Swallowing disorders: pathophysiology and rehabilitation of neurogenic dysphagia

Swallowing requires a complex, well coordinated interaction of structures of the mouth, pharynx, larynx and esophagus for moving liquids, food and secretions from the upper aerodigestive tract to the stomach. These structures are supplied by five cranial nerves and the upper three cervical nerves, governed by pattern generators in the brainstem with influences of higher cortical and subcortical structures. Numerous neurogenic diseases can affect the normal propulsive and contractile movements of the muscles, resulting in retention and misdirection of the bolus. This may lead to life threatening malnutrition and pulmonary complications as well as to considerable reduction in quality of life. While it used to be the case that patients were exclusively fed via nasal tube or PEG and frequently had to permanently retain a canula, the last two decades have seen a fundamental change in diagnosis and therapy. This review describes the physiologic and pathophysiologic events during swallowing, the etiology of neurogenic swallowing disorders and the diagnostic procedures which are prerequisites for developing therapeutic measures. Treatment programs and techniques developed to restore, compensate or adapt for neurogenic swallowing disorders are summarized. (C) 1998 Elsevier Science Ireland Ltd.