A video-polygraphic analysis of ictal oro-alimentary automatisms

Purpose: to investigate the clinical and polygraphic features of different types of ictal oro-alimentary behaviours and to attempt to describe their localizing value. Method: Among the series of patients selected for presurgical investigation in the last decade at S. Paolo Hospital and Niguarda Hospital, Milan, two independent observers analyzed seizures with oro-alimentary (OA) manifestations. A study of video-EMG-EEG/SEEG correlations has been attempted, in order to subdivide and classify clinical subgroups and to investigate their possible localizing value. The study of neuropsychological functions, in particular memory functions, has been compared in different clinical subgroups. Results: We observed two main clinical-polygraphic subgroups of OA behaviours: (1) a chewing pattern and (2) an masticatory-deglutitory pattern. Most patients had a widespread ictal discharge in the temporal region concomitant with OA behaviours of type 1, while OA automatisms of type 2 could be related also with extratemporal involvement. The same pattern of chewing has been observed comparing ictal and postictal automatisms and voluntary mastication in the same patient, while eating. Despite the lacking of a significant difference in memory scores in two OA subgroups, patients with ictal chewing behaviour more frequently refer memory disturbances. Conclusions: we propose a clinical division in subgroups of oro-alimentary ictal patterns, possibly involving different motor circuits. The polygraphic analogies between ictal and postictal chewing and voluntary mastication support the hypothesis that a releasing mechanism of the physiological central pattern generator for mastication is subtending ictal OA automatisms, probably resulting from inactivation of cerebral modulations of the motor control.