Bettina Schrader

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 Parkinsons 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.

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.

Manic episode with psychotic symptoms induced by subthalamic nucleus stimulation in a patient with Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN–DBS) is an established therapy for Parkinsons disease (PD). A manic episode with psychotic symptoms induced by STN–DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN–DBS in influencing not only motor but also emotional behaviour.

Effects of bilateral subthalamic nucleus stimulation on parkinsonian gait

Gait analysis was carried out to assess the effects of l-dopa and bilateral subthalamic nucleus stimulation on gait velocity, cadence, stride length, and gait kinematics in nine patients with PD. Substantial effects of bilateral subthalamic nucleus stimulation on gait, with an increase in gait velocity and stride length comparable to that of a suprathreshold l-dopa dose, were found. Interestingly, stride length was more improved by l-dopa and cadence more by subthalamic nucleus stimulation. In two patients with freezing during the “on” period, subthalamic nucleus stimulation failed to reduce this symptom effectively.

Effect of subthalamic deep brain stimulation on the function of the urinary bladder

Detrusor hyperreflexia is a relevant clinical symptom for patients suffering from Parkinsons disease. In a series of 16 patients, we demonstrated that subthalamic deep brain stimulation has a significant and urodynamically recordable effect leading to a normalization of pathologically increased bladder sensibility.

Spontaneous intracranial haematomas caused by neoplasms.

Summary¶ We report about 50 patients with spontaneous intracerebral haematomas (ICH) caused by intracranial neoplasms to assess the underlying histological condition, their presentation on admission, diagnostic work-up, treatment, histological diagnosis, and clinical outcome. These patients were identified in a prospective series of 2041 patients with intracranial neoplasms and 692 patients with spontaneous ICH, which were both consecutively collected over a nine-year-period. The frequency of ICH in patients with intracranial neoplasms was 2.4%. The frequency of tumour related ICH in the ICH group was 7.2%. The leading cause of tumour related ICH were metastases of extracranial origin (n=18; 36%), followed by glioblastoma multiforme (n=15; 30%). Nine patients (18%) had benign primary intracranial neoplasms. On admission 18 patients were somnolent (36%) and 14 patients (28%) were comatose. In 29 cases (58%) ICH was the first clinical sign of neoplastic disease, while in 21 patients (42%) a malignant tumour was already known. We operated on 45 patients (90%), four patients (8%) were not operated on because of poor clinical condition and died, one patient refused surgical treatment. Six patients (12%) died despite surgery. This series confirms the importance of a proper neuroradiological and clinical work-up of patients with suspected tumour related ICH followed by operative treatment and histological confirmation of the diagnosis. This is supported by the fact that 18% of patients had prognostically favourable intracranial tumours which would not otherwise have been adequately treated.

Thalamic, pallidal, or subthalamic surgery for Parkinson's disease?

Abstract Levodopa is a highly effective treatment of all motor symptoms of Parkinson’s disease. However, long-term treatment with levodopa can lead to motor fluctuations and levodopa-induced dyskinesias. Motor side effects can become so disabling as to warrant surgical treatment. Both ablative surgery and deep brain stimulation (DBS) for Parkinson’s disease (PD) can be performed in different target areas. Thalamic surgery mainly improves tremor, and to a lesser extent also rigidity and dyskinesias, whereas pallidal and subthalamic nucleus surgery improves all motor symptoms and levodopa-induced dyskinesias. The efficacy and safety of unilateral pallidotomy is well established. DBS has a lower morbidity and is safe enough to be performed bilaterally. The subthalamic nucleus (STN) presently seems to be the most promising target for DBS in advanced stage PD.

Magnetic Resonance Imaging-Based Morphometry and Landmark Correlation of Basal Ganglia Nuclei

Summary. The two principle targets for deep brain stimulation or lesioning in patients with Parkinsons disease, the subthalamic nucleus (STN) and the globus pallidus internus (GPi), reveal a high degree of individual variability which is relevant to the planning of stereotactic operations. Both nuclei can clearly be delineated in T2WI spin echo MRI which was acquired under stereotactic conditions in general anesthesia before surgery. Such images of 35 patients served for retrospective morphometric analysis of different basal ganglia nuclei (STN, GP, red nucleus, and substantia nigra) and several anatomical landmarks (anterior and posterior commissure, maximum width of third ventricle, brain length and width). The average AC-PC distance was 25.74 mm (range 21 to 29 mm) and is in agreement with previous studies. On average, the center of the STN was located 12.65 mm (±1.3) lateral from the midline as determined 3 mm ventral to the intercommissural plane. The average width of the third ventricle was 7.05 mm (±2.41). The width of the third ventricle correlated with the laterality of the STN (rright=.78; rleft=.83) and GP (rright=.76; rleft=.68). Although to a lesser extent, significant correlations were also observed between the laterality of the STN and brain width, improving prediction of STN laterality by multiple linear regression analysis (rright=.82; rleft=.87). Similarly, the laterality of GP correlated with brain width. In addition, gender-specific differences were detected. The STN and GP was located farther lateral in males which may be due to overall brain anatomy as gender-specific differences were also observed for brain width and length and AC-PC distance. MRI-based in vivo-localization of different basal ganglia nuclei extend statistical information from common histological brain atlases which are based on a limited number of brains. The correlations observed between different basal ganglia nuclei, i.e. the STN and GPi, and anatomical landmarks may be useful for surgical planning.

Dyskinesias and grip control in Parkinson's disease are normalized by chronic stimulation of the subthalamic nucleus.

Deep‐brain stimulation of the subthalamic nucleus appears to reduce levodopa‐induced dyskinesias, but whether this effect is caused by the reduction of the total levodopa ingestion or represents a direct effect on the motor system is unknown. Precision grip force of grasping movements and levodopa‐induced dyskinesias was analyzed in 10 parkinsonian patients before and after 3 months of deep‐brain stimulation of the subthalamic nucleus. Peak grip force was abnormally increased before surgery in the off‐drug state and, particularly, in the on‐drug state (sensitization). This grip force upregulation normalized with chronic deep‐brain stimulation in both conditions (desensitization). Peak‐dose dyskinesias also improved, and off‐dystonia was completely abolished. Mean dosage of dopaminergic drugs was reduced, but force overflow and dyskinesias were equally improved in 2 patients without a reduction. Despite the same single levodopa test dose, force excess and levodopa‐induced dyskinesias were drastically reduced after 3 months of deep‐brain stimulation of the subthalamic nucleus. This indicates that direct effects of deep‐brain stimulation of the subthalamic nucleus on levodopa‐induced dyskinesias are likely to occur. Grip force overflow is a promising parameter to study the desensitizing effect of chronic deep‐brain stimulation on levodopa‐induced dyskinesias.

Deep brain stimulation for idiopathic or secondary movement disorders

Deep brain stimulation has gained increasing interest in the treatment of movement disorders. Presenting our clinical series of 179 patients operated upon since 1999, the indications, risks and benefits for the patients are discussed in order to further improve the techniques and their applications.