Neuromodulation : journal of the International Neuromodulation Society
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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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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.
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Introduction. Gait speed is often used as a proxy for gait quality. However, some users of FES devices for correction of dropped foot choose to continue to use the device despite no significant change in speed. The Psychosocial Impact of Assistive Devices Scale (PIADS) was used to evaluate the effects of the Odstock Dropped Foot Stimulator (ODFS) on perceived quality of life (QOL) for people with stroke and multiple sclerosis (MS) and was compared with change in walking speed. ⋯ These were significantly greater for the stroke than the MS group for Competence, p= 0.04 and Adaptability, p= 0.006. There was no significant correlation between changes in PIADS and changes in walking speed. Conclusions. FES for correction of dropped foot has a beneficial effect on perceived QOL for people with stroke and MS but this is not correlated with an objective measures of gait.
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Objectives. We present a case report of a patient with complete lead wire fracture with approximately 3-mm separation of the wire fragments that had three electrode impedance measurements and therapy impedance measurement that would be consistent with an intact wire. Materials and Methods. Retrospective chart review. ⋯ This led to further diagnostic evaluation and eventual surgical replacement of the lead wire. Conclusions. Impedance measurements are not absolutely reliable for the detection of hardware malfunction in a patient with a Kinetra neurostimulator.