The emerging postural instability phenotype in idiopathic Parkinson disease.

Identification of individuals at high risk for rapid progression of motor and cognitive signs in Parkinson disease (PD) is clinically significant. Postural instability and gait dysfunction (PIGD) are associated with greater motor and cognitive deterioration. We examined the relationship between baseline clinical factors and the development of postural instability using 5-year longitudinal de-novo idiopathic data (n = 301) from the Parkinson's Progressive Markers Initiative (PPMI).

A longitudinal neurite and free water imaging study in patients with a schizophrenia spectrum disorder.

Diffusion tensor imaging (DTI) studies show widespread white matter abnormalities in schizophrenia, but it is difficult to directly relate these parameters to biological processes. Neurite orientation dispersion and density imaging (NODDI) is geared toward biophysical characterization of white matter microstructure, but only few studies have leveraged this technique to study white matter alterations. We recruited 42 schizophrenia patients (30 antipsychotic-naïve and 12 currently untreated) and 42 matched controls in this prospective study.

Micro- and Macrostructural White Matter Integrity in Never-Treated and Currently Unmedicated Patients With Schizophrenia and Effects of Short-Term Antipsychotic Treatment.

Background: Schizophrenia is associated with progressive white matter changes, but it is unclear whether antipsychotic medications contribute to these. Our objective was to characterize effects of short-term treatment with risperidone on white matter diffusion indices.

Methods: We recruited 42 patients with schizophrenia (30 never treated and 12 currently untreated) and 42 matched healthy control subjects in this prospective case-control neuroimaging study.

High-Intensity Exercise Acutely Increases Substantia Nigra and Prefrontal Brain Activity in Parkinson's Disease.

BACKGROUND Pathologic alterations in resting-state brain activity patterns exist among individuals with Parkinson's disease (PD). Since physical exercise alters resting-state brain activity in non-PD populations and improves PD symptoms, we assessed the acute effect of exercise on resting-state brain activity in exercise-trained individuals with PD. MATERIAL AND METHODS Resting-state functional magnetic resonance imaging (fMRI) was collected twice for 17 PD participants at the conclusion of an exercise intervention.

The visual kinetic depth effect is altered with Parkinson's disease.

Background: People with Parkinson's disease (PD) often have visual-perceptual disorders. The goal of this study was to learn if they can develop a three dimensional (3D) percept that depends on the kinetic depth effect; that is, the viewer's ability to spatially integrate over time images that are moving along many trajectories.

Methods: Sixteen patients with PD and 12 healthy matched controls were presented with stimuli that were comprised of a circular region of randomly placed dots that moved as orthographic projections of a sphere.

Parkinson's disease-related network topographies characterized with resting state functional MRI.

Spatial covariance mapping can be used to identify and measure the activity of disease-related functional brain networks. While this approach has been widely used in the analysis of cerebral blood flow and metabolic PET scans, it is not clear whether it can be reliably applied to resting state functional MRI (rs-fMRI) data. In this study, we present a novel method based on independent component analysis (ICA) to characterize specific network topographies associated with Parkinson's disease (PD).

Allocentric But Not Egocentric Pseudoneglect of Peripersonal Space.

Background And Objective: Healthy adults often deviate leftward on line bisection tasks (allocentric pseudoneglect) but rightward on body part bisection tasks (egocentric pseudoneglect). People visually estimate distance in peripersonal space by comparing the distance to the length of a body part such as an arm's length (an egocentric reference) or using standard units of distance such as inches (an allocentric reference). Our objective was to learn whether people have pseudoneglect when estimating distances in peripersonal space using egocentric versus allocentric reference frames.

A full-brain, bootstrapped analysis of diffusion tensor imaging robustly differentiates Parkinson disease from healthy controls.

There is a compelling need for early, accurate diagnosis of Parkinson's disease (PD). Various magnetic resonance imaging modalities are being explored as an adjunct to diagnosis. A significant challenge in using MR imaging for diagnosis is developing appropriate algorithms for extracting diagnostically relevant information from brain images.

Ventral tegmental area/midbrain functional connectivity and response to antipsychotic medication in schizophrenia.

Medication management in schizophrenia is a lengthy process, as the lack of clinical response can only be confirmed after at least 4 weeks of antipsychotic treatment at a therapeutic dose. Thus, there is a clear need for the discovery of biomarkers that have the potential to accelerate the management of treatment. Using resting-state functional MRI, we examined the functional connectivity of the ventral tegmental area (VTA), the origin of the mesocorticolimbic dopamine projections, in 21 healthy controls and 21 unmedicated patients with schizophrenia at baseline (pre-treatment) and after 1 week of treatment with the antipsychotic drug risperidone (1-week post-treatment).

Hypometric allocentric and egocentric distance estimates in Parkinson disease.

Objective And Background: Persons with Parkinson disease (PD) show hypometric movements and make hypometric estimates of imagined actions. These deficits may be related to misestimates of the length of body parts. Our objective was to learn whether patients with PD are impaired in their estimations of their arm's length and standard units of distance.

Reliability analysis of the resting state can sensitively and specifically identify the presence of Parkinson disease.

Parkinson disease (PD) is characterized by a number of motor and behavioral abnormalities that could be considered deficits of a "no task" or "resting" state, including resting motor findings and defects in emerging from a resting state (e.g., resting tremor, elevated resting tone, abulia, akinesia, apathy).

Apathy, depression, and motor symptoms have distinct and separable resting activity patterns in idiopathic Parkinson disease.

Apathy and depression are heterogeneous syndromes with symptoms that overlap clinically. This clinical overlap leads to problems with classification and diagnosis in clinical populations. No functional imaging study has attempted to separate brain regions altered in apathy from those altered in depression in a clinical population.

Connectivity brain networks based on wavelet correlation analysis in Parkinson fMRI data.

Recent studies have shown that aging, psychiatric and neurologic diseases, and dopaminergic blockade all result in altered brain network efficiency. We investigated the efficiency of human brain functional networks as measured by fMRI in individuals with idiopathic Parkinson's disease (N=14) compared to healthy age-matched controls (N=15). Functional connectivity between 116 cortical and subcortical regions was estimated by wavelet correlation analysis in the frequency interval of 0.

Anxiety and depression severity are related to right but not left onset Parkinson's disease duration.

Depression and anxiety have both been associated with relative left frontal hypoactivation and the motor symptoms of Parkinson's disease typically begin in a lateral or asymmetrical fashion. Hence, PD patients with right hemibody onset may experience heightened depression and anxiety. However, research is mixed regarding whether right or left hemibody onset PD is associated with elevated levels of depression and anxiety.

White matter microstructure changes in the thalamus in Parkinson disease with depression: A diffusion tensor MR imaging study.

Background And Purpose: Depression occurs frequently in PD; however the neural basis of depression in PD remains unclear. The aim of this study was to characterize possible depression-related white matter microstructural changes in the thalamus of patients with DPD compared with those with NDPD.

Materials And Methods: FA and MD maps from DTI were obtained in 14 patients with DPD and 18 patients with NDPD.

Influence of left versus right hemibody onset Parkinson's disease on cardiovascular control.

Whereas the left hemisphere is involved in regulating the parasympathetic nervous system, the right hemisphere regulates the sympathetic. Given the asymmetrical onset of motor symptoms and neuropathology in PD, differences in cardiovascular functions might be expected between PD patients with left hemibody onset (LHO) versus right hemibody onset (RHO). A total of 66 PD patients served as participants, including 31 LHO patients and 35 RHO PD patients.

Verbal and visuospatial memory in lateral onset Parkinson disease: time is of the essence.

Objective: This investigation sought to study immediate and delayed verbal and visuospatial recall in Parkinson disease (PD) patients with left hemibody (LHO) and right hemibody (RHO) onset of motor symptoms and to examine the role of mental processing speed in recall of this information.

Background: Research is mixed regarding material specific memory impairments in LHO and RHO PD. However, earlier research has not used a factorial approach in investigating material specific memory in LHO and RHO PD.

Anxiety affects working memory only in left hemibody onset Parkinson disease patients.

Objective: This investigation sought to examine the potential moderating influence of heightened anxiety on working memory in Parkinson disease (PD) patients. Further, we wanted to determine whether this moderating influence of anxiety differentially affects PD patients with left hemibody (LBH) versus right hemibody (RHB) onset of motor symptoms.

Background: Research has examined the neurocognitive effects of depression in PD.

Bilateral restless legs affecting a phantom limb, treated with dopamine agonists.

Background: Restless legs syndrome (RLS) is a common condition characterised by unpleasant sensations deep inside the legs, which usually occurs at rest and especially at night. These sensations are accompanied by an urge to move the limb, and movements result in a temporary relief of the symptoms. The pathophysiology of RLS is not completely known, especially the role of afferent feedback.

Turning off artistic ability: the influence of left DBS in art production.

Background: The influence of Parkinson's disease (PD) as well as deep brain stimulation (DBS) on visual-artistic production of people who have been artists is unclear. We systematically assessed the artistic-creative productions of a patient with PD who was referred to us for management of a left subthalamic region (STN) DBS. The patient was an artist before her disease started, permitting us to analyze changes in her artistic-creative production over the course of the illness and during her treatment with DBS.

Conceptual hypometria? An evaluation of conceptual mapping of space in Parkinson's disease.

When interacting with objects in their environment, patients with Parkinson's disease (PD) often make hypometric movements (e.g., micrographia).

Creativity in Parkinson's disease as a function of right versus left hemibody onset.

Objective: Creativity is heavily dependent on divergent thinking and divergent thinking appears to be strongly dependent on fontal lobe function. Since patients with Parkinson's disease (PD) often have evidence of frontal lobe dysfunction we wanted to learn if these patients have a reduction of creativity, as well as learning if the side of onset (right versus left) influences the type (verbal versus visuospatial) of decrement in creativity.

Design: Participants of this study were patients with right (RHO) or left (LHO) onset PD as well as matched controls.

Artistic creativity and DBS: a case report.

Background: Deep brain stimulation (DBS) is a treatment for patients with Parkinson's disease (PD) who are not adequately controlled with medications. An artist reported changes in her artistic creativity and art appreciation when treated with left DBS. We sought to study her artistic productions and her appreciation of art while both "on" and "off" left DBS.