Pathomechanisms and compensatory efforts related to Parkinsonian speech.

Voice and speech in Parkinson's disease (PD) patients are classically affected by a hypophonia, dysprosody, and dysarthria. The underlying pathomechanisms of these disabling symptoms are not well understood. To identify functional anomalies related to pathophysiology and compensation we compared speech-related brain activity and effective connectivity in early PD patients who did not yet develop voice or speech symptoms and matched controls.

The value of putaminal diffusion imaging versus 18-fluorodeoxyglucose positron emission tomography for the differential diagnosis of the Parkinson variant of multiple system atrophy.

Differentiating the Parkinson variant of multiple system atrophy (MSA-P) from idiopathic Parkinson's disease (PD) and other forms of atypical parkinsonism can be difficult because symptoms overlap considerably. 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) is a powerful imaging technique that can assist in the diagnosis of MSA-P via detection of putaminal and cerebellar hypometabolism. Recent studies suggest that diffusion-weighted imaging (DWI) might be of similar diagnostic value, as it can detect microstructural damage in the putamen by means of an increased mean diffusivity (MD).

Correlation of active contact positions with the electrophysiological and anatomical subdivisions of the subthalamic nucleus in deep brain stimulation.

Background: The most effective contacts in subthalamic nucleus (STN) deep brain stimulation are reported to be dorsolateral, and suppression of synchronized oscillatory activity might be a mechanism of action.

Objectives: To analyze the optimal contact position in regard to the anatomical and electrophysiological position and to determine whether oscillatory and bursty activity is more frequent around the active contact.

Methods: In 21 patients, the clinically most effective contacts were analyzed according to their relative position to the anatomical and electrophysiological STN center, which was assessed by T2-weighted MRI and microrecording.

Diurnal variation of hypothalamic function and chronic subthalamic nucleus stimulation in Parkinson's disease.

Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) improves quality of life in patients with advanced Parkinson's disease (PD), but is associated with neuropsychiatric side effects and weight gain in some individuals. The pathomechanisms of these phenomena are still unknown. Considering anatomical and functional connections of the STN with the hypothalamic-pituitary (HP) system, we prospectively investigated whether chronic STN-DBS alters HP functioning in 11 PD patients.

ATXN2-CAG42 sequesters PABPC1 into insolubility and induces FBXW8 in cerebellum of old ataxic knock-in mice.

Spinocerebellar Ataxia Type 2 (SCA2) is caused by expansion of a polyglutamine encoding triplet repeat in the human ATXN2 gene beyond (CAG)(31). This is thought to mediate toxic gain-of-function by protein aggregation and to affect RNA processing, resulting in degenerative processes affecting preferentially cerebellar neurons. As a faithful animal model, we generated a knock-in mouse replacing the single CAG of murine Atxn2 with CAG42, a frequent patient genotype.

Parkinson's disease and dementia: a longitudinal study (DEMPARK).

Background: Parkinson's disease (PD) is a progressive neurodegenerative motor disorder. However, non-motor complications frequently alter the course of the disease. A particularly disabling non-motor symptom is dementia.

Intraoperative microelectrode recording for the delineation of subthalamic nucleus topography in Parkinson's disease.

Background: The subthalamic nucleus (STN) as an effective target for deep brain stimulation (DBS) in advanced Parkinson's disease is functionally divided into the dorsolateral sensorimotor and the ventromedial limbic and associative parts. To implant electrodes for DBS close to the sensorimotor region is considered crucial for optimal motor benefit and for avoidance of potential cognitive and behavioral side effects.

Objective: The aim of this study was to determine whether the functional segregation of the STN is associated with distinct and region-specific neuronal activity patterns and action potential properties obtained by intraoperative microelectrode recordings.

Resting state fMRI reveals increased subthalamic nucleus-motor cortex connectivity in Parkinson's disease.

Parkinson's disease (PD) is associated with abnormal hypersynchronicity in basal ganglia-thalamo-cortical loops. The clinical effectiveness of subthalamic nucleus (STN) high frequency stimulation indicates a crucial role of this nucleus within the affected motor networks in PD. Here we investigate alterations in the functional connectivity (FC) profile of the STN using resting state BOLD correlations on a voxel-by-voxel basis in functional magnetic resonance imaging (fMRI).

Diffusion tensor imaging of white matter involvement in essential tremor.

This study set out to determine whether there is white matter involvement in essential tremor (ET), the most common movement disorder. We collected diffusion MRI and analysed differences in fractional anisotropy (FA) and mean diffusivity (MD) between ET patients and control subjects as markers of white matter integrity. We used both classical ROI-based statistics and whole-brain analysis techniques, including voxel-wise analysis with SPM5 and tract-based spatial statistics (TBSS).

Quantitative mapping of T1 and T2* discloses nigral and brainstem pathology in early Parkinson's disease.

Quantitative magnetic resonance imaging is a promising in vivo imaging technique revealing insights into different aspects of brain morphology in neurodegenerative diseases based on the determination of physical tissue parameters. Using combined T1- and T2*-mapping, we investigated changes of local relaxation times in the midbrain and lower brainstem of 20 patients with early Parkinson's disease (PD) compared to 20 healthy controls. Voxelwise statistical parametric mapping disclosed a widespread reduction of midbrain T1 values contralateral to the clinically more severely affected limbs.

Phosphorus and proton magnetic resonance spectroscopy demonstrates mitochondrial dysfunction in early and advanced Parkinson's disease.

Mitochondrial dysfunction hypothetically contributes to neuronal degeneration in patients with Parkinson's disease. While several in vitro data exist, the measurement of cerebral mitochondrial dysfunction in living patients with Parkinson's disease is challenging. Anatomical magnetic resonance imaging combined with phosphorus and proton magnetic resonance spectroscopic imaging provides information about the functional integrity of mitochondria in specific brain areas.

Prism adaptation in spinocerebellar ataxia type 2.

Patients with spinocerebellar ataxia type 2 (SCA2), develop severe pontine nuclei, inferior olives, and Purkinje cell degeneration. This form of autosomal dominant cerebellar ataxia is accompanied by progressive ataxia and dysarthria. Although the motor dysfunction is well characterized in these patients, nothing is known about their motor learning capabilities.

Saccade velocity is controlled by polyglutamine size in spinocerebellar ataxia 2.

We assessed maximal saccade velocity (MSV) in 82 spinocerebellar ataxia type 2 (SCA2) patients and 80 controls, correlating it to disease duration, polyglutamine expansion size, age at onset, ataxia score, age, and sex. Little overlap with normal values was found even at earliest stages. Stepwise linear regression analysis showed that 60-degree MSV was strongly influenced by polyglutamine size and less by disease duration, whereas the reverse was found for ataxia score.

High prevalence of GBV-C/HGV among relatives of GBV-C/HGV-positive blood donors in blood recipients and in patients with aplastic anemia.

Background: The prevalence of GB virus C (GBV-C)/HGV is high in individuals with parenteral risk factors. The frequency of GBV-C/HGV in blood donors is significantly lower, however it is still far above other parenterally transmitted viruses like HBV and HCV. Therefore, transmission routes apart from parenteral transmission must be considered.