Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2007
ReviewClinical experience with vagus nerve stimulation and deep brain stimulation in epilepsy.
Patients with refractory epilepsy present a particular challenge to new therapies. Vagus nerve stimulation (VNS) for the control of intractable seizures has become available since 1989. VNS is a relatively noninvasive treatment. ⋯ Analysis of larger patient groups and insight in the mode of action may help to identify patients with epileptic seizures or syndromes that respond better either to VNS or to DBS. Randomized and controlled studies in larger patient series are mandatory to identify the potential treatment population and optimal stimulation paradigms. Further improvements of clinical efficacy may result from these studies.
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Brain stimulation has been receiving increasing attention as an alternative therapy for epilepsy that cannot be treated by either antiepileptic medication or surgical resection of the epileptogenic focus. The stimulation methods include transcranial magnetic stimulation (TMS) or electrical stimulation by implanted devices of the vagus nerve (VNS), deep brain structures (DBS) (thalamic or hippocampal), cerebellar or cortical areas. TMS is the simplest and least invasive approach. ⋯ Finally, another line of research investigates the usefulness of implantable seizure detection devices. The current chapter presents the most important evidence on the above methods. Furthermore, other important issues are reviewed such as the selection criteria of patients for brain stimulation and the potential role of brain stimulation in the treatment of depression in epileptic patients.
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Acta Neurochir. Suppl. · Jan 2007
ReviewSacral neuromodulation as a functional treatment of bladder overactivity.
Sacral neuromodulation, namely the electrical stimulation of the sacral nerves has become an alternative treatment for cases of idiopathic bladder overactivity. The mechanism of action in this type of spinal cord modulation is only partially understood but it seems to involve stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. ⋯ In experienced hands, this is a safe procedure. When the patients are selected on the basis of sound criteria, more than three-quarters of them show a clinically significant improvement with a reduction in the frequency of incontinence episodes by more than 50%; however, the results vary according to each author's method of evaluation. The application of this technique should be combined with careful follow-up and attentive adjustments of the stimulation parameters in order to optimize the coordination of activity between the neurological systems involved.
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Acta Neurochir. Suppl. · Jan 2007
ReviewStimulation of primary motor cortex for intractable deafferentation pain.
The stimulation of the primary motor cortex (M1) has proved to be an effective treatment for intractable deafferentation pain. This treatment started in 1990, and twenty-eight studies involving 271 patients have been reported so far. The patients who have been operated on were suffering from post-stroke pain (59%), trigeminal neuropathic pain, brachial plexus injury, spinal cord injury, peripheral nerve injury and phantom-limb pain. ⋯ The mechanism of pain relief by the electrical stimulation of M1 has been under investigation. Recently, repetitive transcranial magnetic stimulation (rTMS) of M1 has been reported to be effective on deafferentation pain. In the future, rTMS may take over from electrical stimulation as a treatment for deafferentation pain.
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Acta Neurochir. Suppl. · Jan 2007
ReviewAn introduction to neural networks surgery, a field of neuromodulation which is based on advances in neural networks science and digitised brain imaging.
Operative Neuromodulation is the field of altering electrically or chemically the signal transmission in the nervous system by implanted devices in order to excite, inhibit or tune the activities of neurons or neural networks and produce therapeutic effects. The present article reviews relevant literature on procedures or devices applied either in contact with the cerebral cortex or cranial nerves or in deep sites inside the brain in order to treat various refractory neurological conditions such as: a) chronic pain (facial, somatic, deafferentation, phantom limb), b) movement disorders (Parkinson's disease, dystonia, Tourette syndrome), c) epilepsy, d) psychiatric disease, e) hearing deficits, and f) visual loss. These data indicate that in operative neuromodulation, a new field emerges that is based on neural networks research and on advances in digitised stereometric brain imaging which allow precise localisation of cerebral neural networks and their relay stations; this field can be described as Neural networks surgery because it aims to act extrinsically or intrinsically on neural networks and to alter therapeutically the neural signal transmission with the use of implantable electrical or electronic devices. ⋯ The article also brings forward particularly interesting lines of research such as the carbon nanofibers electrode arrays for simultaneous electrochemical recording and stimulation, closed-loop systems for responsive neuromodulation, and the intracortical electrodes for restoring hearing or vision. The present review of cerebral neuromodulatory procedures highlights the transition from the conventional neurosurgery of resective or ablative techniques to a highly selective "surgery of networks". The dynamics of the convergence of the above biomedical and technological fields with biological restorative approaches have important implications for patients with severe neurological disorders.