The history of dementia associated with Lewy bodies (DLB) began not long after the history of Alzheimer's disease. Alois Alzheimer described neurofibrillary tangles in a case of presenile dementia in 1907 and Friederich Lewy first described cytoplasmic inclusions in neurons of the substantia innominata in cases of parkinsonism in 1912. In 1923, Friederich Lewy published a monograph containing neurological, psychiatric, and neuropathological data on 43 patients with parkinsonism amongst whom 21 were demented (see also Forstl & Levy, 1991). Dementia associated with Lewy bodies was later described by Hassler (Hassler, 1938) and over two decades later in 1962, Woodard (see also Woodard, 1985) reported a series of psychiatric cases in which Lewy bodies were identified at autopsy – he called these cases of “Lewy body disease”. An isolated case was also reported in 1961 by Okazaki (Okazaki et al., 1961). Then in the early 1970s, the concept of ‘incidental Lewy body disease’ arose from the findings of Forno (1969) on long-stay psychiatric patients – cases that in retrospect most likely included cases of DLB. Dating from 1976, Japanese neuropathologists including Kosaka (see Kosaka, 1990) were responsible for describing the detailed clinical and pathological features of demented patients with cortical Lewy bodies which they termed ‘Diffuse Lewy body disease’ and divided into subgroups such as cortical type or brainstem type, based on the distribution of Lewy bodies and clinical presentation primarily with dementia or parkinsonism.

From the late 1980s onwards several groups raised the profile of this form of dementia by suggesting that it may be more common than previously suspected.