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ABSTRACT: To perform a pilot study to investigate the relationship between the microlesion effect (MLE) seen in deep brain stimulation (DBS) of the ventralis intermedius nucleus (VIM) and subsequent tremor response and DBS parameter settings.
Nineteen thalami in 12 patients (11 essential tremor and 1 Parkinson's disease), who underwent unilateral (n=5) and bilateral VIM-DBS (n=7) were assessed at pre- and 24-h post-operation, at their initial DBS activation, and at 6-month follow-up. The severity of tremor was rated (from 0 to 4) for each activity including hand at rest, outstretched, wing beating, finger-nose-finger, dot approximation and spiral drawing (total score ranging from 0 to 24). The difference of total tremor score before and 24-h after electrode implants (MLE) was segregated into 3 groups based on immediate (24h) post-operative tremor improvement: (1) minimal (none or mild, 0-2), (2) moderate (>2-4), and (3) marked (>4). At the initial activation (23.4+/-3.7 days post-operation), the mean OFF tremor scores were still marginally better in marked than the minimal and moderate MLE groups.
At 6 months, 14 of 19 thalami (74%) were eligible for follow-up analysis. The "OFF" stimulation MLE disappeared in all groups. There was no significant difference of mean ON tremor scores among the groups; however, DBS parameter settings, including amplitude and pulse width, trended to be mildly lower in those with a marked MLE.
MLE has minimal long term clinical effect except for possibly allowing for lower DBS settings.
Clinical neurology and neurosurgery 11/2009; 112(2):106-9. · 1.30 Impact Factor
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ABSTRACT: Advanced Parkinson's disease (PD) is associated with various motor and non-motor symptoms which adversely impact health-related quality of life (HRQoL). Subthalamic nucleus (STN) deep brain stimulation (DBS) has been reported to improve some dimensions of HRQoL in appropriately selected candidates. Prior studies of HRQoL following DBS have used instruments comprising a predetermined list of questions which assess issues that are generally relevant in PD, but that may not be of equal or consistent importance to all individuals. In this study, we evaluate the effect of STN DBS on quality of life using the QLS(M), a modular questionnaire in which satisfaction scores for each item are weighted in light of patient-rated importance.
We prospectively analysed QLS(M) scores in 21 patients with PD (11 men, mean age 61.5+/-8.6 years) before STN DBS surgery and at a mean 7.4+/-1.5, and again at a mean 16.6+/-6.8 months postoperatively.
Following STN DBS, patients experienced an improvement in HRQoL as measured by various items of the movement disorder and health modules of the QLS(M). Specifically, QLS(M) items pertaining to energy level/enjoyment of life, independence from help, controllability/fluidity of movement and steadiness when standing and walking showed significant improvements, although items concerning general life issues (eg, occupational function, interpersonal relationships, leisure activities) did not improve.
Following STN DBS, symptomatic and functional improvements translate into higher HRQoL, with high satisfaction in domains related to movement disorders and general health.
Journal of neurology, neurosurgery, and psychiatry 10/2009; 81(3):315-9. · 4.87 Impact Factor
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ABSTRACT: The authors present a unique case of hyperhidrosis as a side effect of a misplaced deep brain stimulation (DBS) electrode near the ventrointermedius (Vim) nucleus in a patient with essential tremor. Magnetic resonance imaging of the brain showed electrode placement in the left anterior thalamus traversing the hypothalamus. High-frequency electrical stimulation possibly resulted in unilateral activation of the efferent sympathetic pathways in the zona incerta. Although a rare complication, hypothalamic dysfunction may occur as a stimulation-related side effect of Vim-DBS.
Journal of Neurosurgery 12/2007; 107(5):1036-8. · 2.96 Impact Factor
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ABSTRACT: The object of this study was to assess the long-term safety of deep brain stimulation (DBS) in a large population of patients with a variety of movement disorders.
All patients treated with DBS at the authors' center between 1995 and 2005 were assessed for intraoperative, perioperative, and long-term adverse events (AEs). A total of 319 patients underwent DBS device implantation. Of these 319, 182 suffered from medically refractory Parkinson disease; the other patients had essential tremor (112 patients), dystonia (19 patients), and other hyperkinetic movement disorders (six patients). Intraoperative AEs were rare and included vasovagal response in eight patients (2.5%), syncope in four (1.2%), severe cough in three (0.9%), transient ischemic attack in one (0.3%), arrhythmia in one (0.3%), and confusion in one (0.3%). Perioperative AEs included headache in 48 patients (15.0%), confusion in 16 (5.0%), and hallucinations in nine (2.8%). Serious intraoperative/perioperative AEs included isolated seizure in four patients (1.2%), intracerebral hemorrhage in two patients (0.6%), intraventricular hemorrhage in two patients (0.6%), and a large subdural hematoma in one patient (0.3%). Persistent long-term complications of DBS surgery included dysarthria (4.0%), worsening gait (3.8%), cognitive dysfunction (4.0%), and infection (4.4%). Revisions were completed in 25 patients (7.8%) for the following reasons: loss of effect, lack of efficacy, infection, lead fracture, and lead migration. Hardware-related complications included 12 lead fractures and 10 lead migrations.
The authors conclude that in their 10-year experience, DBS has proven to be safe for the treatment of medically refractory movement disorders.
Journal of Neurosurgery 05/2007; 106(4):621-5. · 2.96 Impact Factor
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ABSTRACT: Unilateral thalamic ventral intermediate (VIM) deep brain stimulation (DBS) is now accepted as an effective treatment for essential tremor (ET) and tremor related to Parkinson's disease (PD). The effects of unilateral placement on the side ipsilateral to the surgical site have not been carefully evaluated. To systematically assess the effects ipsilateral to the surgical side and to determine the effects of device inactivation on the baseline tremor, we evaluated tremor in 73 patients approximately 3 months after their unilateral thalamic placement. Assessment included blinded and unblinded ratings using the Unified Parkinson's Disease Rating Scale for PD patients and a modified Tremor Rating Scale in ET patients. All measures of tremor contralateral to the implantation site improved significantly and robustly in both PD and ET. Implantation did not worsen tremor by any measure on the ipsilateral side. There was mild ipsilateral improvement as measured by lower observed tremor scores in ET (6.0 ± 1.8 to 5.0 ± 1.9, P < 0.005), but not PD. There was no rebound augmentation of tremor in either hand after the devices were deactivated in either group. We conclude that VIM DBS may mildly improve ipsilateral ET, and that concerns about meaningful ipsilateral tremor augmentation after device deactivation are not warranted. © 2001 Movement Disorder Society.
Movement Disorders 10/2001; 16(6):1137 - 1142. · 4.51 Impact Factor
