Alterations of Cortical Electrical Activity in Patients with Sacral Neuromodulator
Introduction
Sacral neuromodulation can be a beneficial treatment option in patients suffering from therapy-resistant detrusor instability or detrusor hypocontractility [1], [2], [3], [4], [5]. The neuro-anatomical basis and the mechanism of action is unclear. A sacral reflex mechanism as well as supraspinal centres of modulation have been postulated [4], [5]. On the one hand Schmidt et al. postulate that the efficacy of neuromodulation depends on intact sacral and supraspinal reflex pathways, which was confirmed by Hohenfellner et al. who were able to show that no neuromodulation effect was seen in patients with high incomplete and complete spinal cord injuries [6], [7]. On the other hand Zvara et al. showed a restoration of bladder hyperreflexia in a rat model with complete spinal lesions [8]. Further Blok et al. were able to show that in human volunteers cortical and pontine micturition sites are strongly involved in co-ordinated micturition and that direct stimulation of the pontine micturition centre results in a relaxation of the urethral sphincter and in a contraction of the detrusor muscle [9], [10].
The aim of this pilot study was to assess possible effects of sacral (S3) nerve neuromodulation on cortical electrical activity.
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Material and methods
We studied 10 patients who had been implanted a sacral (S3) one-channel neuromodulator after a diagnostic positive PNE-test (six men, four women). All the patients showed an improvement of 50% or more after neuromodulator implantation, which was identified urodynamically (in accordance to the multicenter study by Jonas et al. [11]). The mean age was 49 years (28–69). Four patients had been diagnosed with a neurogenic bladder dysfunction, six patients had an idiopathic bladder dysfunction (Table
Results
All patients (Table 1) displayed very similar effects on cortical electrical activity after neurostimulation of S3 root (Fig. 5). Due to technical reasons we had to consider a delay of 110 ms after pressing the “on button” for the onset of sacral root stimulation (Fig. 3, Fig. 5). A first electronegative peak, occurring with a mean latency of 50 ms and with a mean amplitude of 23 μV which can be referred to as an early sensory evoked potential comparable to pudendal evoked potentials was
Discussion
Long latency somatosensory evoked potentials (SSEPs) were described for many decades. Although the knowledge of their generators is still limited, they have been widely used, for example in the odd-ball paradigm in psychometric and dementia testing, the best known component being the P300, a positive cortically recorded potential with a mean latency of 300 ms, commonly regarded as a cognitively mediated phenomenon. On the other hand, early SSEP components like the pudendal SSEPs have become a
References (21)
- et al.
Sacral (S3) segmental nerve stimulation as a treatment for urge incontinence in patients with detrusor instability: Results of chronic electrical stimulation using an implantable neural prosthesis
J. Urol.
(1995) - et al.
Treatment of refractory urge incontinence with sacral spinal nerve stimulation in multiple sclerosis patients
Lancet
(1996) - et al.
The tailored laminectomy—New technique for neuromodulator implantation
J. Urol.
(1999) - et al.
Sacral root neuromodulation in idiopathic nonobstructive chronic urinary retention
J. Urol.
(1998) - et al.
Sacral root neuromodulation: An effective treatment for refractory urge incontinence
J. Urol.
(1998) - et al.
Electrical stimulation of the dorsal cry commisure evokes relaxation of the external urethral sphincter in the cat
Neurosci. Lett.
(1998) - et al.
Efficacy of sacral nerve stimulation for urinary retention: 18 months after implantation
J. Urol.
(2001) - et al.
Cerebral responses evoked by stimulation of the vesico-urethral junction in normal subjects
Electroencephalogr. Clin. Neurophysiol.
(1986) - et al.
Studies of latency of pelvic floor contraction during peripheral nerve evaluation show that the muscle response is reflexly mediated
J. Urol.
(2000) - et al.
Neurostimulation and neuromodulation: A guide to selecting the right urological patient
Eur. Urol.
(1998)
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