[From Parkinson's disease to Lewy body disease].

Lewy bodies are intraneuronal inclusions initially found in the pigmented brainstem nuclei of patients with Parkinson's disease. Their aspect varies according to their neuronal or cerebral situation. They have been a long time the hallmark of Parkinson's disease, but in recent years it has emerged that a small group of rare disorders or rare variants of common degenerative diseases are also sometimes associated with Lewy bodies in the nervous system. Pathological studies have also individualized a new disorder characterized by the presence of numerous Lewy bodies throughout the cerebral cortex and the brainstem: Lewy body disease. The clinical syndrome associates dementia, parkinsonian features, dysautonomia and motor neuron disease. The dementia is cortical in type and psychiatric symptoms such as agitation, hallucinations or delusions are frequent. The pathological features are nerve cell loss, diffuse Lewy bodies, and sometimes senile plaques. The origin of this disorder remains unclear, but it could be a primitive abnormality of neuronal cytoskeleton.