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Olfactory Assays for Mouse Models of Neurodegenerative Disease
Published on: August 25, 2014
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Longitudinal brain changes in Parkinson's disease with severe olfactory deficit
Kazuya Kawabata1, Epifanio Bagarinao2, Klaus Seppi3
1Department of Neurology, Medical University Innsbruck, Innsbruck, Austria; Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Parkinsonism & Related Disorders
|March 2, 2024
Summary
Parkinson's disease (PD) patients with anosmia (loss of smell) show greater brain atrophy. Concurrent REM sleep behavior disorder (RBD) accelerates these cortical changes, impacting cognitive function.
Area of Science:
- Neuroscience
- Neurology
- Neuroimaging
Background:
- Olfactory dysfunction and REM sleep behavior disorder (RBD) are linked to cognitive changes in Parkinson's disease (PD).
- The neurobiological basis for these associations, particularly patterns of neurodegeneration, is not fully understood.
- This study investigates longitudinal cortical changes in early PD with severe olfactory loss (anosmia), with and without probable RBD.
Purpose of the Study:
- To examine longitudinal cortical atrophy and thinning in early-stage PD patients.
- To compare these changes in individuals with severe olfactory deficit (anosmia) versus those without.
- To investigate the impact of concurrent probable RBD on cortical changes in anosmic PD patients.
Main Methods:
- Analysis of longitudinal MRI data from 134 de novo PD patients and 49 healthy controls over four years (Parkinson Progression Marker Initiative cohort).
- Utilized a linear mixed-effects model to assess changes in brain volume and cortical thickness.
- Patients were categorized based on olfactory function (UPSIT score ≤ 18 for anosmia) and presence of probable RBD.
Main Results:
- PD patients with anosmia showed significantly greater longitudinal declines in volume and thickness in the parahippocampal gyri and right transverse temporal gyrus compared to those without anosmia.
- Patients with concurrent anosmia and probable RBD exhibited more pronounced longitudinal declines in cortical volume and thickness.
- These accelerated changes in the anosmia + RBD group involved additional regions: bilateral precuneus, left inferior temporal gyrus, right paracentral gyrus, and right precentral gyrus.
Conclusions:
- Atrophy and thinning patterns in early PD with anosmia involve critical cognitive regions, potentially explaining the link between severe olfactory deficit and cognitive decline.
- Concurrent RBD appears to exacerbate the rate of cortical changes in Parkinson's disease.
- These findings suggest distinct neurodegenerative trajectories based on olfactory status and RBD in early PD.
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