Investigating the clinico-anatomical dissociation in the behavioral variant of Alzheimer disease

• Published in: Alzheimer's research & therapy 2020-11, Vol.12 (1), p.148-148, Article 148
• Main Authors: Singleton, Ellen H, Pijnenburg, Yolande A L, Sudre, Carole H, Groot, Colin, Kochova, Elena, Barkhof, Frederik, La Joie, Renaud, Rosen, Howard J, Seeley, William W, Miller, Bruce, Cardoso, M Jorge, Papma, Janne, Scheltens, Philip, Rabinovici, Gil D, Ossenkoppele, Rik
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Alzheimer Disease - diagnostic imaging; Alzheimer's disease; Atrophy; BASIC BIOLOGICAL SCIENCES; Behavior; Biomarkers; Brain research; Clinical Medicine; Comparative analysis; Dementia; Diagnosis; Frontotemporal dementia; Frontotemporal Dementia - diagnostic imaging; Glucose; Gray Matter; Humans; Klinisk medicin; Magnetic Resonance Imaging; Medical and Health Sciences; Medical imaging; Medicin och hälsovetenskap; Metabolism; MRI; Neurobiology; Neuroimaging; Neurologi; Neurology; Patients; PET; Physiological aspects; Retrospective Studies; Scanners
• ISSN: 1758-9193; 1758-9193
• DOI: 10.1186/s13195-020-00717-z

We previously found temporoparietal-predominant atrophy patterns in the behavioral variant of Alzheimer's disease (bvAD), with relative sparing of frontal regions. Here, we aimed to understand the clinico-anatomical dissociation in bvAD based on alternative neuroimaging markers. We retrospectively included 150 participants, including 29 bvAD, 28 "typical" amnestic-predominant AD (tAD), 28 behavioral variant of frontotemporal dementia (bvFTD), and 65 cognitively normal participants. Patients with bvAD were compared with other diagnostic groups on glucose metabolism and metabolic connectivity measured by [ F]FDG-PET, and on subcortical gray matter and white matter hyperintensity (WMH) volumes measured by MRI. A receiver-operating-characteristic-analysis was performed to determine the neuroimaging measures with highest diagnostic accuracy. bvAD and tAD showed predominant temporoparietal hypometabolism compared to controls, and did not differ in direct contrasts. However, overlaying statistical maps from contrasts between patients and controls revealed broader frontoinsular hypometabolism in bvAD than tAD, partially overlapping with bvFTD. bvAD showed greater anterior default mode network (DMN) involvement than tAD, mimicking bvFTD, and reduced connectivity of the posterior cingulate cortex with prefrontal regions. Analyses of WMH and subcortical volume showed closer resemblance of bvAD to tAD than to bvFTD, and larger amygdalar volumes in bvAD than tAD respectively. The top-3 discriminators for bvAD vs. bvFTD were FDG posterior-DMN-ratios (bvAD