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Transcranial direct current stimulation ( tDCS) and neurostimulation

A new report by IRCM ethics experts raises important questions and concerns about transcranial direct current stimulation ( tDCS). During the past several decades, neurostimulation techniques such as transcranial direct current stimulation (tDCS) have gradually gained favor in the public eye. In a new report, "The Rising Tide of tDCS in the Media and Academic Literature," published May 21, 2014 in the scientific journal Neuron, IRCM ethics experts raise important questions about the rising tide of tDCS coverage in the media, while regulatory action is lacking and ethical issues need to be addressed.

Transcranial direct current stimulation ( tDCS) and neurostimulation.
Anne Hart, illustration and photography.

TDCS is a non-invasive form of neurostimulation, in which constant, low current is delivered directly to areas of the brain using small electrodes. Originally developed to help patients with brain injuries such as strokes, tDCS is now also used to enhance language and mathematical ability, attention span, problem solving, memory, coordination, and even gaming skills. Recently, states the report, tDCS has caused excitement in the lay public and academia as a ‘‘portable, painless, inexpensive and safe’’ therapeutic and enhancement device.

“Despite these claims, the effects of tDCS are hard to predict,” explains Eric Racine, PhD, according to the May 22, 2014 news release, "What is being said in the media and academic literature about neurostimulation?" Racine is Director of the Neuroethics research unit at the IRCM who supervised the research project. “The safety and efficacy of tDCS have only been demonstrated in controlled laboratory settings and, without supervision, the use of tDCS for enhancement might cause serious adverse effects such as temporary respiratory paralysis.”

Dramatic increase in public information on tDCS

The report shows the amount of publicly-available information on tDCS has increased dramatically in recent years, both in academic literature and print media articles. IRCM researchers analyzed the available information and found a considerable mismatch in tone and focus between academic and print media articles.

While academic articles focused on therapeutic and investigative uses of tDCS, discussions in print media articles mainly concentrated on potential enhancement uses, as well as therapeutic applications. In addition, media discussions have been optimistic, with little information concerning ethical issues, therapeutic limitations, or side effects that could result from widespread use, whereas academic articles usually involved a more balanced discourse.

“We encountered strong and potentially misleading statements about the real-world effects and applications of tDCS in print media headlines,” says Veljko Dubljevic, PhD, according to the news release. Dubljevic is a postdoctoral fellow in the IRCM’s Neuroethics research unit and first author of the report. “In our entire sample of media articles, only 3.5 per cent advised caution or mentioned the possibility of adverse effects.”

Given the nature of tDCS and the lack of oversight governing its use, the report explains that academic and print media discourse could shape the public’s risk-benefit perceptions, impact the uptake of this technology, and, consequently, lead to negative implications for ethical and regulatory oversight

“With the rapid evolution of tDCS in the public domain and in academia, we recommend three areas of action to tackle the social, ethical and policy implications,” adds Dr. Dubljevic, according to the news release. “First, to curtail misunderstandings about tDCS, professional societies, researchers and government agencies should work toward increasing neuroscientific literacy by providing objective neutral data to the media and the public. Second, tDCS devices, as well as their marketing and manufacturing standards, need to be monitored and regulated. Training and licensing procedures should also be considered. Finally, we believe that physicians and other clinicians should become actively engaged in the discussion about ethical, clinical and policy aspects of tDCS.”

“The current regulatory gap means that tDCS is readily available as a service, product, or even a homemade device, in many countries without any guidance being provided by policy makers,” concludes Dr. Racine. “A response to the policy and regulatory aspects of tDCS is urgently needed.”

This research project was funded by the Social Sciences and Humanities Research Council. Authors for this report also included Victoria Saigle, research assistant in the IRCM’s Neuroethics research unit. For more information, please refer to the article published online, "The Rising Tide of tDCS in the Media and Academic Literature," by Neuron. Authors of the paper are Veljko Dubljević, Victoria Saigle, and Eric Racine. You also may wish to check out the website of the Institut de recherches cliniques de Montreal.

Cognitive enhancement trade-offs

A noteworthy article, "The Mental Cost of Cognitive Enhancement," published March 6, 2013 in the Journal of Neuroscience, looks at cognitive enhancement, explaining that there's a trade off when it comes to boosting brain power by electrical stimulation. See, "Boosting Brain Power Comes At A Price." The research also explains that noninvasive brain stimulation provides a potential tool for affecting brain functions in the typical and atypical brain and offers in several cases an alternative to pharmaceutical intervention, according the study's abstract. If you wonder whether brain stimulation with electricity can help you do better in math, you may wish to first read the article, "New Brain Stimulation Technique Makes You Better At Math."

The stimulation isn't electrical as in plugging your brain into a socket. What it's about consists of a process known as transcranial random noise stimulation (tRNS). The stimulation has been around for a few years. It's really more like excitability. tRNS works by enhancing the excitability of the brain, and it does so by applying random electrical noise to target regions of the cortex via stimulation electrodes placed on the surface of the scalp, notes the article, "New Brain Stimulation Technique Makes You Better At Math."

Some studies have suggested that transcranial electrical stimulation (TES), a form of noninvasive brain stimulation, also can be used to enhance cognitive performance. Critically, research so far has primarily focused on optimizing protocols for effective stimulation, or assessing potential physical side effects of TES while neglecting the possibility of cognitive side effects, says the article.

What the researchers assessed in the study is the possibility of potential side effects of TES

Here's how it works as far as what's in the study's abstract: The scientists targeted the high-level cognitive abilities of learning and automaticity in the mathematical domain. Notably, learning and automaticity represent critical abilities for potential cognitive enhancement in typical and atypical populations.

During a period of 6 days, healthy human adults underwent cognitive training on a new numerical notation while receiving TES to the posterior parietal cortex or the dorsolateral prefrontal cortex. Stimulation to the the posterior parietal cortex facilitated numerical learning, whereas automaticity for the learned material was impaired.

In contrast, stimulation to the dorsolateral prefrontal cortex impaired the learning process, whereas automaticity for the learned material was enhanced. The observed double dissociation indicates that cognitive enhancement through TES can occur at the expense of other cognitive functions. These findings have important implications for the future use of enhancement technologies for neurointervention and performance improvement in healthy populations.

One of the latest fads in Sacramento is stimulating your brain to perform better by wearing various headband-type sensors

Only a year ago wearable headband-like devices were featured on the TV program, "Through the Wormhole" as improving the performance and accuracy by stimulating the brain by wearing a "creativity cap." See, "Through the Wormhole: Creativity Cap: Video: Science Channel." Transcranial stimulation devices also are used for some migraine sufferers and to awaken some coma patients. Nearly 20 million Americans over the age of 18 suffer from a major form of depression -- and many look for help outside of traditional medicine because pills can have a lot of side effects.

Some transcranial stimulation devices come with a government warning. Scientists and amateurs have been tinkering with wearable head band-type sensors that stimulate the brain to make people smarter, more accurate, or generally more able to do tasks better, says numerous news articles. For example, check out the Youtube video, "How to Make a DIY tDCS Device (Tutorial) - v1.0." Also check out the TV video online on the "I-brain." There's a difference between individually-tailored rehabilitation technology and various products online used by amateurs for transcranial stimulation in order to supposedly make themselves better able at a particular skill.

There's a new treatment called transcranial magnetic stimulation, says a Getty News images blurb. But what happens when devices get into the hands of the general public and are used for other than individually-tailored purposes?

Transcranial stimulation is big news nowadays but there's a health warning and a recall on some products. For example, see the California Department of Health, located in Sacramento's recall warning site, "CDPH Warns Consumers Not to Use TDCS Home Device Kit." In Sacramento, the government's June 28, 2013 news release from the The California Department of Public Health (CDPH) warned consumers not to use the unapproved medical device sold on the Internet as a TDCS (Transcranial Direct Current Stimulation) Home Device Kit.

TDCS Device Kit, Inc. of Petaluma, California is voluntarily recalling the TDCS Home Device Kits because the product has not been federally approved to market in the United States, and has not been determined to be safe and effective for their intended use. During a recent inspection, CDPH determined that the devices had not been manufactured in compliance with good manufacturing practices for medical devices. Also, the devices were found to be labeled without adequate directions for use and without adequate warnings against uses that may be dangerous to health.

Injuries and health risk warning

Use of the device could pose a health risk including, but not limited to: epileptic seizures, cardiac arrhythmias, cardiac arrest, optic and otic nerve injuries, skin irritation, headaches, blurred vision, and dizziness. No illnesses or injuries have been reported at this time. Recalled TDCS Device Kits were manufactured and distributed worldwide from November 2012 through April 2013. The devices have no identifying control numbers, for example, lot codes, serial numbers, or production dates printed either on the packaging, or the units themselves, but would have been received by mail from TDCS Device Kit, Inc.

Consumers with questions may contact the company via telephone between the hours of 10 a.m. to 4 p.m. Pacific Standard Time. The phone number is listed at the CDPH website, "CDPH Warns Consumers Not to Use TDCS Home Device Kit." Consumers may also contact the company via e-mail at Consumers who have experienced any injury or illness associated with the use of this product should contact their health care provider.

Wearable sensors for the blind are on the horizon

City College of New York-led research could lead to wearable sensors for the blind. Wearable sensors that allow the blind to "see" with their hands, bodies or faces could be on the horizon, thanks to a $2 million award from the National Science Foundation (NSF) to researchers at The City College of New York and Georgia Institute of Technology (Georgia Tech). The $2 million National Science Foundation award represents a huge payoff for City College of New York's City SEED Grants promoting interdisciplinary collaboration.

The grant, through the NSF "Emerging Frontiers in Research and Innovation" program, funds a multidisciplinary team investigating devices for "alternative perception" and the principles underlying the human-machine interaction. Alternative perception emulates vision by combining electronics and input from the other senses. In addition to aiding the visually impaired, the researchers expect the findings to lend themselves to other applications, such as the development of intelligent robots.

The grant is the first to result from a collaboration supported by CCNY's City SEED Grants program, an internal award of $50,000 in seed money to promote interdisciplinary faculty research partnerships. The program, initiated in the fall of 2010 by President Lisa S. Coico, requires grant recipients to include a plan to expand their projects and apply for further funding from other organizations.

The initial collaboration involved Dr. Zhigang Zhu, professor of computer science and computer engineering in City College's Grove School of Engineering, the principal investigator on the NSF grant, Dr. Tony Ro, professor of psychology and director of the Program in Cognitive Neuroscience, and Dr. Ying Li Tian, professor of electrical engineering. "The whole project needed something more interdisciplinary, so I looked for complementary research and found my neighbor Tony (Ro's laboratory) is right next door," says Professor Zhu in the September 28, 2011 news release, "City College of New York-led research could lead to wearable sensors for the blind."

"(This) was truly a good example of an interdisciplinary proposal and members with a complementary expertise -- not just similar overlapping expertise -- which is unusual," explains CCNY Associate Provost for Research Larry Bank, who oversees the City SEED Grants program, according to the news release. "We must integrate input from the sciences, engineering and, often, art and humanities, to have a true understanding of phenomena."

How humans learn to coordinate input from their senses

The researchers joined forces to disentangle how humans learn to coordinate input from their senses. Scientists research vision and touch -- with movements, like reaching for a glass or moving through a crowded room. Then they map out how machines, such as robots and computers, learn similar tasks, in order to model devices that can assist humans.

The team, which combines expertise in engineering, computer science, neuroscience, motor control and biomechanics, envisions a multifunctional array of sensors on the body and has already developed prototypes for some of the devices. The full complement of wearable sensors would help a sightless person navigate by conveying information about his or her surroundings.

Navigation and obstacle detection by robots

Professor Zhu works on navigation and obstacle detection by robots. For the project, he will focus on machine sensing and computer learning to understand the human-computer interaction. He also refines displays that would feed information from electronic sensors to the human wearer of the device. His lab tested a sensor that can detect proximity to an object and convey its distance with vibration on the hand or other body part. As one gets closer to a table, for example, it gradually increases the intensity of the stimulation.

Professor Ro, a neuroscientist, provides a window into what is going in the brain as sighted and visually impaired individuals navigate a room or virtual environment with and without devices to assist them. Using Professor Zhu's distance sensor, he tests how sensitive people are in discriminating vibrations to the hand that tell them how far it is from an object. He then determines whether they can make accurate judgments and whether they might be using the visual parts of the brain.

Understanding by machines such as detecting and identifying doors, exit signs, and stairs in rooms

Professor Tian works on higher-level visual understanding by machines, such as detecting and identifying doors, exit signs, colors or stairs in a room. A system like this could audibly tell the wearer that an object on the floor was a cat or a footstool, for example. Dr. Kok-Meng Lee, professor of mechanical engineering and director of the Advanced Intelligent Mechatronics Research Laboratory at Georgia Tech, who has expertise in mechanotronics -- the combination of mechanics and the electronics of information systems -- works on machine vision and novel sensor designs. He will help develop the theory and methods for detecting objects thermally and magnetically and find out how this affects walking. This will help break down the essentials of orienting oneself in a new environment and navigating through it.

Dr. Boris Prilutsky, professor in the School of Applied Physiology at Georgia Tech, studies sensory feedback in motor control or how one learns and organizes movements -- like walking or reaching out -- using sensory information. He will look at how quickly people with normal and impaired vision can learn to use devices for alternative perception and help develop models for some of the findings.

Wearable electronic devices to help the blind to 'see'

The researchers hope their findings on perception, and the prototypes they develop, will spawn a raft of wearable electronic devices to help the blind to "see" their environment at a distance through touch, hearing and other senses. The technology would also benefit sighted individuals who must navigate in poor visibility, such as firefighters and pilots.

Such devices could outperform existing assistive technologies by providing more information and being lower in cost. There are even advantages over one of the best forms of assistance for the blind, the guide dog. "A service dog can't convey what is around you, it can just guide," notes Professor Ro. "This [device] can actually tell you how far things are or what things are in much more detail." For more information on technology for rehabilitation, check out the news about another study, "Wearable technology can monitor rehabilitation."

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