Neuromodulation : journal of the International Neuromodulation Society
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Objectives. Vagus nerve stimulation (VNS) is an accepted treatment for medically intractable epilepsy. However, predictive factors associated with responsiveness to VNS remained unclear. We therefore sought to identify predictive factors that influence responsiveness to VNS in both children and adults. ⋯ Transient hoarseness and cough were observed in eight of all patients and wound infection and generator failure in one patient each. Conclusions. These results suggest that VNS may be a more effective treatment in children with intractable epilepsy than in adults. It remains difficult to predict which patients will respond to VNS therapy.
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Objectives. The clinical efficacy of subthalamic nucleus (STN) deep brain stimulation (DBS) for major motor symptoms of Parkinson's disease (PD) is well established, but its effects on visually guided vs. internally generated eye movements in the medication off state need to be studied further. Since the basal ganglia are thought to be involved in the generation of voluntary movements under internal control, we hypothesized that voluntary saccades would show improvements with STN DBS. Materials and Methods. Seven PD patients with STN DBS performed visually guided and internally generated (anti- and memory-guided) saccades with STN DBS on and off following 12 hours of levodopa withdrawal. ⋯ STN DBS also improved the first saccade gain of the anti- and memory-guided saccades, but not of the visually guided saccades. Conclusions. These results demonstrate that STN DBS has differential effects on the parameters of visually guided and internally generated saccades. These effects may be mediated by the influence of STN DBS on cortical ocular motor areas, the basal ganglia, ocular motor loop, or downstream structures such as the brainstem saccade generating circuits.
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Objectives. Medically refractory cervical dystonia has recently been treated using deep brain stimulation (DBS), targeting the subthalamic nucleus (STN). There has been limited literature regarding short-term outcomes and no literature regarding long-term outcomes for refractory cervical dystonia following DBS of the STN. Materials and Methods. Two patients with medically refractory cervical dystonia underwent STN DBS. ⋯ The STN and SNr were easily identified as having activity similar to off-state Parkinson's patients. Conclusions. DBS therapy for cervical dystonia utilizing the STN as the surgical target may be novel and may be an alternative target to the globus pallidus internus as supported by this first long-term outcome report. Further studies need to be performed to confirm these conclusions.
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Objective. To clarify the efficacy of subthalamic nucleus (STN) stimulation in young-onset Parkinson's disease (PD), we compared the effects of STN stimulation on the motor symptoms between young-onset PD (YOPD) and late-onset PD (LOPD). Methods. We analyzed the effects of STN stimulation on motor function and motor fluctuations in 15 patients with YOPD, and 113 patients with LOPD who underwent STN stimulation during the same period. The Unified Parkinson's Disease Rating Scale (UPDRS) was evaluated during the on-period and off-period, which are defined as the times at which the motor symptoms are the best and worst during the daily active time with sustaining anti-parkinsonian drugs. ⋯ Conclusions. STN stimulation can reduce the LED and improve motor fluctuations in patients with YOPD. The effects of STN stimulation on the motor symptoms of YOPD patients are superior to those in LOPD. The present findings suggest that YOPD patients suffering from several problems related to pharmacological therapy are probably good candidates for STN stimulation.
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Objective. Evaluate the possible decrease of chemically induced perseverative behavior in rats after electrical stimulation at different frequencies in the thalamic reticular nucleus. Material and Methods. A total of 28 male rats were divided in four groups: control, sham, OFF stimulation, and ON stimulation (450 µsec, 1 V, 6 and 120 Hz) that underwent the administration of saline solution and 8-OH-DPAT. The animals were evaluated in a T-maze model in which three choices or more in the same branch are considered as perseverative. ⋯ Sham group mean of 1.3 pre and 3.4 post 8-OH-DPAT administration; OFF stimulation group 1.1 pre and 3.3 post 8-OH-DPAT administration; and for ON stimulation 1.1 pre and 1.9 post 8-OH-DPAT administration for stimulation at low frequency (6 Hz) and 3.4 at high frequency (120 Hz). Evident intergroup statistical differences were shown (p < 0.01). Conclusions. Electrical stimulation with the low-frequency group was the only group that after manipulation with 8-OH-DPAT showed a decrease in perseverative behavior, even close to baseline.