My family member's bilateral Soletras lasted approximately four years; similar voltage to yours, but in bi-polar and multi-polar contact selections.
After change to bilateral Activa SCs, he was able to settle down after a while to similar settings.
Beyond Dr. Okun's comment on intra-battery variability, and end-of-life voltage for the Soletra:
- it is my understanding that the SC has a somewhat different pulse shape form
- I assume that you're comparing both models with all settings the same: constant voltage mode
- could your therapeutic window be smaller than a 10% variability in field strength?
Two additional reactions I'd like to request of Dr. Okun:
- it has been our experience, that -- all other parameters having changed little -- the battery life of the Activa SC was only half that of the Soletra
- Activa SC battery duration indication: given your promoting online formulas for residual battery life, would you be able to predict time left for this model, given current IPG voltage indication and bi-polar / multi-polar settings?
Hello am0665 (Bonjour Andy !), hello Dr OKUN,
My old Soletras lasted from November 2006 till January 2014. They could have lasted even longer , at least 6 months, but we anticipated the need as I am planning an overseas trip and did not want to be caught unguarded. Now I have the same parameters since August 2009, i. e., one side monopolar, with case +, and the other side bipolar with case off. I’m not sure I fully grasp what you mean by 10% variability in field strength (never had a passion for physics!), All I can say is the Fq is always the same (130 HZ), DI is always 60, and AMP is 2V on the bipolar side and 2.5V on the other and when we tried to move that one up a bit, it was counterproductive.
While these almost 4 and a half years went without any change, the first three were very chaotic, with frequent changes of the parameters (with a different neurologist).
To update my initial impression on my new equipment, I have experienced a similar feeling after replacement of my neurostimulators as I had for the initial DBS surgery; a feeling that my body is freed of a lot of weight, not completely cured but a lot better; this feeling is sometimes referred as the “lesioning effect”after DBS surgery, which obviously cannot apply in this case. I don’t know if any patient of Dr Okun has ever reported the same experience. Unfortunately, this wonderful feeling only lasted a few days. The reason why I can be so precise about my parameters is that my neurologist always fill up my Patient Follow up Book (provided by Medtronic) each time he checks my stimulators. I can only encourage patients who do not have this information to press their neurologist or programmer to take the time to fill up these data; it is so important for patients to have knowledge of what is being tried, even if you do entirely master the subjects.
Now, exactly three weeks after replacement surgery, I feel exactly the same with my new equipment as with my previous Soletras. For your information, the previous IPG was an ITREL II and lasted from March 15, 2000 (won't forget the day !) till November 2006.
Hope this information is of some help.
Mimi (aka Mireille)