It's worth noting that I am participating in rTMS as part of a clinical trial, which means data from my treatment will be collected and possibly used for research and publication purposes. I'm quite happy with this, as I believe in scientific advancement. I was relieved to know that this is not a randomized double-blind trial, which would have involved the use of 'sham' coils in some of the participants (in other words, a placebo coil that replicates the external conditions of rTMS but without the application of any actual current). Although I believe these kinds of trials are absolutely necessary for scientific advancement, at this point in my life - and at this point in my current depression - I would have been unwilling to try anything that would definitively have absolutely no effect at all.
Moving onward.
The first thing that happens is I go to the Douglas and look at this awesome sign in the waiting room:
Of everything I've been through, nothing quite brings home the fact that there's something wrong with my brain more than this sign. It's both comforting and daunting to think in terms of brains as the problem here. I can't reduce this illness to a moral failing, to not having tried hard enough, to some sort of problem in the way I make decisions and the effects of those decisions. Those are all factors in what it means, for me, to live with depression. But, somehow, I am not responsible. Because this is my brain, my body, going wrong. In a way I feel like I'm being betrayed by my own body, which brings up all sorts of old and new emotions. In a way I feel helpless, because my brain isn't something I can control in the way I could take responsibility for, say, consistent moral faults. In a way I feel relieved, because I can lay down the burden of feeling like my enduring depression is my own fault.
So, after looking at this sign for a while, the technician administering my treatment calls me into a room. I sit on a comfortable, mostly-reclined chair with a pillow on my lap that I can rest my hands on. RTMS utilizes a biphastic magnetic stimulator (coil) to indroduce an electrical field in a targeted area of the brain. The charge is greatest at the edges of the coil, and drops rapidly to null as you move further away from the coil. Hence, rTMS is much more targeted than ECT, and much less targeted than what would happen if you inserted an electrode (or 'brain pacemaker') into the subgenual cingulate (BA25) and turned it on.
During my first-ever session, and once a week for the duration of treatment, the coil was positioned over my left primary motor cortex, which you can sort-of visualize the location of by putting a headband on your head directly in front of your ears; the motor cortex starts above the ear and follows the trajectory of the headband. The technician moves the coil around about 7.5 centimeters above the ear, finding the area that causes the right thumb to twitch. This feels very weird, and very cool. Your thumb really moves without any volition, it's awesome! The minimum intensity of current necessary to cause the thumb to twitch is called the motor threshold, and this measure is used as benchmark throughout the course of your treatment. The stimulation intensity during treatment begins at 100% of the motor threshold and is increased by 5% each treatment until you are receiving pulses at 120% of motor threshold. This allows a consistent measure to be used across the sample and provides a means of standardization. It is, however, somewhat problematic to assume that motor threshold is an accurate indication of activity in the prefrontal cortex, but this strikes me as a minor quibble.
Anyway, once motor threshold has been established, the coil is moved to the area of the brain that will be stimulated during treatment. The technician draws on your head to find the correct area, in my case the right dorsolateral prefrontal cortex. This is because we're using the alternative protocol: most people receiving rTMS for major depression will have the coil placed on the left side of their head. The theory underlying rTMS is that people suffering from major depression have lower levels of neural activity in the left prefrontal cortex than in the right. Ordinarily, rTMS uses 'fast' stimulation at a rate of 10 pulses per second (10Hz) for 4 seconds, with 26 seconds of rest between bursts. In my case, I am receiving 'slow' rTMS, at a rate of 1 pulse (1 Hz) per second for about 20 minutes. I'm not sure if this protocol was chosen based on my symptom profile, if it's because I also have PTSD, or if it was randomized. I hope I have a chance to ask!
'Fast' rTMS is excitatory, causing the stimulated left prefrontal cortex to 'speed up' to the same rate as the right. 'Slow' rTMS is inhibitory, causing the right prefrontal cortex to 'slow down' to the same speed as the left. In both cases, the aim is to synchronize the right and left prefrontal cortex. The DL-PFC is involved in executive functions like decision making, conflict or choice resolution, working memory, syllogistic reasoning, planning, and cognitive flexibility.
Because of the noise involved, I wear earplugs to prevent damage to the auditory canal. Because I have tiny, child-sized ears, I'm not able to wear things like ear buds, so I find the sensation of having earplugs in to be unusual and somewhat disconcerting. I think, for a normal person, this wouldn't be an issue. When the coil is active, I can hear the machine making between three and five sounds: I was also surprised that earplugs don't result in complete sensory deprivation! Of these sounds, I'm absolutely sure the machine is actually producing two of them. The first is the loud, hard-sounding sound make when a pulse is produced, and the second is the constant loud soft-sounding hum of the machine being on. Two of the sounds may be actually produced by the machine, but they might also exist entirely inside my head, either as reverberations or as products of my imagination. One follows the loud rapping sound of the pulse as a slight-delayed, softer, rounder sound that feels slightly fuzzy; the other is a constant low-grade high-pitched hum and may be a secondary sound of the machine being on. I find both these sounds to have a different timbre or texture than the first two. The third sound is one I only heard once, and it was a sort-of grinding or mechanical sound that happened when the coil was discharging.
As some of you know, I'm sensitive to certain kinds of sounds, partly because I have difficulty filtering and tuning them out. This is one reason I'm glad we're doing slow rTMS, because the rapid-pulse-then-silence pattern to fast rTMS is the kind of sound I find acutely anxiety-provoking. Yay for alternative protocol!
When the coil pulses, it feels like someone is tapping my head, and the area around my right eye twitches a bit. It's not uncomfortable, just a little strange. All in all, the experience of rTMS is not difficult, and kind of relaxing. I like to spend the time focusing on my breathing and on the roundness and quality of the sounds I'm hearing. And of course cuddling with Puffy, my magical unicorn, who comforts me when I'm feeling stressed out and anxious! I hope this gives you an idea of what I do with my day. :)
In terms of whether or not I've seen any difference yet, here's the breakdown. One person has said I seem to be smiling a bit more. One person has said my online comments are more sarcastic, which he thinks is a good sign! Personally, I've noticed that colours seem brighter and more saturated, and I spontaneously decided that I wanted to start taking pictures again (wanting something! It feels so good to want something!!). I tasted a subtle flavor the other day: banana! I have an easier time reading fiction, although I still have attentional gaps. I feel like I have more emotional lability, and my voice is less flat. These are all good signs. I do have a lot of exhaustion, which might be a side-effect of treatment. I still have a lot of difficulty writing, especially posts like this one that involve recalling, synthesizing, and integrating technical or scientific information. All in all, I think it's going well.
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