96 results found
Nandi D, Stein JF, Aziz TZ, 2002, Exploration of the role of the upper brainstem in motor control., Stereotact Funct Neurosurg, Vol: 78, Pages: 158-167, ISSN: 1011-6125
The rostral areas of the brainstem have been extensively studied in higher mammals and to a lesser extent in humans in the last two decades, looking for anatomical, electrophysiological and neurochemical evidence of involvement in the initiation and control of voluntary movement. This has come with the realisation that the axial symptoms of advanced Parkinson's disease (PD), like akinesia, postural impairment and gait freezing, are relatively less responsive to current medical and surgical treatments directed primarily at the basal ganglia and thalamus. The pedunculopontine nucleus (PPN) is one such area of interest. We have found that lesioning and electrical stimulation at high frequencies of the PPN region in the normal behaving primate induces akinesia, and low frequency stimulation can induce tremor. Micro-injections of gamma-aminobutyric acid (GABA) receptor A agonist, muscimol, into the PPN decreases activity. In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treated Parkinsonian primate model, bicuculline, a GABA(A) antagonist, can alleviate akinesia when infused into the PPN region. This may suggest new targets for treating the intractable akinetic symptoms of advanced PD.
Joint C, Nandi D, Parkin S, et al., 2002, Hardware-related problems of deep brain stimulation., Mov Disord, Vol: 17 Suppl 3, Pages: S175-S180, ISSN: 0885-3185
Deep brain stimulation for the alleviation of movement disorders and pain is now an established therapy. However, very little has been published on the topic of hardware failure in the treatment of such conditions irrespective of clinical outcome. Such device-related problems lead to significant patient morbidity and increased cost of therapy in the form of prolonged antibiotics, in-patient hospitalization, repeat surgery, and device replacement. We report a prospective review of our experience at the Radcliffe Infirmary Oxford from the period of April 1998 to March 2001. Overall there is a 20% rate of hardware-related problems in this series, which falls between the 7% and 65% rates reported by other groups. The majority of these failures occurred early on in the series, and numbers declined with experience. Some of the problems may be idiosyncratic to the methodology of individual groups.
Motor cortex stimulation is increasingly reported in the literature as a surgical option for the alleviation of neuropathic pain. The authors review the published literature and present their results including those demonstrated in a randomized controlled trial that confirmed the efficacy of the procedure. Patient selection and prediction of outcomes, however, remain difficult issues.
Parkin S, Nandi D, Giladi N, et al., 2001, Lesioning the subthalamic nucleus in the treatment of Parkinson's disease., Stereotact Funct Neurosurg, Vol: 77, Pages: 68-72, ISSN: 1011-6125
Ever since it was demonstrated about twenty years ago by two independent groups (Aziz et al. and Bergman et al.) that the cardinal clinical features of MPTP-induced Parkinson's disease (PD) in non-human primate models can be alleviated by lesions of the subthalamic nucleus (STN), this structure has been the focus of interest for functional neurosurgeons involved in the treatment of PD. Initially lesioning and later chronic high frequency stimulation of the STN has become the standard surgical target of akinetic PD. In this brief report we present our experience with 14 STN lesions (8 unilateral and 3 bilateral) confirmed by post-operative imaging. We found significant improvement in OFF rigidity and in ON tremor following unilateral lesions. The major complications were speech disturbance and L-Dopa resistant limb dystonia. Functional disability scores showed inconsistent reduction. There was insufficient data to comment on the significance of bilateral lesions; however, there was a similar pattern of improvement in tremor and speech disturbance. In addition, there was worsening of gait. We comment on the lower degree of improvement in motor scores in our series compared to the few others in recent literature and stress that even in these studies the UPDRS benefits did not translate directly into functional benefit for the patients.
Liu X, Rowe J, Nandi D, et al., 2001, Localisation of the subthalamic nucleus using Radionics Image Fusion and Stereoplan combined with field potential recording. A technical note., Stereotact Funct Neurosurg, Vol: 76, Pages: 63-73, ISSN: 1011-6125
Subthalamic nucleus stimulation is an effective therapy for alleviating parkinsonian tremor, rigidity and bradykinesia. Although microelectrode recording is said to be essential for accurate targeting, this often prolongs the operation and the multiple recording tracts required may increase the incidence of complications, particularly haemorrhage. We describe a technique for implantation of deep brain electrodes in the subthalamic nucleus using MRI/CT fusion for anatomical localisation followed by bipolar recording of focal field potentials via the implanted stimulating electrode for neurophysiological confirmation of the stimulation site. The technique is effective, safe and requires much less time, and can be used as an alternative method to microelectrode recording.
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