Cerebral glucose metabolism and cognition in newly diagnosed Parkinson's disease: ICICLE-PD study.
To assess reductions of cerebral glucose metabolism in Parkinson's disease (PD) with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), and their associations with cognitive decline.



FDG-PET was performed on a cohort of 79 patients with newly diagnosed PD (mean disease duration 8 months) and 20 unrelated controls. PD participants were scanned while on their usual dopaminergic medication. Cognitive testing was performed at baseline, and after 18 months using the Cognitive Drug Research (CDR) and Cambridge Neuropsychological Test Automated Battery (CANTAB) computerised batteries, the Mini-Mental State Examination (MMSE), and the Montreal Cognitive Assessment (MoCA). We used statistical parametric mapping (SPM V.12) software to compare groups and investigate voxelwise correlations between FDG metabolism and cognitive score at baseline. Linear regression was used to evaluate how levels of cortical FDG metabolism were predictive of subsequent cognitive decline rated with the MMSE and MoCA.



PD participants showed reduced glucose metabolism in the occipital and inferior parietal lobes relative to controls. Low performance on memory-based tasks was associated with reduced FDG metabolism in posterior parietal and temporal regions, while attentional performance was associated with more frontal deficits. Baseline parietal to cerebellum FDG metabolism ratios predicted MMSE (β=0.38, p=0.001) and MoCA (β=0.3, p=0.002) at 18 months controlling for baseline score.



Reductions in cortical FDG metabolism were present in newly diagnosed PD, and correlated with performance on neuropsychological tests. A reduced baseline parietal metabolism is associated with risk of cognitive decline and may represent a potential biomarker for this state and the development of PD dementia.
Institute of Neuroscience and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK.
M J
0000-0002-9536-0185
MJ
Firbank
Institute of Neuroscience and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK.
A J
AJ
Yarnall
Institute of Neuroscience and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK.
R A
RA
Lawson
Department of Geriatric Medicine, University of Edinburgh, Edinburgh, UK.
G W
GW
Duncan
School of Medicine & Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia.
T K
TK
Khoo
Department of Nuclear Medicine, Freeman Hospital, Newcastle upon Tyne, UK.
G S
GS
Petrides
Department of Psychiatry, University of Cambridge, Cambridge, UK.
J T
JT
O'Brien
John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
R A
RA
Barker
Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK.
R J
RJ
Maxwell
Institute of Neuroscience and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK.|Division of Neuroscience, Imperial College London, London, UK.|Institute of Clinical Medicine, Aarhus University, Denmark.
D J
DJ
Brooks
Institute of Neuroscience and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK.
D J
DJ
Burn
D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D060825:Cognitive Dysfunction / Q000097:blood / Q000000981:diagnostic imaging; D015331:Cohort Studies; D004739:England; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood* / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D013223:Statistics as Topic
D001786:Blood Glucose; D019788:Fluorodeoxyglucose F18