Clinical Significance of the Gag Reflex in Evaluating Swallowing Disorders

Abstract

This study was designed to determine the clinical significance of the gag reflex in evaluating swallowing disorders. The degree of gag reflex was classified into four groups: “positive”, “slightly decreased”, “decreased”, and “absent”, and the relation between the gag reflex degree and aspiration or penetration into the larynx detected by videofluorography (VF) was investigated. Among the 67 patients studied by VF for swallowing disorders the “absent” group plus the “decreased” group accounted for 79%. The degree of the gag reflex was affected by hemiparesis, dementia, and bilateral or multiple lesions. The findings of VF were affected by bilateral hemiparesis, gag reflex degree, and the water-drinking test profile. Choking during the water-drinking test was highly sensitive (91%) in screening for aspiration, and aspiration was observed in 73% of the subjects who choked and whose gag reflex was absent. Among the subjects who did not choke during the test, no aspiration or penetration into the larynx was observed in the “positive”, “slightly decreased”, or “decreased” groups, whereas aspiration or penetration into the larynx accounted for 60% of those in the “absent” group. The results suggested that it might be possible to some degree to predict the risk of aspiration based on a combination of bedside evaluation of the degree of gag reflex and the presence of choking during the water-drinking test.