Dysphagia--ingestion or deglutition?: a proposed paradigm

The current classifications of dysphagia are based on local structural or central nervous system pathology causing dysfunction of the aerodigestive tract. The result is a clinical science grounded in the analysis of the swallow with its lingual, pharyngeal, and esophageal stages. Adding bolus preparation to the swallowing paradigm improves but still constrains the study of dysphagia and treatment of the dysphagic patient. Those pre-oral facets of mealtime behavior that may evoke or exacerbate dysphagia remain beyond the existing classification boundaries imposed by the conceptual swallow and anatomic aerodigestive tract. We offer a more inclusive strategy for investigating dysphagia based on a five-stage process of ingestion: pre-oral (anticipatory), preparatory, lingual, pharyngeal, and esophageal. The first stage considers the interaction of pre-oral motor, cognitive, psychosocial, and somataesthetic elements engendered by the meal. The limited literature regarding the interaction of the pre-oral stage with other ingestion stages, in both normal subjects and patients with cortical, basal ganglia, and psychogenic diseases, is reviewed. The neurophysiologic and clinical justifications for embracing a pre-oral stage, and thus for the paradigm shift from deglutition to ingestion, are presented.