Mi-Ryoung Kim

Chronic subthalamic deep brain stimulation improves pain in Parkinson disease

BackgroundPain is a well recognized feature of Parkinson disease (PD). Like motor fluctuations, pain in PD may fluctuate as ‘non-motor fluctuations’. Subthalamic deep brain stimulation (STN DBS) is an established treatment for motor fluctuations in PD. However, the effect of STN DBS on the pain in PD is only partially investigated.MethodsPD patients who were considered for STN DBS were asked if they had pain. The severity of pain was scored in each body part. In patients with motor fluctuation, the pain in the ‘on’ and ‘off ’ state were recorded separately. Patients were evaluated preoperatively and 3 months after surgery. Some patients were followed for 6 months.ResultsTwenty-three of 29 patients had pain preoperatively. Of 24 with motor fluctuation, 21 had pain, and 18 had fluctuating pain. Pain improved in 20 out of 23 with preoperative pain at 3 months postoperatively. Of 18 with fluctuating pain, 12 reported a decrease in, and 5 complete disappearance of the ‘off ’ pain. Of 4 with nonfluctuating preoperative pain, 2 reported improvement. Pain was severe and functionally disabling in some. The STN DBS improved pain to a tolerable degree. In 7 of 29, new pain developed during the 3 month follow-up. Sixteen patients were followed for 6 months. All 11 patients who had improvement at 3 months continued to get benefit from STN DBS. Two additional patients who had no improvement at 3 months reported improvement at 6 months.ConclusionsPain is frequent in PD and STN DBS improves pain, especially the ‘off ’ pain in PD.

The effects of bilateral Subthalamic Nucleus Deep Brain Stimulation (STN DBS) on cognition in Parkinson disease

The effects of subthalamic nucleus (STN) stimulation on cognition and mood have not been well established. The authors estimated cognitive and mood effects of bilateral subthalamic nucleus deep brain stimulation (STN DBS) in patients with Parkinsons disease (PD) at 6 months and 1 year postoperatively. Forty-six patients were recruited from the Movement Disorder Center at Seoul National University Hospital. Neuropsychologic tests were performed three times, before, 6 months after, and 1 year after surgery. Mean patient age was 58 and mean education duration 8 years. Eighteen of the 46 patients were men. The instruments used for assessing cognitive functions were; the Mini-Mental Status Examination (MMSE), the Trail Making Test (TMT), the Korean Boston Naming Test (K-BNT), the Rey-Kim Memory Battery, the Grooved pegboard test, the Stroop test, a fluency test, the Wisconsin Card Sorting test (WCST), and the Beck depression inventory (BDI). Of these tests, the verbal memory test, the Stroop test, and the fluency test showed statistically significant changes. The verbal memory test using the Rey-Kim memory battery showed a decline in delayed recall and recognition at 6 months and 1 year postoperatively, whereas nonverbal memory showed no meaningful change. In terms of frontal lobe function tests, Stroop test and fluency test findings were found to be aggravated at 6 months and this continued at 1 year postoperatively. Previous studies have consistently reported a reduction in verbal fluency and improvements in self-reported symptoms of depression after STN DBS. However, in the present study, Beck depression inventory (B.D.I.) was not significantly changed. Other tests, namely, MMSE, TMT, K-BNT, Grooved pegboard test, and the WCST also failed to show significant changes. Of the baseline characteristics, age at onset, number of years in full-time education, and L-dopa equivalent dosage were found to be correlated with a postoperative decline in neuropsychological test results. The correlation of motor improvement and cognitive deterioration was not significant, which suggests that the stimulation effect is rather confined to the motor-related part in the STN. In conclusion, bilateral STN DBS in Parkinsons disease did not lead to a significant global deterioration in cognitive function. However, our findings suggest that it has minor detrimental long-term impacts on memory and frontal lobe function.

Reprogramming guided by the fused images of MRI and CT in subthalamic nucleus stimulation in Parkinson disease

OBJECTIVE To evaluate the usefulness of the visual information about the location of the contacts in deep brain stimulation (DBS) programming, we compared the outcomes of subthalamic nucleus (STN) stimulation before and after reprogramming guided by the fused images of MRI and CT. METHODS Of the 65 patients with Parkinsons disease, who underwent bilateral STN-DBS surgery between March 2005 and September 2006 and had been managed for at least 6 months with conventional programming which was only based on the physiological responses from the patients, 54 patients were reprogrammed based on the 3D anatomical location of the contacts revealed by the fused images of pre-operative MRI and post-operative CT scans taken at 6 months after surgery. A total 51 patients completed the evaluation after reprogramming. RESULTS Reprogramming significantly improved the UPDRS part III scores during the on- and off-medication condition. The daily levodopa-equivalent dose was significantly reduced. Improvement in the UPDRS part III scores after reprogramming was greater in the patients with electrodes in the STN than the patients with electrodes off the STN. CONCLUSIONS CT-MR fusion images helped to reprogram stimulation parameters with ease and confidence in a time-saving manner and resulted in further clinical improvement. This method could complement the conventional method of adjusting stimulation parameters after bilateral STN-DBS.

Influence of Propofol and Fentanyl on Deep Brain Stimulation of the Subthalamic Nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinsons disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7±16.8 spikes/sec, n=78) and the right side MERs (35.5±17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinsons Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinsons disease improving the overall experience of the patients. Graphical Abstract

The clinical impact of precise electrode positioning in STN DBS on three-year outcomes

Few studies have analyzed the clinical impact of subthalamic nucleus (STN) deep brain stimulation (DBS) as a function of the positioning of the inserted electrode. We investigated retrospectively the three-year outcomes in Parkinsons disease (PD) patients following bilateral STN DBS in terms of the electrode positions. Forty-one advanced PD patients were followed up for over three years following bilateral STN DBS. Patients were evaluated with the Unified Parkinsons Disease Rating Scale (UPDRS), Hoehn and Yahr staging, Schwab and England Activities of Daily Living (ADL), and the Short Form-36 Health Survey (SF-36) before surgery and one, two, and three years after surgery. The patients were divided into two groups according to the electrode position based on the fused preoperative MRI and postoperative CT images: group I included patients who had both electrodes in the STN (n=30) while group II included patients who had one of the electrodes in the STN (n=11). The UPDRS, the Hoehn & Yahr staging, the Schwab and England ADL, and the SF-36 scores showed significant improvements with decreased l-dopa equivalent daily doses (LEDDs) in both groups as well as in the group as a whole for up to three years following bilateral STN DBS. However, the off-medication UPDRS total and motor (part III) scores significantly deteriorated with increased LEDDs for patients in group II three years after STN DBS compared to that of the group I patients. We conclude that more accurate electrode positioning in the STN leads to better long-term outcomes in advanced PD patients following DBS.

Patients' reluctance to undergo deep brain stimulation for Parkinson's disease

BACKGROUND Many patients with advanced Parkinsons disease (PD) are reluctant to undergo the subthalamic nucleus deep brain stimulation (STN-DBS) when surgery is warranted. Reasons for this reluctance have not been examined. We undertook to establish the rate and causes of this reluctance for STN-DBS in patients with advanced PD. METHODS A reluctant group was defined as patients who were hesitant to undergo DBS. Clinical information included age, onset age, disease duration, the Unified Parkinson Disease Rating Scale, Hoehn and Yahr stage and levodopa equivalent dose when they were evaluated with a view to consider surgery. RESULTS We enrolled 186 patients who underwent STN-DBS. 84 patients (45%) belonged to the reluctant group. Between the reluctant and the non-reluctant, there were no differences in preoperative characteristics. Main reasons for hesitation were fear of complications (74%) and economic burden (50%). The main reasons that they finally underwent the DBS were confidence in the doctors decision (80%) and encouragement from their family (36%). CONCLUSIONS Building trust between patients and physicians is an important factor in guiding patients to undergo this treatment. To reduce the reluctance to undergo DBS at the appropriate time, we need to find effective ways of reducing their psychological and economic burden.

Long-Term Clinical Outcome of Internal Globus Pallidus Deep Brain Stimulation for Dystonia

Background GPi (Internal globus pallidus) DBS (deep brain stimulation) is recognized as a safe, reliable, reversible and adjustable treatment in patients with medically refractory dystonia. Objectives This report describes the long-term clinical outcome of 36 patients implanted with GPi DBS at the Neurosurgery Department of Seoul National University Hospital. Methods Nine patients with a known genetic cause, 12 patients with acquired dystonia, and 15 patients with isolated dystonia without a known genetic cause were included. When categorized by phenomenology, 29 patients had generalized, 5 patients had segmental, and 2 patients had multifocal dystonia. Patients were assessed preoperatively and at defined follow-up examinations postoperatively, using the Burke-Fahn-Marsden dystonia rating scale (BFMDRS) for movement and functional disability assessment. The mean follow-up duration was 47 months (range, 12–84) Results The mean movement scores significantly decreased from 44.88 points preoperatively to 26.45 points at 60-month follow up (N = 19, P = 0.006). The mean disability score was also decreased over time, from 11.54 points preoperatively to 8.26 points at 60-month follow up, despite no statistical significance (N = 19, P = 0.073). When analyzed the movement and disability improvement rates at 12-month follow up point, no significant difference was noted according to etiology, disease duration, age at surgery, age of onset, and phenomenology. However, the patients with DYT-1 dystonia and isolated dystonia without a known genetic cause showed marked improvement. Conclusions GPi DBS is a safe and efficient therapeutic method for treatment of dystonia patients to improve both movement and disability. However, this study has some limitations caused by the retrospective design with small sample size in a single-center.

Bilateral Deep Brain Stimulation of the Subthalamic Nucleus under Sedation with Propofol and Fentanyl

Awakening during deep brain stimulation (DBS) surgery may be stressful to patients. The aim of the current study was to evaluate the effect on MER signals and their applicability to subthalmic nucleus (STN) DBS surgery for patients with Parkinson’s disease (PD) under sedation with propofol and fentanyl. Sixteen consecutive patients with PD underwent STN-DBS surgery with propofol and fentanyl. Their MER signals were achieved during the surgery. To identify the microelectrodes positions, the preoperative MRI and postoperative CT were used. Clinical profiles were also collected at the baseline and at 6 months after surgery. All the signals were slightly attenuated and contained only bursting patterns, compared with our previous report. All electrodes were mostly located in the middle one third part of the STN on both sides of the brain in the fused images. Six months later, the patients were improved significantly in the medication-off state and they met with less dyskinesia and less off-duration. Our study revealed that the sedation with propofol and fentanyl was applicable to STN-DBS surgery. There were no significant problems in precise positioning of bilateral electrodes. The surgery also improved significantly clinical outcomes in 6-month follow-up.