Has your hospital done one damn thing with tDCS in the past decade?
Well then write this up as a protocol AND DISTRIBUTE it to all stroke hospitals in the world. This is your responsibility since our fucking failures of stroke associations are DOING NOTHING FOR SURVIVORS.
Is anyone ever going to put together a protocol on using tDCS and which type? Otherwise all this fucking research and reviews are totally worthless. This is why we need strong stroke leadership, to actually help stroke survivors.
HD-tDCS (7 posts to January 2013)
cathodal tDCS (6 posts to February 2018)
anodal tDCS (23 posts to August 2015)
tDCS (94 posts to April 2011)
Transcranial Direct Current Stimulation in StrokeRehabilitation: A Review of Recent Advancements
Abstract
Transcranial direct current stimulation (tDCS) is a promising technique to treat a wide range of neurological conditions including stroke. The pathological processes following stroke may provide an exemplary system to investigate how tDCS promotes neuronal plasticity and functional recovery. Changes in synaptic function after stroke, such as reduced excitability, formation of aberrant connections, and deregulated plastic modifications, have been postulated to impede recovery from stroke. However, if tDCS could counteract these negative changes by influencing the system’s neurophysiology, it would contribute to the formation of functionally meaningful connections and the maintenance of existing pathways. This paper is aimed at providing a review of underlying mechanisms of tDCS and its application to stroke. In addition, to maximize the effectiveness of tDCS in stroke rehabilitation, future research needs to determine the optimal stimulation protocols and parameters. We discuss how stimulation parameters could be optimized based on electrophysiological activity. In particular, we propose that cortical synchrony may represent a biomarker of tDCS efficacy to indicate communication between affected areas. Understanding the mechanisms by which tDCS affects the neural substrate after stroke and finding ways to optimize tDCS for each patient are key to effective rehabilitation approaches.
1. Introduction
Poststroke consequences including sensorimotor and cognitive impairments impose a stressful situation and a great burden to the victims, their families, and the society. Indeed, stroke is one of the leading causes of adult disability in the western world [1]. Among extensive efforts devoted to the search for more effective rehabilitation therapies of stroke, the idea of using electricity can be traced back almost a century ago (as noted by Priori [2]). After diminished interest due to mixed results, recent studies with promising results regained the interest in the application of mild electrical currents to the brain as a potential therapy for neurological disorders [2]. Research by Priori [2, 3] and Nitsche and colleagues [4–6] led to the development of a technique consisting of the application of weak electrical currents through the scalp, which is now called transcranial direct current stimulation (tDCS). Recent findings suggest that tDCS may be beneficial in a wide range of disorders such as epilepsy [7, 8], Parkinson’s disease [9–11], chronic pain [12–14], depression [15], drug cravings [16], pain conditions such as fibromyalgia [17–19], and traumatic spinal cord injuries [12, 20, 21]. Over the past few years, the potential therapeutic benefit of tDCS for improvement of cerebral function after stroke has also been reported [22–28]. Nevertheless, more evidence is needed in order to consider tDCS as a standard therapeutic technique to help patients with stroke and other brain disorders.
The modulation of cortical excitability by tDCS has gained particular interest because of its beneficial neurorehabilitative effects after stroke [29]. However, neither the detailed mechanisms of how tDCS facilitates recovery from stroke nor optimal parameters of stimulation are well understood yet, thus limiting the tDCS application to stroke patients [30]. Elucidation of the physiological mechanisms of tDCS and the optimization toward the need for stroke rehabilitation would be crucial in successful use of this therapy [31]. This paper will, therefore, focus on the physiological effects of tDCS and their implications in stroke rehabilitation.
After stroke, considerable modifications in synaptic organization and plasticity take place. They may account for some of the spontaneous recovery in the loss of sensation, movement, or cognition following stroke [32]. It has been suggested that increased general cortical excitability as well as modifications in synaptic plasticity such as LTP-like modulation, increments in calcium currents, and activation of neurotrophic factors in the affected hemisphere are relevant mechanisms for stroke recovery [32]. However, it should be noted that these effects might be region-specific and could be related to the orientation of the stimulated fibers. In addition, different protocols of stimulation, electrode position, and current polarization make it difficult to determine the appropriate parameters for stroke rehabilitation [31]. Due to the significant reorganization of neuronal connections after stroke, it would also be necessary to evaluate the effects of tDCS as a function of post-infarct interval.
This paper will summarize recent findings that support tDCS as a suitable complementary rehabilitative technique to promote stroke recovery. We will also discuss the possibility of determining stimulation parameters based on electrophysiological activity. We propose that if stimulation protocols can be adjusted to individual needs, tDCS would become a more effective therapy to support recovery from stroke.
2. General Considerations of the Technique
A detailed description of the methodological procedure has been published in numerous previous publications [2–6, 30, 33–36]. Generally, tDCS protocols utilize two surface electrodes, one serving as the anode and the other one as the cathode or reference, although other configurations have been also reported [37, 38]. The position of the electrodes appears to be critical for the spatial distribution and direction of the flow of the current which may determine the effectiveness of the stimulation. It is generally agreed that anodal tDCS has an excitatory effect on the local cerebral cortex by depolarizing neurons, while the converse applies to the cathode through the process of hyperpolarization (Figure 1(a)). Typically these electrodes have relatively large surfaces of 20–35 mm2 that limit the focus of stimulation. On the other hand, the large surface allows the use of low current densities, which constitutes one of the critical parameters for patient safety [5].
(a)
(b)
(c)
It has also been widely accepted that the surface area of the electrodes determines the outcome of transcranial stimulation [41]. For example, increasing the surface area of the reference electrode and reducing the surface of the stimulation electrode allow for more focal treatment effects [42]. Increasing the distance between the electrodes has been shown to enhance the current flow into the brain and the depth of the current density [37]. Maintaining low current densities is important to prevent patient's discomfort and allows application of tDCS for long periods of time [4]. A direct current of 1-2 mA has been generally applied for a timespan ranging between 8 and 30 min. Approximately 45% of this range of the current delivered to the skull reaches the surface of the cortex [6].
In order to evaluate the nureophysiological effects of tDCS in stroke rehabilitation, clinical and preclinical studies need to be accompanied by animal model studies. So far, there has been proposed multiple approaches to study electrophysiological effects of direct current stimulation in animals [40, 43–49]. In this paper, we included the results of those studies in animal models, but it is important to note that some of the animal studies are not strictly comparable to the human tDCS method. For example, to achieve more localized effects, in animal studies electrodes may be placed on the top of the dura mater or intracortically, thus making it more difficult to directly relate to human tDCS.
In summary, tDCS has been shown to be easy to apply, inexpensive, and portable. It can be applied simultaneously with other rehabilitation therapies and can potentially affect a range of neuronal networks.
More at link.
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