Definition and Implications of Novel Pharyngo-Glottal Reflex in Human Infants Using Concurrent Manometry Ultrasonography

Abstract

OBJECTIVES: Glottal relationships during swallowing dominate the etiology of dysphagia. We investigated the pharyngo-glottal relationships during basal and adaptive swallowing. METHODS: Temporal changes in glottal closure kinetics (frequency, response latency, and duration) with spontaneous and adaptive pharyngeal swallows were defined in 12 infants using concurrent pharyngoesophageal manometry and ultrasonography of the glottis. RESULTS: Frequency, response latency, and duration of glottal closure with spontaneous swallows (n = 53) were 100%, 0.27±0.1 s, and 1±0.22 s, respectively. The glottis adducted earlier (P < 0.0001 vs. upper esophageal sphincter relaxation) within the same respiratory phase as swallow (P = 0.03). With pharyngeal provocations (n = 41), glottal adduction (pharyngo-glottal closure reflex (PGCR)) was noted first and then again with pharyngeal reflexive swallow (PRS). The frequency, response latency, and duration of glottal closure with PGCR were 100%, 0.56±0.13 s, and 0.52±0.1 s, respectively. Response latency to PRS was 3.24±0.33 s; the glottis adducted 97% within 0.36±0.08 s in the same respiratory phase (P = 0.03), and remained adducted for 3.08±0.71 s. Glottal adduction was the quickest with spontaneous swallow (P = 0.04 vs. PGCR), and the duration was the longest during PRS (P < 0.005 vs. PGCR or spontaneous swallow). CONCLUSIONS: Glottal adduction during basal or adaptive swallowing reflexes occurs in either respiratory phase, thus ensuring airway protection against pre-deglutitive or deglutitive aspiration. The independent existence and magnitude (duration of adduction) of PGCR suggests a hypervigilant state of the glottis in preventing aspiration during swallowing or during high gastroesophageal reflux events. Investigation of pharyngeal–glottal relationships with the use of noninvasive methods may be more acceptable across the age spectrum.

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants

“…1) as previously described (12,13,17). Per protocol, if the subject had a nasogastric or orogastric tube for feeding at the time of evaluation, it was removed before manometry catheter placement.…”

“…Aerodigestive reflexes were evaluated as described previously (12,13,17). Initial response was defined as the first aerodigestive response to pharyngeal provocation until a pause in pharyngeal signaling and/or esophageal propagation.…”

“…Supranuclear pathways relay to the thalamus, basal ganglia, and cerebral cortex (pre-and postcentral gyrus), which participate in further modulation of perception, volitional, and central regulatory swallowing and feeding behaviors. We have previously shown in healthy premature infants that pharyngeal stimulation activates several airway-protective reflexes that modulate safe swallowing sequences along with respiratory adaptation (11)(12)(13)(14)17). These adaptive responses include pharyngeal reflexive swallowing (PRS), pharyngo-upper esophageal sphincter contractile reflex (PUCR), pharyngo-lower esophageal sphincter relaxation reflex (PLESRR), deglutition apnea, and adaptive respiratory changes (11)(12)(13)17).…”

“…Swallowing difficulties are frequently associated with the above situations, and the pharynx is the locus of provocation in most of these scenarios. Anticipation and prevention of aspiration is a skill that is acquired, developed, and further modulated by multiple sensory motor neural pathways involving multiple cranial nerves (V, VII, IX, X, XI, XII) and the brain stem (13,15). Supranuclear pathways relay to the thalamus, basal ganglia, and cerebral cortex (pre-and postcentral gyrus), which participate in further modulation of perception, volitional, and central regulatory swallowing and feeding behaviors.…”

Maturation of upstream and downstream esophageal reflexes in human premature neonates: the role of sleep and awake states

“…These findings again implicate development of appropriate local sensory-motor interactions and adaptive regulatory abilities during sleep, favoring increased occurrence of SP in healthy thriving premature infants. The occurrence of EDR can coactivate multiple neural pathways modifying respiratory rhythm and deglutition apnea during swallowing (20,22). Such regulation appears present in premature infants during sleep.…”