Vision Therapy and tDCS (2): How and what?

First of all I want to thank my buddy Andrew for blazing this trail. I knew about TMS and tDCS but I was not planning on trying it myself anytime soon. That was until he figured out what supplies were needed and had successfully tried it on himself with promising results. I'd like to refer to some of his blog entries to get you more acquinted with his DIY vision therapy tDCS adventures.

- http://vtwithsyntonics.blogspot.be/2013/11/167-session-tdcs-with-syntonics.html
- http://vtwithsyntonics.blogspot.be/2013/12/170-session-tdcs-works-very-well.html
- http://vtwithsyntonics.blogspot.be/2013/12/reddit-discussion.html
- http://vtwithsyntonics.blogspot.be/2013/12/174-session-sensory-fusion-driving.html
- http://vtwithsyntonics.blogspot.be/2013/12/178-session-what-tdcs-seems-to-do.html

He even made a video tutorial breaking down what's involved in setting up tDCS.

So I bought a Chattanooga Ionto Dual Channel Drug Delivery Phoresor Device, four 2 by 2 inch Mettler sponge electrodes, a couple of stereo wires and two hair bands. There are cheaper devices but I like to put current through my brain in a reliable manner. It took a while for all that stuff to get here, but finally it did. I bought the stereo wires in a local electronics store and some hair bands in a shop called Claire's. Turns out one never knows when he is going to need French women's accessoires.

Some more interesting resources and tutorials in addition to the research papers I mentioned in the previous entry:
- http://www.jove.com/video/2744/electrode-positioning-montage-transcranial-direct-current
- There's a pretty numerous tDCS community on reddit
  http://www.reddit.com/r/tDCS/comments/1apltw/tdcs_setup/
  http://www.reddit.com/r/tDCS/comments/1procy/chattanooga_ionto_how_do_i_start_using_it/
- Video on the physiological effects of tDCS

- Video on clinical applications of tDCS

Really cool video, check it out.  tDCS approaches to paresis, motor learning, reading, aphasia, visio-spacial neglect, pain, depression, ... Some pretty awesome information in there. On YouTube you can find related videos from that same conference.


What can I say about tDCS after using it for one week?
Because the device has two outlets you can use four electrodes, that is 2 anodes and 2 cathodes, at once. However I thought I'd start slowly and only used 1 anode and 1 cathode this week. The amount of current I applied was 2 mA for 20 minutes twice a day. The 'conventional' idea is that the anode excites the brain region it is placed on and the cathode inhibits the brain region it is placed on. If you wet the electrodes appropriately tDCS does not really hurt. Just some minor irritation on the skin in the beginning of the session and then it fades away.

I tried two kinds of electrode placements this week.
- The anode on the right side of the occipital lobe, that is the right hand side of the visual cortex.
The cathode was placed more or less 8 cm lower almost on the left neck/shoulder. This way I get to excite the visual cortex, hit some of the cerebellum and then the current exits below.
- The anode placed on the right or middle of the occipital lobe as before. Instead of placing the cathode 8 cm down, this time I placed it 8 cm upwards over the top of the head also on the right hand side.

In both cases there is a subtle but noticeable difference. Subjectively the second placement felt a little more intense. It's not a dramatic effect but I feel like tDCS does intensify perception during the session and for a time after the session has ended. At the same time it feels stimulating and relaxing. I had read test subjects sometimes experience an altered sense of time perception. I did in fact feel like I lost track of time and was more focused on what I was doing.  As if I was more 'in the zone' and less distracted. Although I did  not experience things spontaneously getting bigger as Andrew described. I think that because all brains are different, also the strabismic ones, every tDCS experience will inevitably vary. Nonetheless I definitely think it's helpful tool for enhancing behavioral therapies. While stimulating I did a number of VT procedures like the brock string, bar reading, eccentric circles, saccades, tracking, balance boarding or just freely playing with my vision. I don't know whether it has to do with tDCS but this week I made the 'ten pages a day' mark with regards to bar reading. I couldn't do ANY bar reading prior January 2014 so that's nice!

The most salient effect for me was being more relaxed and having more energy this week. I was able to be more productive. I've been able to rise a little earlier without loss of functional vision (as would usually be the case). Those must be the 'connectivity driven remote effects'. You are not just stimulating the areas beneath the pads but entire neural networks.

I'm also going to revisit some of the papers I read because I remember other placements being used to enhance attention and perception. I think it might be useful to stimulate motor areas too, aside from solely focusing on the visual cortex. For instance, placing the anode on the motor cortex and the cathode on the frontal cortex as shown in the Jove video. After all, vision is just as much about motor learning as it is about sensory learning.  

It might be placebo or it might be the arrival of spring, but I don't think so. Next week I will start using both outlets and all four of the sponge electrodes. I'm curious to learn what the effects of tDCS will be over a longer period of time.

Vision Therapy and tDCS (1): Why?

When it comes to strabismus and visual processing disorders most of the medical community seems to have to luxury of living in the 19th century. Other parts of society however move on. Researchers, the military, professional athletes, educators, you name it... Visual training has been pioneered throughout the 20th century by many notable behavioral optometrists and is being confirmed by neuroscientists ever since they had some decent tools to work with. It's a fact. No doubt about it. Acknowledgement depends on whether you are really interested and motivated to solve the problem or not. So let's move on to real questions like how might one accomplish results more easily and improve functional ability and quality of life more quickly? How could we make a steep up hill battle less so by probing the brain to be more plastic by targeting specific areas of weakness?

From 'New perspectives in amblyopia therapy on adults'

I'd say eating and sleeping well combined with moderate exercise is a good start. Avoiding negative influences and toxic people isn't too bad an idea either. It has been said (New perspectives in amblyopia therapy on adults - 2011) that certain medications and anti-depressants can induce more plasticity and make one more receptive to neural change. Personally I'm not a big drug man. Often there's no way of predicting how a certain medication will interact with your particular brain chemistry. Moreover, not only does it take weeks for a certain course of treatment to take effect, it will also take weeks to get it out of your system if you don't react well to something. Since doctors don't really know your situation and just prescribe whatever and I always seem to react rather peculiarly to things, I am not getting in line to take pharmaceuticals for the moment. But that's just me.




But there's more. On top of all the 'conventional' evidence for perceptual learning, a lot of interesting research is being published about the effects of TMS (transcranial magnetic stimulation) and tDCS (transcranial direct current stimulation) on attention, perception and learning.
- Long lasting effects of daily theta burst rTMS sessions in the human amblyopic cortex (2013)
- Anodal transcranial direct current stimulation reduces psychophysically measured surround suppression in the human visual cortex (2012)
- Anodal transcranial direct current stimulation transiently improves contrast sensitivity and normalizes visual cortex activation in individuals with amblyopia (2013)
- From motor cortex to visual cortex: the application of noninvasive brain stimulation to amblyopia (2010)
- tDCS guided using fMRI significantly accelerates learning to identify concealed objects  (2010)
- The role of timing in the induction of neuromodulation in Perceptual learning by Transcranial Electric Stimulation (2013)
- Anodal tDCS to V1 blocks visual perceptual learning consolidation (2013)
- Battery powered thought: enhancement of attention, learning and memory in healthy adults using transcranial direct current stimulation (2013)

I've read or, more accurately, listened to some of those papers completely and some of them partly. The 'conclusions and future directions' as stated in 'Battery powered thought' provide a good overview of what the technique might offer: "Intriguing results have been demonstrated using tDCS for cognitive enhancement in healthy volunteers, and some studies have additionally found positive effects of tDCS in clinical populations. Though much more research is needed, cognitive enhancement with transcranial electrical brain stimulation may even eventually be accepted as an alternative form of treatment for clinical populations, and neuroenhancement for healthy populations. Compared to other techniques, tDCS offers many advantages due to its relative safety, noninvasiveness, low-cost, and portability. Research into the effects of tDCS on cognition will undoubtedly continue and, along with other brain stimulation methods, may spark a new age in the way we think about treating neurocognitive dysfunction." 

As you can see from some of the research titles, not all of this research is conclusive. On the other hand, there's definitely something to tDCS. It's not just a smoke screen. The US military for instance uses TMS to enhance perception and perceptual learning in drone pilots. I'm sure it sounds pretty crazy to run electricity through your brain but if you really start thinking about it, it makes an awful lot of sense. The small amount of current is not dangerous and is far more targeted than taking pills, few or no side effects have been reported, it doesn't take weeks for it to work or get off it and it's cheap. Since the brain is an electrochemical mass I'd rather add some electricity for a small while with the option of just taking the electrodes off my head than taking pills for weeks before knowing what is up. Because of these advantages, I'm sure we are going to hear a lot about tDCS in the future as its applications are numerous.

Since it is a low cost technique and I don't have any more time to waste, I bought tDCS supplies online and with some help from a strab friend I went for it. By the end of this week I'll summarize the details and my experiences in part 2.