Anterior opercular cortex lesions cause dissociated lower cranial nerve palsies and anarthria but no aphasia: Foix-Chavany-Marie syndrome and "automatic voluntary dissociation" revisited.

Anarthria and bilateral central facio-linguovelo-pharyngeo-masticatory paralysis with "automatic voluntary dissociation" are the clinical hallmarks of Foix-Chavany-Marie syndrome (FCMS), the corticosubcortial type of suprabulbar palsy. A literature review of 62 FCMS reports allowed the differentiation of five clinical types of FCMS: (a) the classical and most common form associated with cerebrovascular disease, (b) a subacute form caused by central nervous system infections, (c) a developmental form probably most often related to neuronal migration disorders, (d) a reversible form in children with epilepsy, and (e) a rare type associated with neurodegenerative disorders. Bilateral opercular lesions were confirmed in 31 of 41 patients who had CT or MRI performed, and by necropsy in 7 of 10 patients. FCMS could be attributed to unilateral lesions in 2 patients. The typical presentation and differential diagnosis of FCMS provide important clues to lesion localization in clinical neurology. FCMS is a paretic and not an apraxic disorder and is not characterized by language disturbances. Its clinical features prove divergent corticobulbar pathways for voluntary and automatic motor control of craniofacial muscles. Precise clinico-neuroradiological correlations should facilitate the identification of the structural substrate of "automatic voluntary dissociation" in FCMS.