Cerebral Metabolism Related to Cognitive Impairments in Multiple System Atrophy

Objective: We aimed to characterize the cognitive profiles in multiple system atrophy (MSA) and explore the cerebral metabolism related to the cognitive decline in MSA using F-18-fluorodeoxyglucose (F-18-FDG) Positron Emission Tomography (PET). Methods: In this study, 105 MSA patients were included for cognitive assessment and 84 of them were enrolled for F-18-FDG PET analysis. The comprehensive neuropsychological tests covered five main domains including execution, attention, memory, language, and visuospatial function. The cognitive statuses were classified to MSA with normal cognition (MSA-NC) and MSA with cognitive impairment (MSA-CI), including dementia (MSA-D), and mild cognitive impairment (MSA-MCI). With F-18-FDG PET imaging, the cerebral metabolism differences among different cognitive statuses were analyzed using statistical parametric mapping and post-hoc analysis. Results: Among 84 MSA patients, 52 patients were found with MSA-CI, including 36 patients as MSA-MCI and 16 patients as MSA-D. In detail, the cognitive impairments were observed in all the five domains, primarily in attention, executive function and memory. In F-18-FDG PET imaging, MSA-D and MSA-MCI patients exhibited hypometabolism in left middle and superior frontal lobe compared with MSA-NC (p < 0.001). The normalized regional cerebral metabolic rate of glucose (rCMRglc) in left middle frontal lobe showed relative accuracy in discriminating MSA-CI and MSA-NC [areas under the curve (AUC) = 0.750; 95%CI = 0.6391-0.8609]. Conclusions: Cognitive impairments were not rare in MSA, and the hypometabolism in frontal lobe may contribute to such impairments.

Automated summary

This study aimed to characterize cognitive profiles in multiple system atrophy (MSA) and explore cerebral metabolism related to cognitive decline. The results showed that cognitive impairments are not rare in MSA, predominantly affecting attention, executive function, and memory. Hypometabolism in the frontal lobe may contribute to these impairments.