Neuromodulation : journal of the International Neuromodulation Society
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This study aimed to assess the long-term results of deep brain stimulation (DBS) for patients affected with Gilles de la Tourette syndrome, documenting refractoriness to conservative treatments. ⋯ Gilles de la Tourette syndrome is a complex neuropsychiatric disorder with a significant prevalence in the general population. More than 50% of the patients with TS present a behavioral comorbidity, and anxiety and depression are, to various degrees, associated to this "waxing and waning" clinical picture. DBS in our experience proved to be a valid treatment modality for those patients who fail to respond to conservative treatment modalities. A multidisciplinary team is nevertheless necessary to properly handle this complex therapeutic option.
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Rechargeable spinal cord stimulation (RSCS) systems have been advocated as a way to reduce replacement surgeries, overall costs, and the morbidity of therapy. However, little data exist as to patients' experiences with these devices, which require more care and maintenance than prior primary cell systems. We analyzed patient experiences with RSCS. ⋯ RSCS systems benefit most patients. However, in some patients, the lifestyle costs of recharging may not make RSCS an appropriate means of pain management. Several areas of improvement exist for the design of future devices.
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The excitability of sensorimotor cortex and spinal motoneurones can be modulated by afferent signals arising from the periphery. Low- and high-frequency vibrations activate separate classes of afferent units in the periphery. Low-frequency vibrations (2-100 Hz) activate the type I fast adapting afferent units (FA-I), whereas high-frequency vibrations (60-1000 Hz) preferentially activate the type II units (FA-II). Muscle spindles are also sensitive to high-frequency mechanical vibrations. Motor-evoked potentials (MEP) generated in response to transcranial magnetic stimulation (TMS) can be modulated by afferent signals. However, it is not clear whether these interactions take place at cortical or spinal cord levels. ⋯ The results suggest that a cerebrovascular accident influences the modulatory effects of afferent inputs at both spinal and cortical levels, and in time, as reorganization takes place, these altered influences settle towards normal levels.
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Deep brain stimulation technology now allows a choice between constant current and constant voltage stimulation, yet clinical trials comparing the two are lacking. Impedance instability would theoretically favor constant current stimulation; however, few publications address this with long-term follow-up. In this report, we review our series for impedance change and discuss our findings and their implications for future study design. ⋯ No significant change in the same electrode therapeutic impedance was identified. Given the assumption that stimulation current is the critical parameter influencing clinical outcomes, these findings would not disadvantage constant voltage stimulation. However, inter-patient variability suggests a possible advantage for constant current stimulation when generalizing experience and comparisons over multiple patients. Further study of the relationship of stimulation efficacy to stimulation mode and impedance change is warranted.
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Deep brain stimulation applied to the periaqueductal grey matter (PAG) of the midbrain in humans has been shown to increase or decrease arterial blood pressure during rest and to resist the postural fall on standing. The mechanism by which this effect is elicited is unknown. We hypothesize that PAG stimulation modulates performance of the autonomic nervous system. ⋯ PAG stimulation modulates autonomic nervous system activity and thereby elicits changes in cardiovascular performance. Understanding of the mechanisms by which this therapy causes cardiovascular modulation will inform future innovation in this field with the aim of improving the efficacy and safety of patient treatment options.