Relationship between cerebral blood flow reduction patterns on scintigraphy and nonmotor symptoms in new-onset Lewy body disease

Background: This study aimed to investigate the relationship between patterns of reduced cerebral blood flow (CBF) evaluated by means of 123I-N-isopropyl-p-iodoamphetamine ([123I]IMP) scintigraphy and nonmotor symptoms in new-onset Lewy body disease (Parkinson's disease and dementia with Lewy bodies [DLB]). Material and methods: Twenty-four patients diagnosed with new-onset Parkinson's disease or DLB underwent [123I]IMP CBF scintigraphy at St. Marianna Medical University Hospital between January 1, 2010, and March 30, 2018. The reductions in CBF in various brain regions were analyzed using the three-dimensional stereotactic surface projection method and were compared to standard database values, yielding extent values (%). The extent values were evaluated in relation to the presence/absence of motor or nonmotor symptoms such as visual hallucinations, auditory hallucinations, delirium, depression, delusions, and dementia. Results: The extent value was 100% in the angular, supramarginal, and lingual gyri; 95% in the orbital gyri; and 92.6% in the fusiform gyri. The extent value in patients without hallucinations and those with visual hallucinations was 41.2% and 54.3%, respectively, in the frontal lobe (p = 0.02) and 33.3% and 51.0%, respectively, in the medial prefrontal gyri (p = 0.02). Age -adjusted multivariate analysis showed that extent values in the frontal lobe were associated with visual hallucinations (odds ratio: 1.09, 95% confidence interval 1.00-1.18, p = 0.04). Conclusions: The above results show that the CBF is reduced in several areas of the cerebral cortex and suggest an association between reduced blood flow in the frontal lobe and the appearance of visual hallucinations in patients with new-onset DLB.