Search

The clinical diagnosis in patients with parkinsonian disorders can be challenging, and a definite diagnosis requires neuropathological confirmation. The aim of this study was to examine whether a clinical diagnosis of Parkinson's disease (PD) and atypical parkinsonian disorders predict the presence of Lewy pathology (LP) and concomitant neuropathological lesions.We included 293 donors with a history of parkinsonism without dementia at disease onset, collected by the Netherlands Brain Bank (NBB) from 1989 to 2015. We retrospectively categorized donors according the International Parkinson and Movement Disorder Society clinical diagnostic criteria for PD (MDS-PD criteria) as 'not PD', 'probable PD' or 'established PD'. We compared the final clinical diagnosis to presence of neuropathological lesions as defined by BrainNet Europe and National Institute on Aging - Alzheimer's Association guidelines.LP was present in 150 out of 176 donors (85%) with a clinical diagnosis of PD, in 8 out of 101 donors (8%) with atypical parkinsonian disorders and in 4 out of 16 donors (25%) without a definite clinical diagnosis. Independent from age at death, stages of amyloid-β, but not neurofibrillary tau or neuritic plaques, were higher in donors with LP compared to other types of pathology (p = 0.009). The MDS-PD criteria at a certainty level of 'probable PD' predicted presence of LP with a diagnostic accuracy of 89.3%. Among donors with LP, 'established PD' donors showed similar Braak α-synuclein stages and stages of amyloid-β, neurofibrillary tau and neuritic plaques compared to 'not PD' or 'probable PD' donors.In conclusion, both a clinical diagnosis of PD as well as MDS-PD criteria accurately predicted presence of LP in NBB donors. LP was associated with more widespread amyloid-β pathology, suggesting a link between amyloid-β accumulation and LP formation.

Purpose To gain more insight into the pathophysiological mechanisms of visual hallucinations (VHs) in patients with Parkinson disease (PD) by analyzing whole-brain resting-state functional connectivity in PD patients with VH (hereafter, referred to as PD + VH patients) and without VH (hereafter, referred to as PD - VH patients) and control participants. Materials and Methods For this retrospective study, 15 PD + VH patients, 40 PD - VH patients, and 15 control participants from a prospective cohort study were included, which was approved by the local ethics board and written informed consent was obtained from all participants. Functional connectivity was calculated between 47 regions of interests, of which whole-brain and region-specific means were compared by using a general linear model with false discovery rate control for multiple comparisons. Results Whole-brain mean functional connectivity was significantly lower in PD patients compared with control participants, with regional decreases involving paracentral and occipital regions in both PD + VH and PD - VH patients (mean whole-brain functional connectivity in PD + VH vs PD - VH, 0.12 ± 0.01 [standard deviation] vs 0.14 ± 0.03, respectively; control participants, 0.15 ± 0.04; P < .05, corrected). In PD + VH patients, nine additional frontal, temporal, occipital, and striatal regions showed decreased functional connectivity compared with control participants (mean of these nine regions in PD + VH, PD - VH, and control participants: 0.12 ± 0.02, 0.14 ± 0.03, and 0.16 ± 0.04, respectively; P < .05, corrected). Resting-state functional connectivity was unrelated to motor performance (r = 0.182; P = .184) and related to cognitive deficits such as attention and perception (ρ, -0.555 and -0.558, respectively; P < .05). Conclusion The findings show a PD-related effect on resting-state functional connectivity of posterior and paracentral brain regions, whereas the presence of VH is associated with a more global loss of connectivity, related to attention and perception. These findings suggest that the pathophysiological mechanisms of VH in PD may include a global loss of network efficiency, which could drive disturbed attentional and visual processing. © RSNA, 2017 Online supplemental material is available for this article.