Clinics of NeurologyCONTROVERSY exists as as to if Parkinson disease (PD) and dementia with Lewy bodies (DLB), which includes diffuse Lewy human body disorder in addition to a Lewy body variant of Alzheimer illness (AD),1 signify 2 distinct nosologic entities or whether or not they exist together the spectrum of only one ailment, Lewy body disease.