Oral and Pharyngeal Function and Dysfunction

A prospective study was undertaken to define the incidence, duration, and consequences of dysphagia in an unselected group of 91 consecutive patients who had suffered acute stroke. The site of the present lesion and of any previous stroke was determined clinically and was confirmed by computed tomography of the brain or necropsy in 40 cases. Of 41 patients who had dysphagia on admission, 37 had had a stroke in one cerebral hemisphere. Only seven patients showed evidence of lesions in both hemispheres. Nineteen of 22 patients who survived a stroke in a hemisphere regained their ability to swallow within 14 days. Dysphagia in patients who had had a stroke in a cerebral hemisphere was associated in this study with a higher incidence of chest infections, dehydration, and death.

Upper esophageal sphincter function was investigated during swallows of graded volumes in 8 normal volunteers. Concurrent recordings of video-fluoroscopic and manometric studies were obtained and correlated with each other by means of a videotimer. Maximal upper esophageal sphincter (UES) pressure was typically located 1.5 cm distal to the air-tissue interface between the hypopharynx and the proximal margin of the sphincter. The region in which UES pressure was greater than or equal to 50% maximal averaged 1.0 cm in length. Thus, the physiologic high-pressure zone of the UES corresponds in size and location to that of the cricopharyngeus muscle. Fluoroscopic analysis of sphincter movement indicated that the sphincter high-pressure zone moved 2.0-2.5 cm orally during swallowing and that the magnitude of the orad movement was directly related to the volume of barium swallowed. The maximal anterior-posterior diameter of sphincter opening during a swallow ranged from 0.9 to 1.5 cm and was also directly related to the volume swallowed. The intervals of UES opening and relaxation increased significantly with increasing bolus volume; the duration of UES relaxation ranged from a mean of 0.37 s for dry swallows to 0.65 s for 20-ml swallows. Thus, the dynamics of UES function during deglutition are dependent upon the volume of the swallowed bolus. Larger bolus volumes are accommodated by both an increased diameter of sphincter opening and by prolongation of the interval of sphincter relaxation. Analysis of the timing of other reference points within the pharyngeal swallow sequence indicated that as the manometric interval of UES relaxation increased, the period of laryngeal elevation was prolonged, the UES relaxed earlier and contracted later, and the interval between the onset of laryngeal elevation and hypopharyngeal contraction increased.

We report differential patterns of swallowing in 40 patients with their first ischemic middle cerebral artery (MCA) stroke and compare these to 20 nonstroke controls. Stroke patients were divided a priori, into groups by right or left and, post hoc, primarily anterior or posterior MCA territory lesions. The left hemisphere subgroup was differentiated from controls by longer pharyngeal transit durations and from the right hemisphere group by shorter pharyngeal response durations. The right hemisphere subgroup was characterized by longer pharyngeal stage durations and higher incidences of laryngeal penetration and aspiration of liquid. Anterior lesion subjects demonstrated significantly longer swallowing durations on most variables compared to both normal and posterior lesion subjects. Changes in the consistency of foods and other modifications for safe nutrition should be considered during the first month of recovery for unilateral stroke patients with swallowing difficulty.