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TITLE: Levodopa Withdrawal After Bilateral Subthalamic Nucleus Stimulation in Advanced Parkinson Disease.
AUTHORS: Molinuevo JL; Valldeoriola F; Tolosa E; Rumia J; Valls-Sole J; Roldan H; Ferrer E
AUTHOR AFFILIATION: Servei de Neurologia, Hospital Clinic Universitari, Villarroel 170, Barcelona 08036, Spain.
SOURCE: Arch Neurol 2000 Jul;57(7):983-988
[Record as supplied by publisher]
CITATION IDS: PMID: 10891980 UI: No Cit. ID assigned
ABSTRACT: CONTEXT: Subthalamic nucleus (STN) stimulation may be effective in ameliorating parkinsonian symptoms even to the extent to permit levodopa withdrawal.

OBJECTIVES: To analyze the efficacy of STN stimulation in patients with Parkinson disease (PD) and to determine if levodopa may be withdrawn after surgery. DESIGN: Before-after trial.

SETTING: Referral center, hospitalized care.

PATIENTS: Fifteen patients with advanced PD. INTERVENTIONS: Microelectrode-guided bilateral STN high-frequency stimulation.

OUTCOME MEASURES: Before surgery patients were evaluated in off-medication and on-medication conditions. Dopaminergic drug dosages were reduced after surgery, aiming for complete withdrawal. Six months after surgery, patients were reeavaluated in off- and on-medication conditions, with the stimulation turned on and off. RESULTS: Total Unified Parkinson's Disease Rating Scale (UPDRS) motor score in the off-medication condition improved by 65.9%; and axial symptoms, bradykinesia, rigidity, and tremor improved by 65.8%, 60.4%, 66.1%, and 81.1%, respectively. UPDRS part II scores were reduced by 71.8% and Schwab and England scores improved by 45.3%. Levodopa was withdrawn in 8 patients and the overall levodopa dose was reduced 80.4%. "Off" time was reduced 89.7% and the severity of dyskinesias decreased 80.6% after surgery. All results reached significance (P<.001). Stimulation of the STN achieved antiparkinsonian effect similar to that of treatment with levodopa. No life-threatening adverse effects occurred.

CONCLUSIONS: Bilateral STN stimulation safely improves all parkinsonian symptoms, decreases or eliminates the need for levodopa, and ameliorates motor fluctuations and dyskinesias. Complete withdrawal of levodopa is feasible with this technique and the overall motor effect of STN stimulation is quantitatively comparable to that obtained with levodopa. Arch Neurol. 2000;57:983-988

2000/07
2000/13 11:00

TITLE: Deep brain stimulation of subthalamic area for severe proximal tremor [In Process Citation]
AUTHORS: Kitagawa M; Murata J; Kikuchi S; Sawamura Y; Saito H; Sasaki H; Tashiro K
AUTHOR AFFILIATION: Departments of Neurology (Drs. Kitagawa, Kikuchi, Sasaki, and Tashiro) and Neurosurgery (Drs. Murata and Sawamura), Hokkaido University of Medicine, and Sapporo Azabu Neurosurgical Hospital (Dr. Saito), Japan.
SOURCE: Neurology 2000 Jul 12;55(1):114-6
[MEDLINE record in process]
CITATION IDS: PMID: 10891917 UI: 20351635
ABSTRACT: ARTICLE ABSTRACT: Proximal tremors are often refractory to nucleus ventrointermedius thalami thalamotomy. Subthalamotomy has been suggested to be effective for treatment of tremor, although this procedure is associated with considerable adverse effects, and has rarely been considered a suitable treatment modality. The authors demonstrate the efficacy and safety of subthalamic deep brain stimulation in two patients, one with a severe, refractory proximal essential tremor and one with tremor with dystonia.

2000/07
2000/13 11:00


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TITLE: Effects of medial thalamotomy and pallido-thalamic tractotomy on sleep and waking EEG in pain and parkinsonian patients.
AUTHORS: Roth C; Jeanmonod D; Magnin M; Morel A; Achermann P
AUTHOR AFFILIATION: Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
SOURCE: Clin Neurophysiol 2000 Jul 1;111(7):1266-1275
[Record as supplied by publisher]
CITATION IDS: PMID: 10880802 UI: No Cit. ID assigned
ABSTRACT: Objectives: Investigation of sleep and sleep EEG before and after stereotactic neurosurgery.Methods: All-night polysomnographic recordings were obtained in 3 neurogenic pain patients and 3 parkinsonian patients. One subject of each group was recorded in addition 3 months after surgery. Stereotactic operations were performed in the medial thalamus and on the pallido-thalamic tract to relieve neurogenic pain and parkinsonian symptoms, respectively.

Results: Sleep efficiency was little affected by the surgical intervention in neurogenic pain patients and a dramatic reduction in REM sleep occurred, which had recovered in the subject recorded after 3 months. After the surgery parkinsonian patients showed an increase in total sleep time and in sleep efficiency, and a decrease in REM sleep latency. Sleep efficiency remained elevated in the 3 months follow-up. Medial thalamotomy abolished spindle frequency activity (SFA) in the power and coherence spectra in non-REM sleep stage 2 systematically. Pallido-thalamic tractotomy attenuated SFA only to varying degrees. After 3 months SFA had reemerged. The alpha peak of the waking EEG was shifted to lower frequencies after surgery in 5 of 6 patients and had reverted to the original frequency 3 months later.

Conclusions: Medial thalamotomy or pallido-thalamic tractotomy had acute and reversible effects on the EEG and long-term deleterious side effects of stereotactic surgery on sleep and sleep EEG are improbable. The results provide further evidence for the involvement of the human thalamus in the generation of sleep spindles.

2000/07
2000/06 11:00


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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: Evidence that ventrolateral thalamotomy may eliminate the supraspinal component of both pathological and physiological tremors [In Process Citation]
AUTHORS: Duval C; Panisset M; Bertrand G; Sadikot AF
AUTHOR AFFILIATION: Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Quebec, Canada.
SOURCE: Exp Brain Res 2000 May;132(2):216-22
[MEDLINE record in process]
CITATION IDS: PMID: 10853946 UI: 20310993
ABSTRACT: Ventrolateral (VL) thalamotomy produced a marked reduction of oscillations related to the supraspinal components of Parkinson's disease tremor (4-7 Hz) and physiological tremor (8-12 Hz). Finger tremor was examined in nine patients undergoing unilateral VL thalamotomy and in nine age-matched controls. In comparison to the preoperative state, the relative percentage of power within the 7.6-12.5 Hz band did not increase after the surgical procedure. Furthermore, the amount of absolute power within the 7.6-12.5 Hz band was much lower for post-surgical patients in comparison to matched controls when periods of tremor having equal amplitudes were compared. These results suggest that VL thalamotomy interrupts a common circuit involved in the supraspinal component of both physiological and pathological tremors. We provide evidence that the thalamus may be involved in circuits generating physiological tremor in humans.

2000/06
2000/15 09:00


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TITLE: A comparison of surgical approaches for the management of tremor: radiofrequency thalamotomy, gamma knife thalamotomy and thalamic stimulation [In Process Citation]
AUTHORS: Niranjan A; Jawahar A; Kondziolka D; Lunsford LD
AUTHOR AFFILIATION: Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pa., USA.
SOURCE: Stereotact Funct Neurosurg 1999;72(2-4):178-84
[MEDLINE record in process]
CITATION IDS: PMID: 10853075 UI: 20312936
ABSTRACT: Objective: Between April 1994 and January 1999, 39 stereotactic procedures for patients with intractable tremor were performed at the University of Pittsburgh Medical Center. A retrospective analysis of results of radiosurgical thalamotomy (n = 15), MR-guided stereotactic radiofrequency thalamotomy (n = 13), and deep brain thalamic stimulation (DBS; n = 11) was performed to study relative advantages and risks of these procedures.

Methods: All options were discussed with the patients, but radiosurgery usually was performed in elderly patients with concurrent medical problems. Stereotactic thalamotomy and DBS was performed with MR guidance and macrostimulation. For radiosurgery, a median dose of 140 Gy (range 130-150 Gy) was delivered using a single 4-mm collimator.

Results: Of the 13 patients who underwent radiofrequency thalamotomy, 5 had immediate complete arrest of tremor, 6 had a significant reduction and 2 had partial reduction. All 11 patients who underwent DBS had excellent control of tremor immediately after the procedure, and in longer-term follow-up 10/11 maintained excellent tremor control. Of the 12 evaluable radiosurgery patients, 10 noted excellent relief and 2 had partial relief. Conclusion: Stereotactic procedures for tremor control are safe and effective. Each procedure has specific advantages and disadvantages that are important for patient selection. Copyright 2000 S. Karger AG, Basel

2000/06
2000/15 09:00


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TITLE: Stereotactic ventral intermedial thalamotomy for the treatment of essential Tremor:Results of a series of 37 patients [In Process Citation]
AUTHORS: Akbostanci MC; Slavin KV; Burchiel KJ
AUTHOR AFFILIATION: Department of Neurological Surgery, Oregon Health Sciences University, Portland, Oreg., USA.
SOURCE: Stereotact Funct Neurosurg 1999;72(2-4):174-7
[MEDLINE record in process]
CITATION IDS: PMID: 10853074 UI: 20312935
ABSTRACT: We have analyzed 43 ventral intermediate thalamotomies performed in our center for treatment of medically intractable essential tremor (ET) in 37 patients. The mean age of patients was 70.9 years (range 42-84), duration of symptoms 33.3 years (1-65). The surgery in all cases was performed with stereotactic technique using MRI or CT localization. Intraoperative neurophysiological confirmation of the target location was obtained using a macrostimulation technique. All patients experienced either complete abolition of the contralateral tremor or significant improvement in tremor intensity immediately after the surgery. At follow-up examination 1-13 months after the operation, 60.5% of patients had no tremor, and 13.9% had mild residual tremor without interference with daily life. Tremor recurrence was observed in 5 patients, all of whom underwent repeat ventral intermedial (VIM) thalamotomy with excellent results. Transient problems with speech and motor functions were observed after 15 thalamotomies, permanent hemiparesis and speech difficulties were seen in 6 patients. We conclude that VIM thalamotomy is a highly effective procedure for medically intractable ET and may be performed with no mortality and low morbidity rate. Copyright 2000 S. Karger AG, Basel


2000/06
2000/15 09:00


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TITLE: Acute effects of thalamotomy and pallidotomy on regional cerebral metabolism, evaluated by PET.
AUTHORS: Henselmans JM; de Jong BM; Pruim J; Staal MJ; Rutgers AW; Haaxma R
AUTHOR AFFILIATION: Department of Neurology, University Hospital Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands
SOURCE: Clin Neurol Neurosurg 2000 Jun 1;102(2):84-90
[Record as supplied by publisher]
CITATION IDS: PMID: 10817894 UI: No Cit. ID assigned
ABSTRACT: The subacute effect of thalamotomy and pallidotomy on regional cerebral metabolism was studied by means of Positron Emission Tomography (PET). In this way we aimed to identify the pattern of functional deafferentiation following a specific lesion in the basal ganglia. The cerebral distribution of 2-[18F]fluoro 2-deoxy-D-glucose (FDG) uptake at 1-2 weeks after operation was compared with the uptake before operation. Analysis of the changes was done by statistical parametric mapping (SPM). Thalamotomy resulted in a reduction of FDG uptake in predominantly the lateral prefrontal- and the parietal cortex, whereas pallidotomy affected only uptake in the (pre)frontal cortex. The absence of change in the primary sensory-motor cortex after either surgical procedure may suggest that, in man, the motor portions of the thalamus exert a predominantly indirect influence on the human motor cortex.


2000/05
2000/19 09:00


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TITLE: The pedunculopontine nucleus: its role in the genesis of movement disorders.
AUTHORS: Lee MS; Rinne JO; Marsden CD
AUTHOR AFFILIATION: Department of Neurology, Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. myungs56@yumc.yonsei.ac.kr
SOURCE: Yonsei Med J 2000 Apr;41(2):167-84
CITATION IDS: PMID: 10817016 UI: 20277029
ABSTRACT: The pedunculopontine nucleus (PPN) is located in the dorso-lateral part of the ponto-mesencephalic tegmentum. The PPN is composed of two groups of neurons: one containing acetylcholine, and the other containing non-cholinergic neurotransmitters (GABA, glutamate). The PPN is connected reciprocally with the limbic system, the basal ganglia nuclei (globus pallidus, substantia nigra, subthalamic nucleus), and the brainstem reticular formation. The caudally directed corticolimbic-ventral striatal-ventral pallidal-PPN-pontomedullary reticular nuclei-spinal cord pathway seems to be involved in the initiation, acceleration, deceleration, and termination of locomotion. This pathway is under the control of the deep cerebellar and basal ganglia nuclei at the level of the PPN, particularly via potent inputs from the medial globus pallidus, substantia nigra pars reticulata and subthalamic nucleus. The PPN sends profuse ascending cholinergic efferent fibers to almost all the thalamic nuclei, to mediate phasic events in rapid-eye-movement sleep. Experimental evidence suggests that the PPN, along with other brain stem nuclei, is also involved in anti-nociception and startle reactions. In idiopathic Parkinson's disease (IPD) and parkinson plus syndrome, overactive pallidal and nigral inhibitory inputs to the PPN may cause sequential occurrences of PPN hypofunction, decreased excitatory PPN input to the substantia nigra, and aggravation of striatal dopamine deficiency. In addition, neuronal loss in the PPN itself may cause dopamine-resistant parkinsonian deficits, including gait disorders, postural instability and sleep disturbances. In patients with IPD, such deficits may improve after posteroventral pallidotomy, but not after thalamotomy. One of the possible explanations for such differences is that dopamine-resistant parkinsonian deficits are mediated to the PPN by the descending pallido-PPN inhibitory fibers, which leave the pallido-thalamic pathways before they reach the thalamic targets.

2000/06
2000/03 09:00


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TITLE: Posteroventral pallidotomy in Parkinson's disease.
AUTHORS: Herrera EJ; Viano JC; Caceres M; Costello G; Suarez M; Suarez JC
AUTHOR AFFILIATION: Service of Neurosurgery, Stereotaxy and Functional Neurosurgery Unit, Cordoba, Republica Argentina.
SOURCE: Acta Neurochir (Wien) 2000;142(2):169-75
CITATION IDS: PMID: 10795891 UI: 20254908
ABSTRACT: OBJECTIVE: We analyse the clinical aspects, results and reliability of posteroventral pallidotomy (PVP) carried out as treatment for the principal symptoms and treatment induced complications in patients with Parkinson's disease (PD).

PATIENTS AND METHODS: Between August 1995 January 1998, 17 patients with PD were treated surgically, 13 patients with PVP. A pre- and post-surgical clinical evaluation was carried out. Riechert's Stereotactic System (MHT, Freiburg, Germany) was used. Ventriculography under stereotactic conditions was used in the PVP procedures, Laitinen's co-ordinates as anatomical target, and electrical stimulation for physiological determination. 3 4 radiofrequency lesions were made at 83 degrees C for 20". The mean age was 60 +/- 10.8 years, ages ranging from 45-79 years. 8 (60.5%) of the patients were male. The cardinal symptoms of the series were bradykinesia and rigidity. The duration of the illness ranged from 8.6 +/- 3.7 years with a range of 4-15 years. 7 (53.8%) presented with a duration of 10 years or more. 6 (46,2%) of the patients underwent left PVP, the remaining 7 (53.8%) right PVP. Only one patient received treatment with right PVP and ipsilateral thalamotomy in the same surgical procedure. The mean post-surgical follow up was 16 +/- 7 months, with a range of 2 to 26 months.

RESULTS: An up to date evaluation was carried out on all patients showing significant changes after PVP in UPDRS motor (P < 0.005), complete rigidity relief (P < 0.005), bradykinesia relief (P < 0.005) and complete tremor relief (P < 0.005). An important improvement in contralateral dyskinesia was noted after PVP. A subjective evaluation of the results showed excellent results in 4 (30.8%) patients, good in 6 (46.2%) and fair in 3 (23%). No significant correlation was found between age and duration of illness (P = 0.7). Two patients suffered slight side effects, one patient with worsening of hypophonia whilst the other suffered subjective visual impairment controlled by normal post operative ophthalmological examinations. There was no peri-operative mortality.

CONCLUSION: PVP is considered a safe and effective surgical method for the treatment of both the principal symptoms of PD and the complications of DOPA medication.

2000/07
2000/15 11:00


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TITLE: The surgical treatment of Parkinson's disease.
AUTHORS: Follett KA
AUTHOR AFFILIATION: Division of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City 52242, USA. kenneth-follett@uiowa.edu
SOURCE: Annu Rev Med 2000;51:135-47
CITATION IDS: PMID: 10774457 UI: 20236272
ABSTRACT: Surgical treatment of Parkinson's disease (PD) can provide gratifying symptomatic improvements for many individuals who suffer from persistent disabling symptoms despite the best available medical management. Current surgical therapies include ablative techniques (thalamotomy and pallidotomy), augmentative techniques (nondestructive) (deep brain stimulation), and restorative techniques (tissue transplantation and gene therapy). Ablative procedures can provide substantial clinical benefit, but the current trend is toward deep brain stimulation, which can provide similar symptomatic improvement in a nondestructive manner. Restorative techniques, such as tissue transplantation and gene therapy, are exciting but have significant obstacles to overcome before their promise can be realized. Until the underlying pathological defect of PD can be identified and treated, surgical intervention is likely to remain important in the symptomatic treatment of this disabling disease.

2000/06
2000/08 09:00


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TITLE: Functional brain imaging of movement disorders.
AUTHORS: Eidelberg D; Edwards C
AUTHOR AFFILIATION: North Shore University Hospital, Manhasset, NY 11030, USA.
SOURCE: Neurol Res 2000 Apr;22(3):305-12
CITATION IDS: PMID: 10769825 UI: 20232658
ABSTRACT: Functional brain imaging techniques such as positron emission tomography (PET) have contributed to our understanding of the pathophysiology of Parkinson's disease (PD) and other movement disorders. PET employs small amounts of positron emitting radioligands to produce quantitative measures of physiological and biochemical processes in the brain and other organs. In a PET experiment, a subject is given a compound of biological interest. The spatial and temporal distribution of the radiotracer is measured quantitatively in the course of the PET study, providing a tomographic representation of regional radioactivity concentration. In this review, we focus on the potential application of PET in the selection of suitable candidates and the assessment of surgical interventions such as pallidotomy, thalamotomy, and deep brain stimulation.

2000/06
2000/10 09:00


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TITLE: Advances in neurostimulation for movement disorders.
AUTHORS: Gross RE; Lozano AM
AUTHOR AFFILIATION: Department of Neurosurgery, University of Utah Health Sciences Center, Salt Lake City 84132, USA.
SOURCE: Neurol Res 2000 Apr;22(3):247-58
CITATION IDS: PMID: 10769817 UI: 20232650
ABSTRACT: In just 12 years since its introduction, deep brain stimulation (DBS) has become well established as a safe and effective therapy in the treatment of medically refractory movement disorders. Ventralis intermedius (Vim) DBS has virtually replaced thalamotomy in the routine clinical treatment of essential tremor, affording relief to thousands of patients who previously would not have undergone surgery, and there is increasing usage of Vim DBS in other tremors of intention (e.g., multiple sclerosis). Subthalamic nucleus (STN) and globus pallidus internus (GPi) DBS have revolutionized the treatment of advanced stage Parkinson's disease, improving all cardinal disease features and increasing 'on' time without dyskinesias. Finally, DBS of various sub-cortical structures is being developed and tested in other less prevalent movement disorders such as dystonia. Future developments in this rapidly advancing area will no doubt include widening indications for this relatively safe surgical procedure, elucidation of the mechanisms of action of electrical stimulation, and technological advancements improving effectiveness and convenience.

2000/06
2000/10 09:00


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TITLE: Future prospects of brain stimulation.
AUTHORS: Benabid AL; Koudsie A; Pollak P; Kahane P; Chabardes S; Hirsch E; Marescaux C; Benazzouz A
AUTHOR AFFILIATION: Inserm U 318, CHU of Grenoble, France.
SOURCE: Neurol Res 2000 Apr;22(3):237-46
CITATION IDS: PMID: 10769816 UI: 20232649
ABSTRACT: Chronic high frequency (130 Hz) stimulation (HFS) of the thalamic target Vim has replaced thalamotomy as a treatment of tremor of various origins and was extended to two other targets (Subthalamic nucleus (STN) and the medial pallidus (GPi)), since 1993 based on recent experimental data in rats and monkeys. STN appears to be a target of major interest, able to control the three cardinal symptoms and to allow the decrease or suppression of levodopa treatment, which then suppresses also levodopa induced dyskinesias. The mechanisms of action of HFS are not fully understood, but are definitely related to high frequency and are probably different depending on the target. Inhibition of cellular activity or of network functions could be induced, by jamming of a retroactive loop for tremor, or by shutdown of neurotransmitter release in STN. All cardinal symptoms are alleviated from tremor to akinesia and rigidity. The effects remain stable over more than five years chronic HFS of STN, as the method of choice when a surgical procedure is indicated for the treatment of Parkinson's disease and even more when a bilateral procedure is necessary. Recent data show that STN stimulation could be useful in the treatment of dystonia as well as some forms of epilepsies. It is therefore possible that DAS in STN as well as in other targets could become a potent therapeutic tool in the future for neurological disorders. The future of brain stimulation will depend on new technologies (new circuits, electrodes, web based programmers), waveforms (alternatives to square waves, random distribution), targets (hypothalamic nuclei, locus coeruleus) and indications (dystonia, epilepsy, eating disorders.

2000/06
2000/10 09:00


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TITLE: Surgery for levodopa-induced dyskinesias.
AUTHORS: Lang AE
AUTHOR AFFILIATION: Toronto Western Hospital, Division of Neurology, Morton & Gloria Shulman Movement Disorders Clinic, and the University of Toronto, Ontario, Canada.
SOURCE: Ann Neurol 2000 Apr;47(4 Suppl 1):S193-9; discussion S199-202
CITATION IDS: PMID: 10762148 UI: 20222802
ABSTRACT: The effects of surgical interventions for levodopa-induced dyskinesias (LIDs) in Parkinson's disease are reviewed. Since the introduction of levodopa, thalamotomy has been reported to have variable effects on LIDs. Striking benefit has been demonstrated, and efficacy is probably dependent on the size and location of the lesion. However, it remains unclear whether it is an effective treatment for all types of LIDs. Currently, pallidotomy is probably the most reliable and effective surgical treatment for LIDs, and will continue to play an important role in its management until other treatments become more widely available. Deep brain stimulation is an extremely exciting mode of therapy, particularly in the subthalamic nucleus and the globus pallidus, and early results of its use in the treatment of LIDs are promising. The effects of cerebral transplantation, still an experimental technique, on LIDs are inconsistent and controversial, and there is little reliable evidence that gamma knife radiosurgery can be safely applied to parkinsonian patients for the treatment of LIDs.

2000/04
2000/29 09:00


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TITLE: Neurocognitive correlates of stereotactic thalamotomy and thalamic stimulation in Parkinsonian patients.
AUTHORS: Hugdahl K; Wester K
AUTHOR AFFILIATION: Department of Biological and Medical Psychology, University of Bergen, Norway. hugdahl@psych.uib.no
SOURCE: Brain Cogn 2000 Mar;42(2):231-52
CITATION IDS: PMID: 10744922 UI: 20211269
ABSTRACT: In the present paper we have reviewed five different studies that relate to neuropsychological consequences of stereotactic thalamotomy and thalamic stimulation in patients with Parkinson's disease. The neuropsychological results are in a strict sense confined to thalamotomy and thalamic stimulation, although the more general message of the importance of investigating cognitive functions before and after surgery applies to other stereotactic techniques for surgical treatment of movement disorders as well. It is argued in the paper that stereotactic thalamotomy provides a unique model for basic research on the neuropsychology of the thalamus, while in return, neuropsychological tests for cognitive dysfunction after surgery may be the most important clinical follow-up.

Three general conclusions seem warranted from the data.

(1) Parkinsonian patients are impaired on a range of cognitive functions, including language processing, memory, and executive functions.

(2) Stereotactic thalamotomy does not further impair the patient; instead, we observed improvement on some tests, particularly verbal memory.

(3) In general, there does not seem to be a laterality effect, depending on which side the thalamotomy lesion is applied. An exception to this are dichotically presented simple speech sounds and autonomic responses. In both instances, left-sided brain stimulation produced enhanced performance, while lesioning the left thalamus impaired dichotic listening performance. Finally, we present a new hypothesis for a mechanism behind the thalamotomy effect, based in part on changes in arousal thresholds. Copyright 2000 Academic Press.

2000/05
2000/16 09:00



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