Perfusion ECD/SPECT in the characterization of cognitive deficits in Parkinson's disease

Cognitive abnormalities have been reported in a large percentage of patient s with Parkinson's disease (PD). Often cognitive changes are sub-clinical a nd involve frontal lobe function. In other occasions they develop into full dementia. Functional neuroimaging may help characterize these abnormalitie s. We have studied brain perfusion with SPECT and the tracer ECD in 44 PD p atients, 22 presenting with normal cognitive function and 22 with clinical and neuropsychological signs of dementia. Compared with 21 healthy controls , demented PD patients showed significant perfusion decrements in all corti cal areas, particularly temporal and parietal regions; in the non-demented cohort reductions were limited to the frontal lobe area. These results sugg est that brain perfusion abnormalities are present in PD patients. It is sp eculated that different pathological mechanisms underlie perfusion differen ces.