Adverse events associated with deep brain stimulation in patients with childhood-onset dystonia.

BACKGROUND: Data on pediatric DBS is still limited because of small numbers in single center series and lack of systematic multi-center trials. OBJECTIVES: We evaluate short- and long-term adverse events (AEs) of patients undergoing deep brain stimulation (DBS) during childhood and adolescence. METHODS: Data collected by the German registry on pediatric DBS (GEPESTIM) were analyzed according to reversible and irreversible AEs and time of occurrence with relation to DBS-surgery: Intraoperative, perioperative (<4 weeks), postoperative (4 weeks < 6 months) and long term AEs (>6 months). RESULTS: 72 patients with childhood-onset dystonia from 10 DBS-centers, who received 173 DBS electrodes and 141 implantable pulse generators (IPG), were included in the registry. Mean time of postoperative follow-up was 4.6 ±â€¯4 years. In total, 184 AEs were documented in 53 patients (73.6%). 52 DBS-related AEs in 26 patients (36.1%) required 45 subsequent surgical interventions 4.7 ±â€¯4.1 years (range 3 months-15 years) after initial implantation. The total risk of an AE requiring surgical intervention was 7.9% per electrode-year. Hardware-related AEs were the most common reason for surgery. There was a tendency of a higher rate of AEs in patients aged 7-9 years beyond 6 months after implantation. DISCUSSION: The intraoperative risk of AEs in pediatric patients with dystonia undergoing DBS is very low, whereas the rate of postoperative hardware-related AEs is a prominent feature with a higher occurrence compared to adults, especially on long-term follow-up. CONCLUSION: Factors leading to such AEs must be identified and patient management has to be focused on risk minimization strategies in order to improve DBS therapy and maximize outcome in pediatric patients.

Dysarthria in pallidal Deep Brain Stimulation in dystonia depends on the posterior location of active electrode contacts: a pilot study.

BACKGROUND: Pallidal Deep Brain Stimulation (GPi-DBS) is an efficient treatment for primary dystonia. We investigated stimulation-induced dysarthria, which is the most frequent side-effect of GPi-DBS. METHODS: Speech was recorded while reading a standard text, and performing rapid syllable repetitions ON and OFF DBS in ten dystonia patients (6 men; 3 cervical, 4 segmental, 3 generalized, unselected for DBS-related speech impairments). Speech and articulation rate, pauses, and syllable repetition rates were extracted via acoustic analysis. Locations of active stimulation contacts and volumes of tissue activated (VTA) were calculated. RESULTS: The number of pauses increased significantly ON vs. OFF stimulation (Wilcoxon test, p < 0.05). More posteriorly localized active contacts were associated with slower syllable repetition (Pearson correlation, p < 0.05). VTA size did not correlate with any measure of dysarthria. CONCLUSION: Using quantitative acoustic signal analysis, this study demonstrates that GPi-DBS alters motor aspects of speech. Both inadvertent stimulation of parts of the internal capsule, or interference with GPi function and outflow are possible causes. Understanding causes of GPi-DBS-induced speech changes can improve DBS programming.

German registry of paediatric deep brain stimulation in patients with childhood-onset dystonia (GEPESTIM).

BACKGROUND: Data on paediatric deep brain stimulation (DBS) is limited, especially for long-term outcomes, because of small numbers in single center series and lack of systematic multi-center trials. OBJECTIVES: We seek to systematically evaluate the clinical outcome of paediatric patients undergoing DBS. METHODS: A German registry on paediatric DBS (GEPESTIM) was created to collect data of patients with dystonia undergoing DBS up to the age of 18 years. Patients were divided into three groups according to etiology (group 1 inherited, group 2 acquired, and group 3 idiopathic dystonia). RESULTS: Data of 44 patients with a mean age of 12.8 years at time of operation provided by 6 German centers could be documented in the registry so far (group 1 n = 18, group 2 n = 16, group 3 n = 10). Average absolute improvement after implantation was 15.5 ± 18.0 for 27 patients with pre- and postoperative Burke-Fahn-Marsden Dystonia Rating scale movement scores available (p < 0.001) (group 1: 19.6 ± 19.7, n = 12; group 2: 7.0 ± 8.9, n = 8; group 3: 19.2 ± 20.7, n = 7). Infection was the main reason for hardware removal (n = 6). 20 IPG replacements due to battery expiry were necessary in 15 patients at 3.7 ± 1.8 years after last implantation. DISCUSSION: Pre- and postoperative data on paediatric DBS are very heterogeneous and incomplete but corroborate the positive effects of DBS on inherited and acquired dystonia. Adverse events including relatively frequent IPG replacements due to battery expiry seem to be a prominent feature of children with dystonia undergoing DBS. The registry enables collaborative research on DBS treatment in the paediatric population and to create standardized management algorithms in the future.

Modulation of local field potential power of the subthalamic nucleus during isometric force generation in patients with Parkinson's disease.

Investigations of local field potentials of the subthalamic nucleus of patients with Parkinson's disease have provided evidence for pathologically exaggerated oscillatory beta-band activity (13-30 Hz) which is amenable to physiological modulation by, e.g., voluntary movement. Previous functional magnetic resonance imaging studies in healthy controls have provided evidence for an increase of subthalamic nucleus blood-oxygenation-level-dependant signal in incremental force generation tasks. However, the modulation of neuronal activity by force generation and its relationship to peripheral feedback remain to be elucidated. We hypothesised that beta-band activity in the subthalamic nucleus is modulated by incremental force generation. Subthalamic nucleus local field potentials were recorded intraoperatively in 13 patients with Parkinson's disease (37 recording sites) during rest and five incremental isometric force generation conditions of the arm with applied loads of 0-400 g (in 100-g increments). Repeated measures analysis of variance (ANOVA) revealed a modulation of local field potential (LFP) power in the upper beta-band (in 24-30 Hz; F(3.042)=4.693, p=0.036) and the gamma-band (in 70-76 Hz; F(4)=4.116, p=0.036). Granger-causality was computed with the squared partial directed coherence and showed no significant modulation during incremental isometric force generation. Our findings indicate that the upper beta- and gamma-band power of subthalamic nucleus local field potentials are modulated by the physiological task of force generation in patients with Parkinson's disease. This modulation seems to be not an effect of a modulation of peripheral feedback.

[Parkinson's disease: current standards in diagnostics and therapy]. / Morbus Parkinson: Aktuelle Standards in Diagnostik und Therapie.

Idiopathic Parkinson's disease is still a clinical diagnosis. However, modern imaging and nuclear techniques allow very early diagnosis and lead to higher security in the differential diagnosis between idiopathic Parkinson's disease and atypical Parkinson syndromes. At early stages of the disease, modification of disease progression and symptom control are key factors of the therapy. Continuous dopaminergic stimulation is even more important at later stages with first fluctuations. In stages where conservative medical options have been exhausted continuous pump therapies with Duodopa and apomorphine are attractive options. Deep brain stimulation in the subthalamic nucleus has turned out in the last years, especially in younger patients, to be a highly successful treatment option. Deep drain stimulation requires, however, a close preoperative work-up and individual consideration of potential effects and side effects.

Dystonia in neurodegeneration with brain iron accumulation: outcome of bilateral pallidal stimulation.

Neurodegeneration with brain iron accumulation encompasses a heterogeneous group of rare neurodegenerative disorders that are characterized by iron accumulation in the brain. Severe generalized dystonia is frequently a prominent symptom and can be very disabling, causing gait impairment, difficulty with speech and swallowing, pain and respiratory distress. Several case reports and one case series have been published concerning therapeutic outcome of pallidal deep brain stimulation in dystonia caused by neurodegeneration with brain iron degeneration, reporting mostly favourable outcomes. However, with case studies, there may be a reporting bias towards favourable outcome. Thus, we undertook this multi-centre retrospective study to gather worldwide experiences with bilateral pallidal deep brain stimulation in patients with neurodegeneration with brain iron accumulation. A total of 16 centres contributed 23 patients with confirmed neurodegeneration with brain iron accumulation and bilateral pallidal deep brain stimulation. Patient details including gender, age at onset, age at operation, genetic status, magnetic resonance imaging status, history and clinical findings were requested. Data on severity of dystonia (Burke Fahn Marsden Dystonia Rating Scale-Motor Scale, Barry Albright Dystonia Scale), disability (Burke Fahn Marsden Dystonia Rating Scale-Disability Scale), quality of life (subjective global rating from 1 to 10 obtained retrospectively from patient and caregiver) as well as data on supportive therapy, concurrent pharmacotherapy, stimulation settings, adverse events and side effects were collected. Data were collected once preoperatively and at 2-6 and 9-15 months postoperatively. The primary outcome measure was change in severity of dystonia. The mean improvement in severity of dystonia was 28.5% at 2-6 months and 25.7% at 9-15 months. At 9-15 months postoperatively, 66.7% of patients showed an improvement of 20% or more in severity of dystonia, and 31.3% showed an improvement of 20% or more in disability. Global quality of life ratings showed a median improvement of 83.3% at 9-15 months. Severity of dystonia preoperatively and disease duration predicted improvement in severity of dystonia at 2-6 months; this failed to reach significance at 9-15 months. The study confirms that dystonia in neurodegeneration with brain iron accumulation improves with bilateral pallidal deep brain stimulation, although this improvement is not as great as the benefit reported in patients with primary generalized dystonias or some other secondary dystonias. The patients with more severe dystonia seem to benefit more. A well-controlled, multi-centre prospective study is necessary to enable evidence-based therapeutic decisions and better predict therapeutic outcomes.