Dementia with Lewy bodies (DLB) is clinical syndrome characterized by progressive dementia, parkinsonism and neuropsychiatric symptoms (McKeith et al.,2004a). Pathologically, DLB is a synuclein disorder with widespread Lewy body pathology in the brainstem and cerebral cortex. Research has suggested that in individuals over 75 years, DLB is the second most common type of neurodegenerative dementia after Alzheimer's disease (AD). Although prevalent, our understanding of this complex disorder is in its relative infancy. The accurate diagnosis of DLB can be difficult owing to its frequent co-occurrence with AD and perceived similarity to other motor disorders such as Parkinson's disease (PD). However, the identification of individuals with DLB is extremely important because of the potential for life-threatening reactions to neuroleptic medications, and more encouraging, their ability to benefit greatly from treatment with anticholinesterase (AChEI) therapies.
Epidemiological estimates have suggested that after AD, DLB is the second most common dementia in individuals over 75, with a prevalence rate of approximately 22% (Rahkonen et al., 2003). Similarly, estimates of prevalence based on pathological data have suggested that DLB may represent between 15–35% of all dementia cases (Zaccai et al., 2005), while population-based studies have estimated that DLB accounts for 5% of the population (Rahkonen et al., 2003). In a pathologically confirmed sample, Williams et al. (2006) found that DLB was associated with increased mortality rates compared with AD (hazard ratio = 1.88), with a median survival of 78 years in DLB and 85 years in AD.