Identifying mixed Lewy body and Alzheimer’s disease pathologies using functional neuroimaging
Soumya Bouchachi1, Jessica Truelove1, Kristina Rawson1, Jennifer Icenhour1, Michael Knopp1, Chad Wright1, Douglas Scharre1
1Ohio State University
Objective:
To distinguish between Alzheimer's disease, Lewy body dementia and Parkinson's disease using functional neuroimaging.
Background:
Lewy body dementia (LBD) and Alzheimer’s disease (AD) are the two most common neurodegenerative causes of dementia. Autopsy studies report many cases with these clinical diagnoses having mixed pathology with alpha-synuclein, tau and amyloid proteinopathies. There is limited research in trying to distinguish these potential mixed pathology conditions prior to death.
Design/Methods:
43 subjects were recruited from Ohio State University Memory Disorder and Movement Clinics. Subjects were diagnosed based on standard clinical criteria for DLB, PD and AD by fellowship trained cognitive and movement disorders faculty. Cognitive testing performed included MMSE and SAGE. We used neuroimaging methods including FDG PET, amyloid PET, and DaTscan SPECT to evaluate subjects diagnosed with dementia with Lewy bodies (DLB), AD and PD to investigate how often potential mixed pathologies could be present. The neuroimaging evaluations were blinded to clinical diagnosis.
Results:
28 subjects with clinical diagnosis of Lewy body disease (15 DLB and 13 PD) and 15 subjects with clinical diagnosis AD were compared. The Lewy body subjects were 69.5 ± 7.2 years old, MMSE 26.6 ± 4, and SAGE 18.4 ± 4.7. AD subjects were 68.4 ± 9.3 years old, MMSE 16.3 ± 6.4, and SAGE 7.4 ± 6.1. 5 subjects (33%) of the clinical AD cases showed abnormal DAT scan uptake, 3 subjects (20%) of the clinical AD cases were negative for amyloid with normal DaTscan uptake, 3 subjects (20%) of the clinical DLB cases showed mixed LBD and AD features, 2 subjects (13%) of the clinical DLB cases were positive for amyloid with normal DaTscan uptake, and 1 (8%) subject with clinical PD had normal DAT scan.
Conclusions:
Based on functional neuroimaging, 26% of clinically diagnosed AD or DLB subjects had evidence of potential mixed pathologies and 25% were misdiagnosed.