S Wang

Publications (7)14.26 Total impact

• Article: Neural signatures in patients with neuropathic pain.

  A L Green, S Wang, J F Stein, E A C Pereira, M L Kringelbach, X Liu, J-S Brittain, T Z Aziz
  Neurology 03/2009; 72(6):569-71. · 8.31 Impact Factor
• Article: Local field potential beta activity in the subthalamic nucleus of patients with Parkinson's disease is associated with improvements in bradykinesia after dopamine and deep brain stimulation.

  N J Ray, N Jenkinson, S Wang, P Holland, J S Brittain, C Joint, J F Stein, T Aziz
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  ABSTRACT: Parkinson's disease is treated pharmacologically with dopamine replacement medication and, more recently, by stimulating basal-ganglia nuclei such as the subthalamic nucleus (STN). Depth recordings after this procedure have revealed excessive activity at frequencies between 8 and 35 Hz (Brown et al., 2001; Kuhn et al., 2004; Priori et al., 2004) that are reduced by dopamine therapy in tandem with improvements in bradykinesia/rigidity, but not tremor (Kuhn et al., 2006). It has also been shown that improvements in motor symptoms after dopamine correlate with single unit activity in the beta range (Weinberger et al., 2006). We recorded local field potentials (LFPs) from the subthalamic nucleus of patients with Parkinson's disease (PD) after surgery to implant deep brain stimulating electrodes while they were on and off dopaminergic medication. As well as replicating Kuhn et al., using the same patients we were able to extend Weinberger et al. to show that LFP beta oscillatory activity correlated with the degree of improvement in bradykinesia/rigidity, but not tremor, after dopamine medication. We also found that the power of beta oscillatory activity uniquely predicted improvements in bradykinesia/rigidity, but again not tremor, after stimulation of the STN in a regression analysis. However improvements after STN stimulation related inversely to beta power, possibly reflecting the accuracy of the electrode placement and/or the limits of STN stimulation in patients with the greatest levels of beta oscillatory activity.
  Experimental Neurology 06/2008; 213(1):108-13. · 4.70 Impact Factor
• Source

  Available from: David J Paterson

  Article: Deep brain stimulation: a new treatment for hypertension?

  A L Green, S Wang, R G Bittar, S L F Owen, D J Paterson, J F Stein, P G Bain, D Shlugman, T Z Aziz
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  ABSTRACT: We report a 61-year-old hypertensive man who underwent deep brain stimulation of the periventricular/periaqueductal grey area for the relief of chronic neuropathic pain affecting his oral cavity and soft palate. During intraoperative stimulation, we were able to modulate his blood pressure up or down, depending on electrode location. This is the first evidence that hypertension could be effectively treated with electrical stimulation of the midbrain.
  Journal of Clinical Neuroscience 07/2007; 14(6):592-5. · 1.25 Impact Factor
• Article: The periaqueductal grey area and the cardiovascular system.

  A L Green, S Wang, S L F Owen, T Z Aziz
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  ABSTRACT: In this chapter, we report that blood pressure can be increased or decreased depending on whether an electrode is in ventral or dorsal PAG. We also describe that it is theoretically possible to treat orthostatic hypotension. These are exciting developments not only because they provide an example of direct translational research from animal research to humans but also because they highlight a potential for future clinical therapies. The control of essential hypertension without drugs is attractive because of the side effects of medication such as precipitation of heart failure [10]. Similarly, drug treatment of orthostatic hypotension cannot differentiate between the supine and standing positions and can therefore lead to nocturnal hypertension [22, 29]. A stimulator could be turned off at night or contain a mercury switch that reacts to posture.
  Acta neurochirurgica. Supplement 02/2007; 97(Pt 2):521-8.
• Source

  Available from: soton.ac.uk

  Article: Deep brain stimulation for neuropathic pain.

  S L F Owen, A L Green, D D Nandi, R G Bittar, S Wang, T Z Aziz
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  ABSTRACT: Deep brain stimulation (DBS) for pain was one of the earliest indications for the therapy. This study reports the outcome of DBS of the sensory thalamus and the periventricular and peri-aqueductal grey area (PVG/PAG) complex for different intractable neuropathic pain syndromes. Forty-seven patients (30 males and 17 females) were selected for surgery; they were suffering from any of the following types of pain: post-stroke neuropathic pain, phantom limb pain, post-herpetic neuralgia, anaesthesia dolorosa, brachial plexus injury and neuropathic pain secondary to neural damage from a variety of causes. Of the 47 patients selected for trial stimulation, 38 patients proceeded to permanent implantation. Patients suffering from post-stroke pain were the most likely to fail trial stimulation (33%), in contrast to individuals with phantom limb/post-brachial plexus injury pain and anaesthesia dolorosa, all of whom underwent permanent implantation. PVG stimulation alone was optimal in 17 patients (53%), whilst a combination of PVG and thalamic stimulation produced the greatest degree of analgesia in 11 patients (34%). Thalamic stimulation alone was optimal in 4 patients (13%). DBS of the PVG alone was associated with the highest degree of pain alleviation, with a mean improvement of 59% (p <0.001) and a > or =50% improvement in 66% of patients. Post-stroke pain responds in 70% of patients. We conclude that the outcomes of surgery appear to vary according to aetiology, but it would appear that the effects are best for phantom limb syndromes, head pain and anaesthesia dolorosa.
  Acta neurochirurgica. Supplement 01/2007; 97(Pt 2):111-6.
• Source

  Available from: Ned Jenkinson

  Article: Using magnetoencephalography to investigate brain activity during high frequency deep brain stimulation in a cluster headache patient.

  Nj Ray, Ml Kringelbach, N Jenkinson, Slf Owen, P Davies, S Wang, N De Pennington, Pc Hansen, J Stein, Tz Aziz
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  ABSTRACT: Treatment-resistant cluster headache can be successfully alleviated with deep brain stimulation (DBS) of the posterior hypothalamus [1]. Magnetoencephalography (MEG) is a non-invasive functional imaging technique with both high temporal and high spatial resolution. However, it is not known whether the inherent electromagnetic (EM) noise produced by high frequency DBS is compatible with MEG. We used MEG to record brain activity in an asymptomatic cluster headache patient with a DBS implanted in the right posterior hypothalamus while he made small movements during periods of no stimulation, 7 Hz stimulation and 180 Hz stimulation. We were able to measure brain activity successfully both during low and high frequency stimulation. Analysis of the MEG recordings showed similar activation in motor areas in during the patient's movements as expected. We also observed similar activations in cortical and subcortical areas that have previously been reported to be associated with pain when the patient's stimulator was turned on or off [2,3]. These results show that MEG can be used to measure brain activity regardless of the presence of high frequency deep brain stimulation.
  Biomedical Imaging and Intervention Journal 01/2007; 3(1):e25.
• Source

  Available from: John Frederick Stein

  Conference Proceeding: Revealing the dynamic correlation between neural and muscular signals using time-dependent granger causality analysis

  S. Wang, Y. Chen, M. Ding, J. Feng, J.F. Stein, T.Z. Aziz, X. Liu
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  ABSTRACT: Functional correlation between oscillatory neural and muscular signals during tremor can be revealed by Fourier-transform-based coherence estimation. The coherence value in a defined frequency range reveals the interaction strength between the two signals. However, coherence estimation does not provide directional information, preventing the further dissection of the relationship between the two interacting signals. We have therefore investigated functional correlations between the subthalamic nucleus (STN) and muscle in Parkinsonian tremor using adaptive Granger autoregressive modelling. During intermittent resting tremor we analysed the inter-dependence of local field potentials (LFPs) recorded from the STN and surface electromyograms (EMGs) recorded from the contralateral forearm muscles. We compared the Granger causality with coherence estimation, an adaptive Granger causality based on autoregressive modelling with a running window was used to reveal the time-dependent causal influences between the LFP and EMG signals. Our results showed that during persistent tremor, there was a directional causality predominantly from EMGs to LFPs corresponding to the significant coherence between LFPs and EMGs at the tremor frequency; and over episodes of transient resting tremor, the inter-dependence between EMGs and LFPs was bi-directional and alternatively varied with time. We conclude that the functional correlation between the STN and muscle is dynamic, bi-directional, and dependent on the tremor status.
  Medical Applications of Signal Processing, 2005. The 3rd IEE International Seminar on (Ref. No. 2005-1119); 12/2005