THE ROLE OF THE INSULAR CORTEX IN DYSPHAGIA

Recent data indicate that dysphagia may occur following unilateral cor tical stroke; however, the elucidation of specific cytoarchitectonic s ites that produce deglutition disorders remains unclear. In a previous study of unilateral cortical stroke patients with dysphagia, Daniels et al. [8] proposed that the insula may be important in swallowing as it was the most common lesion site in the patients studied, Therefore, 4 unilateral stroke patients with discrete lesions of the insular cor tex were studied to further facilitate understanding of the role Of th e insula in swallowing, Dysphagia. as confirmed by videofluoroscopy, w as evident in 3 of the 4 patients: all had lesions that involved the a nterior insula, whereas the only patient without dysphagia had a lesio n restricted to the posterior insula, These data suggest that the ante rior insula may be an important cortical substrate in swallowing. The anterior insula has connections to the primary and supplementary motor cortices, the ventroposterior medial nucleus of the thalamus, and to the nucleus tractus solitarius, all of which are important regions in the mediation of oropharyngeal swallowing, Therefore, discrete lesions of the anterior insula may disrupt these connections and, thereby, pr oduce dysphagia.