Pathophysiological Decrease in the Regional Cerebral Blood Flow in Pure Autonomic Failure with Lewy Body (P7.074)

OBJECTIVE: To investigate the regional changes in cerebral blood flow (CBF) in patients with pure autonomic failure with Lewy body (PAF with LB) using brain single photon emission computed tomography (SPECT) with N -isopropyl-p-[ 123 I]iodoamphetamine (IMP). BACKGROUND: PAF with LB was previously considered to be a peripheral limited form of Lewy body diseases (LBDs) including Parkinson’s disease (PD) and dementia with Lewy body (DLB). Although recent autopsy studies demonstrated that Lewy bodies latently spread to brain also in PAF with LB, the changes in regional CBF (rCBF) in common with PAF with LB and other LBDs remain obscure. DESIGN/METHODS: Four patients (3 males/1 female, mean age 75.8±2.8) who had presented mainly with chronic autonomic symptoms without obvious parkinsonism nor dementia underwent autonomic functional examinations, skin biopsy, myocardial [ 123 I]metaiodobenzylguanidine (MIBG) scintigraphy and brain IMP-SPECT. They had experienced orthostatic hypotension, constipation and REM sleep behavior disorder as initial symptoms for 1-44 years. The obtained SPECT images were compared between the patients and a control database using the 3-dimensional stereotactic surface projection (3D-SSP) analysis. RESULTS: All patients presented with orthostatic hypotension and decreased uptake of cardiac MIBG. Lewy neuritis were observed in the skin of 2 of 4 patients. The rCBF of all patients was significantly decreased in the bilateral anterior cingulate cortex (ACC) and bilateral posterior lobe (PL) ( P <0.05, respectively). CONCLUSIONS: Statistical analysis of IMP-SPECT demonstrated decreased rCBF in the ACC, which was reported to be associated with autonomic dysfunction, in addition to the PL, which is observed in PD and DLB in general, in the patients with PAF with LB despite these patients had no significant symptoms of parkinsonism or dementia. These findings therefore indicate that the pathophysiological changes in PAF with LB involves the brain same as other LBDs as well as the peripheral autonomic system. Study Supported by: This study was supported in part by Grants-in-Aid for Young Scientists (B) from the Japan Society for the Promotion of Science. Disclosure: Dr. Kamisawa has nothing to disclose. Dr. Ikawa has nothing to disclose. Dr. Saito has nothing to disclose. Dr. Muramatsu has nothing to disclose. Dr. Matsunaga has nothing to disclose. Dr. Yamamura has nothing to disclose. Dr. Hamano has nothing to disclose. Dr. Murayama has nothing to disclose. Dr. Nakamoto has nothing to disclose. Dr. Okazawa has nothing to disclose. Dr. Yoneda has nothing to disclose.