Early diagnosis of Lewy body disease in patients with late-onset psychiatric disorders using clinical history of rapid eye movement sleep behavior disorder and [123 I]-metaiodobenzylguanidine cardiac scintigraphy.

The severity of %RWA was highly correlated with the value of cardiac [123 I]-MIBG uptake, but not with specific binding ratio on DAT scan. Clinical history of RBD and cardiac [123 I]-MIBG scintigraphy are helpful for an early differential diagnosis of LBD from late-onset psychiatric disorders, even before parkinsonism or dementia appears.