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Comment by npalli | Hacker News Reader

Anyone who wants to see the dramatic impact of deep brain stimulation needs to see this video[1]. Just by turning off and on his neurostimulator (see starting 2:00-ish) see the dramatic change in his body.

[1]http://www.youtube.com/watch?v=uBh2LxTW0s0

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To clarify the above, the video starts with the deep brain stimulation device turned on. The changes mentioned are due to the Parkinson's Disease effect showing themselves once the DBS device is turned off.

That's a really interesting video on this debilitating disease. Are there any notable examples of where DBS has failed or what could entail as "the risk" of undergoing such a surgery?

I have a friend whom I can refer about this procedure.

DBS surgeries are somewhat invasive as they involve sticking a 3mm electrode all the way through cortex and deeper structures into the basal ganglia. That being said, anecdotally I believe the side effects are mostly modest, though can't speak on that authoritatively.

http://www.mayoclinic.com/health/deep-brain-stimulation/MY00...

it's actually not too bad. There is a small micro electrode that is sub-millimeter, and the DBS electrode itself is ~1-1.5 mm depending on the model.

The one traumatic part of it is that some groups use a device popularized by some of the French groups that use a 5-microelectrode array for the mapping portion of the surgery, which has a 4x4 cross sectional spread. This probably pins and destroys a lot of the brain tissue in its path, but the people who use it claim it gives them "better spatial resolution" in the mapping recordings. Which doesn't apparently improve overall accuracy anyway, but some people are married to using that damn device.

Most surgeons in the US use 1-3 single electrode passes sequentially, which is a lot better.

Truth be told, these are early days even though we have used stimulation for a while now (artificial cardiac pacemakers). After all, this is brain surgery. You implant electrodes bilaterally into the deep brain (thalamic region for Parkinson's) and send small shocks. The hope is this in turn will impact the neuronal signaling that causes excessive or too little movement. In addition, it is not clear what the signals do the nearby neurons (question: do they die and in turn what happens to other brain functions etc.) and impact over longer term as you keep stimulating (what happens to the neurotransmitter responses etc.). So, definitely a lot of studies like the DARPA one need to be undertaken.

So the usual caveats apply. You need to have tried other means (pharmacological, exercise), need to be healthy and willing to risk adverse consequences. In the case of the video linked, it is somewhat of a no brainer. The person is young 39 years old with a family. He seems to have a pretty bad case of Parkinsons. I'm sure he is willing to enjoy a much better quality of life even if it is risky.

Actually, DBS has been around since the 1980's, just Medtronic sat on the patent and it was little more than a glorified converted cardiac pacemaker. now the patent is up, all of the sudden all sorts of research into closed-loop stimulation, electrode designs, battery design, etc suddenly pops out of the woodwork.

They're trying to do some sort of closed loop feedback instead of some clinician inputting random settings of volts/frequency/pulse width into the device, but no one knows exactly what signals in the brain to listen for yet. The EE-oriented neuro types are looking at signal processing, i.e. using FFT's to look at power spectra of local recordings, etc, but nothing too promising yet.

As far as what the physiologic mechanism of the electrical stimulation does, no one really knows, but there's some data from monkeys and mice optogenetics suggesting it activates passing axonal fibers. Generally, nerves don't die due to the electricity, unless your surgeon does the implant French-style and shoves a 5-microelectrode array into your head, therefore boring a nice 2-4mm tunnel into your brain...

Typical risks - there's a 1-2% prevalence of hemorrhage which usually isn't too bad. It's really rare to have a major event. The other major risk is infection (as with all implanted hardware), or device malfunction.

Otherwise, the most common side effects that could happen is that the stimulation causes some spasms or tingling. There's some hand-waving as to whether it may increase susceptibility to depression or falls, but that is hard to tease out between disease progression.

Of note, if it's Parkinson's, one hard part is that the meds will have to be adjusted a lot post-op which cause some folks problems.

It's pretty terrifying what the implications of this could be. Want super soldiers who will obey any order given? I imagine they'll try to experiment with this kind of control mechanism.

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