Biomedical subjects

Dieter Weinert

Publications and source records attributed to Dieter Weinert.

4 recordsLinked to original sources

PubMed2004

Most effective stimulation site in subthalamic deep brain stimulation for Parkinson's disease.

The optimal stimulation site in subthalamic deep brain stimulation (STN-DBS) was evaluated by correlation of the stereotactic position of the stimulation electrode with the electrophysiologically specified dorsal STN border. In a series of 25 electrodes, best clinical results with least energy consumption were found in contacts located in the dorsolateral border zone, whereas contacts within the subthalamic white matter, e.g., zona incerta, were significantly less effective. We suggest that the dorsolateral STN border should be covered by STN-DBS.

Electric Stimulation Therapy↗

PubMed2003

Subthalamic nucleus stimulation for Parkinson's disease preferentially improves akinesia of proximal arm movements compared to finger movements.

Deep brain stimulation of the subthalamic nucleus (STN-DBS) reduces akinesia in Parkinson's disease but its impact on fine motor functions was unknown. We assessed the effects of DBS and a levodopa (L-dopa) test on the timing of the precision grip in 18 patients. Improvement on UPDRS-items reflecting hand functions and the shortening of the first phases of the precision grip were more distinct in the L-dopa test than in the pure STN-DBS condition. Other akinesia items and the time for build-up of lifting force were equally improved in both conditions. This suggests that routine STN-DBS might not be equally effective on all aspects of fine motor functions.

Antiparkinson Agents↗

PubMed2003

Two-year follow-up of subthalamic deep brain stimulation in Parkinson's disease.

We studied 48 patients after bilateral subthalamic nucleus deep brain stimulation (STN-DBS) who were evaluated 6 months after the surgical procedure using the Unified Parkinson's Disease Rating Scale (UPDRS) in a standardized levodopa test. Additional follow-up was available in 32 patients after 12 months and in 20 patients after 24 months. At 6 months follow-up, STN-DBS reduced the UPDRS motor score by 50.9% compared to baseline. This improvement remained constant at 12 months with 57.5% and at 24 months with 57.3%. Relevant side effects after STN-DBS included intraoperative subdural hematoma without neurological sequelae (n = 1), minor intracerebral bleeding with slight transient hemiparesis (n = 1), dislocation of impulse generator (n = 2), transient perioperative confusional symptoms (n = 7), psychotic symptoms (n = 2), depression (n = 5), hypomanic behaviour (n = 2), and transient manic psychosis (n = 1). One patient died because of heart failure during the first postoperative year. The current series demonstrates efficacy and safety of STN-DBS beyond the first year after surgical procedure. Complications of STN-DBS comprise a wide range of psychiatric adverse events which, however, were temporary.

Electric Stimulation↗

PubMed2002

Documentation of electrode localization.

In evaluating the success of deep brain stimulation (DBS), the benefit for the patient is the most important criteria. Nevertheless, correct placement of electrodes should also be determined in terms of their anatomic position. Therefore, we propose a suite of different imaging modalities and further processing, which leads to an exact anatomic and statistically comparable documentation of electrode localization. Forty-three consecutive patients with a total of 85 implanted DBS electrodes were evaluated with respect to postoperative imaging. T1-weighted magnetic resonance imaging (T1-MRI) was performed in all patients, 34 patients received T2-MRI, in 18 patients stereotactic X-ray of the scull was performed in anteroposterior and lateral projections, whereas 6 patients were additionally evaluated by pre- and postoperative MR-image fusion between T1-data sets and calculation of coordinates for electrode contacts. In T1-MRI, the artefacts of each electrode contact could be delineated in relation to anatomic reference structures, whereas T2-MRI allowed reproducibly for delineation of electrode artefacts within subthalamic nucleus or globus pallidus pars interna. By MR-image fusion it could be shown that the difference between planned target coordinates and coordinates of the active electrode contact ranged below 1 mm except for the z axis. The comparison with values obtained from stereotactic X-ray confirmed these results. The sequential and complementary use of the described imaging modalities and further image processing provide clinically reliable and statistically comparable results to prove the exact anatomic electrode positioning in DBS in addition to the objective and subjective improvements of the patients' symptoms.

Adult↗