A Benazzouz

Effect on parkinsonian signs and symptoms of bilateral subthalamic nucleus stimulation

In monkeys rendered parkinsonian, lesions and electrical stimulation of the subthalamic nucleus reduce all major motor disturbances. The effect of electrical stimulation of the subthalamic nucleus was assessed in three patients with disabling akinetic-rigid Parkinsons disease and severe motor fluctuations. Quadripolar electrodes connected to a pulse generator were implanted in the subthalamic nuclei on both sides. Patients were evaluated with the unified Parkinsons disease rating scale and timed motor tests. 3 months after surgery, activities of daily living scores had improved by 58-88% and motor scores by 42-84%. This improvement was maintained for up to 8 months in the first patient operated upon. One patient was confused for 2 weeks after surgery, and another developed neuropsychological impairment related to a thalamic infarction which improved over 3 months. In one patient, stimulation could induce ballism that was stopped by reduction of stimulation. This is the first demonstration in human beings of the part played by the subthalamic nuclei in the pathophysiology of Parkinsons disease.

Stimulation of subthalamic nucleus alleviates tremor in Parkinson's disease

STN in the pathophysiology of parkinsonian tremor. STN stimulation can be considered as an alternative to Vim or pallidal surgery, even in patients severely disabled by parkinsonian rest and postural tremor, since it induces a dramatic effect not only on akinesia and rigidity, but also on tremor. In our centre, 49 patients with Vim stimulation for predominant tremor were followed up for longer than 4 years. In 32 (65%) the most disabling symptoms were motor fluctuations, levodopa-induced dyskinesias, or both, whereas tremor was well controlled. In patients with tremor-dominated PD, STN stimulation should be preferred to Vim stimulation since most of these patients will develop disabling akinesia not improved by Vim stimulation.

Chronic electrical stimulation of the ventralis intermedius nucleus of the thalamus and of other nuclei as a treatment for Parkinson's disease

Abstract:During stereotaxy in nonanesthetized patients with Parkinsons disease or essential tremor, tremor was suppressed by test stimulation of the thalamic ventralis intermedius nucleus (Vim) at high frequency (130 Hz). Based on this finding, the authors have used chronic stimulation of the Vim a

Ineffective subthalamic nucleus stimulation in levodopa-resistant postischemic parkinsonism

Article abstract The authors report a patient with postischemic parkinsonism who responded neither to levodopa nor to bilateral subthalamic nucleus (STN) stimulation. MRI revealed bilateral lesions of the substantia nigra, the striatum, the external pallidum, and part of the internal pallidum. PET showed reduced striatal dopa-decarboxylase activity, D2 receptor binding, and glucose metabolism. Perioperative microrecording showed low-frequency activity of STN cells. This case suggests that parkinsonian patients who do not have a good response to levodopa or in whom a postsynaptic dopaminergic lesion can be shown may not be good candidates for STN surgery.

Tiefe Hirnstimulation des Nucleus subthalamicus (STN) und der Substantia nigra pars reticulata (SNr) bei der pharmakoresistenten Epilepsie

Die Notwendigkeit der Suche nach alternativen Behandlungsmethoden der Epilepsie wird dadurch deutlich, dass trotz wesentlicher pharmakologischer Fortschritte [18] etwa 30% der Patienten, welche an einer Epilepsie leiden, auch unter medikamentoser Behandlung Anfalle haben, die zu einer Behinderung im Alltagsleben fuhren [23]. Ablative chirurgische Eingriffe mit Entfernung von epileptogenem Hirngewebe sind dann in Betracht zu ziehen, wenn die Anfalle einen fokalen Ursprung haben, und wenn die praoperative Abklarung zeigt, dass die Entfernung des Gewebes nicht mit zusatzlichen und inakzeptablen neurologischen oder kognitiven Defiziten einhergeht [12]. Stimulationsverfahren zur Neuromodulation wurden fruher in verschiedenen Hirnregionen eingesetzt: im Cerebellum [7, 31], im Nucleus anterior thalami [8], im Centrum medianum thalami [13, 26], im Nucleus ventralis intermedius thalami (eigene unveroffentlichte Daten), und im Nucleus caudatus [6]. Bekannter wurde die Stimulation des Nervus vagus [15, 25]. Abgesehen von diesen indirekten Zugangen wurde auch vorgeschlagen eine fokale Stimulation der epileptogenen Areale selbst vorzunehmen [27]. Aufgrund experimenteller Untersuchungen gibt es mittlerweile auch genugend Daten, die es rechtfertigen, die chronische Stimulation im nigralen System bzw. im Nucleus subthalamicus beim Menschen zu untersuchen.