Just in Time for Back to School! Super Specific Devices tDCS!

Introduction

It’s been a very busy summer and I’m long overdue in writing a review of Super Specific Devices (SSD) line of tDCS* equipment targeting the DIY marketplace.  SSD has been quietly building some high-quality gear for several months now and their various models deserve a good look.

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(The SSD Voltage Selectable tDCS Device)

The Basics

Let’s start with the basic unit – on the SSD website, you choose a unit powered by either a 9 or 12 volt battery and an analog or digital meter.

The tDCS circuit is a simple but reliable LM type current regulator with the added safety bonus of in-circuit current limiting diodes.  All components are nicely soldered to a PC board and all connections to that board are secured with glue.  SSD has chosen to build their tDCS devices into a nicely made and finished wood box – it has a more professional appearance than do many of the tDCS devices on the market today. Electrodes are connected to the device via a small “TENS” style connector on the side of the unit.

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(Inside the 12 volt version of the SSD tDCS device is simple and neat. The type 23A battery can be seen to the right and the current regulator board is to the top left of the box. Approx $115)

All units are supplied with a starter set of lead-wires, non-stick electrodes, sponges, and self-adhering tape (rather than a headband).  If you are really serious about tDCS, you might want to consider the accessory banana plug adapter cord for use with Amrex and similar sponge electrodes (about $10).

 

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(Operation is simple! Start with the unit turned off and the dial rotated fully counter-clockwise. Place wetted sponge electrodes as desired, turn on the unit, and adjust current to desired level. Run session for planned treatment time and at completion, rotate the dial fully counter-clockwise and turn the unit off.)

The SSD Voltage Selectable tDCS Device

Super Specific Devices also offers a new tDCS device that provides switch-selectable 9, 12, and 18 volt settings. The selectable voltage range helps deal with difficult electrode setups (like one electrode placed on the shoulder or arm, or stick-on electrodes) where a 9 volt tDCS device may not be able to overcome the higher resistance to deliver the desired current level. The ability to switch to 12 or 18 volts may make all the difference in reaching a desired treatment current level.

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(The inside of the voltage selectable tDCS device is obviously more congested. A 9 volt battery powers the analog meter unit with the voltage boost circuit at the bottom left and the regulator circuit at the top center of the box.  The selector switch is at the very top left of this photo. The wiring looks more ominous than it really is. Much of the wire is related to selecting voltage and illuminating the tri-color LED appropriately. With so much point-to-point wiring, careful soldering and quality checks are a must though.)

The circuit in the voltage selectable units is again built around an LM current regulator with current limiting diode backup so maximum current cannot exceed 2.5 mA.  Interestingly the digital display version of the voltage selectable unit is USB rechargeable! According to the SSD web site, the device is switch protected so that USB energy cannot be used during a tDCS session.  This is a wise safety feature. The use of rechargeable batteries (rather than throw-away) and USB charging might be a good trend for all tDCS manufacturers to follow – just adopt the practice of isolating charging from operation as SSD has done!

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(From the SSD web site. The voltage selectable, digital display, USB charging version. Approx $175)

My Testing

I have tested the 12 volt version (analog meter) and the voltage selectable version (analog meter) from Super Specific Devices and like them very much. They are solidly built using a tried and tested tDCS device design and are likely to provide reliable service for years.  Given the low price of SSD units, I can’t imagine an individual going to the trouble to find all the components and taking the time to build tDCS device(s) with this level of construction.  Time would be better spent buying and using the SSD device!

I subjected each of the SSD devices I have on hand to my usual torture and use tests. In every case, the units delivered the current level specified. In my simulated failure modes, I was never able to exceed 2.5 mA output current.

As with most tDCS vendors servicing the DIY market, SSD does not provide medical advice (diagnosis, treatment recommendations, etc.) The instructions they provide with each unit are complete in the sense of learning how to operate the supplied unit.  However, each customer is expected to seek out other sources for information on tDCS, what is possible, and treatment montages.

Final Comments

I continue to be pleased to see a wide variety of capable tDCS devices available to the public from a number of vendors.  Units span a wide range from simple and cheap to more expensive and very sophisticated.  Super Specific Devices seems to have found a niche in the middle with products that have a low price but a quality build, nice appearance, and solid features.

Super Specific Devices web site: http://www.superspecificdevices.com/

*tDCS is transcranial direct current stimulation

 

 

 

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Apex Type A tDCS Device Review

Introduction

I am so pleased that an assortment of excellent tDCS* devices is now reaching the market – making the benefits of tDCS available to more and more people worldwide.  The range of devices is impressive – from simple and cheap to expensive and very sophisticated.

I won’t take the time or space here to detail all the potential benefits of tDCS or why you should consider obtaining a device – but suffice it to say that millions of people could dramatically improve their lives with tDCS. tDCS can be used to treat depression, chronic pain, enhance memory, and much more.  See the web sites I list below as a good starting point for more information on tDCS.

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(Apex Type A Main Unit)

The Apex Type A

The Apex type A “Adjustable Direct Current Generator” is a low priced but well-built device that uses a classic tDCS design that includes a 9 volt battery, an LM334 current regulator, a programming resistor to limit delivered current to about 2 mA and a meter to monitor current delivered.  This design (and variations) have been used by do-it-yourselfers for years (I’ve built several myself) and has proven to be very reliable, simple, and safe.

Apex saves you the considerable time and trouble to locate all the parts to build your own device by manufacturing a solid unit that looks like it will last for many years. The base unit alone sells for about $99 and a complete kit including head-band, electrodes, wires, etc. is about $139 (plus shipping).

Apex kit
(Apex Type A and accessories – from the Apexdevice.net web site)

As with most other tDCS device manufacturers, Apex does not provide medical advice, information about which tDCS electrode placements will work for you, etc. They leave it up to you to do your homework by reading the considerable about of material available online (see example links below) to decide if tDCS is right for you and what treatment method will work best.

The Apex Type A comes with a well written user guide that takes the user step-by-step through installing a 9 volt battery, connecting wires and electrodes, and running a simple test to see that the unit is working as it should.  There are two controls and two indicators on the type A:

  • On-off switch: clearly marked
  • Current adjustment dial: clockwise rotation raises current, the opposite to reduce current
  • Indicator LED: glows blue when the unit is turned on
  • Meter: I consider this almost a must-have in a consumer tDCS device. It clearly shows the amount of current being delivered during a tDCS session.

It’s also worth noting that the Apex Type A allows for the simultaneous connection of two sets of electrodes. Most users would rarely if ever do this – and it’s important to remember that device output current (max 2 mA) will divide between the sets of electrodes (probably not evenly – due to different resistance through the head at different locations.)

Testing and Use

As I mentioned above, I’m very familiar with the classic design of the Apex Type A and can say that the device performed exactly as expected – delivering a clean, DC current at a maximum of 2 mA (depending on dial setting.)

Construction

As you can see from the photos of the inside of the unit, build quality is very high.  All solder joints are well-made and clean, and mechanical attachment of the circuit board, controls, etc. is very solid. Some may object to the use of hand-assembly / perf-board instead of machine assembly / printed circuit board – and I might too except that the electronics of this classic design are very simple and as you can see involve only six solder joints on the circuit board itself.  As long as Apex continues good quality control and inspection procedures, this method of construction is perfectly fine.

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(Construction is simple and solid.)

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(Assembly is neat and well done.

Is 9 Volts Enough?

As far as a tDCS device is concerned, a human head is nothing but a big, liquid filled resistor. All the device does is try its best to deliver a consistent, stable one to two milliamps to cause the desired treatment effect.  9 volts is about the minimum that can reliably deliver the desired current level given circuit, hair, skin, etc. resistance that does it’s best to limit current flow.  Many commercial tDCS devices use 12 or 18 volts – some go as high as 80 volts! The higher voltages make it easier to overcome higher resistance (for example if one electrode is on the forehead and one on the shoulder). But the higher the voltage, the more opportunity there is for a painful (if not dangerous) experience if something goes wrong.  So many of the simpler tDCS devices elect to use a single 9 volt battery (or sometimes two in series).

Given the low voltage of the Apex Type A, it is very important that you do at least the following to make sure your treatment current is as you select:

  1. Use saline water and sponge electrodes (you can make your own saline and sponge electrodes if you like)
  2. Get the sponges really wet, then squeeze them out a bit (you don’t want water dripping down your head)
  3. Use a good head-band. Your head-band will need to be tight – not uncomfortably so, but tight

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(Controls are simple and work well. This is a Type A set for maximum current, with a new battery and shorted anode and cathode leads. Note the maximum current of about 2 mA.)

When you start a tDCS session, expect current to rise slowly (over two or three minutes) as your scalp or skin gets wetter. You may find it desirable to adjust the current control on the Apex Type A once or twice during your tDCS session.

Finally

Apex does a nice job of providing a simple, reliable, well-built tDCS device that will do exactly what it is supposed to do – provide clean 1 to 2 mA DC for your tDCS application. They provide good operation instructions with the device and have a wide array of backup material on their web site. Well done Apex!

Links

www.apexdevice.net

www.speakwisdom.com

www.diytdcs.com

www.reddit.com/r/tdcs

*tDCS is transcranial direct current stimulation

Time to Take Another Look At foc.us tDCS and more

History

About two years ago foc.us burst on the do-it-yourself tDCS scene with a headset marketed to “gamers” – claiming to offer improved game performance (higher scores).  A few folks like myself recognized the foc.us headset (V1) for what it was – a remarkable, capable tDCS device that could be used for ANY tDCS related purpose including treating depression, chronic pain, enhancing memory, etc. – and yes, improving game scores!  The V1 headset was truly a leap beyond anything else available to the DIY community offering an all-in-one headset that could be controlled via Bluetooth, offered built-on and external electrodes, all in a very nicely designed package.

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(Famous or infamous foc.us V1 ad campaign)

Critics quickly emerged, as they often do, describing customer relations related problems with foc.us – many justified, and technical issues with the product – many unjustified.  It seemed foc.us was surprised by their own success and unprepared for the order volume and normal support requirements of such a leading edge product. By the time foc.us got its organizational problems resolved, the V1 was winding down and the company was preparing to launch the V2.

The foc.us V2

Several months ago, Transcranial Ltd. launched it’s new foc.us tDCS product, the V2. It, like the V1, sets a  high bar for the DIY tDCS market. In a tiny package easily small enough to misplace with your car-keys, foc.us engineers included all of the technical features of the V1, plus the added versatility of upgradeable firmware (new features), display screen with scrollable selection, redesigned and industry leading headsets, the ability to use 3rd party headsets and related accessories, and more!

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(The foc.us V2. Tiny! Awesome!)

Interestingly, foc.us via their advertising, now seems to recognize the value of their technology for what it is, a real cranial stimulation device – not just for gamers – but for anyone seeking the benefits of tDCS and more.

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The V2 ad campaign is more general – making clearer the broad capabilities of the V2.)

Since my initial posting about the V2 (see http://bit.ly/1Jilfpg ) Transcranial Ltd. has upgraded the feature set of the V2 in significant ways!  The V2 now supports tDCS, tACS, tPCS, and tRNS as well an upgraded application for Android devices and soon iOS. The V2 can no longer be referred to as just a tDCS device – it’s now a fully capable, research grade, cranial stimulation device!

It’s a Software World Now!

If you purchase a V2 (or own one now), you may wish to update its firmware periodically to take advantage of new features.  Here are some key steps:

  1. Go to the foc.us web site and create an account: https://www.foc.us/customer/account/login/
  2. Log in with the account
  3. Connect your V2 doc to your capable PC (or Mac)
  4. On the left of your screen (once logged in), select “My Downloadable Products”
  5. Click the “Microsoft Software” (or Mac) download button and install
  6. Run the installed application and allow it to check and upgrade your V2 to the latest firmware

Apps

An Android app is available (search for wave tdcs in the store.) An iOS app for the V2 is due anytime (the old V1 app does not seem to work with the current V2 firmware.) I will say that the on-screen display of the foc.us V2 is so good and so versatile that I’m not convinced that the apps currently add much value. Transcranial Ltd. is soon to release a EEG capability called “Quantum” that will apparently link to the V2 – and will probably make the apps very functional and important to use.

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(foc.us Android app)

Anyway, you must pair the foc.us device to your Android or iOS device to use an app. Here are normal pairing procedures:

  1. Make sure Bluetooth is turned on on your Android or iOS device
  2. Turn on the foc.us V2 and scroll to Settings, Bluetooth, and make sure Bluetooth is On.
  3. Very quickly your handheld device should find the foc.us device and request you type in a code number that you will find displayed on the foc.us device. Do that and you are ready to go!
  4. Run the foc.us app, set the desired mode (tDCS, etc.), max voltage (20 is typically fine), current (1 to 2 mA), time (typically 20-25 minutes), sham should be off, and START

I’ve noticed that the Android app does not display remaining session time.  You can see it easily on the foc.us device by tapping the blue joystick.

More Detailed Instructions?

Like most tDCS vendors, Transcranial Ltd. is trying to stay off of the FDA’s radar by making it clear that they are not producing a medical device – so they shy away from writing application guides and notes. This frustrates some. Users are left to their own creativity to learn how to properly use and get full advantage from a foc.us device (V1 or V2). To help V1 headset users, I wrote a pretty detailed set of instructions ( see http://bit.ly/1FSf6wb ) that seem to be popular.  Would you like an equally detailed set of instructions for the V2? Let me know – if there is sufficient interest I’ll be happy to put that together.

Finally, I’ve taken a good bit of heat via email and blogs for being a fan of foc.us. Unlike some, I saw very early on that their unique product(s), if used correctly, could be used to improve the lives of many – and that has turned out to be true. Foc.us continues to be one of my favorites in the world of tDCS and cranial stimulation and I, for one, anxiously await their next DIY leading-edge products and the pace they set for the industry.

I look forward to your comments and questions.

Brent

brent@speakwisdom.com

Notes:
1. Photos in this blog are from the internet and include images from foc.us and speakwisdom
2. If you are new to tDCS, please read and study carefully before taking any action related to tDCS or any cranial stimulation technology.  I suggest as a starting point:
a. speakwisdom.wordpress.com/tdcs/
b. diytdcs.com
c. www.reddit.com/r/tdcs
d. http://www.pubmed.gov (search for tDCS)

Summer is Here! Time for The Brain Stimulator Travel Model!

Travel Model Advanced 2x2 Kit - Unplugged_NEW
(The Brain Stimulator Travel Model shown with available electrodes, wires, and headband. The tDCS module itself is very small and easy to transport.)

I am a longtime fan and proponent of tDCS.  There is plenty of evidence that this simple, safe, technology can be used to reduce or eliminate depression, treat chronic pain (including migraine headaches), enhance memory and learning, and more!  If you are new to tDCS, take a look at the index of tDCS articles I’ve posted at https://speakwisdom.wordpress.com/tdcs/

If you are looking for a high quality tDCS device that also happens to be ideal for summer travel, you should consider “The Brain Stimulator Travel Model”.  This is a well-built, basic, tDCS device that can deliver 1 or 2 mA with the flick of a switch and can stand-up to being repeatedly tossed into a suit-case or travel bag, jostled around, and still come out ready to go and deliver a reliable tDCS session.  Depending on the configuration you buy, it can cost as little as $55 – or a bit more with high quality electrodes and other accessories.

The Brain Stimulator Travel Model also makes an excellent first tDCS device or a supplemental device if you already own something more sophisticated.  It is built by JD Leadam and his team at Neurolectrics – real pioneers in the DIY tDCS marketplace.

 

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(The packaging of the devices is simple, neat, and able to withstand travel related abuse.)

Neurolectics used a tried and true design built around a current regulator and a 9 volt battery. It’s simple, safe, and reliable – but because a 9 volt battery is used as its energy source, it is very important that sponge-electrodes be used and that they be well wetted with a saline solution in order to assure delivery of 1 or 2 mA (depending on switch setting).

I always prefer that a DIY tDCS device have some monitoring capability (digital or analog meter) to assure that the desired current level is being delivered. Neurolectrics chose not to take that path with this device – I assume to keep cost at a minimum and the package as small as possible.  If you are a frequent tDCS user, I’d suggest changing the 9 volt battery every couple of months – and again – be sure to use well wetted sponge electrodes to help assure you receive the selected stimulation level.

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(Neurolectrics places all significant components on a nicely manufactured PC board. This limits point-to-point wiring and makes for a more reliable device – important for a travel device.)

The Brain Stimulator Travel Model could not be easier to use!  Simply wet the electrode sponges, place the electrodes as desired with a headband, flip the switch to 1 or 2 mA, and begin timing your tDCS session (20 to 25 minutes is typical.) When done, switch off the device, take off and stow the electrodes and you are done.  If you really are traveling with the device, I suggest you remove the sponges from the electrode shells and place them in a small water-tight container.  You should also wash them frequently with good soap and plenty of water to prevent anything undesirable from growing in them!

I’ve taken several trips (including through airports and airport security) with the The Brain Stimulator Travel Model and found it to be quite handy for personal use and for demonstrating tDCS as seminars.  Don’t expect any flashing lights or fancy meter with this unit.  It’s basic tDCS – and it works.

Visit the Neurolectics website at https://thebrainstimulator.net/

I welcome your comments and questions.

Brent

 

 

Using the foc.us V2 with the Gamer or Your Own Electrodes

Introduction

In part 1 of my series on the new foc.us V2 tDCS device, I introduced the basic components of the V2 as well as its user interface. I continue to be pleased with the V2 as a user and want to pass along some ideas related to electrode use.

The foc.us Gamer Headset

Foc.us offers two headsets for the V2, the Edge and the Gamer. The EDGE is a special purpose headset designed to facilitate experimentation and research on the use of tDCS to improve athletic ability. As I mentioned in the last post, this is an area of tDCS that is ripe for exploration. A few studies have already been posted that hint at possible uses for tDCS and improvements in physical ability. This will be a very interesting application of tDCS to watch as results from various tests are posted. The EDGE headset is not a general-purpose tDCS headset and should NOT be selected by most users.

The GAMER headset is a more versatile headset for the new or experienced tDCS user. It is made up of a flexible metal band and two electrodes that attach to the band. It is highly adjustable for head-size and comfort. “Out of the box” it is designed to allow stimulation of the pre-frontal cortex, an area associated with memory, learning, etc. It happens that the electrodes of the GAMER can be used independent of the included band – allowing electrode positioning for “savant learning”, treatment of chronic pain, depression, etc. Note: the electrode plainly marked “Left” on the inside of the sponge frame is the anode (+) and the electrode marked “Right” is the cathode (-).

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(The Gamer headset.  Best choice for most.)

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(The Gamer headset in its case.)

 

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(The Gamer on my “test head”. Note electrodes are positions over the pre-frontal area.)

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(You can use the Gamer electrodes without the supplied metal band and place them where you want. Here I’ve used an elastic band to position the electrodes for “savant learning”.)

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(Here is another example with the electrodes positioned to treat chronic pain. In this example, the cathode would be placed on the upper arm or shoulder with another band.)

UPDATE – March 2015

foc.us has updated the firmware on the V2 so that the resistor that tells the tDCS module which headset is connected is no longer needed.  FURTHER – they are also released a patch cable to make attaching 3rd party electrodes even easier. See (  http://www.foc.us/tdcs-tens-cable-adaptor ).  The text below is left for historical reference only.

Using Your Own Electrodes (Amrex)

If you are pretty good with a soldering iron you can easily adapt any electrodes you prefer for use with the foc.us V2. The jack on the V2 tDCS device is a four conductor, 2.5 mm type that has been used on some cell-phones and portable audio gear. Connect your electrodes to a four conductor, 2.5 mm plug and a small resistor and away you go!

Plug Wiring

Tip and Ring 1 – a resistor across these two tells the tDCS device the model of headset connected. (300 ohms for the Edge, and 2,000 ohms for the Gamer by my measurements)
Ring 2 – Cathode connection (-)
Ring 3 – Anode connection (+)

To test this, I used a small RadioShack proto-board and broke out the 4 conductors for easy investigation and tinkering. I used a 100 and 200 ohm resistor in series to get the 300 ohms needed to let the V2 “think” I am connecting an Edge headset, even though I use popular Amrex 3x3s. Actually it seems not to matter whether the V2 thinks an Edge or Gamer is connected – you can still set all the desired tDCS treatment times and current levels.

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(Note the four conductor plug. It is broken out on the proto-board with T, 1, 2, 3 as described above. I use this example with Amrex 3×3 electrodes.)

Perhaps in future firmware, foc.us will include special features for 3rd party headsets that use a different resistance identifier.
BTW Soldering wires to a four conductor, 2.5 mm plug is not for the faint of heart. It’s very easy to short contacts and generally make a mess. I suggest buying a pre-wired 2.5 mm plug from Parts Express (or similar). Their part number is 090-504.

Summary

So there you have it. I suggest that you either buy the foc.us GAMER headset with your V2 and use it as is or with your own headband as I have shown above – or do your own thing with a 4 conductor plug and whatever electrodes you prefer.

Please feel free to send along comments and suggestions related to this post or a future one you would like to see.