain, pain, and conditioned pain modulation. Analyses used nonparametric tests to evaluate differences between day 1 and day 10. Generalized linear mixed models were then used to evaluate change across all three time points for each measure. Bayesian inference was used to provide the posterior probability of longitudinal effects.

RESULTS

Nonparametric tests found improvements in seven measures, and longitudinal models supported improvements in 10 measures, with some nonlinear effects.

CONCLUSIONS

The home-based, remotely supervised intervention improved quantitative measurements of pain in older adults with knee osteoarthritis. This study contributes to the growing body of literature supporting home-based noninvasive stimulation interventions.

Functional Near-Infrared Spectroscopy to Assess Central Pain Responses in a Nonpharmacologic Treatment Trial of Osteoarthritis

BACKGROUND AND PURPOSE

Knee osteoarthritis (OA) is a common source of pain in older adults. Although OA-induced pain can be relieved with analgesics and anti-inflammatory drugs, the current opioid epidemic is fostering the exploration of nonpharmacologic strategies for pain mitigation. Amongs these, transcranial direct current stimulation (tDCS) and mindfulness-based meditation (MBM) hold potential for pain-relief efficacy due to their neuromodulatory effects of the central nervous system, which is known to play a fundamental role in pain perception and processing.

METHODS

In this double-blind study, we used functional near-infrared spectroscopy (fNIRS) to investigate the effects of tDCS combined with MBM on underlying pain processing mechanisms at the central nervous level in older adults with knee OA. Nineteen subjects were randomly assigned to two groups undergoing a 10-day active tDCS and MBM regimen and a sham tDCS and MBM regimen, respectively.

RESULTS

Our results showed that the neuromodulatory intervention significantly relieved pain only in the group receiving active treatment. We also found that only the active treatment group showed a significant increase in oxyhemoglobin activation of the superior motor and somatosensory cortices colocated to the placement of the tDCS anodal electrode. To our knowledge, this is the first study in which the combined effect of tDCS and MBM is investigated using fNIRS.

CONCLUSION

In conclusion, fNIRS can be effectively used to investigate neural mechanisms of pain at the cortical level in association with nonpharmacological, self-administered treatments.

Age as a Mediator of tDCS Effects on Pain: An Integrative Systematic Review and Meta-Analysis

Introduction: The transcranial direct current stimulation (tDCS) is a neuromodulatory technique with the potential to decrease pain scores and to improve chronic pain treatment. Although age is an essential factor that might impact the tDCS effect, most studies are solely conducted in adults. Therefore, the age limitation presents a critical research gap in this field and can be shown by only a handful of studies that have included other age groups. To examine the evidence upon the tDCS effect on pain scores on children, adolescents, or elderly, and indirectly, to infer the age-dependent impact on tDCS effects, we conducted a systematic review and meta-analysis.

Methods: A systematic review searching the following databases: PubMed, EMBASE, and Science Direct using the following search terms adapted according to MeSh or Entree: [(“Adolescent” OR “Children” OR “Elderly”) AND (“tDCS”) AND (“Pain” OR “Pain threshold”) AND (“dorsolateral prefrontal cortex” OR “Motor cortex)] up to April 20th, 2020. We retrieved 228 articles, 13 were included in the systematic review, and five studies with elderly subjects that had their outcomes assessed by pain score or pain threshold were included in the meta-analysis.

Results: For the analysis of pain score, 96 individuals received active stimulation, and we found a favorable effect for active tDCS to reduce pain score compared to sham (P = 0.002). The standardized difference was −0.76 (CI 95% = −1.24 to −0.28). For the pain threshold, the analysis showed no significant difference between active and sham tDCS. We reviewed two studies with adolescents: one study using anodal tDCS over the prefrontal cortex reported a reduction in pain scores. However, the second study reported an increase in pain sensitivity for the dorsolateral prefrontal cortex (DLPFC) stimulation.

Conclusion: Our findings suggest tDCS may reduce pain levels in the elderly group. Nevertheless, the small number of studies included in this review—and the considerable heterogeneity for clinical conditions and protocols of stimulation present—limits the support of tDCS use for pain treatment in elderly people. Larger studies on the tDCS effect on pain are needed to be conducted in elderly and adolescents, also evaluating different montages and electrical current intensity.

Randomized clinical trial comparing of transcranial direct current stimulation (tDCS) and transcutaneous electrical nerve stimulation (TENS) in knee osteoarthritis

BACKGROUND

Due to the limitations of pharmacological and surgical management of knee osteoarthritis (OA), several non-pharmacologic approaches including transcutaneous electrical nerve stimulation (TENS) and transcranial direct current stimulation (tDCS) have been introduced, with promising results.

OBJECTIVE

We aimed to investigate and compare the therapeutic effects of TENS and tDCS for the treatment of patients with knee OA.

METHODS

In this double-blinded randomized controlled trial, a total of 40 adult patients with knee OA were randomly allocated to either the TENS or the tDCS group. Patients in either group received 6 sessions of the TENS or tDCS for 2 weeks. Knee strengthening exercises were performed twice daily for the entire treatment period. Patients were evaluated using the visual analogue scale (VAS) and Western Ontario and McMaster Universities (WOMAC).

RESULTS

Significant improvement was observed in all outcomes in both TENS and tDCS groups at each follow up compared to baseline although the early improvement (first follow-up) in the WOMAC index was not significant in the TENS group. Based on the within-subject analysis, the behavior of two treatment groups did not differ regarding the changes in the course of the VAS, WOMAC score and its subscales, i.e. stiffness, pain and function (p = 0.263, 0.051, 0.198, 0.075, and 0.146, respectively).

CONCLUSIONS

Based on the results of this study, the effect of tDCS and TENS was not significantly different on pain and function of patients with knee OA.

Methods and strategies of tDCS for the treatment of pain: current status and future directions

INTRODUCTION

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique that has been widely studied for the treatment of chronic pain. It is considered a promising and safe alternative pain therapy. Different targets have been tested, each having their own particular mechanisms for modulating pain perception.

AREAS COVERED

We discuss the current state of the art of tDCS to manage pain and future strategies to optimize tDCS' effects. Current strategies include primary motor cortex tDCS, prefrontal tDCS and tDCS combined with behavioral interventions while future strategies, on the other hand, include high-intensity tDCS, transcutaneous spinal direct current stimulation, cerebellar tDCS, home-based tDCS, and tDCS with extended number of sessions.

EXPERT COMMENTARY

It has been shown that the stimulation of the prefrontal and primary motor cortex is efficient for pain reduction while a few other new strategies, such as high-intensity tDCS and network-based tDCS, are believed to induce strong neuroplastic effects, although the underlying neural mechanisms still need to be fully uncovered. Hence, conventional tDCS approaches demonstrated promising effects to manage pain and new strategies are under development to enhance tDCS effects and make this approach more easily available by using, for instance, home-based devices.

Longitudinal effect of transcranial direct current stimulation on knee osteoarthritis patients measured by functional infrared spectroscopy: a pilot study

Significance: Knee osteoarthritis (OA) is a common joint disease causing chronic pain and functional alterations (stiffness and swelling) in the elderly population. OA is currently treated pharmacologically with analgesics, although neuromodulation via transcranial direct current stimulation (tDCS) has recently generated a growing interest as a safe side-effect free treatment alternative or a complement to medications for chronic pain conditions. Although a number of studies have shown that tDCS has a beneficial effect on behavioral measures of pain, the mechanistic action of neuromodulation on pain sensitivity and coping at the central nervous system is not well understood. Aim: We aimed at observing longitudinal changes of cortical hemodynamics in older adults with knee OA associated with a two-week-long tDCS self-treatment protocol. Approach: Hemodynamics was measured bilaterally in the motor and somatosensory cortices with functional near-infrared spectroscopy (fNIRS) in response to thermal pain induced ipsilaterally to the knee primarily affected by OA. Results: We found that both oxyhemoglobin- and deoxyhemoglobin-related functional activations significantly increased during the course of the tDCS treatment, supporting the notion that tDCS yields an increased cortical excitability. Concurrently, clinical measures of pain decreased with tDCS treatment, hinting at a potential spatial dissociation between cortically mediated pain perception and suppression and the prevalence of neuromodulatory effects over cortical pain processing. Conclusions: fNIRS is a valid method for objectively tracking pain in an ambulatory setting and it could potentially be used to inform strategies for optimized tDCS treatment and to develop innovative tDCS protocols.