15 - Opercular epilepsies with oromotor dysfunction

Summary

Introduction

The term operculum insulae denotes the cortical region that covers the insulae Reili. It is made up of frontal, parietal, and temporal cortical convolutions. A bilateral structural or functional disturbance of the cortical motor areas of the anterior part (frontal) operculum, including the inferior rolandic area, and their corticonuclear projections to the nuclei of the 5th, 7th, 9th, and 10th cranial nerves, causes a unique clinical picture of a supranuclear (pseudobulbar) palsy. It presents with swallowing difficulties, anarthria or severe dysarthria, and loss of the ability to imitate oral gestures, resulting from a central disturbance of volitional control of the facio-linguo-glosso-pharyngo-masticatory muscles, while preserving automatic, involuntary, emotional innervation, and reflex motor activity. Pathological crying and laughing are conspicuously absent. It is also designated Foix–Chavany–Marie Syndrome (FCMS), in honour of the authors who described it in 1926, in two adults with bilateral infarction of the anterior operculum (Foix et al., 1926). Bilateral cortical impairment underlies the symptomatology of FCMS as lower cranial nerve brainstem receive innervation from both hemispheres.

The best known form of the syndrome is the classical FCMS due to serial strokes in adults with cerebrovascular disease (Bruyn & Gathier, 1969). FCMS can also occur in infancy and childhood, in relation to diverse etiologies and different clinical evolutions. It can be permanent, secondary to congenital malformation or to acquired structural lesion in early life, or can have an intermittent or reversible expression in the background of certain epileptic disorders involving the perisylvian regions (Christen et al., 2000).