Prodromal dementia with Lewy bodies

Background. The clinical condition of dementia is now recognized as a diagnosis that can only be applied too late in the disease process to be useful for therapeutic approaches centring on disease modification. As a result, in recent years increasing attention has been given to mild cognitive impairment (MCI) and the diagnosis of prodromal dementia. This paper reviews the evidence for the clinical presentation of prodromal dementia with Lewy bodies (DLB). Method. A Medline search was carried out to identify articles with original data on the prodromal presentation of DLB. Results. In MCI cohorts that progress to dementia, the proportion diagnosed with DLB is similar to that reported in dementia cohorts. Prodromal DLB may present as any MCI subtype, although visuospatial and executive domains may be most commonly affected. Rapid eye movement (REM) sleep behaviour disorder (RBD), autonomic symptoms, hyposmia, hallucinations and motor symptoms seem to be more common in prodromal DLB than in prodromal Alzheimer's disease (AD). Some of these symptoms can precede the diagnosis of DLB by several years. There has been little research into the use of biomarkers in prodromal DLB, although in RBD cohorts, clinical and imaging biomarkers have been associated with the development of DLB. Conclusions. The evidence available suggests that prodromal DLB may be differentiated from other dementia prodromes in most cases. Further research is needed to confirm this, and to assess the utility of biomarkers such as I-123-FP-CIT and I-123-MIBG imaging.