Papers by Soledad Navarro
Archives of Neurology, 2008
Tourette syndrome (TS) is thought to result from dysfunction of the associative-limbic territorie... more Tourette syndrome (TS) is thought to result from dysfunction of the associative-limbic territories of the basal ganglia, and patients with severe symptoms of TS respond poorly to medication. High-frequency stimulation has recently been applied to patients with TS in open studies using the centromedian-parafascicular complex (CM-Pf) of the thalamus, the internal globus pallidus (GPi), or the anterior limb of the internal capsule as the principal target. To report the effect of high-frequency stimulation of the CM-Pf and/or the GPi, 2 associative-limbic relays of the basal ganglia, in patients with TS. Controlled, double-blind, randomized crossover study. Medical research. Three patients with severe and medically refractory TS. Bilateral placement of stimulating electrodes in the CM-Pf (associative-limbic part of the thalamus) and the GPi (ventromedial part). Effects of thalamic, pallidal, simultaneous thalamic and pallidal, and sham stimulation on neurologic, neuropsychological, and psychiatric symptoms. A dramatic improvement on the Yale Global Tic Severity Scale was obtained with bilateral stimulation of the GPi (reduction in tic severity of 65%, 96%, and 74% in patients 1, 2, and 3, respectively). Bilateral stimulation of the CM-Pf produced a 64%, 30%, and 40% reduction in tic severity, respectively. The association of thalamic and pallidal stimulation showed no further reduction in tic severity (60%, 43%, and 76%), whereas motor symptoms recurred during the sham condition. No neuropsychological, psychiatric, or other long-term adverse effect was observed. High-frequency stimulation of the associative-limbic relay within the basal ganglia circuitry may be an effective treatment of patients with TS, thus heightening the hypothesis of a dysfunction in these structures in the pathophysiologic mechanism of the disorder.
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Revue Neurologique, 2004
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Neurochirurgie, 2004
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Journal of Neurology Neurosurgery and Psychiatry, 2005
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Archives of Neurology, 2004
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Revue Neurologique, 2007
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Revue Neurologique, 2005
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Revue Neurologique, 2009
Rest tremor, one of the main symptoms in Parkinson's disease (PD), is dra... more Rest tremor, one of the main symptoms in Parkinson's disease (PD), is dramatically improved following subthalamic nucleus stimulation (STN). Results are often better than after l-dopa treatment. The occurrence of rest tremor after neurosurgery in patients without preoperative tremor is uncommon. The aim of this work was to investigate the role of subthalamic nucleus stimulation in the appearance of parkinsonian rest tremor. PATIENTS-RESULTS: Thirty PD patients (14%) out of 215 undergoing STN deep brain stimulation had an akinetorigid form of the disease, without preoperative tremor 11 years after onset of the disease. Six of them experienced the appearance of tremor six months after bilateral STN stimulation when the stimulator was switched off in the Off medication state. This de novo parkinsonian tremor was improved by l-dopa treatment and disappeared when the stimulator was turned on. This finding suggests that infraclinical parkinsonian tremor is probably present in all PD patients.
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Lancet Neurology, 2007
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Archives of Neurology, 2004
High-frequency stimulation of the subthalamic nucleus (STN) is a neurosurgical alternative to med... more High-frequency stimulation of the subthalamic nucleus (STN) is a neurosurgical alternative to medical treatment in levodopa-responsive forms of Parkinson disease. The mechanism of action of STN stimulation remains controversial, although an inhibition of overactive STN neurons has been postulated. To determine the effects of high-frequency STN stimulation on the neuronal activity of STN neurons in Parkinson disease patients. Single-unit recordings of the neuronal activity of the STN were obtained before, during, and after the application of intra-STN electrical stimulation in 15 Parkinson disease patients. Changes in firing frequency and pattern were analyzed using various combinations of stimulus frequency (range, 14-140 Hz). Stimulation at a frequency greater than 40 Hz applied within the STN significantly decreased the firing frequency and increased the burst-like activity in the firing pattern of STN neurons. An aftereffect was observed in cells that had been totally inhibited during high-frequency stimulation. The beneficial effects of high-frequency stimulation result from a change in the firing pattern of cellular discharge and a blockade of the spontaneous overactivity of STN neurons.
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Neurology, 2007
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Neurosurgery, 2006
GM1 Type 3 gangliosidosis is a lysosomal storage disorder for which no specific treatment is avai... more GM1 Type 3 gangliosidosis is a lysosomal storage disorder for which no specific treatment is available. It is characterized by progressive generalized dystonia, which is refractory to pharmacological treatment and results in severe disability and life-threatening complications. We performed bilateral pallidal stimulation in a patient with GM1 gangliosidosis and report the 12-month postoperative course. A 24-year old woman presented with genetically confirmed GM1 gangliosidosis, resulting in severe progressive generalized dystonia. Leads were implanted bilaterally into the internal part of the globus pallidus under stereotactic guidance. At follow-up visits, both the patient and the neurologists who performed the assessment were unaware of whether the neurostimulator was on or off. The patient was videotaped with a standardized protocol and scored by an independent expert. After 1 year of follow-up, double-blind comparison of the patient's status with and without neurostimulation showed a 20% improvement, with a significant functional benefit, but no change in disease progression. Although further studies are needed to evaluate this therapeutic approach, this report suggests that pallidal stimulation might be a promising treatment for dystonia caused by GM1 Type 3 gangliosidosis.
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Journal of Neurophysiology, 2007
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Papers by Soledad Navarro