As you might imagine, just deciding you want to pursue Deep Brain Stimulation (DBS) as part of your PD management doesn't mean you immediately are approved. Because this is major surgery, you have to clear certain hurdles to qualify for the surgery. First and foremost, I think your first step is agreeing with your Movement Disorder Specialist (MDS) in concert with your care partner (in my case, my wife) that DBS makes sense. At a minimum, the 3 of you need to be in agreement this is a logical step.
Consultation
Once your key partners have agreed DBS makes sense, then you need to determine who and where you want to have the surgery done. This may be an easy decision if you live in a big city with lots of resources and have an insurance plan that covers your local neurosurgeon. It may be infinitely more complicated if you either don't have ready access to a DBS experienced neurosurgeon or want to consider other options than local or in network for insurance hospital.
In the US, it can be prohibitively expensive to go out of network, including up to having literally no cap on what your out of pocket expense can be. Do your research before assuming anything. Unfortunately, the reality of pursuing a major "elective" surgery like DBS requires a lot of follow up effort on your part. Be your own best advocate, it is worth it no matter how frustrating or unfair the experience seems.
You may want to talk to more than one neurosurgeon before deciding on the right path. If you are going to a hospital different than your MDS, you will also have to determine that you are comfortable with the MDS that will be in the room when your surgery takes place. I believe there is a lot to be said for the person who will be programming your device to be in the room when it is installed. Regardless, put on your advocate hat and ask EVERY question you have. There is absolutely no benefit to being shy or thinking something is not a good question. Remember, they are drilling holes in your head, you should know everything that is going to happen and why. Different surgeons have different practices, so you cannot assume anything.
Things that you may want to include on your list:
How many surgeries have you done? What results have you experienced?
What is your infection rate?
What placement do you recommend (STN or GPI)?
How many surgeries will I need?
Will I be asleep or awake?
Who will do my programming?
etc.
OFF / ON test
Because DBS results have a very strong correlation to L-dopa results, the specific effectiveness of L-dopa on your symptoms needs to be measured for you to qualify for the surgery. While this test is not fun and is time consuming, it is comforting to know that nobody wants to drill holes in your head without a very good chance it will help treat your symptoms.
As the name implies, your MDS will examine you with no L-dopa in your system (OFF) and then will examine you with your normal dose of L-Dopa at its most effective (ON). You will stop taking meds the night before. You will want to schedule the appointment as early in the day as possible so you don't have to go any longer than necessary without meds just from a comfort standpoint.
For me, that meant borrowing a walker that had a seat on it in case I couldn't walk in the morning. Just be prepared for the worst ... in my case, I was able to get to the MDS office with no issues. However, I did have a terrible dystonia episode in the shower and my wife had to help me get through that safely.
You can expect a regular exam (walk down the hall, open and close your hands, tap your fingers, etc.). You will get lots of questions from your MDS. Then you will switch to part 2. You will take your normal dose (in my case, my MDS crushed the L-dopa into a powder and mixed it with ginger ale to help speed uptake). Then you wait. In my case, my MDS, wife and I talked about DBS and he answered many questions (approx. 40 min). Then, you go through the same exam and questions for a second time.
As long as you show enough improvement in symptoms, you will qualify for DBS as far as this test is concerned . In my case, I qualified for bi-lateral DBS (a lead for each side of my brain).
Neuro/psych exam
Approximately 3 years post diagnosis, I mentioned to my MDS that I felt I was losing some mental "sharpness" and wondered if it was related to PD or just normal aging. She suggested I sit for a Neuro/Psych exam to compare my performance vs norms for my age. Additionally, even if there were no issues, it would provide a good baseline for the future.
So, when I was told I needed to sit for a Neuro/Pysch exam to determine if I have any cognitive loss, I knew what to expect. I recalled the exam being very long and intense. Lots of memory recall, some drawing, some manipulating objects and very mentally taxing! I pulled up my report from my baseline exam to share with the Psychologist who would be performing the one to use to determine if I am a good DBS candidate.
I had to laugh when I read the report from 6 years ago ... they really had a good line on my personality! "Individuals with similar profiles tend to be disciplined individuals and place a premium on avoiding mistakes". I read that to my daughter who recently completed her Masters in Mental Health Counseling, and has a Bachelor's in Psychology ... her response: "That's a fancy way of saying you are a perfectionist!"
Be prepared for the exam to last a few hours. Be prepared to feel like you are missing a lot of questions. I don't think I was 100% on any of them. I still received a clean bill of health. Like the other qualifying exams, it is good to know that they are looking to reduce risk. If someone already has cognitive loss, it can increase the risk of more cognitive loss from the surgery.
MRI
I had a brain MRI before I was diagnosed to be sure there was nothing physical (e.g., tumor) causing my symptoms. Just a month ago, I had my first ever bout with vertigo and ended up in the ER ... they did an MRI just to be sure it wasn't a stroke.
I am far from an MRI expert, but I had 2 under my belt with no issues. I learned in the first one that having a washcloth over my eyes helped me not think about the small tube I was in!
So, when I went in for the DBS MRI, I thought it would be no big deal. Because this MRI serves 2 purposes (1. Be sure there are no physical issues that may preclude placing of leads 2. get a detailed map for placement), it is significantly longer than ones I had in the past. I have been nursing a sore right shoulder, including PT. I didn't think much of it before I was in the tube. I figured I could stand anything for 40 minutes or so. They did not tell me the MRI would be much longer than ones I had in the past.
I noticed immediately the programs were much longer than before. It seemed like I had been in there forever and the pain in my shoulder from being still for an hour was getting unbearable. I hit the button to stop and ask them if I could reset my shoulder. When they pulled me out and put a pillow under my shoulder, I felt better. I asked how much longer and nearly passed out when they said "another 40 minutes"!
I think I would have done better knowing that it was going to be so long. Anyway, it was a clean MRI and now they have the map they need!
Conclusion
Overall, I believe the three major "hurdles" to clear once you and your MDS determine DBS is potential good fit (OFF / ON, Neuro/Psych and MRI) are all designed to take risk out of the surgery. In my mind, that is worth the time and inconvenience!
Next up ... How I decided which hardware to use.