"From a clinical perspective, DLB must be distinguished from idiopathic PD and from AD dementia." We are surprised that this sentence in our editorial was so controversial that it prompted Dr Riley's letter. We agree that the place of DLB in the spectrum of disease between PD and AD is fluid. As the 2 papers in the January issue of the ARCHIVES show, DLB may overlap with both: many patients with AD have cortical Lewy bodies,1 and many patients with idiopathic PD develop dementia as time passes, with most of them having numerous cortical Lewy bodies.2 In our view, however, there are still compelling clinical reasons to distinguish DLB from idiopathic PD. First, the diagnosis of idiopathic PD sets in motion a series of treatment options and expectations that are more favorable than in DLB. Second, the course and prognosis of idiopathic PD is very different from DLB. Not all patients with PD develop dementia.
Pompeu F, Growdon JH. In reply. Arch Neurol. 2002;59(6):1043. doi: