Cortical glucose metabolism in parkinson's and alzheimer's disease

Abstract

Characteristic regional patterns of decreased cerebral glucose metabolism (rCMRG) have been described in a variety of neurodegenerative conditions associated with dementia. The present study was undertaken to determine whether the metabolic pattern in Parkinson's disease is altered by the presence of impaired cognitive function. Glucose metabolism was measured with positron emission tomography in 6 patients with Parkinson's disease and dementia (PDD), 8 patients with Parkinson's disease and normal cognition (PD), and 6 patients with Alzheimer's disease (AD). All AD patients subsequently had the diagnosis proven neuropathologically at autopsy. Correlation coefficients of the metabolic rates across 32 regions of interest were calculated between each pair of patients. Q-component analysis of the correlation matrix showed that the AD and PD groups formed two distinct clusters and that the PDD group had a metabolic pattern which was similar to that of the AD group. Comparison of standardized rCMRG values showed that the PDD group differed from the PD group in having significantly lower relative rCMRG in the left perirolandic and bilateral angular gyrus regions. There were no significant differences between the PDD and AD groups. These results suggest a similar pattern of cortical dysfunction in both Alzheimer's disease and in Parkinson's disease/dementia.

Microglia, Amyloid, and Glucose Metabolism in Parkinson’s Disease with and without Dementia

“…Widespread cortical hypometabolism with particularly severe involvement of the temporo-parietal areas have been reported in earlier studies in PDD (Klein et al, 2010;Peppard et al, 1990;Vander Borght et al, 1997). Studies have also noted cortical involvement, particularly temporo-parietal areas in nondemented PD patients, but to a lesser degree compared with PDD (Hu et al, 2000).…”

Pathological features of cerebral cortical capillaries are doubled in Alzheimer's disease and Parkinson's disease

“…A × 36,000; B × 26,5000: C × 54,5000; D × 48,000; E × 12,500 duced glucose metabolism in AD brains is a well-established phenomenon [2,37]. Although the existence of reduced glucose metabolism in PD is a topic of debate, and contradicting PET results are available [16,35,38], PD with dementia has consistently been shown to be accompanied by reduced cerebral glucose metabolism [35,38,41]. A lower metabolic rate for glucose may be caused by hypoglycemia (resulting from the above-described hypoperfusion) or defective transport through distorted capillary walls.…”

Functional Neuroimaging in Parkinson's Disease

“…This hypometabolism appears more widespread in PD patients with mild cognitive impairment (MCI), encompassing prefrontal and lateral parietal cortices Huang et al 2007aHuang et al , 2008 and may include occipital and medial frontal regions (Hosokai et al 2009;Borghammer et al 2010). Indeed, comparisons of patients with and without MCI, or patients with single-and multiple-domain MCI suggest that the degree and topography of hypometabolism reflects the extent of cognitive dysfunction (Peppard et al 1990;Yong et al 2007;Huang et al 2008;Hosokai et al 2009).…”