Is tDCS Safe? – Neuroelectrics.com

This comes to us via the Neuroelectrics.com blog. I’m very excited to see Neuroelectrics on the scene. I first noticed their device Starstim (pictured),  popping up in news around Roi Cohen Kadish’s ongoing tDCS trials at his Oxford lab (see). I believe Neuroelectrics is a Spanish company. What’s especially exciting to me is that they also make an EEG device called Enobio and are working on the ability to map brain activity with EEG while undergoing tDCS. Think about that! Live, in-the-moment feedback on exactly what effect your tDCS is having.

More than 100 studies have been performed using tDCS in healthy controls and in patient populations, and no serious side effects have occurred for a review, see Nitsche and others 2008. Slight itching under the electrode, headache, fatigue, and nausea have been described in a minority of cases in a series of more than 550 subjects Poreisz and others 2007. Detailed studies have been performed to assess the safety of tDCS. These have shown that there was no evidence of neuronal damage as assessed by serum neuron-specific enolase after application of a 1 mA anodal current for 13 minutes Nitsche and Paulus 2001; Nitsche, Nitsche, and others 2003 or MRI measures of edema using contrast-enhanced and diffusion-weighted MRI measures after application of a 1 mA current for 13 minutes anodal or 9 minutes cathodal; Nitsche, Niehaus, and others 2004 […] In addition, a recent study was performed in rats using an epicranial electrode montage designed to be similar to that used in tDCS Liebetanz and others 2009. This demonstrated that brain lesions occurred only at current densities greater than 1429 mA/cm2 applied for durations longer than 10 minutes. In standard tDCS protocols in humans, a current density of approximately 0.05 mA/cm2 is produced.

More about the Neuroelectrics Enobio EEG device.

via Is tDCS Safe?.

Dr. Vince Clark University of New Mexico

[Update 10/19] Dr. Clark’s TEDxUNM just in. tDCS starts around 6:45

Dr. Clark is a pioneer of tDCS research. He recently spoke at TEDxUNM (TED talk at the University of New Mexico). I’m eagerly awaiting a video of his talk and will post it as soon as it becomes available. In the intro to Dr. Clark’s talk I found this amazing story.

You really need to read the full story. It outlines Dr. Clark’s journey to diagnose a rare disease that affected his 9 year old boy. tDCS is one of 3 treatment modalities he discussed in his talk…

Clark is already using tDCS to help treat drug addicts and reduce symp­toms in peo­ple with Parkinson’s dis­ease. As a part of this research, Clark is exam­in­ing the abil­ity to use tDCS to treat chronic pain, which he learned about while try­ing to find ways to reduce the amount of pain Ryan suf­fered.  He’s been col­lab­o­rat­ing with other research groups that are hav­ing suc­cess using this pro­ce­dure to reduce pain.

“It might be the first time that some­one has come up with a way to treat pain con­sis­tently, but with­out using a drug,” he added.

Update 10/1/12 Dr. Clark is involved in a new site which “is meant to offer information and links about medical alternatives that are cheaper, safer and more effective than the current standard of care.” SmallerMedicine.com (links to tDCS page).

tDCS and CES – A Little History

Is a way to think about the effects of tDCS then, that it increases neuronal ‘excitability’?
Interesting too, the possibility that AC stimulation might actually be affecting neurotransmitter production.

From: Noninvasive Brain Stimulation with Low-Intensity Electrical Currents: Putative Mechanisms of Action for Direct and Alternating Current Stimulation [PDF}

As early as 1794, Aldini had assessed the effect of galvanic head current on himself, and by 1804, he had reported the successful treatment of patients suffering from melancholia. Research continued through the early 20th century; yet because DC induced variable results, or sometime none at all, the use of low-intensity DC (i.e., tDCS) was progressively abandoned…

…between 1938 and 1945, subsequently led to an interest in the application of AC at lower intensities with the first study of “cranial electro-therapy stimulation” (also known as “electrosleep”) published by Anan’ev and others in 1957… Since the 1960s, a series of studies with low-intensity AC stimulation have been published, and cranial AC stimulation devices have become commercially available for personal use (e.g., Alpha-Stim, Fisher Wallace Cranial Stimulator, Transair Stimulator, etc.). However, research in this area has been inconsistent and there remains a lack of solid evidence showing the effects of weak transcranial stimulation with AC.

…During tDCS, low-amplitude direct currents penetrate the skull to enter the brain. Although there is substantial shunting of current at the scalp, sufficient current penetrates the brain to modify the transmembrane neuronal potential and, thus, influences the level of excitability and modulates the firing rate of individual neurons. DC currents do not induce action potentials; rather, the current appears to modulate the spontaneous neuronal activity in a polarity-dependent fashion: For example, anodal tDCS applied over the motor cortex increases the excitability of the underlying motor cortex, whereas cathodal tDCS applied over the same area decreases it. Similarly, anodal tDCS applied over the occipital cortex produces short-lasting increases in visual cortex excitability. Hence, tDCS is believed to deliver its effects by polarizing brain tissue, and although anodal stimulation generally increases excitability and cathodal stimulation generally reduces excitability, the direction of polarization depends strictly on the orientation of axons and dendrites in the indu- ced electrical field.

CES is a nonstandardized and often indistinct method of delivering cranial AC stimulation; indeed many studies cite the method of stimulation simply as “cranial electrotherapy stimulation” without identifying the specific site or other parameters of stimulation (e.g., duration, current density, intensity, electrode size) calling into question existing reviews of this method. Even so, CES has been suggested to be effective in the treatment of anxiety, depression, stress, and insomnia, and the following parameters of stimulation have been reported: frequency (0.5 Hz to 167 kHz), intensity (100 μA to 4 mA), and duration of stimulation (5 min to 6 consecutive days).

… Biochemical changes—neurotransmitter and endorphin release. Several studies suggest that AC stimulation may be associated with changes in neurotransmitters and endorphin release. In this context, subthreshold stimulation induced by AC stimulation would indeed cause significant changes in the nervous system electrical activity.

For further reading on CES (AC stimulation) the wikipedia page is quite good!

GoFlow Kickstarter Campaign DENIED!

I’m on the GoFlow mailing list and received this update this morning.

Hello all you beautiful peoples, 

We’ve been silent for a few weeks now, and it’s time to bring you all up to speed on the GoFlow project again. (The diy tDCS kit if you’ve forgotten) We have officially been rejected from Kickstarter, and are delaying the production of our devices for a short while.

However we do have some progress to share with you all, and enough info to get anyone who is interested a decent way along in building your own. See below.

While it’s too bad that we are not able to rock a Kickstarter campaign, we move forward. During the process of getting the project ready for crowd funding we ran into a few legality concerns that probably would have stopped us from launching as quickly as we had planned, even if we were approved for Kickstarter.

We are taking the time to investigate these concerns now before we do something to prematurely sink our metaphorical ship. If any of you have any experience or thoughts that you’d like to share, we would love to hear from you.

Out main obstacles right now are:

  • FDA classification concerns
  • and subsequently approval

We’d love to hear from any of you that have experience with working with, and or around, the FDA. We’re talking to a few specialists and mentors now, but we are interested in leveraging the collective knowledge of you all as well.

We will keep you all updated to our progress as we move forward.

 

The prototype

This is what we have built so far. Full details available at www.flowstateengeged.com

Current circuit diagram

Our current circuit design. Feel free to download it!

Investigation of visual dream reports after transcranial direct current stimulation (tDCS) during REM sleep

This is one of the applications of tDCS I’ve been waiting to hear about. I was hoping tDCS might help facilitate an active dreaming state or even lucid dreaming.

Conclusions
In summary, using two different methodologies it appears that tDCS had no effect on the presence of dream reports with visual imagery or measures of dream quality. However, this may be due to methodological limitations of these stud- ies, as the delivery methods employed allowed only low levels of tDCS to be delivered without waking participants. Improvements allowing higher levels of stimulation during sleep and stimulation of other cortical regions could poten- tially provide more definitive conclusions regarding the ef- fectiveness of tDCS on dream imagery reported from REM sleep.

Abstract
Investigation of visual dream reports after tran- scranial direct current stimulation (tDCS) during REM sleep (pdf)

 

PLoS ONE: Anodal Transcranial Direct Current Stimulation Reduces Psychophysically Measured Surround Suppression in the Human Visual Cortex

The aim of this study was to assess whether anodal tDCS could reduce inhibitory interactions within the human visual cortex. Psychophysical measures of surround suppression were used as an index of inhibition within V1. Overlay suppression, which is thought to originate within the lateral geniculate nucleus LGN, was also measured as a control. Anodal stimulation of the occipital poles significantly reduced psychophysical surround suppression, but had no effect on overlay suppression. This effect was specific to anodal stimulation as cathodal stimulation had no effect on either measure. These psychophysical results provide the first evidence for tDCS-induced reductions of intracortical inhibition within the human visual cortex.

via PLoS ONE: Anodal Transcranial Direct Current Stimulation Reduces Psychophysically Measured Surround Suppression in the Human Visual Cortex.

Foc.us! And Update

Petr dropped me a line with an update on what brmlab has been up to lately. Wow! Check out the photo album. Very interesting collection of crew and gadgets. Here he is with an early version of his tDCS device.

He also pointed me to the focus. I don’t know how I’d missed it. Unfortunately (for me)…

Due to F.D.A. requirements the focus v1 is not currently available for sale in the United States. If you live in the U.S. and would like to buy a focus device, please pre-register. If there is sufficient demand from U.S. customers we will seek the necessary certification.

I think we can expect a lot of that. But how cool! You can sign up for ‘priority access’ on their site.

One of the things Petr and I discussed is objective testing for use in determining whether or not a tDCS device is actually doing anything. Petr came up with some great links. Both PEBL Psychological Test Battery and Brain Workshop – a Dual N-Back game, seem to be tests you download to your own computer. But I’ve just spent the last 20 minutes doing tests on a site called Quantified Mind. Except for the  Google (only) login, it’s about perfect. A nice collection of tests and the results are collected very nicely into a statistics page that associates with your account. Cool! [Update 5/25/12] Another interesting candidate for measuring effectiveness. Lumosity research partners include Stanford and Harvard. A very basic reaction time test, HumanBenchMark.com.

Petr also mentioned that he corresponded with the GoFlow people and they are going to set up a wiki. In their recent email they announced they were a little bit behind and were waiting to hear back from Kickstarter. But that whether or not they get Kickstarter approval they’ll be moving forward soon.

All for now.
JH

tDCS Transcranial Stimulation Kit

Not from me, but yes you can add one to your cart!

tDCS Transcranial Stimulation Kit

$380.00

Quick Overview

The stimulator is specifically designed for Transcranial Direct Current Stimulation (tDCS) and ensures a safe and comfortable treatment.

Included items
-tDCS stimulator 0.5 – 2.0 mA
-1x 5x5cm sponge electrode with conductive rubber inset
-1x 5x7cm sponge electrode with conductive rubber inset
-1x 7x10cm sponge electrode with conductive rubber inset
-Electrode cables
-Fastening straps for easy electrode positioning

tDCS Stimulator

More Views

  • tDCS Stimulator
  • Sponge electrodes with conductive rubber insets (3)
  • Electrode Cable
  • Velcro fastening straps (3)

via http://www.trans-cranial.com/tdcs-transcranial-stimulation-kit.html

Mother Lode! 446 research tDCS articles found (Abstracts)

tDCS peer-reviewed publications index (MedLine)

Does anodal transcranial direct current stimulation enhance excitability of the motor cortex and motor function in healthy individuals and subjects with stroke: A systematic review and meta-analysis.

2012 Apr

The primary aim of this review is to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on corticomotor excitability and motor function in healthy individuals and subjects with stroke. The secondary aim is to find a-tDCS optimal parameters for its maximal effects. Electronic databases were searched for studies into the effect of a-tDCS when compared to no stimulation.

via http://www.trans-cranial.com/research/

Evaluation of local electric fields generated by transcranial direct current stimulation with an extracephalic reference electrode based on realistic 3D body modeling

General scientific summary Local electric field distributions generated by transcranial direct current stimulation (tDCS) with an extracephalic reference electrode were evaluated to address the safety issues of extracephalic tDCS. We compared the maximum current density and electric field intensity values generated by six different electrode montages. Our simulation results demonstrated that the electric fields in the brainstem generated by the extracephalic reference were comparable to, or even less than, those generated by the cephalic reference, suggesting that the use of extracephalic reference does not lead to unwanted modulation of brainstem autonomic centers.

via Evaluation of local electric fields generated by transcranial direct current stimulation with an extracephalic reference electrode based on realistic 3D body modeling.

Amping Up Brain Function: Transcranial Stimulation Shows Promise in Speeding Up Learning: Scientific American

Wow! Check the article for the photo showing US Army use/placement of electrodes.

They used magnetoencephalography MEG to record magnetic fields brain waves produced by sensory stimulation sound, touch and light, for example, while test subjects received TDCS. The researchers reported that TDCS gave a six-times baseline boost to the amplitude of a brain wave generated in response to stimulating a sensory nerve in the arm. The boost was not seen when mock TDCS was used, which produced a similar sensation on the scalp, but was ineffective in exciting brain tissue. The effect also persisted long after TDCS was stopped. The sensory-evoked brain wave remained 2.5 times greater than normal 50 minutes after TDCS. These results suggest that TDCS increases cerebral cortex excitability, thereby heightening arousal, increasing responses to sensory input, and accelerating information processing in cortical circuits.

Remarkably, MRI brain scans revealed clear structural changes in the brain as soon as five days after TDCS. Neurons in the cerebral cortex connect with one another to form circuits via massive bundles of nerve fibers axons buried deep below the brain’s surface in “white matter tracts.” The fiber bundles were found to be more robust and more highly organized after TDCS. No changes were seen on the opposite side of the brain that was not stimulated by the scalp electrodes.

via Amping Up Brain Function: Transcranial Stimulation Shows Promise in Speeding Up Learning: Scientific American.

More From Reddit: Transcranial direct current stimulation

DIY Kit Overclocks Your Brain With Direct Current (technologyreview.com)

 

via Transcranial direct current stimulation.

Reddit Weighs In: Zap your brain into the zone: Fast track to pure focus

 

[–]Jakeimo 39 points ago

via Zap your brain into the zone: Fast track to pure focus : science.