Laryngo-upper esophageal sphincter contractile reflex in humans deteriorates with age

Recent studies have shown the existence of several reflex connections between the aerodigestive and upper gastrointestinal tracts. Our aim was to study the effect of laryngeal stimulation on upper esophageal sphincter (UES) pressure and to determine the reproducibility of this effect.

We studied 14 young and 10 elderly healthy nonsmoker volunteers and 7 patients with UES dysphagia using a concurrent manometric and video endoscopic technique. Three levels of laryngeal air stimulation were studied: 6 mm Hg/50 ms, 10 mm Hg/50 ms, and 6 mm Hg/2 s. Ten young subjects were studied twice.

For 6-mm Hg/2-s and 6-mm Hg/50-ms duration stimuli, the frequency of UES response to air stimulation as evidenced by mucosal deflection (response/deflection ratio) in the elderly volunteers was significantly lower compared with that of young subjects (P < 0.05). The response/deflection ratio of the 6-mm Hg/2-s stimulus was significantly higher than those induced by stimuli of shorter duration (P < 0.01). Poststimulation UES pressure was significantly higher than prestimulation pressure (P < 0.05) in both groups. The magnitude of the increase in poststimulation UES pressure in the elderly volunteers was similar to that of the young subjects. Findings were similar in repeated studies. Four of 7 dysphagic patients exhibited an abnormal response.

Afferent signals originating from the larynx reproducibly induce contraction of the UES: the laryngo-UES contractile reflex. This reflex is elicited most reliably by 6-mm Hg/2-s air stimulation. Frequency elicitation of this reflex decreases significantly with age while the magnitude of change in UES pressure remains unchanged, indicating a deleterious effect of aging on the afferent arm of this reflex. This reflex is altered in some dysphagic patients.