RESUMEN
BACKGROUND & AIMS: Central control of swallowing is regulated by a central pattern generator (CPG) positioned dorsally in the solitary tract nucleus and neighboring medullary reticular formation. The CPG serially activates the cranial nerve motor neurons, including the nucleus ambiguus and vagal dorsal motor nucleus, which then innervate the muscles of deglutition. This case provides insight into the central control of swallowing. METHODS: A 65-year-old man with a right superior lateral medullary syndrome presented with a constellation of symptoms, including dysphagia. The swallow was characterized using videofluoroscopy and esophageal motility and the results were compared with magnetic resonance imaging (MRI) findings. RESULTS: Videofluoroscopy showed intact lingual propulsion and volitional movements of the larynx. Distal pharyngeal peristalsis was absent, and the bolus did not pass the upper esophageal sphincter. Manometry showed proximal pharyngeal contraction and normal peristaltic activity in the lower esophagus (smooth muscle), but motor activity of the upper esophageal sphincter and proximal esophagus (striated muscle) was absent. MRI showed a lesion of the dorsal medulla. CONCLUSIONS: These findings are compatible with a specific lesion of the connections from a programming CPG in the solitary tract nucleus to nucleus ambiguus neurons, which supply the distal pharynx, upper esophageal sphincter, and proximal esophagus. There is functional preservation of the CPG control center in the solitary tract nucleus and of the vagal dorsal motor nucleus neurons innervating the smooth muscle esophagus.
Asunto(s)
Trastornos de Deglución/fisiopatología , Deglución/fisiología , Síndrome Medular Lateral/fisiopatología , Anciano , Trastornos de la Motilidad Esofágica/fisiopatología , Fluoroscopía , Humanos , Imagen por Resonancia Magnética , Masculino , Manometría , Núcleo Solitario/fisiopatología , Nervio Vago/fisiopatologíaRESUMEN
The feasibility of using the electroglottograph (EGG) to record and measure aspects of the swallow was tested in six nonimpaired, two parkinsonian, and two dysphagic subjects. Low-frequency changes in tissue impedance across the neck were recorded with an EGG during deglutition. On six nonimpaired subjects, EGG waveforms were consistently monophasic and appeared to be well timed with laryngeal height changes. The waveforms of the two dysphagic subjects differed markedly from those of the nonimpaired subjects, and their timing and shapes were consistent with videofluoroscopic descriptions of those of the dysphagic subjects. The two parkinsonian patients also showed aberrant waveform patterns. These observations suggest that use of the EGG has strong potential as a quantitative technique for swallowing evaluation, therapy, and research.