PET-Neuroimaging and Neuropsychological Study for Early Cognitive Impairment in Parkinson’s Disease

To present time, the world science has accumulated a sufficient amount of information on the quantitative changes in the rate of glucose utilization according to positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) in Parkinson’s disease (PD) with dementia. It was found that in the early stages of dementia with PD, there is a dysfunction of the frontal lobes, while PET examination of patients with PD with dementia shows the quantitative changes in the rate of glucose utilization. On this basis, it seems relevant to compare the functional state of the brain structures and the results of neuropsychological studies in patients with PD with varying severity of cognitive impairment. The present research was aimed to investigate the relationship between early cognitive violations according to neuropsychological research and the rate of glucose metabolism in different brain areas during PET scanning in patients with Parkinson’s disease. Neuropsychological testing consisted of clinical interviews, observation, questioning, Mini-Mental State Exam (MMSE) and frontal assessment battery (FAB). According to the research outcomes, it was found that with initial cognitive impairment, determined by FAB, a quantitative change in the rate of glucose utilization is observed, similar to the pattern found in patients with cognitive disorders in PD. Four factors were established: factor 1 – dorsal system of attention (voluntary attention), factor 2 – ventral system of attention (involuntary attention), factor 3 – system of the state of operational rest, factor 4 – visual projective zone. The precentral cortex of the frontal areas and the upper half of the parietal zones of big brain are constitute the 1^st factor. The anterior third of the convexital part of the frontal areas and the lower half of the parietal zones are the 2^nd factor. The 3^rd factor includes the 23, 36, 29 and 30 cytoarchitectonic Brodmann fields (the posterior cingulate gyrus). Primary visual area (17^th Brodmann’s field) is the 4^th factor.