Hypoperfusion of the motor cortex associated with parkinsonism in dementia with Lewy bodies

ObjectiveThis study aimed to investigate the impact of parkinsonism on regional cerebral blood flow (rCBF) in dementia with Lewy bodies (DLB).MethodForty-four probable DLB patients, comprising 13 patients without parkinsonism and 31 patients with parkinsonism, and 16 normal controls were selected for this study. We evaluated the rCBF in each group by means of N-isopropyl-p-[¹²³I] iodoamphetamine (IMP) and single photon emission computed tomography (SPECT). The rCBF in the different groups was compared using voxel-by-voxel Statistical Parametrical Mapping (SPM).ResultPatients with DLB showed low rCBF in the frontal, temporal, and occipital cortex with relative sparing of the paracentral region. DLB patients with parkinsonism (DLB-P) had lower rCBF in the primary motor cortex (M1) and left supplementary motor area (SMA) than DLB patients without parkinsonism (DLB-nonP). DLB-nonP patients showed decreased rCBF in the left temporo-occipital region.ConclusionThis study suggests that two distinct clinical entities are involved in DLB. In addition, CBF changes in the M1 and SMA are seen in the early stages of Parkinson's disease. This result would help in diagnosing DLB in the context of Lewy body (LB) disease.