The article by Thomas et al. validated 123I-FP-CIT dopaminergic neuroimaging for the diagnosis of autopsy-proven dementia with Lewy bodies (DLB).  The authors depicted 3 patients with DLB who met pathologic criteria for LBD but had normal 123I-FP-CIT imaging.  Although further description concerning severity of parkinsonism remains unclear, these patients may not have severe parkinsonism. Thus, the patients’ dopaminergic neuroimaging may not be included in SWEDD (scans without evidence of dopaminergic deficit).
The diagnostic criteria by the consortium of DLB seemed to weight existence of parkinsonism.  They defined DLB as a clinically defined syndrome consisting of a primary dementia characterized by visuoperceptual and executive dysfunction accompanied by prominent visual hallucinations, fluctuating attention, and parkinsonism.  However, in daily practice, we encountered patients with cognitive and behavioral dysfunction, but without parkinsonism for years. In such situations, we cannot diagnose patients with DLB. A certain percentage of patients have Lewy bodies only in the cerebrum, not in the brainstem. For accurate diagnosis of DLB, patients should be studied from psychiatric as well as neurologic viewpoints. Thomas et al. suggested a future direction of clinical study for DLB. 
1. Thomas AJ, Attems J, Colloby SJ, et al. Autopsy validation of 123I-FP-CIT dopaminergic neuroimaging for the diagnosis of DLB. Neurology Epub 2016 Dec 9.
2. McKeith IG, Dickson DW, Lowe J, et al. Diagnosis and management of dementia with Lewy bodies: third report of the DLB Consortium. Neurology 2005;65:1863-1872.
3. McKeith I. Dementia with Lewy bodies and Parkinson’s disease with dementia: where two worlds collide. Pract Neurol 2007;7:374-382.
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