Category Archives: Paper

Language and Memory Improvements following tDCS of Left Lateral Prefrontal Cortex | PLOS ONE

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Using transcranial direct current stimulation, we tested whether stimulation of left lateral prefrontal cortex had discriminate effects on language and memory conditions that rely on executive-control (versus cases with minimal executive-control demands, even in the face of task difficulty). Participants were randomly assigned to receive Anodal, Cathodal, or Sham stimulation of left lateral prefrontal cortex while they (1) processed ambiguous and unambiguous sentences in a word-by-word self-paced reading task and (2) performed an n-back memory task that, on some trials, contained interference lure items reputed to require executive-control. Across both tasks, we parametrically manipulated executive-control demands and task difficulty. Our results revealed that the Anodal group outperformed the remaining groups on (1) the sentence processing conditions requiring executive-control, and (2) only the most complex n-back conditions, regardless of executive-control demands. Together, these findings add to the mounting evidence for the selective causal role of left lateral prefrontal cortex for executive-control tasks in the language domain. Moreover, we provide the first evidence suggesting that brain stimulation is a promising method to mitigate processing demands encountered during online sentence processing.

Source: PLOS ONE: Language and Memory Improvements following tDCS of Left Lateral Prefrontal Cortex

A pragmatic analysis of the regulation of consumer tDCS devices in the U.S. | Anna Wexler

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This is an incredibly well-researched paper. All the nuance of FDA regulation around tDCS and similar devices is made clear. I’ve been picking away at trying to understand this myself, but had become extremely frustrated by the complexity and opacity of FDA jargon and legalese. Anna has collected all the relevant facts and applied them very close to home citing specific devices and situations the DIY tDCS crowd will be familiar with. Anna Wexler is the author as well of The practices of do-it-yourself brain stimulation: implications for ethical considerations and regulatory proposals (gated) . She spoke to myself and at least a handful of other reddit.com/r/tDCS contributors for that paper. In both papers she lays out a very sensible approach to regulating tDCS, or rather, not regulating it. Stating that there is already a body of relevant law stemming from various government agencies (in the U.S.) that could be called upon to regulate tDCS device use as needed.

This paper contributes to the literature on the regulation of consumer brain stimulation devices in the USA by providing a fact-based analysis of the consumer tDCS market and relevant laws and regulations. In the first section, I present a short history of the DIY tDCS movement and the subsequent emergence of DTC devices. In the second and third sections, I outline the basics of FDA medical device regulation and discuss how the definition of a medical device—which focuses on the intended use of the device rather than its mechanism of action—is of paramount importance for discussions of consumer tDCS device regulation. I then discuss how both the FDA and the courts have understood the FDA’s jurisdiction over medical devices in cases where the meaning of ‘intended use’ has been challenged. In the fourth section, I analyse the only instance of tDCS regulatory action to date, in which the California Department of Public Health (CDPH) forced a firm to recall several hundred consumer tDCS devices. Although there exists a common perception that the FDA has not been involved with the regulation of consumer tDCS devices, the California case demonstrates that the CDPH’s actions were instigated by an FDA engineer. Finally, I discuss the multiple US authorities, other than the FDA, that can regulate consumer brain stimulation devices.


Marketing language from the websites of consumer tDCS devices available for purchase as of June 2015.
CONSUMER TDCS DEVICE MARKETING LANGUAGE
Brain Stimulator* https://thebrainstimulator.net/what-is-tdcs/ ‘tDCS allows you to unlock your brain’s true potential’
Cognitive Kit* http://www.cognitivekit.com/ ‘Charge your mind’
tdcs-kit http://www.tdcs-kit.com/ ‘Power your mind’
ApeX Type A* http://www.apexdevice.net/ ‘Be happier. Be focused. Be smarter’
Foc.us* http://www.foc.us/ ‘make your synapses fire faster’, ‘overclock your brain’, ‘take charge’
Thync* http://www.thync.com ‘quiet your mind’, ‘boost your workout’
PriorMind http://www.priormind.com ‘increase your attention span’ ‘tDCS has been widely used to treat depression…’
TCT* http://www.trans-cranial.com ‘when only the best in tDCS therapy will do’
Super Specific Devices* http://www.superspecificdevices.com ‘personal tDCS device’

  • *Website contains some form of a medical or health-related disclaimer.

A pragmatic analysis of the regulation of consumer transcranial direct current stimulation (TDCS) devices in the United States

We Wore Electrodes to Bed to Induce Lucid Dreaming | Motherboard

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Oxley said a paper published in Nature last year, which showed lucid dreams could be induced through stimulating gamma waves in a sleeping person, inspired a lot of customers to try to use foc.us in the same way. So the foc.us team wrote a new program specifically designed to try to ellicit lucid dreams.

“A positive charge will excite a part of the brain and a negative current will sort of turn off that part of the brain,” Oxley said. “The higher function areas at the front of the brain are active during lucid dreams, so the idea is that if we excite that while people are dreaming, they’ll have a greater chance of having a lucid dream.”

Oxley said he uses the device nearly every night, and while it doesn’t always work, when it does it’s very exciting. Unfortunately, my experience was not quite so thrilling. Though the lucid dream program on the foc.us delivers a relatively low electrical current of 1.5 milliamps, it was too high for me. The electrodes immediately started to sting my skin and I had to take them off after about three seconds. So, I enlisted my less-sensitive coworkers to test it out, but the results were just as disappointing.

Source: We Wore Electrodes to Bed to Induce Lucid Dreaming | Motherboard

Our Results Suggest That The Human Brain Resembles A Flock Of Birds

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Indirectly related to tDCS but a fascinating new paper attempts to understand how the frontal cortex is responsible for cognitive control.

“Surprisingly,” Bassett said, “our results suggest that the human brain resembles a flock of birds. The flock comes to a consensus about which way to fly based on how close the birds are to one another and in what formation. Birds that fly at specific places in the flock can drive changes in the flock’s direction, being leaders in a so-called multi-agent system.
—–
“We’re very interested in controlling brain networks with techniques like optogenetics, transcranial magnetic or direct-current stimulation, deep brain stimulation or even neurofeedback,” Bassett said, “but the problem has been that there is little theoretical basis to determine how these stimulations affect the dynamics of the whole brain. In most cases, stimulation is applied via trial and error. This research helps to build up an understanding of the impact of stimulation in one region on cognition as a whole.”

Future research will test whether “wiring” differences between people predict their performance on cognitive tasks. It will also underpin work on therapeutic and adaptive technologies that capitalize on brain networks’ unique advantages over their computerized counterparts.

Article: Penn, University of California and Army Research Lab Show How Brain’s Wiring Leads to Cognitive Control
Paper: Controllability of structural brain networks

Huge Flock of Starlings Caught on Film (Hereford, UK 2014)

tDCS And Mindfulness

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At 20:40 Katie Witkiewitz begins discussing the use of tDCS as a tool for enhancing mindfulness training. Her work is mostly focused around addiction and recovery. She compares her own experience of using tDCS-assisted meditation to day 4 of a multi-day meditation retreat. They are using the anode F10 / cathode left shoulder (“Where’s Waldo” DARPA research) montage. There’s a shot of what she calls the ‘octa box’ which seems to be distributing current from a single ActivaDose device to 8 sets of electrodes for ‘group mindfulness training’ (but I could be wrong). Could tDCS enhance your meditation? Provide that extra bit of calming the chatter? She goes on to say that (including her own personal experience) the montage ‘inhibits verbal ability’ and that trying to lead a guided meditation while stimulating F-10 gave her ‘the worst headache’.

 

Can this electric helmet boost your brain power? | Daily Mail

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We met Ana Maiques, the co-founder of Neuroelectrics, maker of StarStim, in our first podcast. It should be pointed out that StarStim is a research-grade tDCS/EEG device that includes a powerful suite of software. In fact it’s not available to the general public.

Spanish research student, Azahara De La Vega Fernandez (pictured with Brian) is investigating under psychology lecturer Nick Davies how brain stimulation can be used to improve sporting ability Photo: Alistair Heap

Spanish research student, Azahara De La Vega Fernandez (pictured with Brian) is investigating under psychology lecturer Nick Davies how brain stimulation can be used to improve sporting ability Photo: Alistair Heap

She invited me to throw ten darts before being brain-hacked, and ten darts after.
And, while the current was gently sizzling through me, she played me a tape in which a man calmly talked me into picturing how brilliantly I was going to throw those arrows.
There is no point undergoing tDCS if you’re not already mentally focused.
Davis compares it with a weightlifter taking steroids. ‘If he takes them without pumping iron, they won’t give him bigger muscles,’ he says.
He also summons the example of Andy Murray going back to his chair between games, and replaying in his mind the shots he has just played, as well as imagining himself walking up to the net as the eventual winner.
It’s called visualisation, and all modern sportsmen and women are encouraged to do it.
Davis thinks that tDCS could help them do it better, sharpening that mental imagery. That’s why he’s experimenting on people like me.
First I needed to put my thinking cap on. This is the StarStim, a rubber hat with electrodes dangling from it.
Made in Barcelona, it costs £7,000.

Read more: http://www.dailymail.co.uk/sciencetech/article-3251517/Can-electric-helmet-boost-brain-power.html

Mind over matter: Ultrarunner Dean Karnazes’s brain-training device | Sports Illustrated

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Thync works by pulsing small electrical currents, no more than about 20 milliamps, through nerves on the head. A sticky strip of electrodes attaches to places where nerves run close to the skin above the right eyebrow, behind the ear, and on the back of the neck. A small triangular device connects above the eyebrow, and sends electrical pulses out through the electrode strip. According to Jamie Tyler, Thync’s CSO and other co-founder, the effect of pulsing currents along these nerves is to modulate norepinephrine production in the brainstem at the back of the head. The device has two main modes—called “vibes” in Thync-speak—calm and energy. The difference between these two is that energy increases the release of norepinephrine, increasing alertness, whereas calm decreases it.

tDCS seasickness treatment on the horizon | Imperial College London

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We previously showed that application of transcranial direct
current stimulation (tDCS), specifically unipolar
cathodal stimulation over the left parietal cortex,
results in suppression of the vestibular system.
Herein, we assessed whether such suppression of ves-
tibular activity using tDCS in normal controls may
alleviate motion sickness.

Press: Highly effective seasickness treatment on the horizon
Paper (Open): Electrocortical therapy for motion sickness

Non-invasive Human Brain Stimulation in Cognitive Neuroscience: A Primer | Neuron

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tDCSWalsh20150903

Effect of tDCS Current on Single-Pulse MEP (motor evoked potentials) Amplitudes This figure taken from Batsikadze et al. (2013)) shows that the “classic” inhibitory profile of 1 mA of cathodal DC stimulation is reversed when intensity is increased to 2 mA.

The Effects of tDCS Polarity. One of the features of the literature in tDCS cognitive studies is the implicit assumption that anodal stimulation is always excitatory and cathodal stimulation is always inhibitory (see Horvath et al., 2015a). Bestmann et al. (2015)) have given a detailed account of why this cannot be the case. It is broadly true that polarity-dependent tDCS changes are directional; however, the effects are not uniform under the electrodes (Batsikadze et al., 2013) and interactions with different cell morphologies and cortical surface shapes create inhomogeneities that in turn change the net effects of stimulation (Bestmann et al., 2015). This is one reason to approach the link between assumed physiology and behavioral effects with caution. It is an important message of this Primer that the field needs to stop making naive one-to-one links between polarity and behavior.

Source: Non-invasive Human Brain Stimulation in Cognitive Neuroscience: A Primer: Neuron

“Unfocus” on foc.us study (was…) Widely available brain training device could impair memory: study

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[Update 9/3] Because the tweets just keep on tweeting!

Study author Laura Steenbergen:

We performed this study in August/September 2014, which was before the V2 headset or software were available or even announced.

The study states:

In this study, we tested whether the commercial transcranial direct current stimulation (tDCS) headset foc.us improves cognitive performance, as advertised in the media.

In fact, at the time the study took place, using the Focus v1 device, the (June 25, 2014) website stated:

Stronger, faster, quicker

Excite your prefrontal cortex and get the edge in online gaming

 

[Update 8/30 Getting a little bit into the weeds here, but having put some time/thought into this r/tDCS thread reply I thought to post it here too to further clarify my issues with the study.]

I’m not sure why you call it ‘the standard foc.us montage’. The v1 montage was a bad choice, they recognized that and moved on. What would you say about the foc.us product as presented on their website now? Fregni’s study isn’t what I’d hope for in a study either. Maybe this ‘Unfocus’ study should have confirmed Fregni’s results using their testing protocol with a ‘medical tDCS apparatus’ before finding that the foc.us v1 device ‘impairs working memory’. In the study, they state:

In this study, we tested whether the commercial transcranial direct current stimulation (tDCS) headset foc.us improves cognitive performance, as advertised in the media.

But in another interview (translated) she states:

Reuning: The company that sells this device, thus claiming that it improves working memory. Is that correct? Steenbergen: Well, at least for the new version of the device they advertise on their website. The version we tested is intended to improve performance in computer games, according to the manufacturer.

Did foc.us ever state that the v1 ‘improved working memory’? I don’t think so. Here’s what I think this whole study is really about (again, translated from the same article):

…Of the medical equipment we know that they are safe. We know which regulations need to be followed if one wants to use them. But for the non-prescription devices there are no such provisions.

And yes, totally agree that all sorts of claims are being made. It’s a challenge to parse out good science, especially now that VC and DARPA money are coming into brain stimulation. Not to mention claims made by manufacturers of devices. But all that keeps it interesting and fun actually.

I would have been completely okay with this just being another bad tDCS study if it wasn’t so blatant a hatchet job on foc.us and the diy community in general.

[Update 8/28]

“Unfocus” on foc.us study – Our Response
For the record – the original foc.us gamer was tested and CE certified by an independent UK based Notified Body to standards EN60601-1:2006 and EN60601-2-10:2000.
It was the first CE certified consumer tDCS device. As far as we are aware, foc.us remains the only CE certified consumer tDCS device available today.

We welcome researchers who want to test our claims, especially independent 3rd parties who do it without telling us. But we find ourselves disagreeing with the facts presented and thus conclusions of this report.

Michael Oxley
foc.us co-founder

Source: “Unfocus” on foc.us study – Our Response

[Update 8/19] Noticed that Thync’s Jamie Tyler had this to say…

https://twitter.com/jamiethync/status/633650859767910400

https://twitter.com/jamiethync/status/633654698650808321

[Update 8/20] Have been in touch with study author Laura Steenbergen who cleared up my question about which version of the Foc.us device/software was used in the study:

We performed this study in August/September 2014, which was before the V2 headset or software were available or even announced. Hence, we used the software that belonged with the V1 apparatus (which by then was not even available for android yet ;)). Publication of scientific data is a long process, which is one of the reasons we repeatedly state that these findings only apply to V1 (we have no knowledge about V2). Confusingly, some media websites post a picture of the V2 foc.us with our findings… But that is beyond my control… I hope this clarifies the situation.. Best, Laura Steenbergen

Of course in the context of there only being one Focus device at the time, their use of the term ‘device’ would imply the entire contents of the box they received. There were no v2 headsets at the time they conducted the research. It’s my awareness of subsequent product developments that confused my initial impression. That plus the fact that the media are denigrating Focus for a product that doesn’t exist based on research that happened over a year ago.

Confused about this study… They tested the Foc.us v1 headset with the Foc.us v2 software. Then declare the device “…cannot be regarded as an alternative to CE-certified tDCS devices, the use of which has been demonstrated to be successful in promoting WM.” But the v1 headset has been controversial since Foc.us first released it! And having v2 of the app/software would imply that they made the choice not to use the newer headset (which follows a more common montage protocol). Anyway… it got published, and we’re talking about it and the buzz gremlins put their spin on it and spread it hither and yon.

In the current study, psychologists from the Netherlands worked with 24 healthy participants, attaching tDCS electrodes to their foreheads as recommended for stimulating the cortex. They used a commercial tDCS headset called “foc. us” that offers gamified and non-gamified stimulation and claims it can increase athletic endurance in addition to cognition. Participants visited the laboratory two times and were each given — unbeknownst to them — both a real stimulation session and a placebo-like service.

Source: Widely available brain training device could impair memory: study – Yahoo News
Reddit discussion: https://www.reddit.com/r/tDCS/comments/3hbe3s/impaired_memory_with_focus/
Paper: “Unfocus” on foc.us : commercial tDCS headset impairs working memory

Any other type of sensory stimulation (incl different sham) could have produced same weak effects on WM #junk #tDCS http://nws.mx/1gU30dI
@sciencelaer thx read it yesterday – lights, tones, etc really could have produced same minimal WM differences – so much junk tDCS research

It don’t mean a thing if the brain ain’t got that swing | UC Berkeley News

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Not tDCS but these are certainly exciting times. Some breakthroughs heading our way.  Paper: Oscillatory dynamics coordinating human frontal networks in support of goal maintenance [Paywall]

The anterior (blue) and posterior (orange) regions of the prefrontal cortex sync up to communicate cognitive goals to one another. (Image courtesy of Bradley Voytek)

Voytek and fellow researchers at UC Berkeley’s Helen Wills Neuroscience Institute measured electrical activity in the brains of cognitively healthy epilepsy patients. They found that, as the mental exercises became more demanding, theta waves at 4-8 Hertz or cycles per second synchronized within the brain’s frontal lobe, enabling it to connect with other brain regions, such as the motor cortex.
“In these brief moments of synchronization, quick communication occurs as the neurons between brain regions lock into these frequencies, and this measure is critical in a variety of disorders,” said Voytek, an assistant professor of cognitive science at UC San Diego who conducted the study as a postdoctoral fellow in neuroscience at UC Berkeley.

Source: It don’t mean a thing if the brain ain’t got that swing | UC Berkeley News
See Also: voyteklab.com

tDCS – the bigger picture | Body in Mind

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Kerstin Luedtke

Kerstin Luedtke

Things have moved on from there and luckily we now have a randomised controlled trial with a sufficient sample size (n=135) of patients suffering from chronic low back pain and shown that tDCS – at least in this population and using a paradigm of 2mA for 20 mins on 5 consecutive days over the motor cortex – does nothing to reduce the perceived intensity of back pain or the disability associated with chronic low back pain (Luedtke et al., 2015). The results were not only not statistically significant, there wasn’t even a trend into the right direction

Source: tDCS – the bigger picture – Body in Mind

Researchers’ perspectives on scientific and ethical issues with transcranial direct current stimulation: An international survey : Scientific Reports : Nature Publishing Group

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The largest proportion of researchers rated tDCS in research contexts (cognition, motor, affect) as “partly effective” (28-42%) or “mostly effective” (19-33%). Only a small percentage described tDCS as “ineffective” (2-5%) or “absolutely effective” (2-13%; Fig. 1A). Effectiveness ratings were highest for the motor domain (N = 213, mean±SD 1.71 ± 0.77) followed by cognition (N = 218, 1.49 ± 0.69) and affect (N = 143, 1.34 ± 0.68).

Source: Researchers’ perspectives on scientific and ethical issues with transcranial direct current stimulation: An international survey : Scientific Reports : Nature Publishing Group
via: @mancini_flavia

Transcranial direct current stimulation: before, during, or after motor training?

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The ‘online’ (stimulation during training) vs. ‘offline’ (stimulation prior to or after training) question is addressed here in this study I only have the abstract for. But in this case “These data suggest that tDCS performed before – not during or after – promotes optimization of motor training-induced plasticity.” Keep in mind that, there are many (montage, kind of test/training) variables and that other studies have shown advantages to online training.

Noninvasive brain stimulation has recently been used to augment motor training-induced plasticity. However, the exact time during which noninvasive brain stimulation can be combined with motor therapy to maximize neuroplasticity and behavioral changes is unknown. We conducted a randomized sham-controlled crossover trial to examine when (before, during, or after training) transcranial direct current stimulation (tDCS) should be applied to best reinforce motor training-induced plasticity in 12 healthy right-handed participants (mean age: 21.8±1.6) who underwent active or sham tDCS combined with motor training. Transcranial magnetic stimulation-elicited motor-evoked potentials from the right first dorsal interosseous muscle were recorded before (baseline) and immediately after each session. The training task comprised four practice trials – 3 min each (30 s pause between trials) – of repetitive finger movements (thumb abduction/adduction) with the right hand. Anodal tDCS (1 mA, 13 min, on the motor primary cortex) was applied before, during, and after the training. Compared with baseline motor-evoked potentials and the sham condition, tDCS that was applied before, but not during or after, the motor task enhanced corticospinal excitability. These data suggest that tDCS performed before – not during or after – promotes optimization of motor training-induced plasticity.