Difference between revisions of "Transcranial direct-current stimulation"

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== Main Characteristics ==
 
== Main Characteristics ==
  
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The tDCS is done by putting two or more electrodes on the scalp and running weak direct current between them so the current passes through the brain. Different areas of the brain can be affected based on the position of the electrodes. Depending on whether the stimulation is anodal or cathodal, the neuronal resting membrane potential is either depolarized or hyperpolarized respectively. Anodal stimulation enhances excitability, while cathodal stimulation has opposite results. The efficacy of the technique closely depends on the strength of the generated electrical field. Clinically, tDCS is usually administered via two sponge electrodes soaked in a saline solution for conductibility.<ref>NITSCHE, M. A.; PAULUS, W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. The Journal of physiology, 2000, 527.3: 633-639.</ref><ref name="Principle and mechanisms"/>  
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tDCS is done by putting two or more electrodes on the scalp and running weak direct current between them so the current passes through the brain. Different areas of the brain can be affected based on the position of the electrodes. Depending on whether the stimulation is anodal or cathodal, the neuronal resting membrane potential is either depolarized or hyperpolarized, respectively. Anodal stimulation enhances excitability, while cathodal stimulation produces opposite results. The efficacy of the technique closely depends on the strength of the generated electrical field. Clinically, tDCS is usually administered via two sponge electrodes soaked in a saline solution for conductibility.<ref>NITSCHE, M. A.; PAULUS, W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. The Journal of physiology, 2000, 527.3: 633-639.</ref><ref name="Principle and mechanisms"/>  
  
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Prolonged sessions of tDCS result in long-lasting after-effects that may last hours. The mechanism of tDCS outlasting effect is predominantly caused by the induction of synaptic changes, especially in glutamatergic and gamma-aminobutyric acid (GABA) neurons. tDCS also modulates resting membrane potential generally along the whole axons, this may result in non-synaptic mechanism, which might contribute to the long-lasting effect of tDCS in intracortical and corticospinal neurons.<ref name="ardolino">ARDOLINO G., BOSSI B., BARBIERI S., PRIORI A. Non-synaptic mechanisms underlie the after-effects of cathodal transcutaneous direct current stimulation of the human brain. "Journal of Physiology" 2005, 568: 653-63.</ Available online at: http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2005.088 (Retrieved 23th April, 2017)</ref> tDSC might also elicit changes in non-neuronal tissues in the brain, including vessels and connective tissues.<ref name="brunoni" />
+
Prolonged sessions of tDCS result in long-lasting after-effects that may last for hours. The mechanism of tDCS outlasting effect is predominantly caused by the induction of synaptic changes, especially in glutamatergic and gamma-aminobutyric acid (GABA) neurons. tDCS also modulates resting membrane potential generally along the whole axons, this may result in non-synaptic mechanism, which might contribute to the long-lasting effect of tDCS in intracortical and corticospinal neurons.<ref name="ardolino">ARDOLINO G., BOSSI B., BARBIERI S., PRIORI A. Non-synaptic mechanisms underlie the after-effects of cathodal transcutaneous direct current stimulation of the human brain. "Journal of Physiology" 2005, 568: 653-63.</ Available online at: http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2005.088 (Retrieved 23th April, 2017)</ref> tDSC might also elicit changes in non-neuronal tissues in the brain, including vessels and connective tissues.<ref name="brunoni" />
  
 
=== Historical overview ===
 
=== Historical overview ===
 
[[File:Tdcs stimulation2.jpg|thumbnail|right|A schematics showing how tDCS works.]]
 
[[File:Tdcs stimulation2.jpg|thumbnail|right|A schematics showing how tDCS works.]]
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The ability of the electrical current to influence human cognition, especially the perception of pain, has been observer since the 48 CE by the Roman court physician Scribonius Largus. He observed that placing a live fish of the order Torpediniformes, able to deliver electric discharge of up to 220 V, can ease the pain of the headaches his patients suffered. Other great physicians such as Pliny the Elder, Claudius Galen, or Ibn-Sidah noted the beneficial effects of these animals in their works as well. The study of electric rays inspired Luigi Galvani and Alessandro Volta to experiment with the effects of electrical current on human physiology.<ref name="priori">PRIORI, Alberto. Brain polarization in humans: A reappraisal of an old tool for prolonged non-invasive modulation of brain excitability. Clinical Neurophysiology. 2003. '''114'''(4), p. 589–595. Doi: 10.1016/S1388-2457(02)00437-6.</ref> Galvani’s nephew Giovanni Aldini reported the successful treatment of patients suffering from melancholia.<ref>PARENT, André. Giovanni Aldini: from animal electricity to human brain stimulation. The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques. 2004. '''31'''(4), p. 576–584. Doi: 10.1017/S0317167100003851.</ref> He noted, after testing his device on himself first, that the stimulation is rather unpleasant and it's effects lasted for several days:
+
The ability of electrical current to influence human cognition, especially the perception of pain, has been observed since 48 CE by the Roman court physician Scribonius Largus. He observed that placing a live fish of the order Torpediniformes, able to deliver electric discharges of up to 220 V, on patients could ease the pain of the headaches his patients suffered. Other great physicians such as Pliny the Elder, Claudius Galen, and Ibn-Sidah noted the beneficial effects of these animals in their works as well. The study of electric rays inspired Luigi Galvani and Alessandro Volta to experiment with the effects of electrical current on human physiology.<ref name="priori">PRIORI, Alberto. Brain polarization in humans: A reappraisal of an old tool for prolonged non-invasive modulation of brain excitability. Clinical Neurophysiology. 2003. '''114'''(4), p. 589–595. Doi: 10.1016/S1388-2457(02)00437-6.</ref> Galvani’s nephew Giovanni Aldini reported the successful treatment of patients suffering from melancholia.<ref>PARENT, André. Giovanni Aldini: from animal electricity to human brain stimulation. The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques. 2004. '''31'''(4), p. 576–584. Doi: 10.1017/S0317167100003851.</ref> He noted, after first testing his device on himself, that the stimulation is rather unpleasant and its effects lasted for several days:
  
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<blockquote>"First, the fluid took over a large part of my brain, which felt a strong shock, a sort of jolt against the inner surface of my skull. The effect increased further as I moved the electric arcs from one ear to the other. I felt a strong head stroke and I became insomniac for several days." - <small>Giovanni Aldini, 1803</small><ref>ALDINI, G. Précis des expériences galvaniques faites récemment à Londres et à Calais par Jean Aldini […], suivi d’un extrait d’autres expériences, détaillées dans un ouvrage du même auteur, et qui ont été publiées à Londres par M. Nicholson. Paris: Levrault et Barrau, 1803.</ref></blockquote>
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<blockquote>First, the fluid took over a large part of my brain, which felt a strong shock, a sort of jolt against the inner surface of my skull. The effect increased further as I moved the electric arcs from one ear to the other. I felt a strong head stroke and I became insomniac for several days. - <small>Giovanni Aldini, 1803</small><ref>ALDINI, G. Précis des expériences galvaniques faites récemment à Londres et à Calais par Jean Aldini […], suivi d’un extrait d’autres expériences, détaillées dans un ouvrage du même auteur, et qui ont été publiées à Londres par M. Nicholson. Paris: Levrault et Barrau, 1803.</ref></blockquote>
  
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Experiments with the DC stimulation continued until the 1930' when its usage was abandoned in favour of more reliable electroconvulsive therapy which, for a while, overshadowed the practice of brain polarization and later by the advances in pharmaceutics. However, the research into the effects of DC did not cease. In 1964, Joe Redfearn stimulated volunteers with tDCS. He reported that the participants became more 'giggly'. Then he treated also patients with depression. However the results were not conclusive, mainly due to use of low current. The method was rehabilitated recently by Michael Nitsche and Alberto Priori<ref name="nature">FOX, Douglas. Neuroscience: Brain buzz. Nature [online]. 2011, Apr 13. Doi: 10.1038/472156a Available online at: http://www.nature.com/news/2011/110413/full/472156a.html (Retrieved 5th December, 2016).</ref><ref name="priori"/><ref>NITSCHE, Michael A., COHEN, Leonardo G., WASSERMANN, Eric M., PRIORI, Alberto, LANG, Nicolas, ANTAL, Andrea, PAULUS, Walter, HUMMEL, Friedhelm, BOGGIO, Paulo S., FREGNI, Felipe a PASCUAL-LEONE, Alvaro, Transcranial direct current stimulation: State of the art 2008. Brain Stimulation. 2008. '''1'''(3), p. 206–223. Doi: 10.1016/j.brs.2008.06.004. </ref> tDCS is also getting popular among the 'hacker' communities, such as reddit's /r/tDCS,<ref>Reddit [online]. Available online at: https://www.reddit.com/r/tDCS (Retrieved 12th December, 2016).</ref> or DIY tDCS<ref>DIY tDCS [online]. Available online at: http://www.diytdcs.com/ (Retrieved 5th December, 2016).</ref> since they are able to build the devices themselves.
+
Experiments with DC stimulation continued until the 1930s, when its usage was abandoned in favour of more reliable electroconvulsive therapy which, for a while, overshadowed the practice of brain polarization, and later by advances in pharmaceutics. However, the research into the effects of DC did not cease. In 1964, Joe Redfearn stimulated volunteers with tDCS. He reported that the participants became more 'giggly'. Then he also treated patients with depression. However, the results were not conclusive, mainly due to the use of low current. The method was rehabilitated recently by Michael Nitsche and Alberto Priori.<ref name="nature">FOX, Douglas. Neuroscience: Brain buzz. Nature [online]. 2011, Apr 13. Doi: 10.1038/472156a Available online at: http://www.nature.com/news/2011/110413/full/472156a.html (Retrieved 5th December, 2016).</ref><ref name="priori"/><ref>NITSCHE, Michael A., COHEN, Leonardo G., WASSERMANN, Eric M., PRIORI, Alberto, LANG, Nicolas, ANTAL, Andrea, PAULUS, Walter, HUMMEL, Friedhelm, BOGGIO, Paulo S., FREGNI, Felipe a PASCUAL-LEONE, Alvaro, Transcranial direct current stimulation: State of the art 2008. Brain Stimulation. 2008. '''1'''(3), p. 206–223. Doi: 10.1016/j.brs.2008.06.004. </ref> tDCS is also becoming popular among the 'hacker' communities, such as reddit's /r/tDCS<ref>Reddit [online]. Available online at: https://www.reddit.com/r/tDCS (Retrieved 12th December, 2016).</ref> or DIY tDCS<ref>DIY tDCS [online]. Available online at: http://www.diytdcs.com/ (Retrieved 5th December, 2016).</ref>. DIY means Do-It_Yourself since the proponents are able to build the devices themselves.
  
 
=== Purpose ===
 
=== Purpose ===
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== Important Dates ==
 
== Important Dates ==
  
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* 1st century CE - Roman physician Scribonius Largus helps patients with headaches by placing electric rays over their heads.
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* 1st century CE: Roman physician Scribonius Largus helps patients with headaches by placing electric rays over their heads.
−
* 18th century - Galvani and Volta experiment with the effects of electric current on human physiology and the brain.
+
* 18th century: Galvani and Volta experiment with the effects of electric current on human physiology and the brain.
−
* 1930' - tDCS is largely abandoned in favour of electroconvulsive  therapy.<ref name="Electrified"/>
+
* 1930': tDCS is largely abandoned in favour of electroconvulsive  therapy.<ref name="Electrified"/>
−
* 1964 - Joe Redfearn was conducted research on tDCS.
+
* 1964: Joe Redfearn was conducted research on tDCS.
−
* 2000' - Priori and Nietsche's experiments introduced a new era of tDCS research.<ref name="nature"/>  
+
* 2000': Priori and Nietsche's experiments introduced a new era of tDCS research.<ref name="nature"/>  
  
 
== Enhancement/Therapy/Treatment ==
 
== Enhancement/Therapy/Treatment ==

Revision as of 10:14, 9 May 2017

Various models of tDCS devices

List of transcranial direct-current stimulation devices:

Transcranial direct-current stimulation (tDCS) is a neuromodulatory technique in which a small and constant direct current is delivered through the skull in order to inhibit or excite neurons in the brain, that is to say to change the threshold at which the neurons will fire. Therefore it does not directly create new neural activity but influences the existing activity.[1] tDCS probably helps patients suffering from major depression and relieves pain (especially in fibromyalgia) and symptoms of craving in addictions.[2] tDCS could also help patients with neurodegenerative diseases, or enhance human cognition.[3] It is possible, however, that tDCS has no effect on the actual cognitive performance as it has been found by a quantitative review of past tDCS studies in 2015.[4]

Main Characteristics

tDCS is done by putting two or more electrodes on the scalp and running weak direct current between them so the current passes through the brain. Different areas of the brain can be affected based on the position of the electrodes. Depending on whether the stimulation is anodal or cathodal, the neuronal resting membrane potential is either depolarized or hyperpolarized, respectively. Anodal stimulation enhances excitability, while cathodal stimulation produces opposite results. The efficacy of the technique closely depends on the strength of the generated electrical field. Clinically, tDCS is usually administered via two sponge electrodes soaked in a saline solution for conductibility.[5][6]

Prolonged sessions of tDCS result in long-lasting after-effects that may last for hours. The mechanism of tDCS outlasting effect is predominantly caused by the induction of synaptic changes, especially in glutamatergic and gamma-aminobutyric acid (GABA) neurons. tDCS also modulates resting membrane potential generally along the whole axons, this may result in non-synaptic mechanism, which might contribute to the long-lasting effect of tDCS in intracortical and corticospinal neurons.[7] tDSC might also elicit changes in non-neuronal tissues in the brain, including vessels and connective tissues.[3]

Historical overview

A schematics showing how tDCS works.

The ability of electrical current to influence human cognition, especially the perception of pain, has been observed since 48 CE by the Roman court physician Scribonius Largus. He observed that placing a live fish of the order Torpediniformes, able to deliver electric discharges of up to 220 V, on patients could ease the pain of the headaches his patients suffered. Other great physicians such as Pliny the Elder, Claudius Galen, and Ibn-Sidah noted the beneficial effects of these animals in their works as well. The study of electric rays inspired Luigi Galvani and Alessandro Volta to experiment with the effects of electrical current on human physiology.[8] Galvani’s nephew Giovanni Aldini reported the successful treatment of patients suffering from melancholia.[9] He noted, after first testing his device on himself, that the stimulation is rather unpleasant and its effects lasted for several days:

First, the fluid took over a large part of my brain, which felt a strong shock, a sort of jolt against the inner surface of my skull. The effect increased further as I moved the electric arcs from one ear to the other. I felt a strong head stroke and I became insomniac for several days. - Giovanni Aldini, 1803[10]

Experiments with DC stimulation continued until the 1930s, when its usage was abandoned in favour of more reliable electroconvulsive therapy which, for a while, overshadowed the practice of brain polarization, and later by advances in pharmaceutics. However, the research into the effects of DC did not cease. In 1964, Joe Redfearn stimulated volunteers with tDCS. He reported that the participants became more 'giggly'. Then he also treated patients with depression. However, the results were not conclusive, mainly due to the use of low current. The method was rehabilitated recently by Michael Nitsche and Alberto Priori.[11][8][12] tDCS is also becoming popular among the 'hacker' communities, such as reddit's /r/tDCS[13] or DIY tDCS[14]. DIY means Do-It_Yourself since the proponents are able to build the devices themselves.

Purpose

Transcranial direct-current stimulation is a tool used to treat neuropsychiatric diseases and to influence human cognition without the use of invasive methods or pharmaceutics.[6]

Important Dates

  • 1st century CE: Roman physician Scribonius Largus helps patients with headaches by placing electric rays over their heads.
  • 18th century: Galvani and Volta experiment with the effects of electric current on human physiology and the brain.
  • 1930': tDCS is largely abandoned in favour of electroconvulsive therapy.[1]
  • 1964: Joe Redfearn was conducted research on tDCS.
  • 2000': Priori and Nietsche's experiments introduced a new era of tDCS research.[11]

Enhancement/Therapy/Treatment

Position of electrodes in accordance with International system

There were several experiments, which suggested that tDCS could enhance certain abilities and that it could be used as a treatment of various diseases.[15] In contrast, the experiments conducted by Theresa Iuculano and Roi Cohen Kadosh point out that the enhancement of certain abilities could lead to impairment of other abilities.[16] The efficiency of tDCS was also doubted by certain researchers e.g.[4]

The effect of tDCS method is based on neuroplasticity, which is brain's ability to change. Kue et al argue in their paper that tDCS could reverse pathological changes of brain which are responsible for various neuropsychiatric diseases. They specifically mention a treatment of pain, tinnitus, depression, addiction, schizophrenia, anxiety disorder and dementia.[17] In addition, Agnes Flöel, who listed several research concerning tDCS, claims that tDCS treatment could have positive impact to patients who suffers from mild cognitive impairment, Alzheimer's disease, movement disorders, epilepsy, or persistent deficits after stroke.[15]

Recently published evidence-based guidelines on the therapeutic use of tDCS [2] propose the use of tDSC for patients suffering from major depression, pain (fibromyalgia, chronic lower limb neuropathic pain) and craving (concerning alcohol abuse, crack-cocaine abuse and smoking). They also suggest a potential impact of tDCS on Parkinson's disease, but they do not confirm presumed effect of tDCS on tinnitus and drug-resistant depression, as well as they do not currently recommend tDCS as a treatment method for mentioned Alzheimer's disease, multiple sclerosis, or any type of epilepsy.

Anita Jwa points out various fields of cognitive enhancement, which could be provided by tDCS. Namely, tDCS is supposed to improve language learning, numerical learning or performance in video games.[18] Recently, there have been also suggested that tDCS could enhance sport performance due to improvement of motor learning.[19]

Ethical & Health Issues

Although tDCS is non-invasive treatment and is deemed to be safe, there arose several ethical issues. They are linked with the use of tDCS devices in general, with the do-it-yourself community and also with a specific use and setting of certain devices.

The developers of tDCS devices usually point out certain conditions to which it is nor recommended to use tDCS devices. It is primarily the age under 18, since the brain still develops in the youth. Another limits are history of seizures, epilepsy, pregnancy, brain lesions, bipolar depression, or severe heart disease. The patients with implant should also avoid a use of tDCS devices, since they could negatively interfere with their implant. In addition, the session should not exceed certain amount of time (usually 30 minutes) and there should be a certain gap between each session.[20]

The precise effect the direct current has on the brain itself is still not deeply understood. There is a possibility that long-term usage may be harmful and that some unwanted after-effects will occur. However, with observation of the proper experimentation protocol, especially the need to have a constant current density,[21] tDCS stimulation is deemed not to be harmful. More studies, however, have to be conducted to claim this conclusively.

The great deal of issues, which is linked with tDCS devices, rise from the DIY community. tDCS devices were originally used only in laboratory research, but the compelling results made certain tech enthusiasts to create their own tDCS devices. Besides, the components of tDCS devices are relatively cheap and the construction of these devices is not difficult.[22] These practice alarmed the researchers who published in Annals of Neurology an open letter with various concerns concerning tDCS devices, primarily those used outside of laboratories. They point out that there are several issues which could influence an output of the session and could lead to unintended effects. Firstly, electrodes usually extends the regions which should be stimulated, thus the current could influence more regions. Secondly, the stimulation is influenced by the bulk of personal features and activities which precedes and follows after it. Thirdly, the enhancement of one skill could be accompanied with the impairment of other skill. Fourthly, even a small change in the session, could lead to completely different output of the session. Finally, the brain and the physical features of each person is more or less different. The excitability of the brain or position of brain centres variates among population. Factors as handedness, gender or a different head anatomy could influence the output of the session. In addition, they argue that these potential risks are still acceptable in the case of a treatment but it is doubtful if they are worth the enhancement.[23]

The lack of information, is another issue which is connected with the sale of tDCS devices. Especially, the devices which are sold as DIY kits (e.g. Go Flow Pro, TDCS-KIT, TDCS Device Kit, TDCS Transcranial Stimulation Kit) tends to avoid any claim which could lead to FDA concerns. These concerns led to the denial of GoFlow project and it ceased the sale of TDCS Device Kit.[22] Jwa points out that the members of DIY tDCS community regulates those who tent to make dangerous mistakes and advise them on their fora[18] and Wexler argues that these community is acquainted with the research.[24] However, the devices could be purchased by any customers, even those who are not involved in DIY tDCS community. Therefore, the appropriate amount of information about the devices is needed.[25]

The use of tDCS in childhood is another ethical issue. As was mentioned previously the manufacturers of tDCS devices usually claim that their device should not been use by people under 18. There are, however, certain research which focuses on treatment through tDCS.[26] Roi Cohen Kadosh and his colleagues point out several ethical questions with regards to the use of tDCS in a childhood. Namely, they ask, if we should allow parents to let their children to enhance one skill at the cost of another skill. Moreover, if tDCS prove to be efficient and safe even for children, they ask if parents have obligation to treat their children with tDCS.[25]

The relative availability and ease-of-use of tDCS, with the assumption that the effects on cognition are indeed present, raise questions about it being used as a form of 'cheating' or otherwise gaining unfair advantage over non-users. A study on tDCS on athletes resulted in the subjects having better muscle endurance and decreased muscle fatigue.[27] While this is beneficial for treatment of fatigue, it also raises concerns whether this could be used in healthy sportsmen as a form of doping that is undetectable by chemical tests. WADA (the World Anti-Doping Agency) and the International Olympic Committee are aware of this issue. At the moment they investigate, if tDCS is really efficient. If there is scientific proof that tDCS enhance sport performance of athletes, WADA will consider tDCS to be doping, when it will shows that it harms health of athletes or violate "the spirit of sport."[28]

Anita Jwa, who conducted research among DIY tDCS community, claims that 56 out of 121 responding users declared an experience of certain side effects. These are headache, discomforting feeling under electrodes, fatigue, nervousness or mood change, concentration difficulties, sleeping disturbance, change of visual perception or nausea.[18]

Public & Media Impact and Presentation

With the 'brain hacking' community growing, tDCS techniques also got the attention of the media. Elif Batuman describes her experience with tDCS. She underwent stimulation in several sessions. She writes that the stimulation had some unpleasant but temporal effects on her skin and cognitive abilities, but that it was successful in treating her depression she usually takes medication for.[1] An article in The Huffington Post written by an former NASA engineers also calls tDCS brain-hacking. He explains that he feels that 'brain hacking' is essential to making human lives better.[29] Brain stimulation is especially popular among young, more tech-savvy adults. The community holds regular meetups and discussions, for example the Consciousness Hacking Meetup[30] on which the enthusiasts share their experience and on which entrepreneurs introduce their brain stimulation products.

The reactions to tDCS variate from enthusiasm to fear or scepticism. The enthusiastic declamations appear mainly on product reviews of tDCS users. Khrystyne Hastings on Halo Neuroscience's Facebook maintains "This is so cool!! I want to try this!!"[31] However, there are also keen proponents of tDCS among scientists. Markom Bikson the Professor of Biomedical Engineering The City College of The City University of New York argues:

This is my optimistic (hopeful) look forward; one day soon, we will have “Tools for the Mind” (TEDx) that we can use to better ourselves. Certainly we need more research and the technology is early stage, but with something so transformative, the time to discuss its implications to society is now. I mention those issues as a call to action. Pay close attention for a sneak peak image at one technology thats exists today.‪[32]

Nonetheless, the fear of tDCS, especially those tDCS devices used outside laboratories, is more prevalent. Christopher Mims at MIT Technology Review warns:

Now, the first thing I have to say in this post about how to overclock your brain with a straightforward 20-minute application of electrical current is DO NOT TRY THIS AT HOME. The long-term effects of TDCS are unknown, and if you mess up and put orders of magnitude more current through your brain than is typically used in TDCS, obviously, you could kill yourself.[33]

or Jamie Condliffe at Gizmodo claims:

Firstly, while direct current brain stimulation has undergone scientific and military testing, its long term effects are unknown. In the short term it does bring improvements, but there's no way of knowing what the extra currents are going to do to your brain in the long run. Second, if you mess up and for whatever reason mange to shoot a large current through your head, that is a bad and dangerous thing. You only have one brain, and destroying your neurons by pumping too much electricity through them could leave you permanently damaged—or even dead.[34]

Certain journalists and experts express their scepticism concerning efficiency of tDCS devices, e.g. Gizmodo quotes professor Mark S. George who argues:

This area is quite controversial, with positive studies getting published more frequently than failed trials, creating a publication bias [...] If there is an effect here in this study, the tDCS merely improved the ability of the subjects to learn. There was no transfer of information through the brain stimulation.[35]

Additionally, Nicole Lee from Engadget expresses at the beginning of her review of Foc.us that tDCS is not conclusively deemed to be efficient:

Originally used to help patients with brain injuries, tDCS has supposedly been found to increase cognitive performance in healthy adults. These claims haven't been proven yet though, and shocking your own cranium isn't exactly FDA approved.[36]

The reactions on the efficiency of the device differ among users. While some reported that tDCS devices has a huge impact on their life, some customers claims that they do not observe any improvement. NickMason29 on Amazon says about ApeX Type A: "Besides the quality of the unit, it helps to reduce my depression and anxiety symptoms. I feel better since I started to use it."[37] However, there are also negative claims to this product. The user 'tuthers' reports: "No other effects noted. I was very excited and hopeful, but this did nothing good for me. I think it's a technology that will be improved upon in the future, and it's exciting to think of the possibilities. But I think we have a ways to go."[38] The similar sort of claims could be found concerning any available tDCS device. While positive claims tends to be prevalent, there is still possibility that they are caused by placebo effect.[39]

Several concern are link with DIY tDCS community. Certain researchers and journalists point out that it is not a good idea. For instance Cara Santa Maria argues in interview conducted with her at Al Jazeera America:

I'm not surprised that people want to try tDCS at home, but I am concerned. tDCS is not yet a well-defined treatment protocol. Anybody receiving tDCS under a physician's care is doing so as a participant in a research study. That alone is not without risks. But at-home "brain hackers" are taking a dangerous gamble when they set out to change their brain activity via electrical stimulation. The lasting effects aren't fully tested. The voltage might not be well calibrated. The participant's tolerance may be different from that of the general population. I personally wouldn't want to do anything to my brain before there was scientific consensus about its safety and effectiveness.[40]

There were mentioned elsewhere, that tDCS is not entirely supported due to concerns of pharmaceutical companies. Brent Williams argues:

As tDCS gains new significance as an effective depression treatment via web sites, blogs, and the work of research institutions, it will be interesting to watch the reaction of pharmaceutical companies. They stand to lose billions of dollars. Will they try to derail tDCS as a depression treatment via advertising or “sponsored” research? Will the FDA be paying attention? It will be interesting to watch.[41]

and Elijah Wolfson form Al Jazeera America reported:

But getting the research money that might help bring the devices out of the DIY shadows and into the commercial mainstream is still difficult. Because the technology is so simple and cheap, pharmaceutical companies see no possibility of revenue.[42]

Public Policy

tDCS, specifically Sooma tDCS™ is a CE-marked medical device, which is classified as a class IIa medical device approved for treatment of Major Depressive Disorder. [43] None of tDCS devices have been approved as medical device by FDA yet.[18] There were reported FDA actions against GoFlow and TDCS Device Kit.[22] Therefore, tDCS could be regulated in accordance with certain currently existent regulations but there is no regulation which focuses directly on tDCS devices. Maslen and her colleagues suggest that these devices should be regulated just like a medical devices, since in research they are used for treatment of neuropsychiatric diseases. They do not opt for the ban of tDCS devices, since they argue that tDCS devices are not more risky than many medical devices which are already approved.[44]

Related Technologies, Projects or Scientific Research

The tDCS stimulation is dependant on electrodes. Certain devices as TDCS-KIT, Foc.us, Go Flow Pro or GoFlow includes their own electrodes, while manufacturers of others (e.g. BrainStimulator,Cognitive Kit) shipped their devices with sponge electrodes developed by Amrex.[45][46]

References

  1. ↑ 1.0 1.1 1.2 BATUMAN, Elif. Electrified: Adventures in transcranial direct-current stimulation. New Yorker [online]. 2015, Apr 6. Available online at: http://www.newyorker.com/magazine/2015/04/06/electrified (Retrieved 12th December, 2016).
  2. ↑ 2.0 2.1 LEFAUCHEUR J.P.; ANTAL A., et al. Evidence-based guidelines on the therapeutic use of transcranial direct current stimulation (tDCS). "Clinical Neurophysiology" 2017, 128: 56-92.</ Available online at: https://pdfs.semanticscholar.org/bd65/d9d3a7f1a69cb14308586d224be8eb2b6b19.pdf (Retrieved 20th April, 2017)
  3. ↑ 3.0 3.1 BRUNONI, Andre Russowsky, et al. Clinical research with transcranial direct current stimulation (tDCS): challenges and future directions. Brain stimulation, 2012, 5.3: 175-195.
  4. ↑ 4.0 4.1 HORVATH, Jared Cooney et al. Quantitative Review Finds No Evidence of Cognitive Effects in Healthy Populations From Single-session Transcranial Direct Current Stimulation (tDCS). Brain Stimulation [online]. 2015, Jan 16. Doi: http://dx.doi.org/10.1016/j.brs.2015.01.400. Available online at: http://www.brainstimjrnl.com/article/S1935-861X(15)00857-8/abstract (Retrieved 10th November, 2016).
  5. ↑ NITSCHE, M. A.; PAULUS, W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. The Journal of physiology, 2000, 527.3: 633-639.
  6. ↑ 6.0 6.1 ANTAL, A., PAULUS W., NIETSCHE M. A. Principle and mechanisms of transcranial Direct Current Stimulation (tDCS). Journal of Pain Management. 2009. 2(3), 249–257. Available online at: http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=emed9&NEWS=N&AN=2010453470 (Retreived 7th December, 2016).
  7. ↑ ARDOLINO G., BOSSI B., BARBIERI S., PRIORI A. Non-synaptic mechanisms underlie the after-effects of cathodal transcutaneous direct current stimulation of the human brain. "Journal of Physiology" 2005, 568: 653-63.</ Available online at: http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2005.088 (Retrieved 23th April, 2017)
  8. ↑ 8.0 8.1 PRIORI, Alberto. Brain polarization in humans: A reappraisal of an old tool for prolonged non-invasive modulation of brain excitability. Clinical Neurophysiology. 2003. 114(4), p. 589–595. Doi: 10.1016/S1388-2457(02)00437-6.
  9. ↑ PARENT, André. Giovanni Aldini: from animal electricity to human brain stimulation. The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques. 2004. 31(4), p. 576–584. Doi: 10.1017/S0317167100003851.
  10. ↑ ALDINI, G. Précis des expériences galvaniques faites récemment à Londres et à Calais par Jean Aldini […], suivi d’un extrait d’autres expériences, détaillées dans un ouvrage du même auteur, et qui ont été publiées à Londres par M. Nicholson. Paris: Levrault et Barrau, 1803.
  11. ↑ 11.0 11.1 FOX, Douglas. Neuroscience: Brain buzz. Nature [online]. 2011, Apr 13. Doi: 10.1038/472156a Available online at: http://www.nature.com/news/2011/110413/full/472156a.html (Retrieved 5th December, 2016).
  12. ↑ NITSCHE, Michael A., COHEN, Leonardo G., WASSERMANN, Eric M., PRIORI, Alberto, LANG, Nicolas, ANTAL, Andrea, PAULUS, Walter, HUMMEL, Friedhelm, BOGGIO, Paulo S., FREGNI, Felipe a PASCUAL-LEONE, Alvaro, Transcranial direct current stimulation: State of the art 2008. Brain Stimulation. 2008. 1(3), p. 206–223. Doi: 10.1016/j.brs.2008.06.004.
  13. ↑ Reddit [online]. Available online at: https://www.reddit.com/r/tDCS (Retrieved 12th December, 2016).
  14. ↑ DIY tDCS [online]. Available online at: http://www.diytdcs.com/ (Retrieved 5th December, 2016).
  15. ↑ 15.0 15.1 FLÖEL, Agnes. tDCS-enhanced motor and cognitive function in neurological diseases. NeuroImage [online]. 2013, May 30. Doi: 10.1016/j.neuroimage.2013.05.098 Available online at: http://www.sciencedirect.com/science/article/pii/S1053811913006009 (Retrieved 6th December, 2016).
  16. ↑ IUCULANO, Theresa; COHEN KADOSH, Roi. The Mental Cost of Cognitive Enhancement. J Neurosci 10 [online]. 2013, Mar 6. Available online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3672974/ (Retrieved 1st November, 2016).
  17. ↑ KUO, Min-Fang et al. Therapeutic effects of non-invasive brain stimulation with direct currents (tDCS) in neuropsychiatric diseases. NeuroImage [online]. 2013, Jun 4. Doi: 10.1016/j.neuroimage.2013.05.117 Available online at: http://www.sciencedirect.com/science/article/pii/S1053811913006277 (Retrieved 6th December, 2016).
  18. ↑ 18.0 18.1 18.2 18.3 JWA, Anita. Early adopters of the magical thinking cap: a study on do-it-yourself (DIY) transcranial direct current stimulation (tDCS) user community. Journal of Law and the Biosciences [online]. 2015, Jun 2. Doi: 10.1093/jlb/lsv017 Available online at: http://jlb.oxfordjournals.org/content/early/2015/06/01/jlb.lsv017.full.pdf+html (Retrieved 22nd November, 2016).
  19. ↑ ZHU, Frank P. et al. Cathodal Transcranial Direct Current Stimulation Over Left Dorsolateral Prefrontal Cortex Area Promotes Implicit Motor Learning in a Golf Putting Task. Brain Stimulation [online]. 2015, Mar 14. Doi: 10.1016/j.brs.2015.02.005 Available online at: http://www.sciencedirect.com/science/article/pii/S1935861X15008852 (Retrieved 16th November, 2016).
  20. ↑ Foc.us. Focus Go Flow Manual & Instruction Booklet. Foc.us [online]. Available online at: http://help.foc.us//article/38-focus-go-flow-manual-instruction-booklet (Retrieved 28th November, 2016).
  21. ↑ NITSCHE, Michael, LIEBETANZ, David, LANG, Nicolas, ANTAL, Andrea, TERGAU, Frithjof, PAULUS, Walter and PRIORI, Alberto. Safety criteria for transcranial direct current stimulation (tDCS) in humans [1] (multiple letters). Clinical Neurophysiology. 2003, 114(11), p. 2220–2223. Doi: 10.1016/S1388-2457(03)00235-9.
  22. ↑ 22.0 22.1 22.2 WEXLER, Anna. A pragmatic analysis of the regulation of consumer transcranial direct current stimulation (TDCS) devices in the United States. Journal of Law and the Biosciences [online]. 2015, Oct 12. Available online at: http://jlb.oxfordjournals.org/content/2/3/669.full.pdf+html (Retrieved 1st November, 2016).
  23. ↑ WURZMAN, Rachel et al. An open letter concerning do-it-yourself users of transcranial direct current stimulation. Annals of Neurology [online]. 2016, Jul 7. Doi: 10.1002/ana.24689 Available online at: http://onlinelibrary.wiley.com/doi/10.1002/ana.24689/abstract (Retrieved 16th November, 2016).
  24. ↑ WEXLER, Anna. The practices of do-it-yourself brain stimulation: implications for ethical considerations and regulatory proposals. Journal of Medical Ethics [online]. 2015, Aug 31. Doi: 10.1136/medethics-2015-102704 Available online at: http://jme.bmj.com/content/early/2015/08/30/medethics-2015-102704.abstract (Retrieved 18th November, 2016).
  25. ↑ 25.0 25.1 COHEN KADOSH, Roi et al. The neuroethics of non-invasive brain stimulation. Current Biology [online]. 2012, Feb 21. Doi: 10.1016/j.cub.2012.01.013 Available online at: http://dx.doi.org/10.1016/j.cub.2012.01.013 (Retrieved 7th December, 2016).
  26. ↑ For instance: SCHNEIDER Harry D., HOPP Jenna P. The use of the Bilingual Aphasia Test for assessment and transcranial direct current stimulation to modulate language acquisition in minimally verbal children with autism. Clinical Linguistics & Phonetics [online]. 2011, Jun 1. Doi: 10.3109/02699206.2011.570852 Available online at: http://dx.doi.org/10.3109/02699206.2011.570852 (Retrieved 7th December, 2016).
  27. ↑ COGIAMANIAN, F., MARCEGLIA, S., ARDOLINO, G., BARBIERI, S. and PRIORI, A. Improved isometric force endurance after transcranial direct current stimulation over the human motor cortical areas. European Journal of Neuroscience. 2007, 26(1), p. 242–249. Doi: 10.1111/j.1460-9568.2007.05633.x.
  28. ↑ STRICKLAND, Eliza. Olympic Athletes Are Electrifying Their Brains, and You Can Too. IEEE Spectrum [online]. 2016, Aug 23. Available online at: http://spectrum.ieee.org/biomedical/bionics/olympic-athletes-are-electrifying-their-brains-and-you-can-too (Retrieved 12th September, 2016).
  29. ↑ NELSON Noah J. Silicon Valley’s Next Big Hack? Consciousness Itself. The Huffington Post [online]. 2015, Mar 03. Available online at: http://www.huffingtonpost.com/turnstyle/silicon-valleys-next-big_b_6793910.html (Retrieved 12th December).
  30. ↑ Consciousness Hacking [online]. Available online at: http://www.cohack.life/ (Retrieved 12th December, 2016).
  31. ↑ HASTINGS, Khrystyne. Post. Facebook [online]. 2016, Dec 8. Available online at: https://www.facebook.com/halo.neuroscience (Retrieved 13th December, 2016).
  32. ↑ JOHN. A Tool For The Mind | Marom Bikson | TEDxBushwick. DIY TDCS [online]. 2016, July 13. Available online at: http://www.diytdcs.com/2016/07/a-tool-for-the-mind-marom-bikson-tedxbushwick/ (Retrieved 13th December, 2016).
  33. ↑ MIMS, Christopher. DIY Kit Overclocks Your Brain With Direct Current. MIT Technology Review [online]. 2012, Mar 09. Available online at: https://www.technologyreview.com/s/427177/diy-kit-overclocks-your-brain-with-direct-current/ (Retrieved 21st November, 2016).
  34. ↑ CONDLIFFE, Jamie. Why DIY Brain Stimulation Is a Really Dumb Idea. Gizmodo [online]. 2012, Mar 9. Available online at: http://gizmodo.com/5891883/why-diy-brain-stimulation-is-a-really-dumb-idea (Retrieved 23rd November, 2016).
  35. ↑ DVORSKY, George. No, Scientists Have Not Created a Matrix-Like Interface That Instantly Uploads Data to Your Brain. Gizmodo [online]. 2016, Mar 1. Available online at: http://gizmodo.com/no-scientists-have-not-created-a-matrix-like-interface-1762197710 (Retrieved 13th December, 2016).
  36. ↑ LEE, Nicole. Foc.us headset claims to shock the brain for better gaming, we go forehead-on. Engadget [online]. 2013, May 17. Available online at: https://www.engadget.com/2013/05/17/focus-headset-tdcs/ (Retrieved 13th December, 2016).
  37. ↑ NICKMASON29. Quality product and works on my depression. Amazon [online]. 2016. Jun 13. Available online at: https://www.amazon.com/tDCS-ApeX-Type-18V-accessories/dp/B00YG4D6UW/ref=sr_1_2?ie=UTF8&qid=1481637742&sr=8-2&keywords=tDCS (Retrieved 13th December, 2016).
  38. ↑ TUTHERS. Maybe this technology will become more advanced, in future. Amazon [online]. 2016, Oct 7. Available online at: https://www.amazon.com/tDCS-ApeX-Type-18V-accessories/product-reviews/B00YG4D6UW/ref=cm_cr_dp_qt_hist_one?ie=UTF8&filterByStar=one_star&reviewerType=avp_only_reviews&showViewpoints=0 (Retrieved 13th December, 2016).
  39. ↑ DYCE, Andrew. Foc.us Headset Review. Game Rant [online]. 2013. Available online at: https://gamerant.com/focus-tdcs-headset-reviews/ (Retrieved 24th November, 2016).
  40. ↑ ELLIS, Lauren. Contributor Q&A: Cara Santa Maria gets her brain stimulated. Al Jazeera America [online]. 2014, Dec 1. Available online at: http://america.aljazeera.com/watch/shows/techknow/articles/2014/9/26/contributor-q-a-carasantamariagetsherbrainstimulated.html (Retrieved 13th December, 2016).
  41. ↑ WILLIAMS, Brent. tDCS: Real Depression Help Without Medication. Speak Wisdom [online]. 2012, Aug 18. Available online at: https://speakwisdom.wordpress.com/2012/08/18/tdcs-real-depression-help-without-medication/ (Retrieved 13th December, 2016).
  42. ↑ WOLFSON, Elijah. I want to be your neuroscience experiment. Al Jazeera America [online]. 2014, Sep 27. Available online at: http://america.aljazeera.com/articles/2014/9/27/i-want-to-be-yourneuroscienceexperiment.html (Retrieved 13th December, 2016).
  43. ↑ Sooma tDCS. Somamedical [online]. Available online at: http://soomamedical.com/wp-content/uploads/2016/11/C2015-014-A05-White-Paper-EN.pdf (Retrieved 23th April, 2017).
  44. ↑ MASLEN, Hannah et al. The regulation of cognitive enhancement devices: extending the medical model. Journal of Law and the Biosciences [online]. 2004, Mar. Doi:10.1093/jlb/lst003 Available online at: http://jlb.oxfordjournals.org/content/1/1/68.full (Retrieved 7th December, 2016).
  45. ↑ Amrex Electrotherapy Equipment. Sponge Rubber Pad Electrodes. Amrex Electrotherapy Equipment [online]. Available online at: http://stores.amrexusa.com/sponge-rubber-pad-electrodes/ (Retrieved 14th December, 2016).
  46. ↑ The Brain Stimulator. Pair of 3×3″ Amrex Sponge Electrodes. The Brain Stimulator [online]. Available online at: https://thebrainstimulator.net/product/3x3-amrex-sponge-electrodes/ (Retrieved 14th December, 2016).
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