[Editorial] Introducing the thematic series on transcranial direct current stimulation (tDCS) for motor rehabilitation: on the way to optimal clinical use

Introduction

Transcranial direct current stimulation (tDCS) is a method of noninvasive brain stimulation that directs a constant low amplitude electric current through scalp electrodes. tDCS has been shown to modulate excitability in both cortical and subcortical brain areas [1, 2], with anodal tDCS leading to increased neuronal excitability and cathodal tDCS inversely leading to reduced neuronal excitability. tDCS can also modulate blood flow (i.e. oxygen supply to cortical and subcortical areas [3]) and neuronal synapsis strength [4], triggering plasticity processes (i.e. long-term potentiation and long-term depression). There is growing interest in using tDCS as a low-cost, non-invasive brain stimulation option for a wide range of potential clinical applications. Advantages of tDCS over other methods of non-invasive brain stimulation include favorable safety and tolerability profiles and its portability and applicability.

The use of tDCS in motor rehabilitation for neurological diseases as well as in healthy ageing is a growing area of therapeutic use. Although the results of tDCS interventions for motor rehabilitation are still preliminary, they encourage further research to better understand its therapeutic utility and to inform optimal clinical use. Therefore, The Journal of NeuroEngineering and Rehabilitation (JNER. https://jneuroengrehab.biomedcentral.com/) is pleased to present the thematic series entitled “tDCS application for motor rehabilitation”.

The goal of this thematic series is to increase the awareness of academic and clinical communities to different potential applications of tDCS for motor rehabilitation. Experts in the field were invited to submit experimental or review studies. A call for papers was also announced to reach those interested in contributing to this thematic series. This collection of articles was thought to present the most recent advances in tDCS for motor rehabilitation, addressing topics such as theoretical, methodological, and practical approaches to be considered when designing tDCS-based rehabilitation. The targeted disorders include but are not limited to: stroke, Parkinson’s disease, Cerebral Palsy, cerebellar ataxia, trauma, Multiple Sclerosis.

tDCS – A promising clinical tool for motor rehabilitation

tDCS has been used in experimental and clinical neuroscience for the study of brain functions and treatment in a range of disorders of the central nervous system. Of particular interest to this thematic series, a growing body of evidence suggest that tDCS has potential to become a clinical tool for motor rehabilitation.

The existing tDCS protocols using well-defined montages, stimulus durations and intensities are safe and well tolerated by both healthy individuals and clinical populations. There are no reported indications of any serious adverse effects, such as damage of brain tissue or seizure induction, with the use of 1–2 mA protocols [5, 6, 7]. The most commonly reported adverse effects included redness, tingling and itching sensations under the electrodes, as well as headache [6, 8]. Moreover, the overall adverse effect rates are similar between active and sham tDCS [6], which suggests that the mild adverse effects are related to electrode positioning on the skin and not the stimulation itself.

As tDCS is portable, devices can easily be transported, which circumvents accessibility barriers to health care (i.e. tDCS can easily be moved into clinics or wards). It can be implemented in combination with other kinds of interventions, such as cognitive or physical training or exercise, with this pairing possibly leading to synergistic benefit [9]. Although accumulating evidence highlights potential benefits offered by tDCS for motor rehabilitation, further research is required for tDCS to become an approved clinical tool. The majority of existing clinical trials has involved a limited number of participants, which may imply underpowered analysis. Thus, large-scale studies are needed to overcome this major flaw.

Due to the potential for self- or caregiver-application, remotely supervised protocols have been developed and recently found feasible for those with motor impairment [10]. However, these studies employ highly structured protocols and rigorous criteria with real time supervision via teleconference, and do not support a “do-it-yourself” tDCS practice. Instead, the remotely supervised protocols can be used to facilitate the clinical trial designs that are necessary in order to advance tDCS towards therapeutic use.

Data on optimal protocols and predictors of response to tDCS are currently lacking in the literature. Future studies in this field should focus on determining the optimal stimulation parameters and predictors of response to tDCS in different clinical populations. It seems that one size does not fit all in tDCS. However, previous studies may be limited, as standard clinical assessments may miss subtle motor improvements. Future outcomes for determining the effectiveness of tDCS for motor rehabilitation need to be robust. Therefore, combining tDCS protocols with other validated mobile technologies to monitor motor performance, such as wearable inertial sensors or innovative Internet of Things devices, may provide important insight into effectiveness within clinic and beyond.

Despite the positive progression of research to clinical practice, there are still questions to be answered before tDCS can be extensively recommended for motor rehabilitation.

• What is the ideal intensity and duration of the session?

• How many sessions are required?

• What is the ideal interval between sessions?

• What about patients’ characteristics?

• Who will benefit from tDCS?

• Do specific demographic characteristics lead to greater benefits?

Final considerations

We hope the accepted papers will contribute meaningfully to the body of knowledge in the field of tDCS for motor rehabilitation and that they will motivate the development of further research. Additionally, we hope this thematic series will assist both researchers and clinical professionals in making decisions for the achievement of optimal benefits throughout tDCS.

References

1. 1.
   Bolzoni F, Pettersson L-G, Jankowska E. Evidence for long-lasting subcortical facilitation by transcranial direct current stimulation in the cat. J Physiol [Internet]. 2013 [cited 2018 Nov 10];591:3381–3399. Available from: http://doi.wiley.com/10.1113/jphysiol.2012.244764.
2. 2.
   Nitsche MA, Paulus W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. J Physiol [Internet]. 2000 [cited 2018 Nov 10];527 Pt 3:633–639. Available from: http://www.ncbi.nlm.nih.gov/pubmed/10990547.
3. 3.
   Zheng X, Alsop DC, Schlaug G. Effects of transcranial direct current stimulation (tDCS) on human regional cerebral blood flow. Neuroimage [Internet]. 2011 [cited 2019 Feb 14];58:26–33. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21703350.
4. 4.
   Polanía R, Paulus W, Antal A, Nitsche MA. Introducing graph theory to track for neuroplastic alterations in the resting human brain: a transcranial direct current stimulation study. Neuroimage [Internet]. 2011 [cited 2019 Feb 14];54:2287–2296. Available from: https://linkinghub.elsevier.com/retrieve/pii/S1053811910012875.
5. 5.
   Woods AJ, Antal A, Bikson M, Boggio PS, Brunoni AR, Celnik P, et al. A technical guide to tDCS, and related non-invasive brain stimulation tools. Clin Neurophysiol [Internet] 2016 [cited 2018 Nov 10];127:1031–1048. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26652115.
6. 6.
   Moffa AH, Brunoni AR, Fregni F, Palm U, Padberg F, Blumberger DM, et al. Safety and acceptability of transcranial direct current stimulation for the acute treatment of major depressive episodes: Analysis of individual patient data. J Affect Disord [Internet]. 2017 [cited 2018 Nov 10];221:1–5. Available from: http://www.ncbi.nlm.nih.gov/pubmed/28623732.
7. 7.
   Bikson M, Grossman P, Thomas C, Zannou AL, Jiang J, Adnan T, et al. Safety of transcranial direct current stimulation: evidence based update 2016. Brain Stimul [Internet] 2016 [cited 2018 Nov 10];9:641–661. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27372845.
8. 8.
   Fertonani A, Ferrari C, Miniussi C. What do you feel if I apply transcranial electric stimulation? Safety, sensations and secondary induced effects. Clin Neurophysiol [Internet]. 2015 [cited 2018 Nov 10];126:2181–2188. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25922128.
9. 9.
   Kaski D, Dominguez R, Allum J, Islam A, Bronstein A. Combining physical training with transcranial direct current stimulation to improve gait in Parkinson’s disease: a pilot randomized controlled study. Clin Rehabil [Internet]. 2014 [cited 2018 Nov 10];28:1115–24. Available from: http://www.ncbi.nlm.nih.gov/pubmed/24849794.
10. 10.
    Agarwal S, Pawlak N, Cucca A, Sharma K, Dobbs B, Shaw M, et al. Remotely-supervised transcranial direct current stimulation paired with cognitive training in Parkinson’s disease: An open-label study. J Clin Neurosci [Internet]. 2018 [cited 2018 Nov 10];57:51–57. Available from: http://www.ncbi.nlm.nih.gov/pubmed/30193898.

via Introducing the thematic series on transcranial direct current stimulation (tDCS) for motor rehabilitation: on the way to optimal clinical use | SpringerLink

[Abstract] A low cost virtual reality system for home based rehabilitation of the arm following stroke: a randomised controlled feasibility trial

Abstract

OBJECTIVE: To assess the feasibility of conducting a randomised controlled trial of a home-based virtual reality system for rehabilitation of the arm following stroke.

DESIGN: Two group feasibility randomised controlled trial of intervention versus usual care.

SETTING: Patients’ homes.

PARTICIPANTS: Patients aged 18 or over, with residual arm dysfunction following stroke and no longer receiving any other intensive rehabilitation.

INTERVENTIONS: Eight weeks’ use of a low cost home-based virtual reality system employing infra-red capture to translate the position of the hand into game play or usual care.

MAIN MEASURES: The primary objective was to collect information on the feasibility of a trial, including recruitment, collection of outcome measures and staff support required. Patients were assessed at three time points using the Wolf Motor Function Test, Nine-Hole Peg Test, Motor Activity Log and Nottingham Extended Activities of Daily Living.

RESULTS: Over 15 months only 47 people were referred to the team. Twenty seven were randomised and 18 (67%) of those completed final outcome measures. Sample size calculation based on data from the Wolf Motor Function Test indicated a requirement for 38 per group. There was a significantly greater change from baseline in the intervention group on midpoint Wolf Grip strength and two subscales of the final Motor Activity Log. Training in the use of the equipment took a median of 230 minutes per patient.

CONCLUSIONS: To achieve the required sample size, a definitive home-based trial would require additional strategies to boost recruitment rates and adequate resources for patient support.

via A low cost virtual reality system for home based rehabilitation of the arm following stroke: a randomised controlled feasibility trial

[Abstract] Virtual Activities of Daily Living for Recovery of Upper Extremity Motor Function

Abstract

A study was conducted to investigate the effectiveness of virtual activities of daily living (ADL) practice using the SaeboVR software system for the recovery of upper extremity (UE) motor function following stroke. The system employs Kinect sensor-based tracking to translate human UE motion into the anatomical pose of the arm of the patient’s avatar within a virtual environment, creating a virtual presence within a simulated task space. Patients gain mastery of 12 different integrated activities while traversing a metaphorical ‘road to recovery’ that includes thematically linked levels and therapist-selected difficulty settings. Clinical trials were conducted under the study named Virtual Occupational Therapy Application. A total of 15 chronic phase stroke survivors completed a protocol involving three sessions per week over eight weeks, during which they engaged in repetitive task practice through performance of the virtual ADLs. Results show a clinically important improvement and statistically significant difference in Fugl-Meyer UE assessment scores in the study population of chronic stroke survivors over the eight-week interventional period compared with a non-interventional control period of equivalent duration. Statistically significant and clinically important improvements are also found in the wolf motor function test scores. These results provide new evidence for the use of virtual ADL practice as a tool for UE therapy for stroke patients. Limitations of the study include non-blinded assessments and the possibility of selection and/or attrition bias. © 2017 IEEE.

 

via Scopus preview – Scopus – Document details

[ARTICLE] Visualisation of two-dimensional kinematic data from bimanual control of a commercial gaming system used in post-stroke rehabilitation – Full Text PDF

Abstract

Kinematic data from two stroke participants and a healthy control were collected using a novel bimanual rehabilitation system. The system employs two customized PlayStation Move Controllers and an Eye camera to track the participants’ hand movements.

In this study, the participants played a Facebook game by symmetrically moving both hands to control the computer’s mouse cursor. The collected data were recorded during one game session, and movement distribution analysis was performed to create density plots of each participant’s hand motion in the XY plane.

This type of kinematic information that can be gathered by rehabilitation systems with motion tracking capabilities has the potential to be used by therapists to monitor and guide home-based rehabilitation programs.

Full Text PDF

[ARTICLE] The HAAPI (Home Arm Assistance Progression Initiative) Trial

Abstract

Background. Geographical location, socioeconomic status, and logistics surrounding transportation impede access of poststroke individuals to comprehensive rehabilitative services. Robotic therapy may enhance telerehabilitation by delivering consistent and state-of-the art therapy while allowing remote monitoring and adjusting therapy for underserved populations. The Hand Mentor Pro (HMP) was incorporated within a home exercise program (HEP) to improve upper-extremity (UE) functional capabilities poststroke.

Objective. To determine the efficacy of a home-based telemonitored robotic-assisted therapy as part of a HEP compared with a dose-matched HEP-only intervention among individuals less than 6 months poststroke and characterized as underserved.

Methods. In this prospective, single-blinded, multisite, randomized controlled trial, 99 hemiparetic participants with limited access to UE rehabilitation were randomized to either (1) the experimental group, which received combined HEP and HMP for 3 h/d ×5 days ×8 weeks, or (2) the control group, which received HEP only at an identical dosage. Weekly communication between the supervising therapist and participant promoted compliance and progression of the HEP and HMP prescription. The Action Research Arm Test and Wolf Motor Function Test along with the Fugl-Meyer Assessment (UE) were primary and secondary outcome measures, respectively, undertaken before and after the interventions.

Results. Both groups demonstrated improvement across all UE outcomes.

Conclusions. Robotic + HEP and HEP only were both effectively delivered remotely. There was no difference between groups in change in motor function over time. Additional research is necessary to determine the appropriate dosage of HMP and HEP.

via The HAAPI (Home Arm Assistance Progression Initiative) Trial.

[WEB SITE] Stem cells show promise for stroke in pilot study

…A stroke therapy using stem cells extracted from patients’ bone marrow has shown promising results in the first trial of its kind in humans.

Five patients received the treatment in a pilot study conducted by doctors at Imperial College Healthcare NHS Trust and scientists at Imperial College London.

The therapy was found to be safe, and all the patients showed improvements in clinical measures of disability.

The findings are published in the journal Stem Cells Translational Medicine. It is the first UK human trial of a stem cell treatment for acute stroke to be published.

The therapy uses a type of cell called CD34+ cells, a set of stem cells in the bone marrow that give rise to blood cells and blood vessel lining cells. Previous research has shown that treatment using these cells can significantly improve recovery from stroke in animals. Rather than developing into brain cells themselves, the cells are thought to release chemicals that trigger the growth of new brain tissue and new blood vessels in the area damaged by stroke…

Stem cells show promise for stroke in pilot study.

[ARTICLE] A Pilot Study of an Android-Based Game: Stroke Patient Rehabilitation

Abstract

Background Cerebral vascular accidents (strokes) are the primary cause of disability worldwide and the second leading cause of death both in the Philippines and internationally. In recent years, a number of computer-based applications have been developed to assist in the stroke recovery process.

Aim This article discusses an Android-based tablet game, FINDEX, that aids in the rehabilitation process of stroke survivors with impaired fine motor skills.

Method FINDEX was designed and developed in the Philippines. The game contains assessment and monitoring support for tracking the patient’s progress in terms of fine finger dexterity, for example, finger control, isolation and coordination, and range of motions. The baselines for data comparison and analysis were gathered through an initial test with subjects with normal hand function. Three stroke survivors then participated in a pilot study, using the game for a total of nine testing sessions.

Results Objective measures showed that patients’ dexterity did in fact improve, although it is not possible to draw strong conclusions because of the small sample size. In subsequent interviews, patients indicated that they believed that the games helped in their recovery and said that they preferred playing with the game over performing the standard therapeutic activities.

Conclusion The development of this game and the preliminary findings from the pilot study suggest that games may indeed be effective instruments for therapy.

via Stroke Patient Rehabilitation.