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There have been questions on deep brain stimulation (DBS), here is the recent historical and current information on this procedure. There is a side effect that is common with this procedure which makes it, rather saving battery life, the reason for turning it off when not exactly needed to eat, dress or write. The abstracts follow, the newest study is last, which is from our archives. ESSENTIAL TREMOR STUDIES & DEVICES Authors Lin YC. Lenz FA. Institution Department of Neurosurgery, First Hospital, Wenzhou Medical College. Title Distribution and response evoked by microstimulation of thalamus nuclei in patients with dystonia and tremor. Source Chinese Medical Journal. 107(4):265-70, 1994 Apr. Abstract The effect of 806 microstimulations were observed in 16 patients with movement disorders, dystonia (DA, n = 6) and tremor (TR, n = 10). Among the 347 sites in DA patients motor response was seen at 29 sites, the response with increased dystonia was seen at 28 sites. The effect could be seen at 14 sites (50%) in ventrointermedialis (Vim), five sites (18%) in ventrocaudalis (Vc) and five sites (18%) in white matter (Wm). As for the other four sites, one site was in ventraloralis anterior (Voa), two sites in ventraloralis posterior (Vop), and one site in dorsal thalamus (dth), but reduction of dystonia drive was only seen at one site in dth. On the other hand, among the 459 sites in TR patients, motor response leading to reduction of tremor drive was seen at 38 sites, of which 30 sites (79%) were noted in Vim nuclei, and five sites (13.2%) in vc nuclei; of the remaining sites, two were seen in Vop nuclei, one in dth, and no increasing tremor drive was observed in all area. In general, paresthesia was the most common response, which was found at 159 sites (45.8%) with DA and 216 sites (47.1%) with TR. Pain was only seen at one site in Wm of DA; warm/cold and vertigo could be seen in Vop, Vim, and vc nucleus respectively. No responses were shown at 156 sites (45%) in DA, and 201 sites (43.8%) in TR. Authors Burleigh AL. Horak FB. Burchiel KJ. Nutt JG. Institution Department of Physiology, Oregon Health Sciences University, Portland. Title Effects of thalamic stimulation on tremor, balance, and step initiation: a single subject study. Source Movement Disorders. 8(4):519-24, 1993 Oct. Abstract This study was conducted to evaluate the clinically apparent balance improvements in a patient with Parkinson's disease who had stimulating electrodes surgically implanted to the VIM nucleus of the right thalamus for control of left-upper-extremity tremor. Experiments were conducted to determine if balance improved simply because the large-amplitude upper-extremity tremor was reduced or if the neural control of balance improved. Using EMGs and forceplate recordings, we quantified the effects of the thalamic stimulation on the contralateral upper-extremity tremor and on the lower-extremity postural muscle activations for quiet stance, step initiation, and equilibrium responses to surface displacements. The results demonstrated that, beside reducing the amplitude and destabilizing effects of the upper-extremity tremor, the thalamic stimulation was also effective in reducing tremor activity of the trunk and contralateral lower-extremity muscles. In addition, the contralateral lower-extremity muscle activation patterns, strengths, and durations for the balance tasks were enhanced during stimulation. These results suggest that thalamic stimulation improved this patient's balance by reducing tremor in the contralateral extremities and by increasing burst duration and magnitude of the tibialis anterior, which functions as the postural prime mover for the step initiation and balance tasks. Authors Nguyen JP. Degos JD. Institution Department of Neurosciences, Hopital Henri Mondor, Creteil, France. Title Thalamic stimulation and proximal tremor. A specific target in the nucleus ventrointermedius thalami. Source Archives of Neurology. 50(5):498-500, 1993 May. Abstract The severe proximal cerebellar postural tremor (also called action or intention or hyperkinetic tremor) is barely influenced by thalamotomy or stimulation of the thalamus at the classic target in the lower part of the nucleus ventrointermedius thalami (VIM). In four patients with a severe postural distal and proximal tremor, an electrode fitted with four points of contact was introduced within the entire height of the VIM. In each patient, stimulation of the lower part of the VIM was most effective in the distal component of the tremor, whereas its proximal component was specifically reduced by stimulation of its upper part. These results indicate that (1) proximal postural tremors can be as much affected by stimulation of the VIM as distal tremors, (2) there is a somatotopy in the VIM that is similar to that in the nucleus ventralis posterolateralis thalami, and (3) it is possible with this technique to adjust the VIM stimulation site so as to obtain the maximum efficacy according to the locale of the tremor. Authors Benabid AL. Pollak P. Seigneuret E. Hoffmann D. Gay E. Perret J. Institution Department of Neurosciences, INSERM 318, France. Title Chronic VIM thalamic stimulation in Parkinson's disease, essential tremor and extra-pyramidal dyskinesias. Source Acta Neurochirurgica - Supplementum. 58:39-44, 1993. Abstract Stereotactic thalamotomy of the VIM (ventral intermediate) nucleus is considered as the best neurosurgical treatment for Parkinsonian and essential tremors. However, this surgery, especially when bilateral, still presents a risk of recurrence and neurological complications. We observed that acute VIM stimulation at frequencies higher than 60 Hz during the mapping phase of the target suppressed the tremor of Parkinson's disease (PD) and essential tremor (ET). This effect was immediately reversible at the end of the stimulation. This was initially proposed as an additional treatment for patients already thalamotomized on the contralateral side, and then extended as a regular procedure for extra-pyramidal dyskinesias. Since January 1987, we implanted 126 thalami in 87 patients (61 PD, 13 ET, 13 dyskinesias of various origins). Deep brain stimulation electrodes were stereotactically implanted under local anaesthesia, using stimulation and micro-recording to delineate the best site of stimulation. Electrodes were subsequently connected to implantable programmable stimulators. The optimal frequency was around 130 to 185 Hz. The results (evaluated by a neurologist from 0 = no effect to 4 = perfect relief) are related to the type of tremor. Altogether, 71% of the 80 patients benefited from the procedure with grade 3 and 4 results. In 88% of the PD cases, the results were good (grade 3) or excellent (grade 4) and stable with time. Rigidity was moderately for a long improved but akinesia was not. The same level of improvement was observed in 68% of the ET patients and only in 18% of the other types of dyskinesias.(ABSTRACT TRUNCATED AT 250 WORDS) Authors Narabayashi H. Institution Neurological Clinic, Tokyo, Japan. Title Analysis of intention tremor. Source Clinical Neurology & Neurosurgery. 94 Suppl:S130-2, 1992. Abstract A marked effect of stereotaxic thalamotomy on intention tremor is described and a neurophysiological interpretation is offered. Tremor-generating activity seems to start in the ventral intermediate nucleus (VIM) of the thalamus, as revealed by recording of the unitary activity through a microelectrode at the tip of the insertion needle, after diminution of facilitatory input due to pathology of the cerebellum or its efferent pathway to the cerebrum. This secondary change within the VIM and the loss of facilitatory input leads to an intention tremor as one of the cerebellar symptoms seen in various neurological diseases. Authors Caparros-Lefebvre D. Blond S. Pecheux N. Pasquier F. Petit H. Institution Clinique Neurologique, CHU Lille. Title [Neuropsychological evaluation before and after thalamic stimulation in 9 patients with Parkinson disease]. [Review] [French] Original Title Evaluation neuropsychologique avant et apres stimulation thalamique chez 9 parkinsoniens. Source Revue Neurologique. 148(2):117-22, 1992. Abstract Chronic thalamic-VIM stimulation was performed in 9 parkinsonian patients with disabling tremor and poor response to drugs. Neuropsychological assessment was performed before and after deep brain electrode implantation and stimulation. Mild cognitive disorders were observed prior to thalamic implantation. Neuropsychological testing failed to show intellectual function worsening after implantation and stimulation. We conclude that thalamic stimulation could be an appropriate treatment of untractable tremor as this could provide less neuropsychological side-effects than thalamotomy, especially in Parkinson's disease. [References: 43] Authors Benabid AL. Pollak P. Gervason C. Hoffmann D. Gao DM. Hommel M. Perret JE. de Rougemont J. Institution Department of Clinical and Biological Neurosciences, INSERM Preclinical Neurobiology U 318, Joseph Fourier University of Grenoble, France. Title Long-term suppression of tremor by chronic stimulation of the ventral intermediate thalamic nucleus. Source Lancet. 337(8738):403-6, 1991 Feb 16. Abstract The usefulness of high-frequency stimulation of the ventral intermediate nucleus (Vim) as the first neurosurgical procedure in disabling tremor was assessed in 26 patients with Parkinson's disease and 6 with essential tremor. 7 of these patients had already undergone thalamotomy contralateral to the stimulated side, and 11 others had bilateral Vim stimulation at the same time. Chronic stimulating electrodes connected to a pulse generator were implanted in the Vim. Tremor amplitude at rest, during posture holding, and during action and intention manoeuvres was assessed by means of accelerometry. Of the 43 thalami stimulated, 27 showed complete relief from tremor and 11 major improvement (88%). The improvement was maintained for up to 29 months (mean follow-up 13 [SD 9] months). Adverse effects were mild and could be eradicated by reduction or cessation of stimulation. This reversibility and adaptability, allowing control of side-effects, make thalamic stimulation preferable to thalamotomy, especially when treatment of both sides of the brain is needed. Authors Pollak P. Benabid AL. Gross C. Gao DM. Laurent A. Benazzouz A. Hoffmann D. Gentil M. Perret J. Institution Departement des Neurosciences Cliniques et Biologiques, Centre Hospitalier Universitaire de Grenoble, France. Title [Effects of the stimulation of the subthalamic nucleus in Parkinson disease]. [French] Original Title Effets de la stimulation du noyau sous-thalamique dans la maladie de Parkinson. Source Revue Neurologique. 149(3):175-6, 1993. Abstract In Parkinson's disease, experimental studies favour a neuronal hyperactivity of the subthalamic nucleus. We carried out a subthalamic nucleus electrical stimulation in a patient aged 51, suffering for 8 years from a severe akineto-rigid form of Parkinson's disease, complicated with an on-off effect. Stereotaxic surgery was done under local anaesthesia on one side. Within the theoretical target, a 130 Hz stimulation induced akinesia alleviation mainly on the contralateral limbs. No abnormal movement was noticed. Then a long-term quadripolar DBS Medtronic electrode was inserted in that area. The study of the effects of chronic stimulation is in progress to determine the best temporal and electrical stimulation variables. Treatment of Tremor with Deep-Brain Stimulation Jean P. Hubble, K. Busenbark, S. Wilkinson, and W.C. Koller, Kansas City, KS Objective: To determine the safety, tolerability, and effectiveness of deep-brain stimulation (DBS) in the treatment of tremor in essential tremor (ET) and Parkinson's disease (PD). Background: Tremor in ET and PD is often not satisfactorily controlled with medication. Thalamotomy can alleviate tremor but can result in permanent neurological deficits. We hypothesize that DBS may offer a means of controlling tremor with minimal attendant risks. Design/Methods: The DBS lead is stereotactically implanted in the thalamus (VIM nucleus) contralateral to the arm targeted for tremor control. The electrical pulse generator is implanted in the subclavicular region and is turned on/off with a hand-held external magnet. All subjects have disabling tremor refractory to conventional pharmacotherapy in the target arm at baseline. Baseline assessment, DBS placement, and 3-month follow-up assessment have been completed in 8 ET and 2 PD subjects. Results: At 3-month follow-up, 8 subjects rated themselves as markedly (50-100%) improved and 2 as moderately (25-49%) improved. All subjects had significant tremor reduction in the target limb with the stimulator "on" compared to "off" (examiner-rated improvement by >2 points on 0-4 point tremor rating scale). Nine of the ten subjects had marked improvement in global disability ratings. All subjects had improved writing with the stimulator "on". Adverse effects attributable to DBS included transient paresthesia in all subjects and transient weakness in 1 subject. Conclusions: In this 3-month unblinded study, DBS was safe and effective in reducing tremor and functional disability in ET and PD. Study supported by Medtronic Inc. (Neurological Division). John Cottingham [log in to unmask] OR [log in to unmask]