14 September 2009

At the International Neuromodulation Society conference in Seoul 4

15:46. Departing Hongje subway station for the last time. Tomorrow is the last day of the conference and there are no brain-related talks so I'm gonna go hunt big shiny buildigs. Got three more days in Seoul. I'm very happy I had the opportunity to go to this conference. Learned a lot, particularly about the current state of deep brain stimulation (DBS) for psychiatric conditions, which I'll come back to, but I also met at least one guy I hope to stay in touch with, and got to talk to some surgeons who literally stimulate the reward system on a monthly if not weekly basis. And more than that, just the feel of it: all these doctors, their attitude, their training, their responsibilities - it's helped me understand why Laura says if it wasn't for science she'd probably want to become a medical doctor. There's a certain weight to what they do and how they think: they're the only humans allowed to cut into other humans. They will decide whether conditional rewarding brain stimulation methods (iPlants) are put to human use, and the question will be exceedingly straightforward: can it help patients? That's the question that matters. People who think surgery for psychiatric conditions is existentially wrong need to go away, I've seen and heard some horrible stories these last few days (and I didn't even attend the pain talks). One patient with OCD could not stop scrubbing her baby, she knew it was senseless but couldn't stop, social services almost had to take the baby away. Another was utterly unable to leave the house. Etc etc.

My main observation from this conference is that DBS to the reward system, specifically to the ventral striatum and typically the nucleus accumbens, is attracting a lot of attention, and is being performed more and more frequently for a growing number of psychiatric conditions. OCD, depression, anorexia, substance abuse: they all form a cluster, with conspiciously high co-morbidity, that benefits from strong current being applied to the reward system. What I'm gonna do now is read this one mammoth review on DBS to the accumbens (Greenberg et al 2008) that people kept referring to and then make a video on this.

Will we see DBS to the reward system in people who are not extremely ill? The procedure is FDA approved in the states for up to 5000 patients this year whereas, I was glad to hear, its EU approval (called a CE mark) has no such upper limit. But there are reasons the procedure is last resort. Surgical complications (primarily bleeding) still occur from time to time and there are recurring side-effects, possibly due to tissue damage. More importantly, there are long-term problems regarding displacement of the electrode, buildup of scar tissue around the electrode and depletion of the battery within months, all of which require constant follow-ups and interventions. Head trauma, or even a rough shake of the head can dislodge equipment and cause problems. All this equals risk, but also cost. One speaker working on anorexia in China told me the preferred treatment was DBS to the accumbens rather than capsulotomy (a relatively simple lesion), but that often the family simply could not afford the expensive implant.

That said, these problems are common to all forms of DBS and are enthusiastically worked on, not least by the corporate sponsors of this conference who want to sell more implants and have exceedingly deep pockets. Moreover, as I wrote yesterday, the possibilities of conditional rewarding brain stimulation are beginning to receive serious attention, and if you've read through the iPlant site or watched the videos you know iPlants could benefit many more than just the extremely ill and thus create a wider market that would drive down cost. So we'll see, things are definitely moving.

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