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).
 
 
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