Subthalamic nucleus stimulation: improvements in outcome with reprogramming
Moro, Poon, Lozano, Saint-Cyr, & Lang Subthalamic nucleus stimulation: improvements in outcome with reprogramming , Arch Neurol. 2006 Jul 10; Epub ahead of print
Note from the reviewers at The Parkinson Alliance: The following Current Science Review was made intentionally lengthy as it is our opinion that the area of DBS programming is a vital challenge to the PD community and this article expressly addresses these concerns. We hope that you read it with as much interest as we did. This article discusses issues relevant to patients with DBS. The authors discuss that DBS-STN is an effective treatment for PD; however, it does not come without significant cost of money, time, and well-trained professionals. Treatment with DBS can be challenging in that it requires professional familiarity with programming of the device as well as ability to modify medications to treat PD. Similarly to other areas involving DBS, there are no guidelines for DBS programming or specific qualifications to be a programmer, which can be at the expense to the patient. This article suggests that such guidelines and training would help to promote clinical efficacy, battery life, and negative side effects associated with the programming. The authors suggest that currently the task of programming is given to various individuals with various levels of training. They then went on to cite an example of postoperative care at Toronto Western Hospital Movement Disorders Program (authors affiliated with this program include: Drs. Moro and Lang, and Ms. Poon), including hiring a movement disorder neurologist that took over the postoperative care of their patients. This doctor reportedly completed the majority of the programming as well as the medications adjustments based on the individual patient responses to both the stimulator and the medication management. With the changes they made they expressed an interest to evaluate the efficacy of the system, which they had set up. Their initial hypothesis was that the improvements they made to their postoperative care would result in improved patient response for new patients as well as patients that were reportedly stable following their older system.
They studied 44 patients with PD (only 1 patient had surgery outside of their facility) that had DBS STN for at least one year. All patients had the same stimulator and underwent postoperative MRI to confirm the placement of the electrodes. Their "old method" involved programming that was completed 2-3 weeks after surgery, off medication, and staying overnight at the hospital. Patients then went through testing of all electrode sites on each side (if bilateral stimulation) and effects were noted (method is listed specifically in this article). After the "optimal contact" was located on each side then a combination of trials were conducted to evaluate additional efficacy. Patients continued to have additional adjustments made over the course of the following 3 months (daily or weekly). The authors noted that a supervising movement disorder neurologist discussed the setting parameters with the individual making them, but that the neurologist did not "directly observe" all of the effects.
They found that regardless of using the old or new method, patients undergoing the surgery had improvement on the majority of outcome measures administered (e.g. UPDRS, dyskinesia disability score, off duration score, and levodopa equivalent daily dose). According to the authors, the original 44 patients underwent "reprogramming" (new method) at a routine follow up appointment. Patients were evaluated in their off state by the movement disorder neurologist (method is listed specifically in this article, but includes the UPDRS) and then went through reprogramming. The authors noted that the voltage of the stimulator was slightly lower than that needed to produce "disabling dyskinesias." Medication adjustments were then made based on the patient experienced symptoms after the reprogramming. Patients were kept at the hospital setting for 1-2 hours in the event of delayed adverse events (e.g. worsened dyskinesia, general worsening). The authors reported that they kept patients from out of town for a few days for monitoring and those that lived in Toronto could go home but were kept in close phone contact over the course the following few days. Patients were reassessed at a minimum of two times over the course of 14 months after the reprogramming for any additional changes in programming or medications. The authors were interested in changes in patient UPDRS scores.
They found that patients could be divided into three groups, 1. Those that experienced improvement in symptoms (N=24, 54.6%), 2. those with no significant change (N=16, 36.4%), and 3. those that worsened (N=4, 9.1%). The authors found that those that improved (Group 1) tended to be younger, had better preoperative UPDRS motor scores, and worse dyskinesia duration. All patients in Group 1 had stimulator setting changes. Many of these individuals experienced improvement right away in the areas of "resting tremor, rigidity, and bradykinesia." A little over half of these patients developed stimulator induced dyskinesias (SID) after the reprogramming, all of which were managed over the course of 1-2- weeks by either stimulator adjustments or medication changes. On average these patients were seen five times within 14 months (range was 1-16 visits). The patients seen fewer times generally had difficulties coming into the office for follow-up but were contacted via phone for continued contact. Typical areas of improvement after reprogramming included reduced freezing, walking difficulties, dyskinesia disability scores, and levodopa equivalent daily dose. Improvements were not seen in the areas of speech and falling. Only five (31.2%) of the patients in Group 2 required stimulator-setting changes. This group did not evidence significant change and on average were seen 3 times over the 14 months (range 1-8). Of the four patients in Group 3, all experienced worsening in speech and gait, which required changing their settings back to the original values.
The authors concluded this article by noting that their hypothesis for better care with the involvement of a movement disorder specialist was correct in more than half of the patients studied. They highlighted the need for a movement disorder neurologist was necessary as the direct observation of parameter settings and patient responses was beneficial in determining additional settings as well as necessary medication changes. They also noted that need in the medical field for more neurologist trained in movement disorders that is capable of managing patients that have undergone DBS. The authors opined that this neurologist has to have a good balance between programming and medication management of patients to improve general clinical care and possibly reduce the need for medications. The authors indicated that the management of patients treated with DBS does not necessarily have to be hard if a movement disorder neurologist know the benefits, adverse effects, and interactions of the stimulator and medications used to treat PD. The authors suggested that the parameters and dosages of necessary medications typically do not change much over time once optimization is established. The authors suggested that a movement disorder neurologist is also mandatory in treating SID, which the exact method to do so is discussed in the article. They also discussed hypothesis as to why Groups 2 and 3 may not have experienced improvement as compared to Group 1. They also discussed the limitations to their study, which they did not feel affected the results they found. The authors end the article by noting that it is very important to have a movement disorder neurologist affiliated with patients undergoing DBS for at least the first few months after surgery for the best possible optimization of treatment that they can receive.