Autonomic dysfunction and white matter microstructural changes in drug-naïve patients with Parkinson’s disease

Background Autonomic dysfunction (AD) is one of the non-motor features of Parkinson’s disease (PD). Some symptoms tend to occur in the early stages of PD. AD also has a great impact on patient’s quality of life. In this study, we aimed to discover the association between AD (Scales for Outcomes in Parkinson’s disease-Autonomic, SCOPA-AUT) and microstructural changes in white matter tracts in drug-naïve early PD patients to elucidate the central effects of autonomic nervous system impairments. Method In total, this study included 85 subjects with PD recruited from the Parkinson’s Progression Markers Initiative (PPMI) database. Among the 85 PD patients, 38 were in Hoehn & Yahr stage 1 (HY1PD) and 47 were in stage 2 (HY2PD). Diffusion magnetic resonance imaging (DMRI) data were reconstructed in the MNI space using q-space diffeomorphic reconstruction to obtain the spin distribution function. The spin distribution function (SDF) values were used in DMRI connectometry analysis. We investigated through diffusion MRI connectometry the structural correlates of white matter tracts with SCOPA-AUT subscores and total score. Results Connectometry analysis also revealed positive association with white matter density in bilateral corticospinal tract in HY1PD patients and negative association in genu of corpus callosum (CC) and, bilateral cingulum in both groups. In addition, there were associations between gastrointestinal, sexual, thermoregulatory and urinary items and structural brain connectivity in PD. Conclusion Our study reveals positive correlation, suggesting neural compensations in early PD. Cingulum and CC tracts have well-known roles in PD pathology, compatible with our findings that bring new insights to specific areas of AD and its role in central nervous system (CNS) neurodegeneration, paving the way for using prodromal makers in the diagnosis and treatment of PD.

Brain pathway differences between Parkinson's disease patients with and without depressive symptoms

IntroductionDepression occurs frequently in patients suffering from Parkinson's disease (PD). However, the neural basis of depression in PD remains unclear. Diffusion magnetic resonance imaging (DMRI) connectometry is based on the spin distribution function (SDF), which quantifies the density of diffusing water.AimThe aim of this study was to assess the microstructural changes in the brain connectivity of PD patients with and without depressive symptoms.MethodsDMRI was used to assess microstructural abnormalities in the brains of 16 PD patients with depressive symptoms compared to 11 PD patients without depressive symptoms. Data used in the preparation of this paper were obtained from the Parkinson's progression markers initiative (PPMI) database (http://www.ppmi-info.org/data/). This dataset was acquired on a 3-Tesla scanner (Siemens), producing 64 DWI at b = 1000 s/mm2 and one b0 image. Diffusion MRI data were corrected for subject motion, eddy current distortions, and susceptibility artefacts due to magnetic field inhomogeneity. DMRI connectometry was conducted in a total of 27 patients using percentage measurement.ResultsPD Patients with depressive symptoms showed decreased anisotropy (FDR < 0.05) in the fornix bilaterally, left inferior longitudinal fasciculus (ILF) and corticospinal tract bilaterally compared to PD patients without depressive symptoms.ConclusionsLesser WM integrity of the left ILF fibers, which connect visual face recognition areas to the amygdala and hippocampus, seems to be associated with depressive symptoms in PD patients. Our study supports the hypothesis that neurodegenerative processes in projections from the somatosensory, cingulate, and insular cortices may be related to depression in PD.Disclosure of interestThe authors have not supplied their declaration of competing interest.