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TITLE: Surgical treatment of essential tremor.
AUTHORS: Pahwa R; Lyons K; Koller WC
AUTHOR AFFILIATION: Department of Neurology, University of Kansas
Medical Center, Kansas City, Kansas 66160, USA.
SOURCE: Neurology 2000;54(11 Suppl 4):S39-44
CITATION IDS: PMID: 10854351 UI: 20312906
ABSTRACT: Surgical treatment for essential tremor (ET) has been
used since the early 1950s. Initially, different areas were
targeted for tremor control. However, the optimal target was
eventually determined to be the ventralis intermedius (VIM)
nucleus of the thalamus. Thalamotomy improves contralateral
tremor in more than 90% of patients. Long-term studies of
thalamotomy indicate that the benefits continue in most patients.
Persistent morbidity associated with thalamotomy, which occurs in
less than 10% of patients, includes dysarthria, dysequilibrium,
weakness, and cognitive impairment. Bilateral thalamotomy is
associated with substantial morbidity and is usually avoided.
Studies demonstrate that chronic stimulation of the VIM is safe
and effective for tremor. Adverse effects of chronic stimulation
include paresthesia, dysarthria, dysequilibrium, and localized
pain. In many patients, bilateral thalamic stimulation is
performed without a substantial increase in morbidity. ET
patients with disabling medication-resistant tremor are
reasonable candidates for these stereotactic procedures.
2000/07
2000/08 11:00
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TITLE: Pharmacologic treatment of essential tremor.
AUTHORS: Koller WC; Hristova A; Brin M
AUTHOR AFFILIATION: Department of Neurology, University of Miami
School of Medicine, Miami, Florida 33136, USA.
SOURCE: Neurology 2000;54(11 Suppl 4):S30-8
CITATION IDS: PMID: 10854350 UI: 20312905
ABSTRACT: Essential tremor (ET) is a common movement disorder
that often causes functional disability, potentially leading to
physical and emotional difficulties. The paucity of data
available regarding the underlying pathophysiologic mechanism of
ET hinders the development of innovative approaches to
pharmacotherapeutic treatments. Options for drug therapy include
the use of primidone, beta-adrenergic blockers, such as
propranolol, alcohol, and other drugs, such as benzodiazepines,
gabapentin, carbonic anhydrase inhibitors, clozapine,
flunarizine, clonidine, and the methylxanthine derivative
theophylline. Chemodenervation with botulinum toxin type A may be
a therapeutic option for selected patients with ET. Each drug is
classified as to the quality of evidence for efficacy and the
suggested strength of therapeutic recommendation. In general
clinical practice, primidone and propranolol have proven efficacy
in ET.
2000/07
2000/08 11:00
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TITLE: Chronic intracerebral stimulation and abnormal
movements: why and when? Major therapeutic advances in the 90s
VERNACULAR TITLE: Stimulation intracerebrale chronique et
mouvements anormaux: pourquoi et comment? Une avancee
therapeutique majeure des annees 90.
AUTHORS: Caparros-Lefebvre D
AUTHOR AFFILIATION: Service de Neurologie, CHU, Pointre a Pitre.
lefebvdo@ais.gp
SOURCE: Presse Med 2000 Apr 8;29(13):731-6
CITATION IDS: PMID: 10797828 UI: 20258163
ABSTRACT: TECHNICAL ASPECTS: Surgical procedures for abnormal
movements progressively evolved toward microinvasive techniques
performed under stereotaxic control. The next advance was the
development of well-tolerated intracerebral stimulation with
reversible effects. The quality of the results depends on optimal
definition of the stimulation target. Optimally, the surgical
protocol includes stereotaxic ventriculography to identify
targets followed by electrical activity recordings of the
structures crossed by the electrode. Finally, a minute study of
the stimulation effects is performed under sterotaxic control
while the patient is awake.
PARKINSON'S DISEASES: Indications for thalamic stimulation in Parkinson's disease have given way to subthalamic stimulation which improves tremor, bradykinesia and rigidity simultaneously. This result confirms the implication of the subthalamic nucleus in the pathogenesis of Parkinson syndromes. The palladium may be stimulated in Parkinson's patients with major iatrogenic involuntary movements.
ESSENTIAL TREMOR: Thalamic stimulation is indicated for
essential tremor. The efficacy of chronic stimulation is
currently under evaluation in other indications.
2000/06
2000/08 09:00
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TITLE: Neuropsychological functioning in a patient with
essential tremor with and without bilateral VIM stimulation.
AUTHORS: Lucas JA; Rippeth JD; Uitti RJ; Shuster EA; Wharen RE
AUTHOR AFFILIATION: Department of Psychology, Mayo Clinic
Jacksonville, FL 32224, USA.
SOURCE: Brain Cogn 2000 Mar;42(2):253-67
CITATION IDS: PMID: 10744923 UI: 20211270
ABSTRACT: The effects of deep brain stimulation on motor
functions, cognitive abilities, and mood were assessed in an
80-year-old, right-handed male with a chronic history of
essential tremor. Electrodes were implanted bilaterally in the
ventral intermediate nucleus of the thalamus during a single
operation. Upon evaluation at 3 months postsurgery, bilateral
stimulation was associated with a clinically significant
reduction in tremor ratings and improvement in manual dexterity.
At that time, a battery of neuropsychological measures was
administered with and without bilateral stimulation. The patient
demonstrated comparable performances on measures of visuospatial
perception, attention, mental tracking, verbal learning, and
verbal recognition memory in both the "on" and
"off" conditions. Without stimulation, the patient
demonstrated declines of greater than 1 SD on measures of verbal
fluency and verbal recall compared to when the stimulators were
active. Responses to mood rating scales also indicated greater
subjective distress without stimulation. Results are discussed in
the context of previous studies of the effects of thalamic
stimulation on neurocognitive functioning. Copyright 2000
Academic Press.
2000/05
2000/16 09:00
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TITLE: Effect of low and high frequency thalamic
stimulation on sleep in patients with Parkinson's disease and
essential tremor.
AUTHORS: Arnulf I; Bejjani BP; Garma L; Bonnet AM; Damier P;
Pidoux B; Dormont D; Cornu P; Derenne JP; Agid Y
AUTHOR AFFILIATION: Centre d'Investigation Clinique, Federation
de Neurologie and INSERM U 289, Paris, France.
isabelle.arnulf@psl.ap-hop-paris.fr
SOURCE: J Sleep Res 2000 Mar;9(1):55-62
CITATION IDS: PMID: 10733690 UI: 20198509
ABSTRACT: Continuous high frequency stimulation of the ventral
intermediate nucleus of the thalamus (Vim), delivered through
surgically implanted quadripolar electrodes, alleviates tremor in
Parkinson's disease (PD) and essential tremor (ET). The Vim is
adjacent to the thalamic reticular nuclei, where sleep spindles
originate according to animal models. In order to determine
whether Vim stimulation affects sleep spindles, six patients (4
PD, 2 ET), aged 60-69 years, were recorded on a control night and
a stimulation night (130 Hz, 2-3 V; right stimulation in five
patients and bilateral stimulation in one patient). Stimulation
did not modify sleep quality or architecture. Sleep spindles were
present and symmetrical in five out of six patients under
stimulation. However, in one patient with a sustained
'thalamotomy-like effect' that abolished tremor, spindles were
asymmetrical even without stimulation. In each patient, spindle
density was similar on both nights (mean+/- SEM: 2.25+/-0. 61
spindles per min of stage 2 sleep vs. 1.84+/-0.31). In an attempt
to promote sleep two different patterns of stimulation were
applied in the region of ventrooralis posterior and reticularis
nuclei in five patients in the awake state. Continuous low
frequency stimulation (5 Hz, 0.1 V), and repeated trains of 15 Hz
for 1 s every 15 s mimicking the pattern of physiological
spindles, each failed to induce sleep or cortical
synchronization. We conclude that Vim stimulation, unlike
thalamotomy, selectively reduces tremor without altering sleep or
sleep spindles. Our results also suggest that low frequency
stimulation applied in the region of the reticular nuclei does
not induce sleep.
2000/06
2000/03 09:00
--------------------------------------------------------------------------------
TITLE: A comparison of continuous thalamic stimulation
and thalamotomy for suppression of severe tremor [see comments]
AUTHORS: Schuurman PR; Bosch DA; Bossuyt PM; Bonsel GJ; van
Someren EJ; de Bie RM; Merkus MP; Speelman JD
AUTHOR AFFILIATION: Department of Neurology, Academic Medical
Center, Amsterdam, The Netherlands.
SOURCE: N Engl J Med 2000 Feb 17;342(7):461-8
CITATION IDS: PMID: 10675426 UI: 20125069
COMMENT: Comment in: N Engl J Med 2000 Feb 17;342(7):505-7
ABSTRACT: BACKGROUND: Deep-brain stimulation through an electrode
implanted in the thalamus was developed as an alternative to
thalamotomy for the treatment of drug-resistant tremor.
Stimulation is thought to be as effective as thalamotomy but to
have fewer complications. We examined the effects of these two
procedures on the functional abilities of patients with
drug-resistant tremor due to Parkinson's disease, essential
tremor, or multiple sclerosis.
METHODS: Sixty-eight patients (45 with Parkinson's disease, 13 with essential tremor, and 10 with multiple sclerosis) were randomly assigned to undergo thalamotomy or thalamic stimulation. The primary outcome measure was the change in functional abilities six months after surgery, as measured by the Frenchay Activities Index. Scores for this index can range from 0 to 60, with higher scores indicating better function. Secondary outcome measures were the severity of tremor, the number of adverse effects, and patients' assessment of the outcome.
RESULTS: Functional status improved more in the thalamic-stimulation group than in the thalamotomy group, as indicated by increases in the score for the Frenchay Activities Index (from 31.4 to 36.3 and from 32.0 to 32.5, respectively; difference between groups, 4.4 points; 95 percent confidence interval, 2.0 to 6.9). After adjustment for base-line characteristics, multivariate analysis also showed that the thalamic-stimulation group had greater improvement (difference between groups, 5.1 points; 95 percent confidence interval, 2.3 to 7.9). Tremor was suppressed completely or almost completely in 27 of 34 patients in the thalamotomy group and in 30 of 33 patients in the thalamic-stimulation group. One patient in the thalamic-stimulation group died perioperatively after an intracerebral hemorrhage. With the exception of this incident, thalamic stimulation was associated with significantly fewer adverse effects than thalamotomy. Functional status was reported as improved by 8 patients in the thalamotomy group, as compared with 18 patients in the thalamic-stimulation group (P=0.01).
CONCLUSIONS: Thalamic stimulation and thalamotomy are equally
effective for the suppression of drug-resistant tremor, but
thalamic stimulation has fewer adverse effects and results in a
greater improvement in function.
2000/02
2000/26 09:00
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TITLE: Efficacy of unilateral deep brain stimulation of
the VIM nucleus of the thalamus for essential head tremor.
AUTHORS: Koller WC; Lyons KE; Wilkinson SB; Pahwa R
AUTHOR AFFILIATION: Department of Neurology, University of Kansas
Medical Center, Kansas City 66160-7314, USA.
SOURCE: Mov Disord 1999 Sep;14(5):847-50
CITATION IDS: PMID: 10495050 UI: 99423241
ABSTRACT: Essential tremor is a common movement disorder. Deep
brain stimulation of the VIM nucleus of the thalamus has been
reported to be efficacious for reducing essential hand tremor.
The effect of deep brain stimulation of the thalamus on essential
head tremor has not been well studied. Therefore, we evaluated
the effect of DBS of the thalamus in 38 patients with essential
head tremor. Head tremor scores prior to surgery were compared
with scores at 3, 6, and 12 months postimplant with stimulation
"on" and "off." The 3-month evaluations were
blinded for 24 patients and all others were open-label. There was
a significant improvement in head tremor at all postimplant
evaluations compared with baseline. Essential head tremor can be
reduced with deep brain stimulation of the VIM nucleus of the
thalamus and, pending the results of other controlled trials,
should be considered as a treatment option for patients with
disabling essential head tremor unresponsive to medication.
1999/09
1999/24 09:00
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TITLE: The initial treatment of Parkinson's disease
should begin with levodopa.
AUTHORS: Weiner WJ
AUTHOR AFFILIATION: Department of Neurology, University of Miami
School of Medicine, Florida 33136, USA.
SOURCE: Mov Disord 1999 Sep;14(5):716-24
CITATION IDS: PMID: 10495031 UI: 99423222
ABSTRACT: For over two decades controversy has surrounded the
initial choice of therapeutic agent for patients with early
symptomatic Parkinson's disease. Whether levodopa or dopamine
receptor agonist monotherapy in these patients is more
efficacious and/or results in fewer long-term complications of
dopaminergic therapy such as motor fluctuations, dyskinesias, or
psychiatric disorders is unresolved. This article examines the
evidence related to levodopa-sparing strategies and
levodopa-induced toxicity in Parkinson's disease. At this time,
there is little evidence to support levodopa-sparing strategies
or to suggest that levodopa is toxic and harmful to patients with
Parkinson's disease.
1999/09
1999/24 09:00
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Arch Neurol 2000 Aug;57(8):1194-8
Clinical subtypes of essential tremor.
Louis ED, Ford B, Barnes LF
Neurological Institute, Unit 198, 710 W 168th St, New York, NY 10032, USA.
BACKGROUND: There is clinical variability in essential tremor (ET), but it is not clear
whether this variability is because of the existence of distinct clinical subtypes of ET
(ie, forms of ET that may differ in their etiology, rate of progression, or response
to treatment).
OBJECTIVES: To examine in a group of ET cases the age of onset, anatomic
distribution, and rate of progression of tremor, and to look for associations
between these factors.
METHODS: Cases of ET were ascertained from a community
(n = 60) and a tertiary referral clinic (n = 55) in northern Manhattan, New York, NY.
All subjects underwent an interview and videotaped tremor examination. Rate of
progression was estimated based on the tremor severity and reported disease duration
at the time of evaluation.
RESULTS: Age of onset was bimodally distributed in clinic
cases. There were differences in the anatomic distribution of the tremor
(arm tremor only vs head and arm tremor vs isolated head tremor).
Rate of progression was distributed exponentially; there was a large cluster of subjects
with slower rates of progression, and a smaller number who had faster rates.
There was an association between age of onset and rate of progression (r = 0.46-0.50,
P<.002); cases with older age of onset (>60 years) progressed more rapidly (P<.001).
In addition, upper limb tremor progressed more slowly among those with concomitant head
tremor (P =.03).
CONCLUSIONS: Essential tremor is not a homogeneous condition. There are differences in
age of onset, anatomic distribution of tremor, and rate of progression. The ET in
several groups of patients in this study (those with age of onset >60 years and those
without head tremor) progressed more rapidly, suggesting that these ET cases may define
distinct clinical subtypes. These subtypes should be further assessed for etiologic and
genetic heterogeneity as well as differences in responsiveness to therapeutic agents.
Arch Neurol. 2000;57:1194-1198
PMID: 10927801, UI: 20386855
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