Fiber-specific white matter reductions in Parkinson hallucinations and visual dysfunction
| Autor: | Andrew J. Lees, Rimona S. Weil, Peter McColgan, Angeliki Zarkali, Geraint Rees, Louise-Ann Leyland |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Male
medicine.medical_specialty Parkinson's disease Hallucinations Pyramidal Tracts Vision Disorders Splenium Audiology Neuropsychological Tests computer.software_genre Corpus callosum Article 030218 nuclear medicine & medical imaging Corpus Callosum White matter 03 medical and health sciences 0302 clinical medicine Nerve Fibers Parkinsonian Disorders Voxel Fasciculus Medicine Humans Aged Cerebral Cortex biology business.industry Middle Aged biology.organism_classification medicine.disease White Matter Visual Hallucination medicine.anatomical_structure Diffusion Magnetic Resonance Imaging Dementia Female Neurology (clinical) business Posterior Thalamic Nuclei computer 030217 neurology & neurosurgery Diffusion MRI |
| Zdroj: | Neurology |
| ISSN: | 1526-632X 0028-3878 |
| Popis: | ObjectiveTo investigate the microstructural and macrostructural white matter changes that accompany visual hallucinations and low visual performance in Parkinson disease, a risk factor for Parkinson dementia.MethodsWe performed fixel-based analysis, a novel technique that provides metrics of specific fiber-bundle populations within a voxel (or fixel). Diffusion MRI data were acquired from patients with Parkinson disease (n = 105, of whom 34 were low visual performers and 19 were hallucinators) and age-matched controls (n = 35). We used whole-brain fixel-based analysis to compare microstructural differences in fiber density (FD), macrostructural differences in fiber bundle cross section (FC), and the combined FD and FC (FDC) metric across all white matter fixels. We then performed a tract-of-interest analysis comparing the most sensitive FDC metric across 11 tracts within the visual system.ResultsPatients with Parkinson disease hallucinations exhibited macrostructural changes (reduced FC) within the splenium of the corpus callosum and the left posterior thalamic radiation compared to patients without hallucinations. While there were no significant changes in FD, we found large reductions in the combined FDC metric in Parkinson hallucinators within the splenium (>50% reduction compared to nonhallucinators). Patients with Parkinson disease and low visual performance showed widespread microstructural and macrostructural changes within the genu and splenium of the corpus callosum, bilateral posterior thalamic radiations, and left inferior fronto-occipital fasciculus.ConclusionsWe demonstrate specific white matter tract degeneration affecting posterior thalamic tracts in patients with Parkinson disease with hallucinations and low visual performance, providing direct mechanistic support for attentional models of visual hallucinations. |
| Databáze: | OpenAIRE |
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