Summary

Lewy bodies remain an enigma. Their presence in the substantia nigra is often taken as a diagnostic criterion for idiopathic parkinsonism (IP, Parkinson's disease). Yet the first report of Lewy bodies in IP is an account of their appearance in the dorsal motor nucleus of the vagus, and the nucleus basalis of Meynert. More serious problems have arisen in recent years, partly as a result of improved techniques for detecting Lewy bodies. The more they have been looked for, the more they have been found. A further complicating factor is that they have different appearances in different regions of the brain. We know that Lewy bodies are made up from cytoskeletal products and they are associated with the death of neurons. They may contribute to the mechanism driving cell death. Alternatively, their formation may represent a compensatory adjustment in an attempt to ameliorate the demise of neurons. They have not helped us in an attempt to find the aetiology of IP, because they occur in such widely diverse settings as hereditary neurodegeneration (e.g. Hallervorden-Spatz disease) and viral infection (e.g. subacute sclerosing panencephalitis). Thus our knowledge, and our ignorance, concerning Lewy bodies leaves us in a tantalizing situation. Surely they are important clues to neurodegeneration, but as yet we have not been able to reveal the secrets that they should provide to help us unravel the pathogenesis of IP.

Introduction

James Parkinson described the clinical features of the disorder that bears his name in 1817 (Parkinson, 1817). In 1912, Lewy demonstrated the existence of neuronal inclusion bodies in the dorsal motor nucleus of the vagus and nucleus basalis of Meynert in Parkinson's disease.