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.

Alternation, cyclopean eye and the attentional spotlight

As my eyes are aligned most of the time by now I have no real concept of alternating between both eyes anymore. Despite the mechanical alignment of my eyes, I still do not use them equally. My vision still seems to be rather lateralized to the right. When I intentionally give myself double vision by moving my eyes apart, the image from my right eye is still the 'main image' and the one from the left eye feels secondary. In fact, in double vision mode I can still alternate. I can switch main images and make the one from the right eye 'secondary'. So my subjective viewing perspective is not yet positioned in the middle of my head. My cyclopean eye is not positioned behind my nose. Most of the time I'm seeing the world from the right side of my head (subjectively, because this probably indicates there's a strong lateralization towards the left hemisphere). This means that even though my left eye nicely follows my right eye, it's still not an equal part of the team.

I'm doing a couple of things to actively work on that. As mentioned in previous entries I apply filters or transparent tape on my glasses to blur out vision in my dominant eye putting the left eye in charge. This changes the entire visual situation to the other extreme without entirely discouraging binocular eye teaming. I do this while doing all kinds of activities and it is effective in regaining and integrating the left eye into the visual system. But lately there's more... Aside from actively training, it is equally important in my experience to relax and just play with your perception. Often I lie or sit down and let my eyes wander around having things go double. Rather than constant pathological diplopia or double vision this is controlled physiological diplopia I can instantly resolve at will. So during those playful sessions I give myself double vision (vergence), blur and unblur my vision (accommodation) and more generally flex my visual system without overdoing it. Then I try to focus my attentional spotlight in between  the two images so neither one of them is the main or secondary image. I'm trying to rebalance the equation by relaxing, playing, flexing, dreaming, focusing attention in the middle of the double images. It's pretty cool but the circumstances need to be right. One of the biggest problems facing visually impaired people in recovering is intolerance and lack of understanding. After all, I'm well informed  now and I found a place to rest my head but things have been different...

Another interesting topic I wanted to bring up again is how awesome bar reading is. I think this exercise is so cool because of its simplicity and capacity to combine cognitive integration while doing visual exercise. It also clearly shows that visual problems are a biology problem, not a technology problem. All you need is a piece of plastic, cheap glasses, a book and a peaceful environment. In the past I would clearly express to other people how I had to chose between eye alignment or cognitive activity like reading. Not that they'd understand. :) That situation of course makes it very hard to read if you experience double vision rather than suppression... Now I'm entering a stage where I can more or less do the visual stuff and the cognitive stuff at the same time. The line between the visual brain functions and other cognitive abilities is blurry at best so we might just say overall capacity is improving. Reading comprehension while bar reading isn't very good but I'm trying to go for good visual exercise rather than intellectual distinction for the moment. In adherence to this idea, I'm going to try paint an old chess board in red and green colors. That would be nice visual and cognitive integration too if I can make it to be 'cheat proof'.

This week I finally received all supplies needed to try tDCS and I will do it this weekend. To be continued...

Free anti-suppression Solitaire

Get your red green anaglyph glasses and play anti-suppression solitaire. All you need is an internet browser so it works on any platform.

Download the game here

Code by Ed Spencer
Color adjustments by Mark Berbezier

Enjoy!

Pursuing a higher degree of visual freedom

In my last blog entry I talked about 'visual reserves' and how important this concept is for long term comfort and for VT to be successful. The improvement of eye lens focusing and eye movement amplitudes individually is not enough for it to stick. You need to be able to execute those visual skills simultaneously, effortlessly and automatically.

Another great illustration of this processes by Dr Maino is shown below. Mastering those skills paves the way for further consolidation and visual/sensory development of the brain.

Check out the entire slide show for more informative illustrations like these:http://www.slideshare.net/DMAINO/what-is-lazy-eye.

At this point in time, I feel like I'm oscillating between the orange binocular box and the integration stabilization box. However it's not that clear cut. As you do a lot of integration, stabilization and loading, those skills also keep getting better individually while improved timing and daily application make for even more added value.

When it comes to eye lens focusing (accommodation) and eye movement (vergence), I have clear single vision under relaxed, undemanding circumstances. But that's not enough to live a proper life, so you want to go beyond that. To accomplish that you need to artificially separate the accommodation and vergence distance. 

Nice examples of these are cross-eyed 3D photos and parallel viewing stereograms. In case of cross eyed 3D photos, the vergence distance (the intersection of the visual axes) falls in front of your computer screen whereas the accommodation distance is the actual distance of where your screen sits on the desk. You have artificially dissociated both processes.

On the other hand, in case of parallel viewing stereograms the vergence distance is way farther than the accommodation distance. You have to be able to do some serious visual flexing to accomplish both these artificial situations. This kind of visual gymnastics will grant you some nice 'visual reserves' over time.

A classic VT exercise based on the same principle is the aperture rule. Even though you can in principle do the same thing with a computer screen, I very much like the simplicity of this gadget. It's easy to use and makes you jump through the right hoops in order to achieve the same goal. By adjusting the aperture slide you gradually adjust difficulty and have a frame of reference to keep track of your improvements.

In VT the expression 'degrees of freedom' is used in describing the process of building a stronger and more flexible visual system. I very much like that expression. It's accurate in describing the process and correctly implies that visually impaired people are less free in acting, interacting and participating. It also infers that there are degrees in the way that strabismics are affected and no two strabismics are the same.

Susan Barry once said 'You can control your vision and you are learning how to take control'. It's true but it still sucked at the time. After all this time I've already gone from a situation of constant involuntary double vision to one where I can cause myself to have single or double vision at will. I'm well on my way of eliminating my eye muscle palsy. As I gain more control over my vision, I gain more control over my life. I gain more degrees of freedom.

Improvement of accommodation and vergence amplitudes is not enough

I was going through my things and found a piece of information I vividly remember reading and highlighting two years ago. I was very excited to see something I already intuitively grasped written in the 'Optometric Clinical Practice Guidelines ' for dealing with 'Accommodation and Vergence dysfunction'. What an emotional moment it was. I was excited and somehow releaved... I was not going completely insane. At the same time I felt cheated by every doctor I had ever seen and a lot of work was left to be done under difficult circumstances. But at least someone in the world knew what they were talking about and that's something. It's amazing... All this information is freely available online and no one seems to care about it!

Two years later I'm still excited about this paragraph. Maybe even more so because that ultimate 'goal of vision therapy' as it is described has come a hell of a lot closer. To simplify, by vergence is meant the ability to move your eyes towards and maintain appropriate posture and by accommodation is meant the ability to manipulate the shape of your eye lens with the help of tiny little muscles in your eye. It's all managed by the brain and these visual abilities have to be performed at the same time at a level adequate for comfortable vision. It all has to happen in one synchronized motion or things get messy. Back then things were very messy. Vergence was all messed up by strabismic brain development and surgical intervention. Accommodation was all cramped up too. Constant double vision, poor and inconsistent performance of the visual system and wasting massive amounts of energy. This is one of those things that if you try harder, it will get worse. Once you stop trying so hard and relax, things will start to fall into place. These visual problems are not rocket science... You just have to detect them, explain them to the patient/parent and make sure no one gets in the way of recovery. In the search for solutions the right kind of motivation is important. You have to really care. You have to handle the problem as if it is YOUR problem. Clearly that kind of motivation is often lacking these days...

When talking about 'vergence and accommodation dysfunction', it's important to note that we haven't even scratched the surface of what happens when your brain develops amblyopia. We're just talking 'simple mechanics' for the moment. (If amblyopia were to occur or has occured because of lack of prevention or binocular treatment a lot can still be done and the American Optometric Association guidelines for Amblyopia are pretty neat too.)

To get back to my excitement... Lately I often use the phrase 'my vision is leveling out'. By this I simply mean that I possess the reflexes to maintain eye alignment and a clear image the overwhelming majority of the time. Also while doing funky head turns, running, playing basketball, ... The whole caboodle. Until I get really, really tired or tense. Let's say that if vergence scored 20/100 on a random, relative scale two years ago, it now scores 100/100 in comparison. I just about get by for simple, daily living. I have more control over accommodation too which is great for the syncing up process, although my prescription has not radically changed.

Alright, so from the inside of my head the visual dysfuction is less blatant than it was two years ago. Mostly undoubled vision unless you put me in a stressful situation (like reading more than 20 minutes haha). BUT as the paragraph states 'Improvement of amplitudes is not sufficient'. 'The goal of vision therapy is to establish automated, effortless accommodative and vergence responses under any stimulus condition.' 100/100 is not enough. To be comfortable you need 'visual reserves'. You need more than just getting by. You need 200/100. You need to be able to maintain visual performance when things get tough. Not only that, you need it so you can actually focus on seeing rather than trying to see. As my VT friend Matan told me earlier, the most profound changes don't result from improved eye movements. The most changes happen when you can execute those flawlessly and effortlessly. Then the perceptual and cognitive gates really start to open up. Based on the rather radical changes that have already been achieved over the last 3 years, I don't see why that final goal would be out of reach. Ahhh man, this stuff is so exciting and it's basically just a matter of time at this point!

In a following post I'll try to explain how the aperture rule or its computerized equivalents of cross eyed 3D pictures and parallel viewing stereograms are useful in cultivating 'visual reserves'.

Matan Drumer on living with and overcoming Convergence Insufficiency

Previously I wrote about how lately my situation more resembles a Convergence Insufficiency profile rather than a manifest strabismus profile. Most of the time my eyes are grossly aligned and I'm aware of both images although I do have some remaining surround suppression. My cyclopean eye is also still somewhat positioned to the right side of my head. Traditionally I used to be an alternating esotrope with a dominant right eye but after some surgeries the situation has gotten a lot more complex. For the moment the issue most impeding me from being more functional and productive is the inability to comfortably converge causing me to have double vision while reading and making it a highly stressful activity.  I've been in this VT game for a while now and I am not worried that in time with the proper lifestyle this will improve and can be remediated.

Looking through both eyes but being unable to sustain convergence... That sounds like the situation my VT friend Matan Drumer (31) experienced before entering VT. Matan entered VT  at the age of 27 after figuring out CI was the thing keeping him from reading properly and advancing academically. It's impressive he was able to pinpoint the problem and take constructive action towards a solution. That's always the first step. He engaged in an intensive year of visual training followed by another year and a half of less intensive training. The changes he describes are profound and encouraging!

How did his life improve?
1. Before starting Visual Training he used to be tired all the time. This is not the case anymore.
2. He could not pass his driving test. He would lose concentration because of the abnormally high amount of physical exertion needed to coordinate his eyes and see. Using his mirrors correctly and figuring out his relative position to other vehicles seemed impossible. Joining traffic and changing lanes was very risky. He felt like a gambler while driving. No longer.
3. Previously studying had not seemed sustainable and he was forced to pause his studies. After his reading improved by ameliorating eye teaming, he was able to resume them.
4. He feels a lot more comfortable in social situations now. He feels like he can be more open en relaxed around people because he feels more in control of his body and can anticipate and read others' intentions better.

He emphasized that improved ocular motor and muscle control is only the start of a series of amazing changes. Once he learned to operate his eyes and eye muscles correctly and effortlessly, the perceptual changes were intense and overpowering. He feels most people, even practitioners in this field, often don't really understand how visual improvement goes beyond motor and perceptual changes and into the functional and social realm. 'It feels like an awakening.'

Nowadays he still experiences (visual) ups and downs. There are days when Matan feels really sharp and it's easy to read. He confided that it feels like taking a drug. 'It's as if everything is "flowing". My reactions are fast. My thinking is quick. It's really cool.' On the bad days things are harder but never as hard as they have been before VT. I once asked Susan Barry the same question about ups and downs. She said 'I still have good and bad vision days. Only now the bad days are good and the good days are very good.' 

On the topic of stereo vision Matan is less clear. He thinks he had some stereo vision before VT or at least some of the time. He has always viewed the world with both eyes but that might have made bad eye coordination all the more confusing. He is however positive that VT has enhanced his stereo vision and his ability to navigate space allowing him to get his driver's license.

Naturally I was curious about what exercises he had done to accomplish all that. He talked a little bit about the famous Eccentric Circles and the Aperture Rule. Incidentally I myself have rediscovered the Aperture Rule this week and am enjoying the exercise much more as 'perfect execution' (who are we kidding :)) gets closer and closer. Knowingly he added that in many cases the 'how' you do a VT exercise is more important than the 'what'. I couldn't agree more.

Experiences and stories like these will certainly keep me going for another year as I eliminate my residual CI. As ocular motor skills keep improving, all these great improvements Matan is talking about might be just around the corner!