What is tDCS?
Transcranial Direct Current Stimulation, or simply tDCS, is a non-invasive neurostimulation technology, used to modulate neuronal activity and increase synaptic plasticity by applying a low-intensity current to the scalp through two or more electrodes.
The method can affect the activation of neuronal networks but is not strong enough to initiate non-existing neuronal activity.
The technology in itself is nothing new. What is new is that we make this technology available in a simple format, both for the end user and the clinician, to get the full benefits of tDCS.
What can tDCS be used for?
While the modern conception of tDCS is relatively young, at around 20 years, the idea of using subthreshold stimulation to change brain activity has another century of history behind it. These proto-tDCS techniques were used as antidepressants and as an analgesic. Interestingly, both of these applications are seeing a lot of research today.
Overall applications of tDCS can be split into cognitive enhancements observed in healthy individuals, and clinical benefits observed in a number of clinical groups.
The exact effects of tDCS depend on a number of factors, the main one is where the electrodes are placed as this decides which brain areas the current flows over. Different applications may require different montages
SUGGESTED CLINICAL APPLICATIONS
Following succesful TMS treatment, TES stimulation can be a valuable tool in order to prevent relapse and maintain the mental health of your patients
There is level A evidence (definitely effective) for TES stimulation over the left prefrontal cortex to improve depression symptoms. No specific tasks are required by the client and they can wear the TES headset in the comfort of their own home.
There is level B evidence (probably effective) for TES stimulation over the right prefrontal cortex to reduce cravings in various addiction disorders (nicotine, alcohol, cannabis, cocaine, gambling, etc).
As a relatively side effect free method for changing neural activity, there has been a great deal of research in using tDCS as a treatment tool for a variety of disorders. Namely, tDCS is growing in popularity as a treatment tool for depression. Several weeks of sessions are associated with a significant reduction in depressive symptoms (Kalu et al. 2012, Lin et al. 2021). The mild side effect profile of tDCS allows it to be easily combined with other treatments or for it to be used to maintain benefits from treatment. tDCS is approved as a depression treatment in the EU.
There is also strong evidence for the effectiveness of tDCS in the treatment for addiction. Studies show reduced cravings after tDCS stimulation in cases of overeating, and smoking. tDCS also induced changes in white matter structures predicting reduced cravings in drug abuse (Fregni et al. 2008, Sauvaget et al. 2015, Nakamura-Palacios et al. 2016)
Lastly, tDCS has long been examined in the context of pain management. Studies suggest a significant and long lasting reduction in perceived pain after even brief periods of stimulation (Ayache et al. 2016, Boggio et al. 2008).
The study of tDCS is a constantly growing field of research. From a handful of published papers a year two decades ago, to almost 1000 new peer reviewed tDCS papers published annually in recent years. Many of these areas are still too undeveloped for us to focus on, but we are committed to supporting alternative protocols and uses.
Examples of novel tDCS research, that could be replicated with PlatoWork, are as diverse as providing relief from tinnitus (Faber et al. 2012), significantly decreasing auditory hallucinations in schizophrenia (Bunelin et al. 2012), and improving recognition memory in Alzheimer patients(Ferrucci et al. 2008). Along with hundreds of others, in fact there’s a pretty good chance that any application you can think of has already been examined.
What can PlatoWork do?
The PlatoWork headset allows any clinical institution access to high precision and quality tDCS technology. With three electrodes designed to let the user identify correct scalp locations and mount the headset appropriately, the PlatoWork headset allows for a wide variety of montages. In addition, PlatoWork is designed to be completely safe with several layers of failsafe preventing any malfunction of the headset.
Each electrode can act as both anode and cathode, and the headset can be tilted to sit at three different locations on the head, this can create dozens of clinically and scientifically relevant applications. The two most commonly used montages are quite similar though:
Anode left dorsolateral prefrontal cortex, cathode right dorsolateral cortex: Mostly referred to as the bifrontal montage, this is the electrode placement used most frequently in tDCS research. The montage has been found to affect a wide range of cognitive metrics in healthy individuals improving learning speeds and working memory. In clinical settings it has been found to be effective in reducing symptoms of depression, addiction cravings, and pains.
Cathode left dorsolateral prefrontal cortex, anode right dorsolateral cortex: The same montage as above but with the polarities switched. This montage has repeatedly shown to be effective in improving intuition and creativity across a wide range of tests.
What exactly does tDCS do in the brain?
tDCS is, at its core, a fairly simple technology. A battery sends a current over two electrodes placed on the head. The current enters through one electrode, goes through the underlying brain areas and goes out through the other. The interesting thing is what happens in the brain when the electric field is on:
tDCS changes the firing threshold of the neurons thereby making it just slightly easier for them to fire. Because it is now easier for the neurons to activate, there is more neuronal activity. This in turn then causes the onset of a process called long term potentiation, which causes a further increase in firing rates, and also the physical growth of new connections and the strengthening of existing connections (Stagg et al. 2018, Reato et al. 2019). This way, tDCS does not only increase brain activity directly but also makes the brain more plastic, increasing learning speeds and helping the brain break out of negative feedback loops. The direct effects of stimulation last from a few minutes into the stimulation session and up to an hour afterwards. The indirect effects of new connections and changes to the brain states last for much longer.
Prof. Alexander Sack, PhD
Clinical use of TES and neuromodulation
Morten Gørtz Jønsson
tDCS technology and research
- Stimulate up to 5 times a week, 1 session a day
- 30 minute stimulation per session (pre-programmed in the app)
- Stimulation can, with benefit, be applied during other therapeutic interventions such as talk therapy.
General contraindications for the use of tDCS
The list below includes cases where we do not recommend using tDCS, as there are still open questions when it comes to safety:
- During pregnancy
- For individuals under 18 years
- For individuals with metallic or electric implants over the jaw line, e.g metal plates in the skull, cochlear implants or deep brain stimulation electrodes.
- For individuals with epilepsy or a history of seizures
tDCS without clinical supervision
If you are using tDCS without support from clinical personnel, we do not recommend using it as a treatment tool for any psychiatric, neurological or developmental disorders. If you wish to use tDCS in treatment, relevant medical personnel should always be consulted.
Even though tDCS is considered a completely safe form of brain stimulation, there are some crucial safety measures that must be taken into account in devices like PlatoWork to ensure that the product can only deliver the desired current and voltage.
1) The electronics in the control unit are built with a physical maximum load just above the amount needed for stimuli furthermore the design also includes current and voltage limitation circuitry in case of failure. 2) During use, when the headset is open, the charging port is obstructed making it physically impossible to connect the device to any other power source during stimulation. 3) There are several safety measures built into the firmware and software (controlling the hardware) that immediately will stop the stimulation if the continuously measured voltage and current deviates from normal operating limits. As such, it is technically impossible for the product to deliver more electricity than the amount proven to be safe for human subjects. Thus, the software limitations will ensure that the product cannot be used more than these prescribed boundaries.
PlatoWork is registered as a Class I medical device under the EU Medical Device Directive, 93/42/EEC. Ensuring a high quality and safe product for our users is our number one priority.
Potential side effects
Thousands of studies have, repeatedly, confirmed that tDCS has a very high safety profile. For most people the only side effect experienced is a tingling underneath the electrodes and maybe a reddening of the skin after the electrodes are removed. This reddening is caused by increased blood perfusion, that is increased blood inflow to the area, making the skin appear red. It goes away 15 - 30 minutes after stimulation.
More severe side effects do exist but are very rare. First degree burns and tension headaches can happen and a small handful of second degree burns have been reported over the last 20 years.
All reported side effects have been transient and no permanent side effects have ever been reported. It is precisely this safety and tolerability that makes tDCS such a great technology for home use; it meaningfully changes brain activity with far fewer side effects than techniques of comparable potency.
PlatoScience is legal entity registered in Denmark, and the information provided on this page is based on the regulations for the EU device market under the EU Medical Device Regulations (EU) 2017/745. If you are visiting this page from any other territory, PlatoScience is not responsible for the accuracy of the content on this webpage under the local jurisdiction of that territory. For further information, please contact us directly or contact the regulatory authorities for your territory.
Safety of Transcranial Direct Current Stimulation
A safety analysis conducted with over 33 000 sessions and 1000 subjects with repeated sessions.
Physiology of Transcranial Direct Current Stimulation
TDCS physiological mechanism such as acute regional effects, neuroplastic effects, cerebral network impact.
Brain stimulation improves learning more than performance
Evidence for the modulation of long-term synaptic plasticity by tES in practically relevant learning tasks.
tDCS enhances motor synergy and sequence learning
tDCS augmented synergy learning, leading subsequently to faster and more synchronised execution.
References per section
Section 'Clinical use'
Ayache, S. S., Palm, U., Chalah, M. A., Al-Ani, T., Brignol, A., Abdellaoui, M., ... & Lefaucheur, J. P. (2016). Prefrontal tDCS decreases pain in patients with multiple sclerosis. Frontiers in neuroscience, 10, 147.
Boggio, P. S., Zaghi, S., Lopes, M., & Fregni, F. (2008). Modulatory effects of anodal transcranial direct current stimulation on perception and pain thresholds in healthy volunteers. European journal of neurology, 15(10), 1124-1130
Fregni, F., Liguori, P., Fecteau, S., Nitsche, M. A., Pascual-Leone, A., & Boggio, P. S. (2008). Cortical stimulation of the prefrontal cortex with transcranial direct current stimulation reduces cue-provoked smoking craving: a randomized, sham-controlled study. Journal of Clinical Psychiatry, 69(1), 32-40.
Kalu, U. G., Sexton, C. E., Loo, C. K., & Ebmeier, K. P. (2012). Transcranial direct current stimulation in the treatment of major depression: a meta-analysis. Psychological medicine, 42(9), 1791-1800.
Lin, Y. Y., Chang, C. C., Huang, C. C. Y., Tzeng, N. S., Kao, Y. C., & Chang, H. A. (2021). Efficacy and neurophysiological predictors of treatment response of adjunct bifrontal transcranial direct current stimulation (tDCS) in treating unipolar and bipolar depression. Journal of Affective Disorders, 280, 295-304.
Nakamura-Palacios, E. M., Lopes, I. B. C., Souza, R. A., Klauss, J., Batista, E. K., Conti, C. L., ... & de Souza, R. S. M. (2016). Ventral medial prefrontal cortex (vmPFC) as a target of the dorsolateral prefrontal modulation by transcranial direct current stimulation (tDCS) in drug addiction. Journal of Neural Transmission, 123(10), 1179-1194.
Sauvaget, A., Trojak, B., Bulteau, S., Jiménez-Murcia, S., Fernández-Aranda, F., Wolz, I., ... & Grall-Bronnec, M. (2015). Transcranial direct current stimulation (tDCS) in behavioral and food addiction: a systematic review of efficacy, technical, and methodological issues. Frontiers in Neuroscience, 9, 349.
Section 'Cognitive enhancements'
Fregni F, Boggio PS, Nitsche M, Bermpohl F, Antal A, Feredoes E, Marcolin MA, Rigonatti SP, Silva MT, Paulus W, Pascual-Leone A. Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory. Exp Brain Res. 2005 Sep;166(1):23-30. Epub 2005 Jul 6. PubMed PMID: 15999258
Hertenstein, E., Waibel, E., Frase, L., Riemann, D., Feige, B., Nitsche, M. A., ... & Nissen, C. (2019). Modulation of creativity by transcranial direct current stimulation. Brain stimulation.
Ke Y, Wang N, Du J, Kong L, Liu S, Xu M, An X, Ming D. The Effects of Transcranial Direct Current Stimulation (tDCS) on Working Memory Training in Healthy Young Adults. Front Hum Neurosci. 2019 Feb 1;13:19. doi: 10.3389/fnhum.2019.00019.
Mayseless, N., & Shamay-Tsoory, S. G. (2015). Enhancing verbal creativity: modulating creativity by altering the balance between right and left inferior frontal gyrus with tDCS. Neuroscience, 291, 167-176.
Nitsche, M. A., & Paulus, W. (2000). Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. The Journal of physiology, 527(3), 633-639.
Section 'Experimental use'
Faber, M., Vanneste, S., Fregni, F., & De Ridder, D. (2012). Top down prefrontal affective modulation of tinnitus with multiple sessions of tDCS of dorsolateral prefrontal cortex. Brain stimulation, 5(4), 492-498.
Brunelin, J., Mondino, M., Gassab, L., Haesebaert, F., Gaha, L., Suaud-Chagny, M. F., ... & Poulet, E. (2012). Examining transcranial direct-current stimulation (tDCS) as a treatment for hallucinations in schizophrenia. American Journal of Psychiatry, 169(7), 719-724.
Ferrucci, R., Mameli, F., Guidi, I., Mrakic-Sposta, S., Vergari, M., Marceglia, S. E. E. A., ... & Priori, A. (2008). Transcranial direct current stimulation improves recognition memory in Alzheimer disease. Neurology, 71(7), 493-498.
Section 'What exactly does tDCS do in the brain?'
Reato, D., Salvador, R., Bikson, M., Opitz, A., Dmochowski, J., & Miranda, P. C. (2019). Principles of transcranial direct current stimulation (tDCS): introduction to the biophysics of tDCS. In Practical guide to transcranial direct current stimulation (pp. 45-80). Springer, Cham.
Stagg, C. J., Antal, A., & Nitsche, M. A. (2018). Physiology of transcranial direct current stimulation. The journal of ECT, 34(3), 144-152.
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