PRESYNAPTIC NIGRO-STRIATAL FUNCTION IN A GROUP OF ALZHEIMER DISEASE PATIENT WITH PARKINSONISM: EVIDENCE FROM A DOPAMINE TRANSPORTER IMAGING STUDY

Summary. The occurrence of parkinsonism in Alzheimer’s disease (AD) is quite common, however the molecular and neurochemical changes underlying such extrapyramidal features in AD have been not fully understood. Postmortem as well as in vivo imaging study have produced conflicting results as regards the existence of dopaminergic changes in AD. Aim of the present study was to investigate in vivo the nigro-striatal dopaminergic function in a group of AD patients with parkinsonism. Thirteen patients with AD and extrapyramidal features not related to past neuroleptic use (AD-P) underwent SPECT with 123I-FP-CIT, a ligand of dopamine transporter, and the data were compared with those obtained in 15 patients with Diffuse Lewy Body Dementia (DLBD), 20 patients with Parkinson’s disease (PD), and 8 healthy elderly controls. The analysis of the data was performed by regions-of-interest approach and calculations of the striatal-to-non specific (occipital lobes) radioactivity ratios were made. The 123I-FP-CIT striatal uptake in patients with AD-P was similar to that obtained in the control population. Both the DLBD and PD groups showed significantly lower 123I-FP-CIT uptake in all striatal areas with respect to AD-P and control groups (p